Pouch Metal Air Battery

Abstract

The present invention discloses a pouch-type metal-air battery. In the pouch-type metal-air battery, when the electrolyte inside the battery comes out of the electrode assembly due to the application of external pressure, the electrolyte does not reach the space separated by the gas diffusion layer, the electrode assembly and the external material due to the formation of a step by the protrusion of the gas diffusion layer. In this way, a plurality of holes in the external material corresponding to the space may not be blocked. Therefore, since the oxygen selectively permeated from the external material flows into the gas diffusion layer and flows into the electrode assembly through the diffusion portion of the gas diffusion layer, the contact resistance with respect to pressure can be improved and the initial driving condition and driving reproducibility can be ensured.

Description

Technical Field

[0001] The present invention relates to a pouch type metal air battery capable of smoothly flowing a fluid such as oxygen even under pressure conditions for reducing contact resistance. Background Art

[0002] A lithium metal-air battery is a battery that uses air instead of the cathode active material of a lithium-ion secondary battery. The advantage of a lithium metal-air battery is that its energy density is 10 times that of a lithium-ion secondary battery using existing cathode active materials, and because the oxygen contained in the air is used as a raw material for the reduction reaction during the discharge process, it can significantly reduce the weight of the cathode and even the entire battery.

[0003] Such lithium-air batteries may be formed into a pouch type, a cylindrical type, a coin type, etc., and may be in a form in which holes are drilled only in the cathode to allow air to pass through. Among them, the advantage of the pouch type lithium-air battery is that it can be manufactured in various forms to achieve high energy density per unit mass.

[0004] However, since the pouch-type lithium-air battery is prepared by forming an oxygen inlet hole in the cathode, the electrolyte 400 may leak or volatilize from the hole, and these holes also make it difficult to perform compression molding. This results in low energy density and is difficult to form over a large area. In addition, in addition to the inflow of oxygen, moisture and gases (such as carbon dioxide and nitrogen) in the atmosphere also flow in, resulting in side effects such as battery degradation. Therefore, in order to drive the lithium-air battery in the atmosphere, a dehumidification system or a pure oxygen cylinder must be provided, which is inconvenient. Therefore, by sealing the electrode assembly 100 using an external material 300 that only selectively transmits oxygen and simultaneously blocks moisture or gas in the atmosphere, the oxygen permeability of the pouch-type metal-air battery has been improved.

[0005] However, even if the pouch type metal air battery is manufactured by applying the exterior material 300, the inflow of a fluid such as oxygen cannot be smoothly performed. Figure 1A is a cross-sectional view showing the pouch type metal air battery 1 to which the external material 300 is applied when no pressure is applied. Figure 1A As shown, the pouch type metal air battery 1 includes: an electrode assembly 100 including a cathode layer 110, an anode layer 130, and a separator 120 located between the cathode layer 110 and the anode layer 130; a gas diffusion layer 200 located on the electrode assembly 100; and an external material 300 that accommodates the electrode assembly 100 and the gas diffusion layer 200 and has fluid permeability. Although oxygen supplied from the holes 310 included on all surfaces of the external material 300 is smoothly received, if pressure is not applied, contact resistance increases, thereby causing a problem of difficulty in operating the battery.

[0006] also, Figure 1B 3 is a cross-sectional view showing the pouch type metal air battery 1 to which the external material 300 is applied when pressure is applied. Figure 1B As shown, when pressure is applied, oxygen may be supplied to the side of the space in the pouch type metal air battery 1. However, if the width of the external material is equal to or smaller than the width of the gas diffusion layer 200 and the electrode assembly 100, the anode included in the electrode assembly 100 may be pressed by the pressure, so that the sides of the electrode assembly 100 and the gas diffusion layer 200 may be blocked, which makes it difficult to supply sufficient oxygen.

[0007] also, Figure 1C 4 is a cross-sectional view showing the pouch type metal air battery 1 to which the external material 300 is applied and pressure is applied after the electrolyte 400 is injected. Figure 1C As shown, since the electrolyte 400 may be squeezed out of the electrode assembly 100, the sides of the electrode assembly 100 and the gas diffusion layer 200 may be blocked, which also makes it difficult to provide sufficient oxygen. Summary of the invention

[0008] In a preferred aspect, a pouch-type metal-air battery ("battery") is provided. The battery may include: a gas diffusion layer including a diffusion portion in contact with an electrode assembly and one or more protrusions extending from the diffusion portion; an electrode assembly; and an external material. Preferably, a step between the electrode assembly and the gas diffusion layer may be formed by the protrusion, and a space separated by the gas diffusion layer, the electrode assembly, and the external material may be formed. In this way, even when pressure is applied to reduce contact resistance, a fluid such as oxygen can flow smoothly.

[0009] As used herein, the term "pouch-type battery" refers to a battery or battery cell designed to seal, surround, wrap or weld each electrode assembly by a pouch-shaped flexible container (e.g., a conductive material, metal or polymer bag), and each pouch-shaped container carries or accommodates necessary battery cell components or electrode assemblies, such as electrodes (e.g., cathode and anode), separators disposed between the electrodes, electrolytes, gas diffusion layers, etc. Each pouch-shaped container may also include, for example, a connection portion for connection therebetween, or a portion for exchanging materials therein with other pouch-shaped containers, which may be stacked or packaged in a horizontal or vertical direction.

[0010] The object of the present invention is not limited to the above-mentioned object. The object of the present invention will become more apparent through the following description and will be achieved by the means described in the claims and their combinations.

[0011] In one aspect, a pouch-type metal-air battery is provided, which may include: an electrode assembly including a cathode layer, an anode layer, and a separator between the cathode layer and the anode layer; a gas diffusion layer (GDL) located on the electrode assembly; and an external material that accommodates the electrode assembly and the gas diffusion layer and has fluid permeability. Preferably, the gas diffusion layer may include a diffusion portion in contact with the electrode assembly and one or more protrusions extending from the diffusion portion.

[0012] The "diffusion portion" refers to a portion constituting the gas diffusion layer, which allows a material (eg, gas) to flow, diffuse, or permeate.

[0013] A step between the electrode assembly and the gas diffusion layer may be formed by the protrusion, and a space partitioned by the gas diffusion layer, the electrode assembly, and external materials may be formed.

[0014] The gas diffusion layer may include two or more protrusions.

[0015] The pouch type metal air battery may also include a stack body in which a plurality of electrode assemblies 100 are stacked. Preferably, a gas diffusion layer may be located at least between the electrode assemblies adjacent to each other or at both ends of the stack body.

[0016] A ratio of the length of the diffusion portion to the length of the protrusion may be about 1:0.2 to 1:0.4.

[0017] The battery can be between about 0.59 and 1.3 kgf / cm 2 operates under pressure.

[0018] The diffusion portion of the gas diffusion layer may be located on the cathode layer.

[0019] The gas diffusion layer may include a porous metal substrate.

[0020] As used herein, "porous substrate" refers to a porous material including pores (e.g., circular or non-circular), holes, cavities (e.g., microcavities), mazes, channels, etc., formed uniformly or irregularly in various shapes. Exemplary porous substrates may include pores (e.g., closed pores or open pores) within a predetermined size ranging from submicron to micron size, the size being measured by the maximum diameter of the pores.

[0021] The porous metal substrate may include one or more selected from the group consisting of nickel foam, aluminum mesh, and stainless steel mesh.

[0022] The cathode layer may include one or more selected from the group consisting of carbon paper, carbon black, reduced oxide graphene, carbon nanotubes, and acetylene black.

[0023] The cathode layer may include one or more catalysts selected from the group consisting of nickel, gold (Au), silver (Ag), rubidium (Ru), and platinum (Pt).

[0024] The outer material may include a plurality of holes.

[0025] The outer material may be capable of selectively allowing oxygen permeation.

[0026] Oxygen permeated from the external material may flow into the gas diffusion layer (GDL), and may flow into the electrode assembly through a diffusion portion of the gas diffusion layer (GDL).

[0027] The outer material may include one or more materials selected from the group consisting of polyethylene terephthalate (PET), high-density polyethylene (HDPE), polytetrafluoroethylene, and polymethyl methacrylate.

[0028] The outer material may be a metal organic framework permeable membrane mixed with one or more polymers selected from the group consisting of polyethylene terephthalate (PET), high density polyethylene (HDPE), polytetrafluoroethylene, and polymethyl methacrylate.

[0029] According to various exemplary embodiments, the pouch-type metal-air battery provided by the present invention is such that even when the electrolyte in the battery flows out from the electrode assembly by applying external pressure, the electrolyte does not reach the space separated by the gas diffusion layer, the electrode assembly, and the external material due to the step formed by the protrusion of the gas diffusion layer. In this way, the plurality of holes in the external material corresponding to the space may not be blocked. Therefore, since the oxygen selectively permeated from the external material flows into the gas diffusion layer and flows into the electrode assembly through the diffusion portion of the gas diffusion layer, the contact resistance with respect to pressure can be improved in the pouch-type metal-air battery and the initial driving condition and driving reproducibility can be ensured.

[0030] The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all the effects that can be derived from the following description.

[0031] Other aspects of the invention are disclosed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

[0033] Figure 1A is a cross-sectional view showing the pouch type metal air battery 1 to which the external material 300 is applied when no pressure is applied;

[0034] Figure 1Bis a cross-sectional view showing the pouch type metal air battery 1 to which the external material 300 is applied when pressure is applied;

[0035] Figure 1C is a cross-sectional view showing the pouch type metal air battery 1 to which the external material 300 is applied when pressure is applied after the electrolyte 400 is injected;

[0036] Figure 2A is a cross-sectional view schematically illustrating an exemplary pouch type metal-air battery 10 according to an exemplary embodiment of the present invention;

[0037] Figure 2B is a cross-sectional view schematically showing an exemplary pouch-type metal-air battery 10 according to an exemplary embodiment of the present invention, the pouch-type metal-air battery including: an exemplary stack in which a plurality of electrode assemblies 100 are stacked; and an exemplary gas diffusion layer 200 located at least between the electrode assemblies 100 adjacent to each other or at both ends of the stack and having two protrusions 220;

[0038] Figure 3A is a cross-sectional view schematically illustrating an exemplary pouch type metal-air battery 10 according to an exemplary embodiment of the present invention, the pouch type metal-air battery including an exemplary gas diffusion layer 200 having two or more protrusions 220;

[0039] Figure 3B is a cross-sectional view schematically showing an exemplary pouch-type metal-air battery 10 according to an exemplary embodiment of the present invention, the pouch-type metal-air battery including: an exemplary stack in which a plurality of electrode assemblies 100 are stacked; and an exemplary gas diffusion layer 200 located at least between the electrode assemblies 100 adjacent to each other or at both ends of the stack and having two protrusions 220; and

[0040] Figure 4 is a graph showing the capacity of the pouch type metal air battery prepared according to Comparative Example 1 depending on the applied voltage. DETAILED DESCRIPTION

[0041] The above-mentioned purpose, other purposes, features and advantages of the present invention will be easily understood through the following preferred embodiments related to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be implemented in other forms. On the contrary, the embodiments introduced herein are provided to make the disclosed content thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art.

[0042] In describing each of the accompanying drawings, similar reference numerals are used for similar components. In the accompanying drawings, for the clarity of the present invention, the size of the structure is shown in a scale that is larger than the actual one. Unless the context clearly indicates otherwise, a singular expression includes a plural expression.

[0043] In this specification, it should be understood that the term "includes" or "comprising" is intended to indicate the presence of a feature, number, step, action, component, part, or combination thereof described in the specification, and does not exclude the presence or increased possibility of one or more other features or numbers, steps, actions, components, parts, or combinations thereof. In addition, when a portion of a layer, film, region, plate, etc. is referred to as being "on" another portion, it includes not only the case where the portion is "disposed above" another portion, but also the case where other portions are included in between. Conversely, when a portion of a layer, film, region, plate, etc. is referred to as being "under" another portion, it includes not only the case where the portion is "under" another portion, but also the case where other portions are included in between.

[0044] Unless otherwise indicated, all numbers, values ​​and / or expressions relating to quantities of ingredients, reaction conditions, polymer compositions and formulations used herein are to be understood as modified in all instances by the term "about" since such numbers are inherently approximate reflecting the various measurement uncertainties encountered in obtaining such values.

[0045] In addition, unless otherwise specified or apparent from the context, as used herein, the term "about" should be understood as being within the normal tolerance range in the art, such as within 2 standard deviations of the mean. "About" can be understood as being within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless the context clearly indicates otherwise, all numerical values ​​provided herein are modified by the term "about".

[0046] In addition, when numerical ranges are disclosed in this specification, unless otherwise indicated, these ranges are continuous and include all values ​​from the minimum value to the maximum value in the range. In addition, when such ranges refer to integers, unless otherwise indicated, all integers from the minimum value to the maximum value are included.

[0047] In this specification, when describing the range of a variable, it will be understood that the variable includes all values ​​within the range, including the endpoints of the above range. For example, it should be understood that the range of "5 to 10" includes the values ​​of 5, 6, 7, 8, 9 and 10, and any sub-ranges of 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., and also includes any values ​​between the integers in the range, such as 5.5 to 7.5, 5.5 to 8.5, 6.5 to 9, etc. In addition, for example, "10% to 30%" includes all integers ranging from 10%, 11%, 12%, 13%, etc. to 30%, and any sub-ranges of 10% to 15%, 12% to 18%, 20% to 30%, etc., and also includes any values ​​between the valid integers in the range, such as 10.5%, 15.5%, 25.5%, etc.

[0048] Figure 2A 2 is a cross-sectional view schematically showing an exemplary pouch-type metal-air battery 10 according to an exemplary embodiment of the present invention. Figure 2A As shown, the pouch type metal air battery 10 includes: an exemplary electrode assembly 100, the electrode assembly including a cathode layer 110, an anode layer 130, and a separator 120 located between the cathode layer 110 and the anode layer 130; a gas diffusion layer 200 (GDL) located on the electrode assembly 100; and an external material 300, which accommodates the electrode assembly 100 and the gas diffusion layer 200 and has fluid permeability. Here, the term "accommodate" means that the electrode assembly 100 is completely covered by the external material 300. Preferably, the pouch type metal air battery 10 according to the exemplary embodiment of the present invention is provided so that the gas diffusion layer 200 may include: a diffusion portion 210, which is in contact with the electrode assembly 100; and one or more protrusions 220, which extend from the diffusion portion 210.

[0049] The ratio of the length of the diffusion portion 210 to the length of the protrusion 220 may be about 1:0.2 to 1:0.4. When the above ratio is less than about 1:0.2, the electrode assembly blocks the gas diffusion layer by the applied pressure, and when it is greater than about 1:0.4, the area and weight of the gas diffusion layer increase, resulting in a decrease in battery energy density. Specifically, the protrusion 220 having the above length ratio compared to the diffusion portion 210 may be provided so that a step may be formed between the electrode assembly 100 and the gas diffusion layer 200, and a space separated by the gas diffusion layer 200, the electrode assembly 100, and the external material 300 may be formed. Preferably, the pouch type metal air battery 10 may be provided so that since the protrusion 220 of the gas diffusion layer 200 is outside the pressure application area, a space separated by the gas diffusion layer 200, the electrode assembly 100, and the external material 300 may be formed due to the step formed by the protrusion 220. As such, oxygen selectively permeated from the external material 300 may flow into the gas diffusion layer 200 and then flow into the electrode assembly 100 through the diffusion portion 210 of the gas diffusion layer 200 (GDL), thereby improving contact resistance due to pressure.

[0050] When the pouch type metal air battery 10 includes the gas diffusion layer 200 having a ratio of the length of the diffusion portion 210 to the length of the protrusion 220, even when about 0.59 to 1.3 kgf / cm 2 When the pressure is less than about 0.59 kgf / cm 2 When the pressure is greater than about 1.3kgf / cm 2 , the gas diffusion layer may be over-squeezed, making it difficult for external oxygen to flow into the cathode layer through the gas diffusion layer. Specifically, even when the electrolyte 400 in the battery comes out of the electrode assembly 100 when external pressure is applied, a pouch-type metal-air battery can be provided so that the electrolyte 400 does not reach the space separated by the gas diffusion layer 200, the electrode assembly 100 and the external material 300 due to the step brought by the protrusion 220 of the gas diffusion layer 200. In this way, the plurality of holes 310 in the external material 300 corresponding to the space may not be blocked so that oxygen can selectively permeate. Therefore, the pouch-type metal-air battery 10 according to the exemplary embodiment of the present invention may have the following advantages: the contact resistance related to pressure may be improved, and the initial driving conditions and driving reproducibility may be ensured.

[0051] In addition, the pouch type metal air battery 10 according to the exemplary embodiment of the present invention may include: a stack of a plurality of electrode assemblies 100, each electrode assembly including a cathode layer 110, an anode layer 130, and a separator 120 located between the cathode layer 110 and the anode layer 130; a gas diffusion layer 200 located at least between the electrode assemblies 100 adjacent to each other or at both ends of the stack; and an external material 300 that accommodates the electrode assembly 100 and the gas diffusion layer 200 and has fluid permeability. Preferably, the pouch type metal air battery 10 may be provided such that the gas diffusion layer 200 includes: a diffusion portion 210 that contacts the electrode assembly 100; and one or more protrusions 220 that extend from the diffusion portion 210. Figure 2B FIG. 2 is a cross-sectional view schematically showing a pouch-type metal-air battery 10 according to another embodiment of the present invention. Figure 3A As shown, a stack in which four electrode assemblies 100 are stacked may be included, and the gas diffusion layer 200 may be located between the electrode assemblies 100 adjacent to each other. Specifically, the pouch-type metal-air battery 10 may be configured in a stack in which a plurality of electrode assemblies 100 are stacked, so that the charge and discharge performance of the battery can be further improved.

[0052] In addition, the pouch type metal air battery 10 according to the exemplary embodiment of the present invention may include: an electrode assembly 100 including a cathode layer 110, an anode layer 130, and a separator 120 located between the cathode layer 110 and the anode layer 130; a gas diffusion layer 200 (GDL) located on the electrode assembly 100; and an external material 300 that accommodates the electrode assembly 100 and the gas diffusion layer 200 and has fluid permeability. Here, the gas diffusion layer 200 includes: a diffusion portion 210 that contacts the electrode assembly 100; and one or more protrusions 220 that extend from the diffusion portion 210. The protrusion 220 may form a step to be generated between the electrode assembly 100 and the gas diffusion layer 200, and may form a space separated by the gas diffusion layer 200, the electrode assembly 100, and the external material 300. Preferably, the gas diffusion layer 200 may include two or more protrusions 220. For example, the gas diffusion layer 200 may be manufactured in various shapes according to the manufacturing requirements of the pouch type metal air battery, and may preferably be a polygonal shape such as a triangle, a square, a rectangle, a pentagon, and a hexagon. Specifically, when the gas diffusion layer 200 is formed in a polygonal shape, the protrusion 220 of the gas diffusion layer 200 (GDL) may include two or more parts in a direction in which a line segment constituting the polygon extends from the center of the polygon. Figure 3A 2 is a cross-sectional view schematically showing a pouch type metal air battery 10 according to an exemplary embodiment of the present invention. Figure 3A As shown, when the upper gas diffusion layer 200 is formed in a rectangular shape, the parallel line segments may extend in the extending direction so that the protrusion 220 may include two parts.

[0053] However, the present invention is not limited thereto, and the remaining two line segments may be extended so that the protrusion 220 includes four parts. Therefore, the pouch-type metal-air battery 10 according to the exemplary embodiment is provided so that the protrusion 220 of the gas diffusion layer 200 includes two or more parts. In this way, due to the two or more protrusions 220, the space separated by the gas diffusion layer 200, the electrode assembly 100, and the external material 300 formed by the step can be effectively ensured. Therefore, oxygen can selectively penetrate through the space, so that the contact resistance according to the pressure can be improved.

[0054] In addition, the pouch type metal air battery 10 according to the exemplary embodiment of the present invention may include: a stack of a plurality of electrode assemblies 100, each electrode assembly including a cathode layer 110, an anode layer 130, and a separator 120 located between the cathode layer 110 and the anode layer 130; a gas diffusion layer 200 located at least between the electrode assemblies 100 adjacent to each other or at both ends of the stack and including two or more protrusions 220; and an external material 300 that accommodates the electrode assembly 100 and the gas diffusion layer 200 and has fluid permeability. Preferably, the pouch type metal air battery 10 is provided so that the gas diffusion layer 200 may include: a diffusion portion 210 that contacts the electrode assembly 100; and two or more protrusions 220 that extend from the diffusion portion 210. Figure 3B FIG. 2 is a cross-sectional view schematically showing a pouch-type metal-air battery 10 according to another embodiment of the present invention. Figure 3B As shown, a stack in which four electrode assemblies 100 are stacked may be included, and the gas diffusion layer 200 may include two protrusions 220 and may be located between the electrode assemblies 100 adjacent to each other. Specifically, the pouch-type metal-air battery 10 according to the exemplary embodiment of the present invention is provided as a stack structure in which a plurality of electrode assemblies 100 may be stacked. In addition, the space separated by the gas diffusion layer 200, the electrode assembly 100, and the external material 300 may be formed by a step formed due to two or more protrusions 220, and the space may be more effectively secured. In this way, the charging and discharging performance of the battery may be further improved.

[0055] The pouch type metal air battery 10 may include: an electrode assembly 100 including a cathode layer 110, an anode layer 130, and a separator 120 located between the cathode layer 110 and the anode layer 130; a gas diffusion layer 200 located on the electrode assembly 100; and an external material 300 that accommodates the electrode assembly 100 and the gas diffusion layer 200 and has fluid permeability. Preferably, the gas diffusion layer 200 may include: a diffusion portion 210 that contacts the electrode assembly 100; and one or more protrusions 220 that extend from the diffusion portion 210.

[0056] The electrode assembly 100 may be a basic battery unit capable of generating electricity. The electrode assembly 100 may include a cathode layer 110, an anode layer 130, and a separator 120 between the cathode layer 110 and the anode layer 130. The cathode layer 110 may be located on the diffusion portion 210 of the gas diffusion layer 200, and may also include a current collector. However, the cathode layer 110 located on the diffusion portion 210 of the gas diffusion layer 200 may preferably not include a current collector. The specific material of the cathode layer 110 may include carbon black, reduced oxide graphene, carbon nanotubes, and acetylene black, and may preferably include but not limited to carbon-based materials. For example, carbon materials are lightweight and inexpensive materials, so these materials can greatly contribute to improving the energy density and economic efficiency of lithium-air batteries.

[0057] In addition, the catalyst included in the cathode layer 110 includes one or more selected from the group consisting of metals such as Pd, Pt, Ru, RuO, Se, Au, etc., as well as nickel, Au and Ag capable of oxygen reduction reaction and oxygen evolution reaction, but is not limited to a specific metal.

[0058] The current collector that may be included in the cathode layer 110 may include one or more conductive metals selected from the group consisting of stainless steel, aluminum, and nickel, and may preferably include but not limited to porous aluminum. For example, aluminum has high electronic conductivity and is lightweight, and is thus mainly used in lithium-ion batteries, so that porous aluminum (net, foam structure) can introduce air required for lithium-air batteries and serve as an electronic conductor.

[0059] The anode layer 130 may include at least one selected from the group consisting of an anode active layer 131 and a current collector 132. The anode active layer 131 of the anode layer 130 may include one or more metals selected from the group consisting of lithium metal, sodium and magnesium, and preferably includes an electrode containing but not limited to lithium element. For example, lithium element has the lowest potential and is lightweight, which can greatly improve the energy density of the metal air battery.

[0060] The current collector 132 that may be included in the anode layer 130 may be the same as or different from the current collector that may be included in the cathode layer 110. The separator 120 may be made of one or more polymer films selected from the group consisting of polyethylene, polypropylene, and glass fiber.

[0061] In addition, the separator 120 may be obtained by impregnating a polymer film with an electrolyte 400 composed of a lithium salt and an organic solvent. The lithium salt may be one or more selected from the group consisting of but not particularly limited to the following, for example, LiPF 6 , LiBF 4 、LiSbF 6 、LiAsF 6 、LiN(SO 2 C 2 F 5 ) 2 、Li(CF 3 SO 2 ) 2 N, LiC 4 F 9 SO 3 、LiClO 4 、LiAlO 2 、LiAlCl 4 , LiF, LiBr, LiCl, LiI, LiB(C 2 O 4 ) 2 、LiCF 3 SO 3 、LiN(SO 2 CF 3 ) 2 、(LiTFSI), LiN(SO 2 C 2 F 5 ) 2 、LiC(SO 2 CF 3 ) 3 and LiNO 3 The organic solvent may be one or more selected from the group consisting of but not limited to tetraethylene glycol, dimethyl ether, dimethylacetamide and dimethyl sulfoxide. Preferably, 1M LiTFSI may be prepared by mixing tetraethylene glycol and dimethyl ether or by mixing 1M LiNO 3 The electrolyte 400 is obtained by mixing with dimethylacetamide.

[0062] The gas diffusion layer 200 may be a porous electron conducting layer and may include a porous metal substrate. The porous metal substrate may include one or more selected from the group consisting of foamed nickel, aluminum mesh, and stainless steel mesh, and preferably includes but is not limited to porous aluminum. For example, because aluminum has high electron conductivity and is lightweight, it is mainly used in lithium ion batteries, so porous aluminum (net-like, foam structure) can introduce air required for lithium air batteries and serve as an electron conductor.

[0063] The external material 300 is not particularly limited as long as it includes a plurality of holes 310 and prevents moisture or gas (such as carbon dioxide) in the atmosphere from flowing in and selectively allows only oxygen to permeate. The external material 300 can use a material that can selectively allow only oxygen to permeate, and preferably can include one or more selected from the group consisting of polyethylene terephthalate (PET), high-density polyethylene (HDPE), polytetrafluoroethylene and polymethyl methacrylate. In addition, the external material 300 can be a metal organic framework permeable membrane, which is mixed with one or more polymers selected from the group consisting of polyethylene terephthalate (PET), high-density polyethylene (HDPE), polytetrafluoroethylene and polymethyl methacrylate. The material as described above can preferably include a hydrophobic polymer film, and therefore has the advantage of blocking moisture in the atmosphere and is thin and flexible, which enables compression molding. In addition, the external material 300 can also form a resin layer on one surface of the external material 300. The material included in the resin layer can include a commonly used material in the technical field related to the present invention, and is not limited to including a specific material. Since the exterior material 300 further includes a resin layer on one surface, even when pressure is applied to the pouch type metal air battery, adhesion between the exterior material 300 and the electrode assembly 100 may be improved and leakage and volatilization of the electrolyte 400 may be prevented.

[0064] Example

[0065] The present invention will be described in more detail by the following examples. The following examples are only examples for helping to understand the present invention, and the scope of the present invention is not limited thereto.

[0066] Example 1 - A pouch-type metal-air battery including a gas diffusion layer 200 having a diffusion portion 210 The ratio of the length of the protrusion 220 is 1:0.2

[0067] Use carbon nanotube paper (3×5cm 2 ) as the cathode layer 110. A lithium metal sheet (3×5 cm 2 ) was used as the anode active layer 131 of the anode layer 130, and copper was used as the current collector 132. As the separator 120, polyethylene (3.2×5.2 cm 2), in which 1M LiNO 3 Mix with dimethylacetamide. Use nickel foam (3.6×5.0mm 2 ) as the gas diffusion layer 200. Figure 2A As shown, a pouch type metal air battery 10 according to Example 1 was prepared. Specifically, an electrode assembly 100 was prepared in which a cathode layer 110 , a separator 120 , an anode active layer 131 , and a current collector 132 were sequentially stacked on one surface of a gas diffusion layer 200 .

[0068] Here, the ratio of the length of the diffusion portion 210 of the gas diffusion layer 200 to the length of the protrusion 220 is 1:0.2. Then, the pouch type metal air battery 10 is prepared by sealing using an external material 300 that accommodates the upper part of the gas diffusion layer 200 and the lower part of the electrode assembly 100. Here, the external material 300 is made of PET. A plurality of holes 310 with a hole size of 1 μm are drilled in the external material 300 using an ultrafine processing laser (femtosecond laser or ultraviolet laser as a pulse laser).

[0069] Embodiment 2 - A pouch-type metal-air battery including a gas diffusion layer 200, the diffusion portion 210 of the gas diffusion layer The ratio of the length of the protrusion 220 is 1:0.4

[0070] Compared with Example 1, the pouch type metal air battery of Example 2 was prepared in the same manner as Example 1, except that the ratio of the length of the diffusion portion 210 to the length of the protrusion 220 in the gas diffusion layer 200 was 1:0.4 instead of 1:0.2.

[0071] Comparative Example 1—Pouch-type metal-air battery including a gas diffusion layer 200 without a protrusion 220

[0072] Compared with Example 1, a pouch type metal air battery of Comparative Example 1 was prepared in the same manner as Example 1, except that the gas diffusion layer 200 included only the diffusion portion 210 without the protrusion 220 .

[0073] Comparative Example 2 - A pouch-type metal-air battery including a gas diffusion layer 200 having a diffusion portion 210 The ratio of the length of the protrusion 220 is 1:0.6

[0074] Compared with Example 1, a pouch type metal air battery was prepared in the same manner as Example 1, except that the ratio of the length of the diffusion portion 210 to the length of the protrusion 220 in the gas diffusion layer 200 was 1:0.6 instead of 1:0.2.

[0075] Experimental Example—Based on the pressure and the length of the diffusion portion 210 and the length of the protrusion 220 in the gas diffusion layer 200 Comparison of the ratio of the degree to the capacity of the pouch-type metal-air battery

[0076] After preparing the pouch type metal air batteries according to Examples 1 and 2 and Comparative Examples 1 and 2, the capacity of each battery according to external pressure was confirmed, and each result is shown in Table 1 below.

[0077] Table 1

[0078]

[0079] As shown in Table 1, the greater the external pressure applied to the pouch-type metal-air battery according to an exemplary embodiment of the present invention, the smaller the contact resistance, which is beneficial for lithium ion / electron conduction. However, excessive external pressure makes it difficult to introduce oxygen into the oxygen diffusion path along the side of the gas diffusion layer 200 because the pores 310 of the external material 300 (oxygen permeable membrane) are blocked due to the pressing of the component or the extrusion of the electrolyte 400, thereby making it difficult to form discharge products and having a low discharge capacity. In addition, as shown in Comparative Example 1, when the gas diffusion layer 200 does not include the protrusion 220 but only includes the diffusion portion 210, as shown in Figure 4 As shown in Table 1, it is difficult to drive the unit.

[0080] Meanwhile, as in Examples 1 and 2, in the case where the protrusion 220 is included in the gas diffusion layer 200 in the metal-air battery and the length ratio of the protrusion to the diffusion portion 210 is 0.2 to 0.4, since the gas diffusion layer 200 includes the protrusion 220 extending with an appropriate length regardless of the external pressure, the squeezed electrolyte 400 does not deviate from the intrusion range. In this way, it is possible to ensure that oxygen can diffuse through the anode active layer 131 in the electrode assembly 100 to allow the minimum range of oxygen to flow in sufficiently, and thus the ORR discharge operates normally.

[0081] Meanwhile, Comparative Example 2, in which the metal-air battery includes the protrusion 220 in the gas diffusion layer 200, the length ratio of the protrusion to the diffusion portion 210 being 0.6, shows almost the same discharge capacity according to the changed external pressure as Example 2. Therefore, the gas diffusion layer 200 including the excessively long protrusion 220 is ineffective in terms of energy density.

[0082] Therefore, even if the electrolyte 400 inside the battery comes out of the electrode assembly 100 due to the application of external pressure, the pouch type metal air battery according to various exemplary embodiments of the present invention may be designed so that the electrolyte 400 does not reach the space separated by the gas diffusion layer 200, the electrode assembly 100 and the external material 300 due to the step formed by the protrusion 220 of the gas diffusion layer 200. In this way, the plurality of holes 310 corresponding to the space in the external material 300 are not blocked. Therefore, since the oxygen selectively permeated from the external material 300 flows into the gas diffusion layer 200 and flows into the electrode assembly 100 through the diffusion portion 210 of the gas diffusion layer 200, the contact resistance with respect to pressure can be improved in the pouch type metal air battery and the initial driving condition and driving reproducibility can be ensured.

Claims

1. A pouch-type metal-air battery, comprising: An electrode assembly, the electrode assembly comprising a cathode layer, an anode layer, and a separator located between the cathode layer and the anode layer; a gas diffusion layer, the gas diffusion layer being located on the electrode assembly; as well as an external material that accommodates the electrode assembly and the gas diffusion layer and has fluid permeability, wherein the gas diffusion layer comprises: a diffusion portion in contact with the electrode assembly; and one or more protrusions extending from the diffusion portion, wherein a step between the electrode assembly and the gas diffusion layer is formed by the protrusion, and a space separated by the gas diffusion layer, the electrode assembly and the external material is formed, and Wherein, the ratio of the length of the diffusion portion to the length of the protrusion is 1:0.2 to 1:0.

4.

2. The battery according to claim 1, wherein The gas diffusion layer includes two or more protrusions.

3. The battery according to claim 1, further comprising: A stacking body is provided in which a plurality of electrode assemblies are stacked, wherein the gas diffusion layer is located at least between the electrode assemblies adjacent to each other or at both ends of the stacking body.

4. The battery according to claim 1, wherein The battery has a temperature range of 0.59 to 1.3 kgf / cm 2 Operate under pressure.

5. The battery according to claim 1, wherein The diffusion portion of the gas diffusion layer is located on the cathode layer.

6. The battery according to claim 1, wherein The gas diffusion layer includes a porous metal substrate.

7. The battery according to claim 6, wherein The porous metal substrate includes one or more selected from the group consisting of nickel foam, aluminum mesh and stainless steel mesh.

8. The battery according to claim 1, wherein The cathode layer includes one or more selected from the group consisting of carbon paper, carbon black, reduced graphene oxide and carbon nanotubes.

9. The battery according to claim 8, wherein The carbon black is acetylene black.

10. The battery according to claim 1, wherein The cathode layer includes one or more catalysts selected from the group consisting of nickel, gold (Au), silver (Ag), rubidium (Ru), and platinum (Pt).

11. The battery according to claim 1, wherein The outer material includes a plurality of holes.

12. The battery according to claim 1, wherein The outer material is selectively permeable to oxygen.

13. The battery according to claim 12, wherein: Oxygen permeated from the external material flows into the gas diffusion layer, and flows into the electrode assembly through the diffusion portion of the gas diffusion layer.

14. The battery according to claim 1, wherein The outer material includes one or more materials selected from the group consisting of polyethylene terephthalate (PET), high-density polyethylene (HDPE), polytetrafluoroethylene, and polymethyl methacrylate.

15. The battery according to claim 1, wherein The outer material is a metal organic framework permeable membrane mixed with one or more polymers selected from the group consisting of polyethylene terephthalate (PET), high density polyethylene (HDPE), polytetrafluoroethylene and polymethyl methacrylate.

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