KR100897367B1 - Metal/Air Battery with electrolyte isolated from the cell compartment - Google Patents

Abstract

The present invention relates to a metal-air battery constructed as a constituent material with a long shelf life and easy fabrication process and assembly.

It is a disposable metal air battery composed of a flexible and volume-adjustable battery assembly 205 and an electrolyte container 205 and a rigid box containing them.

It is an object of the present invention to provide a means of prolonging the shelf life and providing rapid and inexpensive production means, which are disadvantages of existing metal air batteries, and the present invention has proposed a method of manufacturing an air anode, which is easily adhered or welded, A method of eliminating breakage and loss due to internal discharge during long term storage has been proposed.

Air Anode, Metal Air Cell, Zinc, Self Discharge

Description

Metal / Air Battery with electrolyte isolated from the cell compartment}

1 is a structure of air anodes.

2 are aspects of a defect in the air anode.

3 is a conceptual diagram illustrating a cross section of the air anode.

4 is a molding process diagram of an air anode.

5 is a process chart of manufacturing a metal air cell.

6 is a micrograph of a rubber adhesive portion of an air anode.

7 is a structure of a molded article of the electrode assembly 204.

8 is an internal structural diagram of a battery.

9 illustrates molding of the battery assembly 205.

10 is a component diagram of a battery.

11 is a diagram illustrating a mechanical mechanism for activation of a cell.

12 are views of the assembly and outer case of the battery before and after use.

<Description of main parts of drawing>

1: air (or oxygen) anode 2: porous Teflon membrane

3: nickel foam 4: cellulose nonwoven fabric

5: sintered layer of carbon mixture 6: through crack

7: metal salt 8: electrolyte

9: rubber 10: carbon mixture molding layer

101: granulated carbon mixture barrel 102: granulated carbon mixture

103: vibrating sieve 104: moving film

105: vibration bed 106: rotary brush

107: primary roller 108: secondary roller

109: third roller 110: fourth roller

111: fifth roller 112: molded carbon sheet

113: bottom container 114: drain

201: metal cathode 202: sponge

203: electrode terminal 204: electrode assembly

205: battery assembly 206: electrolyte container

207: connection passage with electrolyte passing battery assembly

208: thin film blocking the passage

209: button to open the passage 210: thin outer membrane

211: electrolyte supply passage 212: awl

213: battery assembly before electrolyte injection

214: battery assembly after electrolyte injection

215: battery outer box 216: air hole

Metal air cells or metal fuel cells use electricity such as zinc, aluminum and magnesium as consumable cathodes and inhale oxygen to generate electricity using air or hydrogen peroxide or other oxidants composed of oxygen electrodes that act as anodes. Devices. These batteries are known as safe, high energy density batteries and are in the spotlight as military or outdoor batteries. The major drawbacks, however, are the difficult assembly characteristics of the oxygen electrodes or air anodes (hereinafter referred to as 'air anodes'), which are essential components of these cells, and the short shelf life of the finished cells. The air anode is a sintered body of hydrophobic adhesive and activated carbon powder, and it has been used for mechanical bonding or metal frame biting due to its disadvantage that it is not easily adhered to general polymers, plastics and metals and is not soldered or welded. . This has the disadvantage of degrading the characteristics of the battery and increasing the production cost, and in the case of a large capacity battery is more difficult to commercialize.

In addition, the air cathode metal air battery has a disadvantage in that both the user and the seller are disadvantageous due to a short period of about one to two years. So, the battery is introduced to inject the electrolyte or water separately, but this also has a lot of inconvenience to use. In particular, injecting an electrolyte consisting of strong alkalis is more dangerous and leakage of the electrolyte formed in the battery may occur even when water is injected. In addition, the metal air battery has a disadvantage in that the volume of the metal cathode is oxidized and the volume expands when the discharge occurs, and thus the volume increases further if the electrolyte is stored separately.

The present invention has been invented to solve the problems of the prior art, the object of the present invention is to provide a user convenience and safety. Specifically, the following problems are technically solved to have these characteristics.

1. The air cathode of the battery is made of a material that is easy to bond and weld. It also develops a convenient and economical way of working.

2. In order to reduce self-discharge, electrolyte should be stored separately and injected when you want to use it.

3. To reduce the volume of the battery, the internal structure has a folded structure using a soft material.

4. Place the battery in a hard case to protect it. Make sure that it has a volume that will not cause destruction as the battery expands.

5. Assemble the battery easily and simply to increase productivity. To do this, choose a structure and material that can mold the battery at once.

As a technical idea for achieving the object of the present invention, the present invention proposes a new air cathode material and the structure of the battery and the material of each component.

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Metal-air battery which isolate | separated and stored the electrolyte solution which concerns on this invention,
A metal anode and a dense carbon mixture sintered layer are thermally bonded to each other, and an air anode machined to facilitate welding and polymer bonding to the metal foam surface, a metal cathode provided in parallel with the air anode, and the air anode and The metal cathode is fixed to face each other to form one cell, and is provided in a form capable of containing an electrolyte in a region between the air anode and the metal cathode, and is provided with a flexible and flexible material. Passages are provided in the form of an assembly, the side of the battery assembly is isolated, the electrolyte passing through the flexible and stretchable material, connected to the battery assembly from the electrolyte container, and is opened by a switching operation And all of the air cathode, the battery assembly, the electrolyte container, and the passage. It characterized in that the outer box comprises a rigid cell.
Here, the battery assembly is characterized in that it is provided with a flexible and flexible material, such as any one selected from silicon rubber, EPDM, urethane rubber, polyurethane, polyethylene, polypropylene, polyvinylidenefluoride (PVDF) and poly tetrafluoroethylene (PTFE). The elastic rubber sponge is inserted between the cells formed by the battery assembly, and the electrolyte container is silicon rubber, EPDM, urethane rubber, polyurethane, polyethylene, polypropylene, PVDF ( It is characterized in that it is made of a flexible and flexible material, such as any one selected from polyvinylidenefluoride (polyvinylidenefluoride) and PTFE (poly tetrafluoroethylene), so that the barrier membrane is included in the electrolyte container side of the passage, the battery assembly before the first use Can be stored for a long time without internal discharge. The passage may include an outer auger provided to rupture the barrier film, and the passage may further include a passage opening button provided to press the auger. And an auxiliary passage provided to supply electrolyte to each cell of the battery assembly, wherein the battery outer box is provided in a form in which the battery assembly and the electrolyte container are completely in contact with each other. The battery outer box is characterized in that it comprises an outer membrane provided to press the passage opening button on the top, the battery outer box is characterized in that it comprises a small hole that can suck air in its side, The air cathodes constituting the battery assembly are formed of adjacent cells. And the air electrode and the metal anode are alternately arranged on a plane, and the battery assembly is connected to the metal cathode. And it is characterized in that the elastic material is coated in the form of a film and integrally formed, wherein the battery assembly further has a concave shape to fold in a zigzag boundary between the pair of the air cathode and the metal cathode. It characterized in that it is molded, wherein the battery assembly is folded into the injection molding machine, and the side and the upper portion is sealed by the flexible and flexible materials are molded to be a container in which a plurality of cells gathered The lid is provided on the top of the container, the lid Is characterized in that it is provided to be connected to the passage.
In addition, according to the present invention, a method of manufacturing an air cathode, which is easy to weld and bond to a polymer, includes a mixing step of mixing activated carbon powder, manganese dioxide powder, Teflon powder, and water, and a powder formed through the mixing process onto a moving film. After sprinkling on, the transfer film is passed between a pair of primary rollers to form a first carbon sheet, and after spraying nickel foam on the carbon sheet, it is separated between a pair of secondary rollers. Passing through and then passing between a pair of tertiary rollers to form a second carbon sheet, removing the transfer film of the second carbon sheet, and forming a third carbon sheet for the air anode. And passing the third carbon sheet through the tertiary rollers to make a fourth carbon sheet with a homogeneous surface, and then, using the fourth and fifth rollers, nonwoven the lower surface of the fourth carbon sheet. A step of forming a molded carbon sheets and, attaching to the molded carbon sheets 112, completing the process and a drying step for drying the molded carbon sheet characterized in that it comprises a series of step of forming hot-press.
Here, the mixing process is carried out so that the weight ratio of the Teflon powder to the activated carbon powder is 0.7 to 2.0, the ratio of water is 4 to 10, manganese dioxide 0.3 to 0.5 range, the transfer film is a polymer Characterized by using a plastic film or stainless steel wire mesh, the process of spraying the powder formed through the mixing process on the moving film is sprayed using a vibrating body to spread evenly and at the same time abut the bottom of the moving film And uniformly spread by a rotating brush, and the drying process is characterized in that the molded carbon sheet is left to dry for 3 days or more at a temperature of 20 to 60 ° C. and dried in air. The process is carried out to form the molded carbon sheet at a pressure of 100 to 500 kg / sq cm and from 280 to It characterized in that the molding at a temperature of 360 ℃, the mixing process is characterized in that to form a powder having a thickness of 0.5 to 5 mm in a ribbon mixer, the nonwoven fabric is characterized in that using a hydrophilic cellulose-based .
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Existing Technology and Types of Air Anodes]

Examine the properties of air cathodes that play a crucial role in battery assembly.

 US 4,129,633 "Process and apparatus for manufacture of an electrode" In the case of Royce E. Biddick, a mixture of carbon and hydrophobic polymer particles is made to be adhesive in a hot fluidized bed, sprinkled on a nickel screen and rolled to bond. to be. This has the disadvantage of inferior homogeneity of the electrode.

US 4,339,325 "One pass process for forming electrode baking sheet" Frank Solomon describes a process for forming a porous hydrophobic Teflon membrane that adheres to an air anode to block leakage.

US 4,615,954 "Fast response, high rate, gas diffusion electrode and method of making same" For Frank Solomon, we proposed the process of dispersing and filtering the constituents of the air cathode using alcohol solvents and having a high electrical conductivity. It is reported that the ratio of / carbon should be in the range 2/3 to 1/4. There are disadvantages in that an organic solvent should be used and there is a leakage because the internal tissue is not dense.

US 4,877,694 "Gas diffusion electrode" Frank Solomon is a method of mixing hydrophobic adhesives and catalyzed hydrophilic carbon particles, spraying them on nickel meshes and thermoforming them. A large amount of organic solvents such as acetone, isopropanol, etc. Due to the high temperature drying process and the filtration process, it is a complicated process. It is also recommended that the carbon content be 60 to 80%.

In the case of US 4,885,217 "Air cathodes and materials" William H. Hoge and US 4,906,535 "Electrochemical cathodes and materials" Laminated at a high temperature using a roller and then nested in the net. A method of making a porous hydrophobic (teflon) membrane by adhering thereon has been described.

US 4,927,514 "Platinum black air cathode, method of operating same, and layered gas diffusion electrode of improved inter-layer bonding" For Frank Solomon, an intermediate layer of hydrophobic polymer is used to improve the adhesion between the hydrophobic coating layer and the sintered layer of activated carbon mixture. A multi-layer electrode was used, and carbon particles dispersed therein were dried and thermoformed using water as a solvent.

US 5,312,701 "Process for preparing a single pass gas diffusion electrode" Eric E. Khasin et al. In this case, the hydrophobic coating layer, the activated carbon mixture sintered layer, and the conductive metal mesh are pressed and heated to sinter the hydrophobic polymer particles. The carbon and hydrophobic polymers were dispersed in isopropyl alcohol, poured over filter paper and conductive metal (nickel) mesh, filtered, and then filtered to form a mud-like carbon molded product, followed by thermoforming. Organic solvents are widely used and undergo complex processes such as dispersion and filtration.

US 6,368,751 "Electrochemical electrode for fuel cell" Wayne Yao et. al. In this case, the carbon mixture dispersion slurry is coated on the porous nickel foam, filled into the empty space of the nickel foam, and then formed by hot rolling, followed by bonding the porous hydrophobic coating layer. A large amount of water is used and there are many disadvantages of the carbon layer.

Since the assembling method of the battery varies greatly depending on the properties of the air cathode, the present invention has developed an air cathode according to the purpose. A comprehensive review of the air anodes developed so far includes three types as shown in FIG. 1, but AC-1 and AC-2 types are already developed and used. Both AC-1 and AC-2 types have the following problems to be used directly in the present invention.

First, the adhesion of the air anode is not easy. The AC-1 type has a porous TEFLON membrane (2), that is, a PTFE (polytetrafloroethylene) membrane, which is very difficult to adhere. Therefore, the surface treatment gives adhesive properties or adhesion with a special adhesive. The process is difficult and inconvenient, which increases the cost, and it is difficult to bond with the case of the battery. There is a problem. Even in the case of the AC-2 type, the Teflon membrane is not used, but adhesion of the surface layer mixed with carbon and Teflon particles is difficult. Therefore, when using electrodes such as AC-1 or AC-2, the electrodes are fixed by mechanical crimping and the gap is sealed by injecting an adhesive material. The disadvantage of this method is the disadvantage of increasing the weight and price of the entire battery due to the metal frame.

Second, no soldering or welding. This is a big disadvantage when making high voltage batteries that connect several batteries. Button-type batteries are generally commercially available, but they are designed to bend and hold down metal canisters. However, in a battery having a flexible structure having a large capacity, the method of attaching the electrode terminals 203 when the cells are connected to each other is too poor. In order to solve it, the patent PCT WO 2005/078852 and PCT WO 2005/114601 use a frame to bond the electrode terminals 203 to each other so that the solution can be solved, but the process is complicated and the probability of defect is high and the weight increases. Economics will be lowered. Since AC-1 type has non-conductor Teflon membrane (2), it is not welded or soldered at all. Therefore, it is necessary to remove and bond Teflon membrane (2) at the site to be bonded, but even then, AC-2 type is distributed on the surface. One Teflon particles can't stick because they interfere with adhesion.

Third, the destruction of air anodes is a problem. Most of the existing technologies developed up to now have a porous hydrophobic coating separately because the carbon mixture sintered layer 5 is not dense. 2 shows the breaking behavior of the air anodes. The most common form is Type A destruction, a phenomenon found in AC-1. Cracks are generated and the electrolyte (8) penetrates into the gaps, and is accumulated between the Teflon membrane and the carbon mixture sintered layer (5) to form a water film, which prevents oxygen from coming in from the outside, resulting in output loss. Decreases a lot. Type B destruction is a form in which water evaporates after forming a water film, and metal salts precipitate and protrude convexly. There is also a decrease in output, which eventually destroys the Teflon membrane and causes leakage. Type C fracture is to be seen when the Teflon membrane is torn or damaged. If the electrolyte solution 8 is not blocked in the carbon mixture sintered layer 5, leakage occurs at the damaged part. AC-2 shows the same breakdown as D type or E type, but instead of using a Teflon membrane, if the internal carbon mixture sintered layer 5 is not strong, electrolyte 8 penetrates and leakage occurs or severe cases The carbon mixture sintered layer 5 itself swells and collapses. Pore formers are often added inside to improve the electrical properties, which causes the electrolyte 8 to come into contact with more electrode surfaces through small passages formed by gas generation during molding. Caused. High performance carbon materials developed in recent years have a sufficiently high current density even when forming a dense layer, so that a pore former does not need to be used.

Fourth, the activated carbon constituting the electrode is a material having a large specific surface area and a high electrical conductivity, which is an important part in determining the characteristics of the electrode. However, the processing is very difficult because of the sponge-like property of absorbing a lot of solvent. In order to make it flow like liquid and apply to existing process, Doctor Blade Process, water or organic solvent equivalent to 20-100 times of activated carbon should be used. Furthermore, in case of using organic solvents such as NMP or alcohols, a large capacity drying device and a ventilation device are required to evaporate all of them, and the energy or solvent cost is high accordingly. In addition, some of the remaining organic solvent may be harmful to the environment by volatilizing to a toxic gas at high temperature firing or hot pressing (hot pressing). In addition, internal defects caused by the volatilization of a large amount of solvent during drying are ultimately difficult to prevent, which leads to an effect on the life of the air anode.

The new type of air cathode AC-3, which is the object of the present invention, should have a structure as shown in FIG. 3, and more specifically, to overcome the above problems, the following conditions are required.

1) Easy welding and bonding.

It is preferable to form a non-hydrophobic treatment of the air contact surface of the air anode, that is, a non-teflon coated nickel mesh or a nickel foam (3) thermally bonded. Among them, the foam form is more suitable for the purpose because the reticulated tissue of the foam facilitates the adhesion and creates a solid tissue penetrated by solder or adhesive penetrated inside. If there are hydrophobic particles such as Teflon, no solder or adhesive is attached, half of them are buried in the sintered layer 5 of carbon mixture containing Teflon, and the rest are exposed to facilitate adhesion and soldering.

Figure 3 shows the structure of the air anode desired in the present invention, a metal or nickel foam having a network structure as a bonded form on the carbon layer rubber and plastic resin (9) infiltrated and exposed to the exposed nickel foam This shows that the solder 11 is also bonded in the same manner.

The nickel foam is preferably made of stainless steel, copper or copper alloy in addition to nickel, or plated with nickel or silver.

2) The sintered layer of carbon mixture (5) is firm and there is no penetration of water or electrolyte (8).

The surface where the electrolyte solution 8 is in contact is wet, but it is important not to penetrate the inside of the carbon mixture sintered layer 5. Often, the AC-1 type is not dense inside the sintered layer 5 of the carbon mixture, and therefore, the electrolyte 8 often penetrates when used for a long time. It should have a structure that does not form cracks or cracks that occur at the air anode.

3) A hydrophilic separator should be attached to the carbon surface to be in contact with the electrolyte (8) to facilitate assembly.

Here, the cellulose nonwoven fabric 4 was used as a separator. Such a separator must be present so that the positive electrode and the negative electrode contact each other so that a discharge does not occur. When handled separately, the assembly process is difficult to automate and the cost is greatly increased. In addition, when the membrane is dried, the probability of cracking is reduced. Perhaps it serves as a dry control film. Therefore, it is highly desirable to carry out such a film attaching operation during manufacture of the air cathode.

[Old Technology of Metal Air Cell Assembly]

A typical metal air battery is a button cell type battery and there are already numerous patents. US 7,001,689 Zinc / air cell, Keith Burkle, is one of the recently registered patents describing a method of firmly biting an air electrode by crimping a metal can. In the form of such a button cell, there is a limit to increase the capacity and it is not possible to have the function of extending the storage period by isolating and storing the electrolyte (8).

Attempts have been made to use flexible structures to partially eliminate the inconvenience of cell structure destruction or fuel electrode exchange due to volume expansion after discharge of large volume metal air cells. WO 2005/078852 "Collapsible metal air battery, Dong-Soo Baik et al. And WO 2005/114601" Flash lamp for rescue at sea "Dong-Soo Baik is a battery made by biting air electrodes using a metal frame attached to a rubber structure WO 2003/061057 “Rechargeable metal air electrochemical cell incorporating collapsible cathode assembly” Tsepin Tsai et al. Reported a flexible anode assembly capable of reducing the internal space to compensate for volume expansion during discharge of the cell.

US 6,844,096 "Easy refueling metal-gas cell battery with soft pocket" De-Qian Yang et al. The structure of the silver zinc fuel cell is made of flexible plastic, making it convenient for inserting and removing fuel electrodes.

In some reports, water injection is also commercialized to prolong the shelf life of the battery, but the need for water injection is a great inconvenience for the user. In general, the metal-air battery used for emergency or outdoor use is recommended to keep the electrolyte (8) in isolation. However, in case of emergency or when used in the military, there is often a case where the electrolyte (8) is isolated. It is a preferred model to allow the battery to be activated while being stored and automatically injected into the electrolyte solution 8 in a very simple operation. In addition, when additional volume is required when storing the electrolyte (8) separately inside, the use range is limited by that amount, which is also a problem to be solved.

In order to solve these problems, the present invention provides several solutions as follows.

First, the flexible cell assembly and electrolyte pail 206 are selected to counteract expansion and contraction of the volume.

Second, it is placed in a rigid container 215 of fixed size, in which volume exchange between the cell assembly 205 and the electrolyte container 206 occurs, thereby minimizing the size of the container.

Third, prior to activation there must be a membrane blocking the passage 211 to prevent the electrolyte 8 from entering the cell assembly from the electrolyte reservoir 206.

Fourth, the blocking film is blown from the outside by simple operation so that the electrolyte solution 8 is injected into the battery assembly.

Fifth, the battery assembly must pressurize the electrolyte container 206 that occupies the remaining space by having a tendency to inflate and secure the internal space so that the electrolyte solution 8 is injected into the battery assembly.

In addition, the following measures are taken to improve the difficult assembly process, increasing economics and productivity.

Sixth, flexible plastic or rubber materials are used to make flexible batteries.

Seventh, the battery assembly 205 uses a structure and method capable of connecting electrodes in a plane, injecting and adhering an insulating layer, and welding the air anode.

Eighth, each cell can be easily folded and additional injection work must be designed to produce the desired multicell.

EXAMPLE

Then, the manufacturing method of the air anode 1 is demonstrated.

5 shows a method for manufacturing the air anode 1. The carbon mixture sintered layer 5 of the air anode 1 is first made and then nickel foam 3 / mesh is attached thereon, and has the following composition and conditions.

Table 1 Composition of the carbon mixture sintered layer 5 of the air cathode

ingredient Specification of raw materials Composition after firing (weight)  Activated carbon powder Specific surface area BET 1400m ² / g or more, excellent electrical conductivity Ketjenblack EC600JD  30 to 50% Teflon powder 1 micron ( μm ) average particle diameter 40-60% Manganese dioxide powder 10 micron ( μm ) or less diameter 10-30%

In order to form the carbon mixture sintered layer 5 is manufactured through the same process as in Figs. 4 and 5, will be described in detail below.

[Production of Carbon Mixture Sintered Layer 5 during Air Anode Manufacturing Process]

In order to make the carbon mixture sintered layer 5, first, a crack-free carbon mixture molded layer 10 should be made. Defects made before sintering do not heal after sintering.

The carbon powder used in the present invention was 600 JD of Ketjenblack International Co., Japan. Various techniques for dispersing and adsorbing various catalytic materials on carbon powders, particularly metals such as platinum, rhodium, silver, and cobalt, are already well known and are not described. In the present invention, water was used as a solvent, and when using the above carbon powder, it is recommended to use a solvent at least 20 times the weight of carbon. However, if such a large amount of solvent is used, it is possible to reduce the amount of water used since the formation of cracks in the material during the drying of the carbon mixture molding layer 10, the corrosion of the molding apparatus, and the economic deterioration due to the increase in the drying cost. Devised a recipe for. When using a small amount of solvent, it is rolled after extrusion to form a thin plate, but activated carbon is not a suitable method because extrusion is impossible. Extrusion is not possible because, once pressure is applied, the solvent quickly exits the activated carbon, and the sponge-like carbons harden together to turn into extremely high viscosity materials. After the trial and error, a method of molding was developed in the process of rolling between a pair of rollers without extrusion. In this process, it was confirmed that the solvent was possible in a significantly smaller amount than in the prior art.

First, experiments for forming the carbon mixture molding layer 10 by the following formulation were made to find suitable formulation conditions.

Mixing Conditions Attempted to Make Carbon Mixture Molded Layer 10

Activated carbon: 1 kg basis

Water: 3-50 kg

Manganese Dioxide: 0.1-1kg

Teflon: 0.6 -3 kg

Additive: Less than 0.1 kg, Carboxymethyl cellulose, Starch

The contents of the experiment are evaluated as shown in Table 2, and the purpose is to find a good condition of the electrode without cracking. A dispersion having 60% solids was used in which a PTFE powder having an average diameter of about 1 micron was dispersed using an ammonium-based dispersant. In Table 2, only the weight of the solid content is calculated and entered. Although other reports use similar fluorine-containing polymers, the present invention does not exclude the use of various fluorine polymers for the purpose of utilizing the hydrophobicity of fluorine-containing polymers. do.

TABLE 2

Activated Carbon Reference Weight (1kg) PTFE (kg) Manganese Dioxide (kg) Water (kg) Continuity after molding ⁽¹⁾ Cracks during drying ⁽²⁾ Destructive aspect after the test ⁽³⁾ Voltage ⁽⁴⁾ at 20 mA / cm ² One 2.33 54 B P D 0.61 One 1.5 30 B P D 0.85 One 1.5 22 B P D 0.84 One 1.64 17 B P D 0.82 One 1.5 15 - P D 0.85 One 1.5 11 - P D 0.84 One One 12.5 - P D 0.92 One One 10 - Z - 0.94 One One 6 - - - 0.98 One 0.6 6 - - E 1.03 One 0.7 0.33 6 - - - 1.12 One 0.8 0.46 6 - - - 1.07 One 0.8 0.57 6 - - - 1.04 One 1.5 0.3 5 - - - 1.15 One 1.5 0.46 5 - - - 1.13 One 1.5 0.57 7.2 - - - 1.13 One 2.1 0.46 7.2 B Z - 0.76 One 1.5 0.46 3 - P D 1.16

⁽¹⁾ Molding: Evaluation of the continuity of the molding sheet which came out of the primary roller. B: Poor,-: Good.

⁽²⁾ Drying: 60% relative humidity, drying at a temperature of 25 ° C. for 10 days, Z: residue, P: penetrating crack.

⁽³⁾ Test: 100 hours at a constant current of 20 mA / cm ² , 12% NaCl, MgAZ91 anode.

⁽⁴⁾ Voltage: Under cell voltage and constant current conditions.

First, although the carbon mixture molding layer 10 attached to the moving film 104 after the primary molding described in FIGS. 4 and 5 may have a continuous film form, some of the carbon mixture molding layer 10 may be broken or aggregated during the molding process. It judged whether it became a film. The “crack on drying” was then observed by microscopic observation of the dried sample to see the presence of cracks and to see if there were any leaks when tested in the cell. If there is a leak or a state of penetration at all, it is expressed as "P" as shown in FIG. The test was carried out by attaching an air anode (1) to the measuring cell, and then adding a magnesium cathode and maintaining a constant current test in a 12% solution of brine, that is, keeping the current density at 20 mA / cm ² for 48 hours to observe leakage or breakdown of the average voltage and electrodes. It was. The failure aspect is shown in FIG. The cell used in the experiments had an electrode area of 15 cm ^2. The gap between the positive electrode 1 and the negative electrode was 10 mm. As a result shown in Table 2, the ratio of carbon and Teflon is important, and unlike the conventional mixing ratio of the air cathode 1, it can be seen that a larger amount of Teflon, that is, a hydrophobic adhesive (binder) is used. This is because a long test results show that a small amount of Teflon increases the likelihood that the carbon mixture sintered layer 5 will collapse while absorbing water. Existing results report that the carbon content is significantly higher, reaching 60-80%, and the properties are significantly lower at the lower levels. However, the activated carbon ketchup black used in the present invention has very little change in properties even when a small amount is used. Shown. Because of the 78% carbon space in ketchup black, the connection between the particles is better than that of acetylene black, which is only 22%. For example, the volume resistivity of ketene black 600JD in 10% polycarbonate is 3.9 Ω · m, but acetylene black is 10 ⁸ Ω · m. Therefore, even when using a large amount of Teflon compared to using a conventional carbon raw material, there is no degradation of properties. Examination of the formed carbon layer showed that the samples of 0.7-2.0 in the Teflon / carbon ratio showed high characteristics without causing breakage. Samples lower than 0.7 showed a collapse of the carbon layer after prolonged testing, resulting in water leakage, and above 2.0 decreased electrode properties. In addition, even in the amount of water used, the appropriate amount was found to be in the range of 4-10 times compared to the carbon weight. When an amount of 4 or less is used, it is not homogeneously formed during the first rolling, and many holes or cracks are generated, and an excess exceeding 10 When used, the molded carbon layer was not dense, there were some loose molded parts or cracks, and a lot of cracks occurred even when dried.

[Forming during air cathode manufacturing process]

The molded part of the air anode described in FIGS. 4 and 5 will be described in more detail. When the above-mentioned mixed components are mixed in a powder mixer for 1 to 20 hours, the particles aggregate together to form small grains, which is called mixing and granulation. Mixing and granulation used a ribbon mixer. The granules produced by this process are about 0.5-5 mm in size and these assemblies are transported through a powder conveying device and sprayed onto the vibrating sieve. The vibrating body 103 is made of stainless steel mesh and vibrates in a traveling direction. Since the AC power is normally used, the object can be achieved with a vibration width of 20 mm or less, having a frequency of 50 or 60 Hz. The coarse carbon assemblies that did not pass through the vibrator 103 overflowed up to be re-introduced into the ribbon mixer through a separate path. Evenly spreading carbon assemblies are sprinkled onto the transfer film 104. It is made of plastic, that is, polyethylene terephthalate (PET), polypropylene (PP), polyester film, or more than 50 mesh stainless steel wire, with a thickness of 0.5 -1.0 mm. The moving film 104 is to be passed between the rollers and to serve to move the assemblies to be formed between the rollers should be a material of high mechanical strength. Since the plastic material tends to stretch as it is rolled up, it must be wound and moved again. The stainless steel wire mesh is a tightly woven fabric with a low opening ratio. The assemblies scattered on the moving film 104 are once more evenly spread in the vibrating bed 105. The vibrating bed 105 vibrates up and down to make commercial frequency vibration at an oscillation width of several mm. The assemblies then have a more even height while passing through the rotary brushes 106. These brushes 106 are plastic fibers embedded in the cylinder and rotate along the advancing direction of the film 104 to level the heights. In addition, it serves to continuously sweep the powder stacked on both corners of the bed 105. It enters between two primary rollers 107 that are vertically engaged and spreads out as soon as it is compressed by the rollers, spreading out as a rigid and dense molded body. In order to be molded, the composition and the moisture content of the carbon mixture molding layer 10 should be appropriate to plastic deformation. Too little water causes the molded carbon sheet to break apart, and too much of the molded body breaks and becomes heterogeneous. In Table 2, it is determined whether the carbon mixture molding layer 10 formed on the moving film 104 by passing through the primary roller 107 is molded to be uniform and continuous. As a result of Table 2, it was found that the amount of moisture is appropriate when added in the range of 4-10 times that of carbon.

The use of nickel foam (3) or other thin separators or nonwovens (4) without the use of transfer film (104) does not only withstand the strong stresses formed between the rollers, but also tears the nickel foam (3) or fabric, The carbon mixture molding layer 10 is not homogeneously molded. In the primary roller 107, a considerable amount of water in the carbon mixture molding layer 10 is released during rolling and falls to the bottom container 113 with excess carbon forming powder and is recollected through the drain hole 114 to be ribbon mixer. Is put into.

The carbon mixture molding layer 10 uniformly coated on the transfer film 104 becomes a homogeneous plate of about 1-2 mm thickness and then enters between the secondary rollers 108. When entering the secondary rollers 108, the metal nickel foam 3 enters from the top. Then, in the secondary rollers 108, the carbon mixture molding layer 10 sandwiched by the nickel foam 3 and the moving film 104 is secondarily rolled. The secondary roller 108 is mechanically bonded to the carbon mixture molding layer 10 which is already relatively hard. At this time, while the nickel foam is flattened to a thin thickness, a part of the nickel foam enters the carbon mixture molding layer 10. The secondary rollers 108 exit and then enter the tertiary roller 109. The moving film 104 attached to the lower surface of the carbon film is separated while passing through the tertiary roller 109 and wound on a separate dust. The moving film 104 enters the powder bed while being wound by the moving film 104 again. At this time an additional tension roll is used to maintain the tension of the moving film 104. The sheet exiting the tertiary roller 109 is moved to the carbon film attached to the nickel foam (3) to enter between the fourth roller 110, the fourth roller 110 to smooth the surface of the carbon sheet Adjust the thickness dimension more precisely. Then, the cellulose fabric or nonwoven fabric 4 film is put under the carbon mixture molding layer 10 and rolled together in the fifth roller 111 to be molded. Then, the nickel foam 3 is formed on the top, and the carbon mixture molding layer 10 is formed on the bottom thereof, and a plate-shaped molded body having a cellulose fabric, ie, a hydrophilic separator, is formed below. As it passes through each of the rollers, water is further removed to fall to the bottom container 113 and recovered through the outlet. Moisture removed through this process corresponds to more than 30% of the content, which can reduce some of the energy required in the separate drying process.

[Drying and Hot Forming of Air Anode]

This plate-shaped carbon molded body 10 enters into a drying process. Most breakages occur during the drying process and should be dried slowly under conditions that will not cause cracks. Winding or cutting the molded carbon mixture sheet 112 into a drying chamber in which humidity and temperature are controlled and stored therein is a homogeneous and dense carbon molded body while the moisture gradually escapes. Drying is to be stored for at least 3 days at a relative humidity of 40-70% and a temperature of 20-50 ° C. In this experiment, it was stored for 10 days and dried. If the cellulose nonwoven fabric 4 is not attached, the probability of cracks being increased significantly. The drying process is out of control. Rapid drying in ovens is inherently difficult to prevent in any case from the formation of cracks or cracks. Therefore it is very advantageous to serve as a "drying speed control layer".

The dried carbon mixture molding layer 10 is cut and then put into a hot press and molded or rolled with a heated roller. In the present invention, a hot press is used, but hot rollers may be used under the same conditions. The conditions for hot forming in a hot press are molding at a pressure of 100 to 500 kg / cm ² at a temperature of 280 to 380 ° C. If the temperature of the sample is uniformly within this temperature range, the molding time may be as short as 1 second.

As shown in FIG. 3, the molded air anode 1 has a cellulose fabric 4 on one side and a nickel foam 3 on the other. The air anode 1 made in this way does not need to use a separate Teflon membrane 2 as in the case of AC-1 or two metal meshes as in the case of AC-2. Nickel foam 3 has a thickness of 1.6 -2.0 mm and has a porosity of 50 to 200 ppi before molding. When formed, the thickness of the nickel foam (3) decreases to 0.4 mm or less, and some of the nickel foam (3) penetrates the carbon layer, some is exposed, and some of the exposed parts are not coated with Teflon particles. The surface is easy to weld. In addition, since the structure of the nickel foam 3 is reticulated so as to enable insert injection or adhesion with rubber or plastic, adhesive assembly is performed without a separate metal frame. Figure 6 shows a micrograph of the product injecting rubber with the air anode (1). The surface on which the cellulose nonwoven fabric 4 is attached is hydrophilic and rapidly wets the electrolyte solution, thus eliminating the phenomenon of low output at the beginning of the battery and acting as a separator that separates the electrodes from touching each other.

[Metal cathode]

In the present invention, the cathode is made to adhere or contact the consumable metal 201 to a thin copper plate of 0.2mm or less in thickness. Consumable metals used in metal air batteries include magnesium, zinc, aluminum and alloys thereof. The shape is also varied, plate-like, porous sponge, powder, fibrous, or those compressed therein are used. In the present invention, a plate shape is mainly used, but a powder or a plated powder or a metal foam may be used. Alternatively, after the battery assembly molding is completed with the thin copper plate 203, it may be separately inserted in the form of powder or foam. When the battery assembly is made, the copper plate is welded to the nickel foam 3 of the anode 1 of the adjacent cell as shown in FIG. In general, when zinc is used as a consumable electrode, it may be inserted after the battery assembly is completed using powder or a compressed form thereof. This is because zinc has high solubility, very low contact resistance, and is well wetted by the copper negative electrode plate 203. Magnesium or aluminum was used by itself, or when the cathode was thick, the cathode was made by riveting with a copper plate terminal.

[Battery Assembly Fabrication]

A process of making the battery assembly 205 with the air cathode 1 material made by the above method will be described. In view of the complex structure of the battery assembly 205, it is difficult to process the molding immediately, and it is difficult to solve the high failure rate. In particular, the work of soldering electrode terminals to be connected between electrodes is difficult in three-dimensional structure. In addition, the parts of the air anode to be opened for air intake must be excluded, so the mold becomes very complicated and the defect rate is high. Therefore, the battery assembly 205 that can be molded on a plane must be completed first.

Since metal air cells have a generated voltage of unit cells in the range of 1.0 -1.6V, they are low in voltage to be used, and several batteries are connected in series. However, connecting several cells in series is one of the very inconvenient processes of a typical metal air battery. In an embodiment of the present invention, a structure for connecting 10 unit cells was attempted to make a 12V battery. Of course, if necessary, the process of connecting more or less is the same process. First, as shown in FIG. 7, the electrode assembly 204 is completed on a plane. The air anode 1 and the metal cathode 201 are alternately arranged, and the opposite electrodes of adjacent cells are connected to each other by welding or soldering. This task is automated and has the advantage of being able to mold 10 cells at once. When welding or soldering is finished, rubber and plastic injection molding is performed on it to form an insulating layer on the edges of the electrodes.

The electrode assembly 204 thus made is bent in a zigzag as shown in Figs. 8 and 9 to arrange the electrodes, and then the side and top portions are additionally injection molded. The surfaces should be already formed on the planar work so that they can bend.

Next, as shown in FIG. 10, a sponge 202 was inserted between the cells to allow the cells to be contracted and expanded while securing a space for air. In addition, while being stored in a folded state when the activation time to expand the elasticity of the sponge 202 to press the electrolyte container 206 serves to quickly flow out the electrolyte therein. Thus, what is completed is called the battery assembly 205, and this is connected with the electrolyte container 206. The electrolyte container 206 is to store the electrolyte solution, and when used, the electrolyte is discharged and it should serve to shrink and give space. Therefore, it must be made of a flexible and foldable material like rubber. Silicone rubber, EPDM, urethane rubber and other rubber materials and flexible materials such as polyurethane, polyethylene, polypropylene, PVDF (polyvinylidenefluoride), Teflon, or PTFE (poly tetrafluoroethylene). The electrolyte is usually brine or alkaline solution and the concentration is in the range of 10-50%. Rubber and plastic used together are selected by chemically stable materials.

[Activation of the battery]

The battery is isolated from and stored in the electrolyte, and the electrolyte penetrates and is activated by a simple operation of the user. As shown in FIG. 11, when the connection passage 211 between the battery assembly 205 and the electrolyte container 206 is blocked with a thin film 208, and the button 209 is pressed from the outside, the awl 212 is pressed. The membrane 208 blocking the electrolyte is blown to move the electrolyte into the battery assembly 205. The outer box of the battery has a thin portion 210, which is more convenient when the user presses the button 209 while being deformed by hand, and when the electrolyte moves from the electrolyte container 206 to the battery assembly 205, the position of the button is also Will move. All of this happens inside the box 215, so the appearance of the battery remains unchanged.

The size of the outer box 215 of the cell is equal to the sum of the minimum size of the electrolyte container 206 and the maximum size of the battery assembly 205, as shown in FIG. For example, in the case of an air zinc battery, zinc has a specific gravity of 7.14, zinc oxide of 5.47, and oxygen from the outside reacts to increase the total weight to 1.27 times, requiring a volume expansion of at least 1.66 times. The zinc oxide formed in the cell is often a low density amorphous hydrate, so there may actually be more volume increase. If carbon dioxide in the air enters and reacts with the alkali of the electrolyte to become alkali carbonate, an increase in weight or volume is added. In addition, when magnesium or aluminum is used as the cathode, the expansion of the volume occurs up to 2-5 times. Therefore, the structure of the present invention that can cope with the change in volume is very effective in the metal-air battery.

In the case of air anodes, unlike conventionally known processes, molding is very quick and convenient, and since the use of the least amount of solvents occurs, the generation of cracks is considerably less. It is also an economical process and can produce air cathodes (1) at low prices. The air anode 1 thus produced is easy to be bonded or soldered / welded, which greatly increases battery assembly, that is, production speed.

The shelf life of the battery is increased. Existing metal air batteries containing an electrolyte therein have a high self discharge rate, but as in the present invention, the electrolyte is isolated and stored in a form in which the battery is not lost even if stored for a very long time since there is no further discharge as long as it is sealed. do.

There is no need to inject the electrolyte or water separately, and it is convenient to use because it can be activated by a simple operation such as a single operation and a button press.

The assembly of the battery and the container containing the electrolyte can be reduced or increased in size as the electrolyte moves, thus efficiently using the battery space and consequently reducing the volume.

This improves productivity by simplifying the connection of the electrode terminal 203, that is, in the case of a metal air battery in which several cells are connected in series, it is difficult to work and increases time and cost. Because of this, the fabrication process is quick and the probability of failure is significantly lower.

Claims (27)

In the metal air battery which isolate | separated and stored electrolyte solution, An air anode (1) in which the metal foam and the dense carbon mixture sintered layer (5) are heat-bonded and processed to facilitate welding and polymer adhesion to the metal foam surface; A metal cathode 201 provided in parallel with the air anode in parallel; The air cathode and the metal cathode are fixed to face each other to form one cell, and the electrolyte is contained in a region between the air anode and the metal cathode, and is flexible and flexible. A battery assembly 205 provided with; An electrolyte container 206 provided in an isolated form on the side of the battery assembly and formed of a flexible and stretchable material; A passage 211 connected to the battery assembly from the electrolyte container and provided in a form opened by a switching operation; And And a solid battery outer box (215) capable of containing all of the air anode, the battery assembly, the electrolyte container, and the passageway. The method of claim 1, The battery assembly is a metal insulated and stored an electrolyte solution, characterized in that it is provided with any one material selected from silicon rubber, EPDM, urethane rubber, polyurethane, polyethylene, polypropylene, polyvinylidenefluoride (PVDF) and poly tetrafluoroethylene (PTFE) Air battery. The method of claim 1, A metal air battery insulated and stored in the electrolyte solution, characterized in that the elastic rubber sponge is inserted between each cell formed by the battery assembly. The method of claim 1, The electrolyte container is a metal insulated and stored in the electrolyte solution, characterized in that it is provided with any one material selected from silicon rubber, EPDM, urethane rubber, polyurethane, polyethylene, polypropylene, polyvinylidenefluoride (PVDF) and poly tetrafluoroethylene (PTFE) Air battery. The method of claim 1, A barrier film is included inside the electrolyte container side of the passage, and the battery assembly can be stored for a long time without internal discharge in a dry state before the first use. The method of claim 5, The passage includes an external auger provided to rupture the blocking film, and further comprises a passage opening button provided to press the auger, the metal-air battery in which the electrolyte is isolated. The method of claim 5, And the passage further comprises an auxiliary passage provided to supply electrolyte to each cell of the battery assembly. The method of claim 1, The battery outer box is a metal-air battery in which the electrolyte is isolated and characterized in that the battery assembly and the electrolyte container is provided in a form that can be completely in close contact. The method of claim 1, The battery outer box is a metal-air battery insulated from the electrolyte, characterized in that it comprises an outer membrane provided to press the passage opening button on the top. The method of claim 1, The battery outer box is a metal air battery insulated from the electrolyte, characterized in that it comprises a small hole in the air to suck the air. delete The method of claim 1, And the air cathode constituting the battery assembly is connected to the metal cathode of an adjacent cell in a welded form. The method of claim 1, The battery assembly is formed integrally by coating the flexible and stretchable material in the form of a film in a region excluding the portion to be exposed for battery function in a state where the air cathode and the metal anode are alternately arranged on a plane. A metal air battery in which an electrolyte is isolated and stored. The method of claim 13, And the battery assembly is further formed in a concave shape to fold the boundary of the pair of the air cathode and the metal cathode in a zigzag form. The method of claim 14, The battery assembly is folded into the injector into the injection machine, the metal and air batteries insulated and stored in the electrolyte solution, characterized in that the side and the top of the flexible and flexible materials are molded to form a container of a plurality of cells . The method of claim 15, A lid is provided on an upper portion of the container, and the lid is provided to be connected to the passage, the metal-air battery in which the electrolyte is isolated and stored. In the air anode provided in claim 1, Mixing process of mixing activated carbon powder, manganese dioxide powder, Teflon powder and water; Sprinkling the powder formed by the mixing process on the moving film (104), and then passing the moving film between a pair of primary rollers (107) to form a first carbon sheet; After spraying nickel foam 3 on the carbon sheet, it is passed between a pair of secondary rollers 108 and then through a pair of tertiary rollers 109 to pass the second carbon sheet. Forming a mold; Removing the moving film (104) of the second carbon sheet and forming a third carbon sheet for the air anode; After passing the third carbon sheet through the tertiary rollers 109 to make a fourth carbon sheet with a homogeneous surface, the fourth carbon sheet using the fourth and fifth rollers 110 and 111 is used. Forming a molded carbon sheet 112 having a nonwoven fabric 4 attached to a lower surface thereof; Drying the molded carbon sheet (112); And And a series of processes for thermoforming the molded carbon sheet (112) after finishing the drying process. The method of claim 17, The mixing process is easy to weld and polymer adhesion, characterized in that the weight ratio of the Teflon powder to the activated carbon powder is 0.7 to 2.0, the ratio of water is 4 to 10, manganese dioxide 0.3 to 0.5 range. Method of manufacturing an air anode. The method of claim 17, The moving film 104 is a method of manufacturing an air cathode easy to weld and polymer adhesion, characterized in that using a polymer plastic film or stainless steel mesh. The method of claim 17, The process of spraying the powder formed through the mixing process on the moving film 104 is sprayed by using the vibrating body 103 to spread evenly and at the same time the vibration bed 105 abuts below the moving film 104 And a method of manufacturing an air anode that is easy to weld and bond to a polymer, characterized in that it is uniformly spread by a rotating brush (106). delete The method of claim 17, The drying process is a method of manufacturing an air cathode easy to weld and polymer adhesion, characterized in that the molded carbon sheet 112 is left to dry for 3 days or more at a temperature of 20 to 60 ℃. The method of claim 17, The hot pressing process is a method of manufacturing an air cathode, which is easy to weld and polymer adhesion, characterized in that the molded carbon sheet 112 is formed at a pressure of 100 to 500 kg / sq cm at a temperature of 280 to 360 ℃. . The method of claim 17, The mixing process is a welding method for producing an air cathode easy to weld and polymer, characterized in that to form a powder having a thickness of 0.5 to 5 mm in a ribbon mixer. The method of claim 17, The nonwoven fabric (4) is a method for producing an air cathode easy to weld and polymer adhesion, characterized in that using a hydrophilic cellulose-based thing. An air anode (1) produced by the method for producing an air anode according to claim 17, wherein the nickel foam (3) is pressed on one side, and the cellulose nonwoven fabric (4) is pressed on the other side. Metallic air cell with electrolyte isolated. The method of claim 26, An upper end portion of the surface of the nickel foam (3) pressed against the air anode (1) is exposed, so that the welding or soldering is easily provided, the metal-air battery containing the electrolyte solution.

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