WO2016144144A1

WO2016144144A1 - Secondary battery and method for manufacturing same

Info

Publication number: WO2016144144A1
Application number: PCT/KR2016/002486
Authority: WO
Inventors: 윤영수; 지승현; 이강수
Original assignee: 가천대학교 산학협력단
Priority date: 2015-03-12
Filing date: 2016-03-11
Publication date: 2016-09-15
Also published as: KR101642871B1

Abstract

The present invention provides a secondary battery comprising: a collector for donating or accepting electrons; a first electrode containing a first active material and formed on the collector; an electrolyte layer formed on the first electrode; and a second electrode containing a second active material and formed on the electrolyte layer, wherein the electrolyte layer comprises: a plurality of supports formed such that the supports are spaced apart from each other; and a liquid electrolyte provided in the spaced gaps between the plurality of supports.

Description

Secondary Battery and Manufacturing Method Thereof

The present invention relates to a secondary battery and a method for manufacturing the same, and more particularly, to a secondary battery using a liquid electrolyte and a method for manufacturing the same.

Power sources for portable electronic devices such as mobile phones, personal digital assistants (PDAs) and portable multimedia players (PMPs); Motor driving power supplies such as high-power hybrid vehicles and electric vehicles; And the use of secondary batteries as power sources for flexible displays, such as electronic ink (e-ink), electronic paper (e-paper), flexible liquid crystal display devices (LCDs), and flexible organic diodes (OLEDs). In addition, the applicability is increasing as a power supply for integrated circuit devices on a printed circuit board.

However, when used as a power source for portable electronic devices, packaging for safety imposes restrictions on various product designs. When used as a power source for driving motors, the need for high output, small size, and light weight is increasing, and when used as a power supply for flexible display, it should be manufactured to be thin and light while being bent. In order to use it as a power source for an integrated circuit device, it must be precisely patterned in a certain form.

In order to meet various demands of such a secondary battery, Korean Laid-Open Patent Publication No. 10-2010-0044087 (2010.04.29) or the like is a method of manufacturing an electrode, instead of the conventional slurry coating technique, the electrode for the secondary battery is thin, uniform and flat. There are printing techniques that can be produced and that can economically produce the desired shape pattern. However, in order to use a liquid electrolyte having excellent overall ionic conductivity and transport rate, a cumbersome process for injecting a liquid electrolyte after forming and packaging the anode and the cathode, respectively, is not performed in one procedure. You have to go through. In addition, there is a problem in that a separator having a thickness of several tens of micrometers is used to prevent electrical current between the positive electrode and the negative electrode. In addition, when the separator is used, the overall thickness of the secondary battery becomes thick, and thus, the secondary battery becomes difficult to have flexible characteristics. In addition, there is a problem in that packaging is difficult because the positive electrode and the negative electrode must be physically spaced apart to place a separator in the middle and inject a liquid electrolyte.

(Patent Document 1) Korean Patent Publication No. 10-2010-0044087

The present invention provides a secondary battery and a method of manufacturing the same, which can easily form a liquid electrolyte therein, can prevent electrical conduction between the positive electrode and the negative electrode with a simple structure, and are easy to package.

Secondary battery according to an embodiment of the present invention is a current collector to send and receive electrons; A first electrode containing a first active material and formed on the current collector; An electrolyte layer formed on the first electrode; And a second electrode formed on the electrolyte layer, wherein the electrolyte layer comprises: a plurality of supports spaced apart from each other; And it may include a liquid electrolyte provided in the spaced space between the plurality of supports.

The plurality of supports may be made of a solid electrolyte.

The liquid electrolyte may be formed by dissolving a solid salt structure having a continuous network structure provided in the separation space in a solvent.

The electrolyte layer may have a thickness of 1 to 200 ㎛.

A secondary battery manufacturing method according to another embodiment of the present invention comprises the steps of forming a current collector; Forming a first electrode on the current collector; Forming an intermediate layer on the first electrode, the intermediate layer including a plurality of supports spaced apart from each other and a salt structure provided in a spaced space between the plurality of supports; Forming a second electrode on the intermediate layer; And dissolving the salt structure in a solvent to form a liquid electrolyte.

The salt structure may be formed in a continuous network structure, and the plurality of supports may be formed in an isolated shape by the salt structure, respectively.

The current collector, the first electrode, the intermediate layer, and the second electrode may all be formed by a printing process.

In the forming of the intermediate layer, any one selected from the plurality of supports and the salt structure may be formed first, and then the other one may be formed.

Forming the intermediate layer can be performed as a procedure.

In the forming of the intermediate layer, the intermediate layer may be formed by 3D printing using a plurality of inks including the constituents of the plurality of supports and the constituents of the salt structure.

The plurality of supports may be formed of a solid electrolyte.

The intermediate layer may be formed to a height of 1 to 200 ㎛.

Secondary battery according to an embodiment of the present invention can easily form a liquid electrolyte therein by forming a salt structure using a salt (for example, lithium salt) and dissolving the salt structure with a solvent. Accordingly, since the salt structure can be formed by a printing technique, it is possible to form all of the current collector, the first electrode, the plurality of supports, the salt structure, and the second electrode at once by 3D printing. As a result, all manufacturing processes can be performed in an inline process, which can shorten the process time and improve productivity and process efficiency. In addition, packaging can be easily performed by packaging one stack formed at a time by 3D printing.

In addition, a plurality of supports are formed between the first electrode and the second electrode to physically block the positive electrode and the negative electrode during the 3D printing process, and to prevent the electrical conduction of the positive electrode and the negative electrode without a thick separator during charge and discharge of the secondary battery. Can be. The thickness of the electrolyte layer can be increased by increasing the ratio of the positive electrode or the negative electrode per unit volume, thereby increasing the amount of the active material per unit volume, thereby improving the energy density of the separator. In addition, the plurality of supports may be formed of a solid electrolyte to allow ions to move to the plurality of supports, thereby improving the overall ionic conductivity.

Meanwhile, in order to further improve energy density, unit cells of the secondary battery may be stacked. Therefore, since a plurality of unit cells are formed to be stacked by 3D printing, the unit cells and the unit cells can be stacked during the continuous process, thereby increasing the process efficiency and reducing the process time, thereby obtaining a secondary battery having a high energy density.

1 is a cross-sectional view showing a secondary battery according to an embodiment of the present invention.

Figure 2 is a perspective view showing a current collector formed by a secondary battery manufacturing method according to another embodiment of the present invention.

3 is a perspective view illustrating a first electrode formed on a current collector in a method of manufacturing a secondary battery according to another embodiment of the present invention.

Figure 4 is a perspective view showing an intermediate layer formed on the first electrode in a secondary battery manufacturing method according to another embodiment of the present invention.

5 is a perspective view illustrating a second electrode formed on an intermediate layer in a method of manufacturing a secondary battery according to another embodiment of the present invention.

Figure 6 is a perspective view of a secondary battery packaged in a packaging material according to a secondary battery manufacturing method according to another embodiment of the present invention.

Figure 7 is a perspective view showing one embodiment of a method of forming a plurality of supports and salt structure according to another embodiment of the present invention.

8 is a perspective view showing a modification of the method of forming a plurality of supports and salt structure according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to the fullest extent. It is provided to inform you. In the description, like reference numerals refer to like elements, and the drawings may be partially exaggerated in size in order to accurately describe embodiments of the present invention, and like reference numerals refer to like elements in the drawings.

1 is a cross-sectional view of a rechargeable battery according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a secondary battery 100 according to an embodiment of the present invention includes a current collector 110 for sending and receiving electrons; A first electrode 120 containing a first active material and formed on the current collector 110; An electrolyte layer 130 formed on the first electrode 120; And a second electrode 140 including a second active material and formed on the electrolyte layer 130.

The current collector 110 serves to flow an electric current in a charging / discharging process by exchanging electrons, and may use a conductive substrate having no porous structure or a conductive substrate without holes. The conductive substrate (ie, current collector) may be formed using one or more selected from copper, aluminum, stainless steel, molybdenum, tungsten, tantalum, titanium, and nickel. However, the present invention is not limited thereto, and any electrode can be used as long as the electrode can be formed to have good adhesion on the surface. The current collector 110 preferably has a thin thickness, and may be metal foil, and the thickness thereof may be 1 nm to 30 μm, preferably 10 μm to 30 μm. When the thickness is less than 10 µm, not only the strength as the electrode can be obtained but also the strain introduced by the expansion and contraction of the active material due to the charge / discharge reaction cannot be alleviated or the anode may be cut. On the other hand, when the thickness exceeds 30 µm, not only the amount of charge of the active material is reduced, but also the flexibility of the electrode is impaired, and there is a possibility that internal short circuit is likely to occur. In consideration of tensile strength, electrochemical stability and flexibility in winding, the current collector 110 is most preferably aluminum foil, and the thickness thereof is preferably 10 μm to 30 μm. The current collector 110 may be formed using a printing technique, electroless plating or electrolytic plating. On the other hand, the current collector 110 may form a concave-convex structure or the like on the surface on which the electrode is formed to control the surface roughness, and may further be subjected to UV or plasma surface treatment. When the surface treatment is performed, the surface energy of the current collector 110 may be increased to increase the uniformity of the electrode when the electrode is formed of a low viscosity ink.

The first electrode 120 may contain a first active material and may be formed on the current collector 110. The first electrode 120 may be any one of a positive electrode and a negative electrode, and the first active material may be an active material of any one of the same positive electrode and the negative electrode as the first electrode 120. The first electrode 120 may include a first active material and a conductive agent, and may further include a binder for binding the first active material. When the first electrode 120 is a positive electrode, most of the ceramic-based positive electrode active material used as the positive electrode may be used. For example, various oxides such as manganese dioxide, lithium manganese composite oxide, lithium-containing nickel oxide, lithium-containing cobalt compound, lithium-containing nickel cobalt oxide, lithium-containing iron oxide, and vanadium oxide containing lithium, titanium disulfide, and molybdenum disulfide And chalcogen compounds. Among them, lithium-containing cobalt oxide (e.g., LiCoO _2), lithium-containing nickel cobalt oxide _{_{_{_{_{(e.g., LiNi 0. 8 Co 0.}}}}} 2 O 2) or lithium manganese composite oxide (for example, LiM ₂ O ₄ , LiMnO ₂ ) can be used to obtain a high voltage. The conductive agent may be acetylene black, carbon black, graphite, or the like as a material for improving conductivity of the active material. The binder may be polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), ethylene propylene diene copolymer (EPDM), styrene butadiene rubber (SBR), or the like. Here, the conductive agent and the binder contain a small amount compared to the first active material.

The electrolyte layer 130 may be formed on the first electrode 120, and may include a plurality of supports 131 and spaced apart from each other and a liquid electrolyte 132 provided in a space between the plurality of supports 131. It may include. The plurality of supports 131 are formed to be spaced apart from each other, and provide a space for separating the liquid electrolyte 132 to have a continuous network structure.

In the conventional secondary battery, a separator is required in the electrolyte layer in order to prevent an electrical conduction shape between the positive electrode and the negative electrode. Conventional separators have a thickness of several tens of micrometers, which not only increases the thickness of the electrolyte layer but are also porous membranes. Therefore, when the second electrode is deposited on the separator in a continuous lamination process using a printing process or a thin-thick film process, Through the minute pores, the conductive material of the second electrode may be coated inside the pores of the separator, thereby causing an electrical short. For this reason, conventionally, there was a limitation in manufacturing the entire secondary battery by the printing process.

However, in the present invention, the second electrode 140 is formed on an intermediate layer made of a salt structure 132 provided in a space between the plurality of supports 131 and the plurality of supports 131 spaced apart from each other. This intermediate layer does not contain micropores unlike conventional separators. Accordingly, when the second electrode is formed by the printing process, the conductive material may be coated inside the microcavity to solve a problem in which a short occurs. Details of the intermediate layer will be described later in the secondary battery manufacturing method according to another embodiment of the present invention.

In addition, in the present invention, ionic conductivity may be controlled through the plurality of supports 131. The thickness of the electrolyte layer 130 may be reduced, and thus, the overall thickness of the secondary battery 100 may be reduced since the electrical conduction of the positive electrode and the negative electrode may be prevented without a thick separator in the electrolyte layer 130. In addition, when the thickness of the electrolyte layer 130 is thin, the ratio of the first electrode (or the anode) or the second electrode (or the cathode) per unit volume can be maximized, thereby increasing the amount of the active material per unit volume. Thus, since the thickness of the electrolyte layer is small and the amount of the active material per unit volume is small, the present invention can improve the energy density in the present invention by solving the conventional problem of low energy density.

In the related art, there is no support structure in the upper and lower portions of the separator, so that it is difficult to keep the distance between the positive electrode and the negative electrode constant. However, in the present invention, the distance between the positive electrode and the negative electrode can be kept constant by the plurality of supports 131. In addition, since the plurality of supports 131 may physically block the positive electrode and the negative electrode, printing of the current collector 110, the first electrode 120, the electrolyte layer (or the plurality of supports), and the second electrode 140 may be performed. It can be formed by technique. In particular, the secondary battery 100 can be manufactured easily and simply by 3D printing technique.

On the other hand, the plurality of supports 131 may be evenly distributed in the plane of the secondary battery 100 so as to make the distribution of the liquid electrolyte 132 uniform, and may be spaced apart from each other to distribute the force to the space. In addition, the space between the plurality of supports 131 is arranged because the plurality of supports 131 are spaced apart from each other even when the plurality of supports 131 are made of a rigid material to support the laminated structure. Liquid electrolyte 132 may be provided. Accordingly, flexibility of the entire secondary battery 100 can be improved without sacrificing flexibility by the plurality of supports 131.

The plurality of supports 131 may be made of a solid electrolyte. When the plurality of supports 131 are made of a solid electrolyte, ions may also move to the plurality of supports 131, thereby improving ion conductivity of the secondary battery 100 than when forming the plurality of supports 131 with an insulating material. You can. Although the said solid electrolyte is not restrict | limited in particular in material, It is preferable to use an oxide type or a sulfide type. For example, it may be a single substance or a mixture of two or more selected from the group consisting of molybdenum oxide, titanium oxide, vanadium oxide, chromium oxide, tantalum oxide, zirconium oxide, hafnium oxide, niobium oxide and tungsten oxide.

The liquid electrolyte 132 may be formed to have a continuous network structure, and may be provided in a spaced space between the plurality of supports 131. Since the liquid electrolyte 132 has better overall ionic conductivity and transport rate than the solid electrolyte, the liquid electrolyte 132 may be used to improve the ionic conductivity of the secondary battery 100. Examples of the material of the liquid electrolyte 132 include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium borofluoride (LiBF ₄ ), lithium hexafluoride (LiAsF ₆ ), and lithium trifluoromethsulfonate ( LiCF ₃ SO ₃ ), lithium titanate (Li ₄ Ti ₅ O ₁₂ ; LTO), lithium iron phosphate (LiFePO ₄ ; LFP), bistrifluoromethylsulfonylimide lithium [LiN (CF ₃ SO ₂ ) ₂ ], etc. One or two or more selected from the lithium salts thereof may be dissolved in a solvent and used. Here, lithium borofluoride (LiBF ₄ ) can suppress the gas generation during supercharge. The solvent may be a nonaqueous solvent, and a known nonaqueous solvent may be used as a solvent of a lithium secondary battery. Propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), 1,2-dimethoxyethane (DME), γ-butyrolactone (γ-BL), tetrahydrofran (THF), 2-methyltetrahydrofran (2-MeTHF), 1,3-dioxolane, 1,3-dimethoxypropane, vinylene carbonate (VC), etc. A mixed solvent may be used, but is not particularly limited thereto.

When the liquid electrolyte 132 is formed to have a continuous network structure, the solid salt structure is formed to have a continuous network structure, and then a solvent for dissolving the salt is injected into one place. The liquid electrolyte 132 may be formed by allowing a solvent to dissolve all of the salts through a continuous network structure. Accordingly, the liquid electrolyte 132 may be simply formed in the secondary battery 100, and since the solvent may be injected only to one place, the sealing area may be reduced, and thus the sealing process may be facilitated. In addition, when the solid salt structure is first formed, all the laminates (that is, the current collector, the first electrode, the plurality of supports, the salt structure, and the second electrode) up to the salt structure may be formed by a printing technique. It is easy and simple to form a laminate that is the basis of the secondary battery 100. When 3D printing is used, lithium hexafluorophosphate and perchloric acid can effectively form a support structure (i.e., salt structure) during the 3D printing process and easily dissolve when a solvent such as ethylene carbonate or diethyl carbonate is supplied. Preference is given to using lithium salts such as lithium. As such, the liquid electrolyte 132 may be formed by dissolving a solid salt structure having a continuous network structure provided in a spaced space between the plurality of supports 131 in a solvent.

On the other hand, the electrolyte layer 130 may have a thickness of 1 to 200 ㎛. The thinner the electrolyte layer 130, the shorter the movement distance of the ions, so the ion transfer rate is faster and the maximum capacity is increased, resulting in better output. However, when the thickness of the electrolyte layer 130 is thinner than 1 μm, a short may be generated without preventing the electrical conduction between the positive electrode and the negative electrode. On the other hand, when the thickness of the electrolyte layer 130 is thicker than 200 μm, the output efficiency may be reduced because the moving distance of the ions is too long and the ion transfer time is long. In addition, when the thickness of the electrolyte layer 130 becomes thin, the ratio of the first electrode (or anode) or the second electrode (or cathode) per unit volume can be maximized, and thus the energy density can be improved because the amount of the active material per unit volume increases. have.

The second electrode 140 may contain a second active material and may be formed on the electrolyte layer 130. The second electrode 140 may be the remaining electrode corresponding to the first electrode 120 among the positive electrode and the negative electrode, and the second active material may be determined according to the polarity of the second electrode 140. Like the first electrode 120, the second electrode 140 may include a second active material and a conductive agent, and may further include a binder for binding the second active material. When the second electrode 140 is a negative electrode, the second active material is a conductive polymer such as polyacetal, polyacetylene, or polypyrrole capable of doping lithium ions, coke, carbon fiber, graphite, or mesophase capable of doping lithium ions. Carbon materials, such as pitch-based carbon, pyrolytic gaseous materials, and resinous plastics, and carbogen compounds such as titanium disulfide, molybdenum disulfide, and niobium selenide, silicon (Si), tin (Sn), vanadium (V), and titanium (Ti) ), Metal materials such as germanium (Ge), oxides thereof, or two or more compounds can be used. Here, the carbon material may be a graphite carbon material, a carbon material in which the graphite crystal part and the amorphous part are mixed, or a carbon material having a laminated structure in which the crystal layer is irregular. The conductive agent may be acetylene black, carbon black, graphite, or the like as a material for improving conductivity of the active material. The binder may be polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), ethylene propylene diene copolymer (EPDM), styrene butadiene rubber (SBR), or the like. Here, the conductive agent and the binder contain a small amount compared to the second active material.

On the other hand, when the first electrode 120 is a cathode and the second electrode 140 is an anode, the first electrode 120 and the second electrode 140 may be formed on the contrary, but the polarity of each electrode may vary. The active material can be selected accordingly. In addition, the current collector 110 may also be formed on the second electrode 140, and the components (that is, the current collector, the first electrode, the plurality of supports, the liquid electrolyte, and the second electrode) which are the base of the secondary battery 100 may be used. ) May be packaged into the exterior material 150. In addition, in order to further improve energy density, unit cells of the secondary battery 100 may be stacked.

2 to 6 are perspective views sequentially showing a secondary battery manufacturing method according to another embodiment of the present invention, Figures 7 to 8 is a method of forming a plurality of supports and salt structure according to another embodiment of the present invention. It is a perspective view shown.

With reference to Figures 2 to 6 and 7 to 8 will be described in detail a secondary battery manufacturing method according to another embodiment of the present invention, with the above-described parts related to the secondary battery according to an embodiment of the present invention Duplicate items should be omitted.

First, the current collector 110 is formed (FIG. 2). The current collector 110 serves to flow current by exchanging electrons in a charging / discharging process, and a conductive substrate having a porous structure or a conductive substrate having no hole may be used. The conductive substrate (ie, current collector) may be formed using one or more selected from copper, aluminum, stainless steel, molybdenum, tungsten, tantalum, titanium, and nickel. However, the present invention is not limited thereto, and any electrode can be used as long as the electrode can be formed to have good adhesion on the surface. The current collector 110 may be formed using a printing technique (or 3D printing technique) as well as electroless plating or electrolytic plating. Meanwhile, in the forming of the current collector 110, the step of forming an uneven structure or the like on the surface of the current collector 110 on which the electrode is formed and the UV or plasma surface treatment of the current collector 110 may be further roughened. .

Next, the first electrode 120 is formed on the current collector 110 (FIG. 3). The first electrode 120 may include an active material and a conductive agent, and the first electrode 120 may be any one of an anode and a cathode. When the first electrode 120 is a positive electrode, most of the ceramic-based positive electrode active material used as the positive electrode may be used as the active material. For example, various oxides such as manganese dioxide, lithium manganese composite oxide, lithium-containing nickel oxide, lithium-containing cobalt compound, lithium-containing nickel cobalt oxide, lithium-containing iron oxide, and vanadium oxide containing lithium, titanium disulfide, and molybdenum disulfide And chalcogen compounds. Among them, lithium-containing cobalt oxide (e.g., LiCoO _2), lithium-containing nickel cobalt oxide _{_{_{_{_{(e.g., LiNi 0. 8 Co 0.}}}}} 2 O 2) or lithium manganese composite oxide (for example, LiM ₂ O ₄ , LiMnO ₂ ) can be used to obtain a high voltage. And it may further comprise a binder for binding the active material, the conductive agent and the binder may be contained in a small amount compared to the active material.

Next, the intermediate layer 130 is formed on the first electrode 120. The plurality of supports 131 are formed to be spaced apart from each other, and the salt structure is provided in a spaced space between the plurality of supports 131. 132 is formed (FIG. 4). At this time, the salt structure 132 may be formed in a continuous network structure, a plurality of supports 131 may be formed in a shape isolated by the salt structure 132, respectively. When the salt structure 132 is formed in a continuous network structure, since the solvent capable of dissolving the salt may move as a whole through the continuous network structure, the solvent is injected into one place to simplify the A liquid electrolyte can be formed inside. In addition, since the solvent needs only to be injected into one place, the sealing area may be reduced, and thus the sealing process may be simplified, and the problem of using a liquid electrolyte in the conventional printing technique may be solved. In addition, since the salt may be stacked while maintaining the shape, all the laminates (ie, the current collector, the first electrode, the plurality of supports, the salt structure, and the second electrode) may be formed by a printing technique. Accordingly, it is possible to easily and simply form the laminate which is the basis of the secondary battery by 3D printing. On the other hand, when using 3D printing, the salt structure 132 may provide a support structure on which the upper stack (eg, the second electrode) can be effectively stacked during the 3D printing process. The salt may include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium borofluoride (LiBF ₄ ), bisodium hexafluoride (LiAsF ₆ ), and lithium trifluoromethsulfonate (LiCF). ₃ SO ₃ ), lithium titanate (Li ₄ Ti ₅ O ₁₂ ; LTO), lithium iron phosphate (LiFePO ₄ ; LFP), bistrifluoromethylsulfonylimide lithium [LiN (CF ₃ SO ₂ ) ₂ ], and the like. It may be one kind or two or more kinds selected from lithium salts (electrolytes). And the solvent may be a non-aqueous solvent, propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), 1,2-dimethoxyethane (DME), γ-butyrolactone (γ-BL), tetrahydrofran (THF), 2-methyltetrahydrofran (2-MeTHF), 1,3-dioxolane, 1,3-dimethoxypropane, vinylene carbonate (VC) and the like A single solvent or two or more mixed solvents selected from among them can be used.

The plurality of supports 131 are spaced apart or isolated from each other to provide a space for forming a liquid electrolyte. Conventionally, in the case of using a liquid electrolyte, a thick separator having a thickness of several tens of micrometers was required in order to prevent an electrical conduction shape between the positive electrode and the negative electrode. However, in the present invention, since the ionic conductivity can be adjusted through the plurality of supports 131, It is possible to prevent the electrical conduction between the positive electrode and the negative electrode without a separator. Accordingly, the thickness of the intermediate layer 130 can be increased to increase the ratio of the first electrode (or anode) or the second electrode (or cathode) per unit volume, thereby increasing the amount of active material per unit volume, thereby improving energy density compared to using a separator. You can. In addition, the plurality of supports 131 together with the salt structure 132 provides a support structure on which the upper stack (eg, the second electrode) can be effectively stacked during the 3D printing process. It is possible to manufacture a secondary battery.

On the other hand, the plurality of supports 131 may be evenly distributed in the plane of the secondary battery 100 so as to make the distribution of the liquid electrolyte uniform, and may be spaced apart from each other to distribute the force to the space. In addition, even when the plurality of supports 131 are made of a rigid material to support the stacked structure, the plurality of supports 131 are spaced apart from each other, so that the liquid electrolyte is disposed in the space between the plurality of supports 131. Since it is provided, flexibility of the entire secondary battery 100 can be improved without sacrificing flexibility by the plurality of supports 131.

The plurality of supports 131 may be formed of a solid electrolyte. When the plurality of supports 131 are made of a solid electrolyte, ions may also move to the plurality of supports 131, thereby improving ion conductivity of the secondary battery 100 than when forming the plurality of supports 131 with an insulating material. You can. Although the said solid electrolyte is not restrict | limited in particular in material, It is preferable to use an oxide type or a sulfide type. For example, it may be a single substance or a mixture of two or more selected from the group consisting of molybdenum oxide, titanium oxide, vanadium oxide, chromium oxide, tantalum oxide, zirconium oxide, hafnium oxide, niobium oxide and tungsten oxide.

In the forming of the intermediate layer, any one of the plurality of supports 131 and the salt structure 132 may be formed, and the other one of the plurality of supports 131 and the salt structure 132 may be formed. In one embodiment, as shown in FIG. 7, the salt structure 132 is first formed to provide a plurality of isolation spaces in which a plurality of supports 131 are formed, and then filled in the provided plurality of isolation spaces. Can be formed. Using this method, it is possible to form the plurality of supports 131 and the salt structure 132 using ink (or printing technique), and simply form the plurality of the supports 131 and the salt structure 132. Can be. On the other hand, a method of providing a plurality of isolation spaces to the salt structure 132 includes a method of stacking only portions except for the plurality of isolation spaces and the method of etching all of the isolation spaces after stacking in a plane. In addition, the method is not limited thereto, and the plurality of supports 131 may be formed first, and the salt structure 132 may be formed in the spaced space between the plurality of supports 131. It is sufficient if the intermediate layer 130 including the 131 and the salt structure 132 can be formed.

Forming the intermediate layer may be performed as one procedure. In this case, the intermediate layer 130 may be formed in a single process, and when the printing technique is used, the intermediate layer 130 may be formed by moving the nozzle 10 in the shortest distance.

In the forming of the intermediate layer, the intermediate layer 130 may be formed by a 3D printing technique using a plurality of inks including components of each of the plurality of supports 131 and the salt structure 132. In one embodiment, the intermediate layer 130 may be formed by 3D printing. As shown in FIG. 8, the plurality of supports 131 and the salt structure 132 may be formed by using a plurality of nozzles 10. It may be formed, and may have a thickness of the intermediate layer 130 at a time when the nozzle 10 passes. On the other hand, the nozzle 10 may have a thickness of the intermediate layer 130 by stacking continuously varying the height in the z-axis, the formation method is not particularly limited. When the intermediate layer 130 is formed by the 3D printing technique, the intermediate layer 130 may be easily and quickly formed by moving the shortest distance of the nozzle 10. In addition, in the present invention, the intermediate layer 130 may be formed of the plurality of supports 131 and the salt structure 132 to form all the laminates that are the basis of the secondary battery by 3D printing. Accordingly, the secondary battery can be manufactured easily and quickly by 3D printing technique. Accordingly, all manufacturing processes of the secondary battery may be performed in an inline process, and thus, the process time may be shortened, and the productivity and process efficiency of the secondary battery may be improved.

The plurality of inks are made of powders of the constituents of the plurality of supports 131 and the constituents of the salt structure 132, and each includes a solvent in which powders of the respective constituents are dissolved or dispersed. It may further include an additive for improving the adhesion and ionic conductivity of. The additive may include at least one or more of a binder, a conductive agent, a humectant, a dispersant, a thickener, and a buffer. In order to perform 3D printing, the ink must maintain an appropriate viscosity, and the additives can be added to prepare an ink having improved conductivity of the active material while maintaining the proper viscosity. The solvent is a deionized water (Deionized water) as a main component, ethanol, methanol, butanol, propanol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, N-methyl-2-pyrrolidone, etc. to control the drying rate The solvent which mixed alcohol type can be used.

The binder serves to impart a binding force to the ink, may be a binder, polyvinyl alcohol, ethylene-propylene-diene terpolymer, styrene-butadiene rubber, polyvinylidene fluoride (PVDF), polytetrafluoro One or more selected from ethylene, tetrafluoroethylene-hexafluoropropylene copolymer, carboxymethylcellulose (CMC) can be used. The conductive agent may be acetylene black, carbon black, graphite, carbon fiber, carbon nanotube, or the like as a material for improving conductivity. In addition, the moisturizing agent serves to prevent the clogging of the nozzle by inhibiting the drying of the ink, glycols, glycerol, pyrrolidone and the like can be used.

The dispersant serves to evenly disperse the active material and the conductive agent, and include fatty acid salts, alkyl dicarboxylic acid salts, alkyl sulfate ester salts, polyhydric acid ester alcohol salts, alkylnaphthalene sulfate salts, alkylbenzene sulfate salts, alkyl naphthalene sulfate salts, and alkyl salts. Sulfonic succinate, naphthenate, alkyl ether carboxylate, acylated peptide, alpha olefin sulfate, N-acylmethyl taurine salt, alkyl ether sulfate, secondary polyhydric alcohol ethoxy sulfate, polyoxyethylene alkyl permil ether sulfate, mono Glysulfate, alkyl ether phosphate ester salt, alkyl phosphate ester salt, alkyl amine salt, alkyl pyridium salt, alkyl imidazolium salt, fluorine- or silicone-acrylic acid polymer, polyoxyethylene alkyl ether, polyoxyethylene sterol ether, poly Lanolin derivatives of oxyethylene, polyoxyethylene / polyoxypropylene copolymer, polyoxyethylene sorbitan Fatty acid ester, monoglyceride fatty acid ester, sucrose fatty acid ester, alkanolamide fatty acid, polyoxyethylene fatty acid amide, polyoxyethylene alkylamine, polyvinyl alcohol, polyvinylpyridone, polyacrylamide, carboxyl group-containing water-soluble polyester , One or a mixture of two or more of hydroxyl group-containing cellulose resins, acrylic resins, butadiene resins, acrylic acids, styrene acrylics, polyesters, polyamides, polyurethanes, alkylbetamins, alkylamine oxides and phosphatidylcholines can be used. Can be. And the thickener serves to improve the viscosity, ethylene-vinyl alcohol copolymer, cellulose derivative (for example, carboxymethyl cellulose, methyl cellulose) and the like can be used. In addition, the buffer is a material that maintains the stability of the ink and adjusts the appropriate pH, it may be used one or more amine compounds selected from trimethylamine, triethanolamine, diethanolamine, ethanolamine or sodium hydroxide, ammonium hydroxide.

On the other hand, in the case of forming all the stacks that are the basis of the secondary battery by the 3D printing technique, the stack is formed by using each ink of the stack, and each of the ink is the powder of each component of the stack and the stack It may include a solvent for dissolving or dispersing each component powder. The printer for 3D printing may be a printer that can be controlled by three axes of x, y, and z, and micronozzles and bulk nozzles may be used. In addition, a pneumatic controller capable of controlling the ejection speed of the inks may be used.

The plurality of supports 131 and the salt structure 132 may be formed to a height of 1 to 200 ㎛. The plurality of supports 131 and the salt structure 132 forms the intermediate layer 130 by dissolving the salt structure 132 in a solvent to form a liquid electrolyte. The thinner the intermediate layer 130 is, the shorter the movement distance of ions becomes. As a result, the ion transfer rate is faster and the maximum capacity is increased, resulting in better output. However, if the thickness of the intermediate layer 130 becomes too thin and becomes thinner than 1 μm, a short may not occur without preventing an electric conduction phenomenon between the positive electrode and the negative electrode. On the other hand, when the thickness of the intermediate layer 130 is thicker than 200 μm, the output distance may be reduced because the moving distance of the ions becomes too long and the ion transfer time is long. When the thickness of the intermediate layer 130 is thin, the ratio of the first electrode (or anode) or the second electrode (or cathode) per unit volume can be maximized, and the energy density can be improved because the amount of the active material per unit volume increases. .

The second electrode 140 is formed on the intermediate layer 130 (FIG. 5). The second electrode 140 may include an active material and a conductive agent, and the second electrode 140 may be a remaining electrode corresponding to the first electrode 120 among the positive electrode and the negative electrode. When the second electrode 140 is a negative electrode, conductive polymers such as polyacetal, polyacetylene, polypyrrole and the like, which are capable of doping lithium ions with an active material, and coke, carbon fiber, graphite, and mesophase pitch system capable of doping lithium ions Carbon materials such as carbon, pyrolytic gaseous carbon materials, resinous plastics, and carbogen compounds such as titanium disulfide, molybdenum disulfide, niobium selenide, silicon (Si), tin (Sn), vanadium (V), titanium (Ti), Metal materials such as germanium (Ge), oxides thereof, or two or more compounds may be used. Here, the carbon material may be a graphite carbon material, a carbon material in which the graphite crystal part and the amorphous part are mixed, or a carbon material having a laminated structure in which the crystal layer is irregular. And it may further comprise a binder (or binder) for binding the active material, the conductive agent and the binder may be contained in a small amount compared to the active material. On the other hand, when the first electrode 120 is a cathode and the second electrode 140 is an anode, the first electrode 120 and the second electrode 140 may be formed on the contrary, but the polarity of each electrode may vary. The active material can be selected accordingly.

The current collector 110, the first electrode 120, the intermediate layer 130, and the second electrode 140 may all be formed by a printing process. In the present invention, the intermediate layer 130 is composed of the plurality of supports 131 and the salt structure 132, and the current collector 110, the first electrode 120, the intermediate layer 130, which are the basis of the secondary battery in the printing process, and All of the second electrodes 140 may be formed. Accordingly, the secondary battery can be manufactured easily and quickly by 3D printing technique. Accordingly, all manufacturing processes of the secondary battery may be performed in an inline process, and thus, the process time may be shortened, and the productivity and process efficiency of the secondary battery may be improved.

Next, the salt structure 132 is dissolved in a solvent to form a liquid electrolyte. In this case, as shown in FIG. 6, the laminate, which is the basis of the secondary battery, may be packaged with the exterior material 150, and a solvent for dissolving the salt structure 132 may be injected into the salt structure 132 to form a liquid electrolyte. have. In this case, the injection hole used for injection of the liquid electrolyte is sealed to prevent leakage of the liquid electrolyte after the injection of the solvent.

Meanwhile, the method may further include forming a current collector 110 on the second electrode 140, and stacking unit cells of the secondary battery 100 to further improve energy density. It may further comprise a step. In addition, the exterior member 150 may be formed by 3D printing, or a plurality of unit cells may be formed by 3D printing to be stacked. In this case, the unit cell and the unit cell can be stacked during the continuous process, thus increasing the process efficiency and reducing the process time, and when forming the exterior material 150 by 3D printing, the laminate which is the basis of the secondary battery is sealed. After forming the exterior material 150, a hole may be formed to form an injection hole for dissolving the salt structure 132. On the other hand, the exterior member 150 may be formed so that the injection hole of the solvent for dissolving the salt structure 132 is formed, and the injection hole is also sealed. In addition, when stacking unit cells of the secondary battery 100, the second electrode of one unit cell and the first electrode of another unit cell may be stacked so as to be in contact with each other. The second electrode and the first electrode of another unit cell may be connected. At this time, there is no particular limitation in the method of connecting the second electrode of any one unit cell and the first electrode of the other unit cell.

As such, the secondary battery according to an embodiment of the present invention can easily form a liquid electrolyte therein by forming a salt structure using a salt (for example, lithium salt) and dissolving the salt structure with a solvent. Salt structures can be formed by printing techniques. Thus, 3D printing can form all of the current collector, the first electrode, the plurality of supports, the salt structure, and the second electrode at once. As a result, all manufacturing processes can be performed in an inline process, which can shorten the process time and improve productivity and process efficiency. In addition, packaging can be easily performed by packaging one stack formed at a time by 3D printing. In addition, a plurality of supports are formed between the first electrode and the second electrode to physically block the positive electrode and the negative electrode during the 3D printing process, and to prevent the electrical conduction of the positive electrode and the negative electrode without a thick separator during charge and discharge of the secondary battery. Can be. The thickness of the electrolyte layer can be increased by increasing the ratio of the positive electrode or the negative electrode per unit volume, thereby increasing the amount of the active material per unit volume, thereby improving the energy density of the separator. In addition, the plurality of supports may be formed of a solid electrolyte to allow ions to move to the plurality of supports, thereby improving the overall ionic conductivity. Meanwhile, in order to further improve energy density, unit cells of the secondary battery may be stacked. Accordingly, since a plurality of unit cells are formed to be stacked by 3D printing, the unit cells and the unit cells can be stacked during the continuous process, thereby increasing the process efficiency and reducing the process time, thereby obtaining a secondary battery having a high energy density.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above-described embodiments, and the general knowledge in the field of the present invention belongs without departing from the gist of the present invention as claimed in the claims. Those skilled in the art will appreciate that various modifications and equivalent other embodiments are possible therefrom. Therefore, the technical protection scope of the present invention will be defined by the claims below.

Claims

A current collector for sending and receiving electrons;

A first electrode containing a first active material and formed on the current collector;

An electrolyte layer formed on the first electrode; And

A second electrode formed on the electrolyte layer, containing a second active material,

The electrolyte layer,

A plurality of supports formed spaced apart from each other; And

Secondary battery comprising a liquid electrolyte provided in the spaced space between the plurality of supports.
The method according to claim 1,

The plurality of supports are secondary batteries made of a solid electrolyte.
The method according to claim 1,

The liquid electrolyte is a secondary battery in which a solid salt structure having a continuous network structure provided in the separation space is dissolved in a solvent.
The method according to claim 1,

The electrolyte layer is a secondary battery having a thickness of 1 to 200 ㎛.
Forming a current collector;

Forming a first electrode on the current collector;

Forming an intermediate layer on the first electrode, the intermediate layer including a plurality of supports spaced apart from each other and a salt structure provided in a spaced space between the plurality of supports;

Forming a second electrode on the intermediate layer; And

A secondary battery manufacturing method comprising the step of dissolving the salt structure in a solvent to form a liquid electrolyte.
The method according to claim 5,

The salt structure is formed into a continuous network structure,

The plurality of supports are secondary battery manufacturing method to form a shape each isolated by the salt structure.
The method according to claim 5,

The current collector, the first electrode, the intermediate layer and the second electrode are all secondary battery manufacturing method is formed by a printing process.
The method according to claim 5,

In the forming of the intermediate layer, the secondary battery manufacturing method of forming any one of the plurality of the support and the salt structure selected first and then the other.
The method according to claim 5,

Forming the intermediate layer, secondary battery manufacturing method is performed as a procedure.
The method according to claim 5,

In the forming of the intermediate layer, the secondary battery manufacturing method of forming the intermediate layer by a 3D printing method using a plurality of inks including the constituents of the plurality of supports and the constituents of the salt structure.
The method according to claim 5,

The plurality of supports are secondary battery manufacturing method to form a solid electrolyte.
The method according to claim 5,

The intermediate layer is a secondary battery manufacturing method to form a height of 1 to 200 ㎛.