All-solid-state battery and method for manufacturing the same

Abstract

The present invention relates to a method for manufacturing an all-solid-state battery, which has a simple manufacturing process, is capable of stacking more electrodes in a desired size, and is easy to align the electrodes, and relates to an all-solid-state battery manufactured thereby.

Description

[Technical Field]

[0001] This application claims priority rights under Korean Patent Application No. 10-2022-0059563 dated May 16, 2022, and Korean Patent Application No. 10-2023-0062454 dated May 15, 2023, and all content disclosed in the documents of the said Korean patent applications is incorporated herein by reference.

[0002] The present invention relates to an all-solid-state battery and a method for manufacturing the same. [Background technology]

[0003] A secondary battery is a device that stores external electrical energy in the form of chemical energy and generates electricity when needed. It is also called a rechargeable battery because it can be recharged multiple times. Commonly used secondary batteries include lead-acid batteries, nickel-cadmium batteries (NiCd), nickel-metal hydride batteries (NiMH), and lithium-ion batteries. Secondary batteries offer both economic and environmental advantages compared to primary batteries, which are discarded after a single use.

[0004] Meanwhile, as wireless communication technology continues to develop, there is a growing demand for lighter, thinner, and smaller portable devices and automotive accessories, and for rechargeable batteries used as energy sources for these devices. In particular, with the practical application of hybrid and electric vehicles, and from the perspective of preventing environmental pollution, research is emerging to reduce manufacturing costs and weight, and extend the lifespan of these next-generation automotive batteries by using rechargeable batteries. Among the various types of rechargeable batteries, lithium-ion batteries, which are lightweight, exhibit high energy density and operating potential, and have a long cycle life, have recently been attracting attention.

[0005] Generally, lithium secondary batteries are manufactured by mounting an electrode stack, consisting of a negative electrode, a positive electrode, and a separator membrane, inside a cylindrical or rectangular metal can or an aluminum laminate sheet pouch-type case, and then injecting an electrolyte into the electrode stack.

[0006] Conventionally, the electrolytes used for lithium secondary batteries have mainly been liquid electrolytes in which lithium salts are dissolved in non-aqueous organic solvents. However, with such liquid electrolytes, there is a high possibility that the electrode material will degenerate and the organic solvent will volatilize, as well as concerns about leakage due to combustion or explosion caused by rising ambient and battery temperatures, making it difficult to realize various forms of lithium secondary batteries with high safety.

[0007] On the other hand, all-solid-state batteries, which use solid electrolytes, have the advantage of being able to fabricate electrode stacks in a safe and simple form because they eliminate organic solvents.

[0008] Solid-state batteries are classified into oxide-based, polymer-based, and sulfide-based types based on the raw materials of their solid electrolyte. Sulfide-based solid-state batteries are attracting attention because they have superior lithium-ion conductivity compared to other types of batteries. However, despite their superior characteristics, they have the disadvantage of higher ionic conductivity and electrical resistance between the positive and negative electrodes compared to liquid batteries, resulting in shorter lifespan and lower output compared to conventional batteries using liquid electrolytes.

[0009] To improve the lifespan and output of a unit cell, methods such as changing the positive and negative electrodes of the solid electrolyte, the type of solid electrolyte, or the assembly method can be considered.

[0010] In the case of sulfide-based all-solid-state batteries, if the electrodes and solid electrolyte are manufactured by pressurizing using a roll-to-roll method, as in conventional lithium-ion batteries (LIBs), a problem arises where the inside of the battery becomes porous, making interfacial contact difficult. Therefore, a three-dimensional pressurization method using hydrostatic pressure is employed. However, when pressurizing using such a hydrostatic method, the size of the cells that can be pressurized is limited by the chamber size of the isotropic pressurization equipment, such as CIP and WIP, which may limit the scale-up of all-solid-state battery production.

[0011] For these reasons, when manufacturing lithium metal all-solid-state batteries in a stacked structure, there is no method to pressurize the negative / positive electrodes and the electrolyte layer simultaneously, which can lead to complex process steps and difficulties in aligning the stacked electrodes.

[0012] Therefore, research into manufacturing methods that can solve the aforementioned problems is necessary. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Korean Published Patent No. 2021-0007149 [Overview of the Initiative] [Problems that the invention aims to solve]

[0014] The present invention aims to provide a method for manufacturing an all-solid-state battery that allows for stacking more electrodes in a desired size, facilitates alignment between electrodes, and has a simple manufacturing method. [Means for solving the problem]

[0015] In order to achieve the aforementioned objective, The present invention includes (1) a plurality of first electrodes spaced apart from each other in the width direction on a current collector, wherein the first electrode active material is applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single The first electrode bending substrate is a double-sided electrode, which is an electrode with electrode active material of the same polarity applied to both sides of the current collector, excluding the surface electrode; (2) The current collector includes a plurality of second electrodes spaced apart from each other in the width direction, and the second electrode active material is applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single The step involves preparing a second electrode bending substrate, which is a double-sided electrode in which electrode active material of the same polarity is coated on both sides of the current collector, excluding the surface electrode; (3) On one side end of the first electrode bending substrate single After overlapping the double-sided electrodes on one side end of the second electrode bending substrate on the surface electrode, alternately fold the first electrode bending substrate and the second electrode bending substrate so that the first electrode and the second electrode are alternately laminated; and (4) Pressurizing the outermost side of the electrode laminate at a high temperature; including Provided is a method for manufacturing an all-solid-state battery in which a solid electrolyte layer covering the entire electrode is formed on at least one of the first electrode bending substrate and the second electrode bending substrate so that the first electrode and the second electrode do not contact each other.

[0016] In one embodiment of the present invention, the first electrode bending substrate single The separation distance between the surface electrode and its adjacent double-sided electrodes is the longest, and the separation distance between its adjacent double-sided electrodes gradually becomes shorter, but the adjacent separation distances may be the same. The second electrode bending substrate single The separation distance between the surface electrode and its adjacent double-sided electrodes is the shortest, and the separation distance between its adjacent double-sided electrodes gradually becomes longer, but the adjacent separation distances may be the same.

[0017] In one embodiment of the present invention, it may further include the step of joining lead tabs to the outermost sides on both sides.

[0018] In one embodiment of the present invention, in the step (4), it may be pressurized at a pressure of 300 to 500 MPa for 10 to 60 minutes at 60 to 100 °C.

[0019] In one embodiment of the present invention, when the first electrode is a negative electrode, the second electrode may be a positive electrode, and when the first electrode is a positive electrode, the second electrode may be a negative electrode.

[0020] In one embodiment of the present invention, the electrodes at the uppermost and lowermost parts of the electrode laminate may be surface electrodes on which the electrode active material is coated only on one side of the current collector. single

[0021] ​One embodiment of the present invention, the uppermost and lowermost single The surface electrodes may have different polarities.

[0022] One embodiment of the present invention, the above single Electrodes other than surface electrodes may be double-sided electrodes in which electrode active materials of the same polarity are coated on both sides of the current collector.

[0023] In one embodiment of the present invention, the solid electrolyte layer may contain a sulfide-based solid electrolyte.

[0024] In one embodiment of the present invention, the solid electrolyte layer may further contain a binder and a solvent.

[0025] In one embodiment of the present invention, when the first electrode or the second electrode is a negative electrode, the negative electrode active material may be lithium metal or a lithium alloy.

[0026] Furthermore, the present invention includes an electrode laminate in which a first electrode bending substrate containing a plurality of first electrodes spaced apart from each other in the width direction on a current collector and a second electrode bending substrate containing a plurality of second electrodes spaced apart from each other in the width direction on a current collector are alternately folded, and the first electrodes and the second electrodes are alternately stacked. The first electrode bending substrate has the first electrode active material applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single The electrodes, excluding the surface electrodes, are double-sided electrodes in which electrode active material of the same polarity is coated on both sides of the current collector. The second electrode bending substrate has the second electrode active material applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single The electrodes, excluding the surface electrodes, are double-sided electrodes in which electrode active material of the same polarity is coated on both sides of the current collector. The present invention provides an all-solid-state battery in which a solid electrolyte layer covering the entire electrode is formed on at least one of the first electrode bending substrate and the second electrode bending substrate, so that the first electrode and the second electrode do not come into contact with each other. [Effects of the Invention]

[0027] The present invention provides a method for manufacturing an all-solid-state battery, which involves directly coating the electrolyte layer onto the upper layer of the electrode substrate. This eliminates the need for a bonding step between the electrode and the solid electrolyte layer, as well as an electrode punching step for electrode stacking. This results in a simpler manufacturing process, allows for stacking more electrodes of a desired size, and facilitates alignment between electrodes. [Brief explanation of the drawing]

[0028] [Figure 1] This figure shows the preparation process of the first electrode substrate according to one embodiment of the present invention. [Figure 2] This figure shows the preparation process for the second electrode substrate according to one embodiment of the present invention. [Figure 3] This figure shows a method for manufacturing an electrode assembly according to one embodiment of the present invention. [Figure 4] This figure shows an all-solid-state battery according to one embodiment of the present invention. [Modes for carrying out the invention]

[0029] The present invention will be described in detail below, based on the attached drawings, so that it can be easily implemented by a person with ordinary skill in the art to which the invention pertains. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein.

[0030] To clearly explain the present invention, irrelevant parts have been omitted, and the same or similar reference numerals have been used throughout the specification for identical or similar components.

[0031] Furthermore, the terms and words used in this specification and the claims shall not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, based on the principle that inventors may appropriately define the concepts of terms in order to best describe their inventions.

[0032] The embodiments will be described in detail below with reference to the attached drawings. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein.

[0033] Among conventional all-solid-state batteries, those using sulfide-based solid electrolytes had a problem: when manufactured using a roll-to-roll pressurization method, many pores (porous) formed inside the electrodes, making interfacial contact difficult. To solve this, a three-dimensional pressurization method was implemented through hydrostatic pressure, but the size of the battery that could be pressurized was limited by the size of the chamber equipped with isotropic pressurization equipment.

[0034] Furthermore, when lithium metal is used as the negative electrode, the low hardness of lithium metal means that when the negative electrode, positive electrode, and all-solid electrolyte layer sheet are pressurized together, the applied pressure may differ. For this reason, when lithium metal is used as the negative electrode, it was not possible to pressurize the negative electrode, positive electrode, and all-solid electrolyte layer sheet at the same time. In other words, the manufacturing of an all-solid-state battery required repeating a complex process of laminating the negative electrode onto the all-solid electrolyte layer sheet and then pressurizing it, then laminating the all-solid electrolyte layer sheet and pressing it, and then laminating the positive electrode and pressing it. Repeating this process made it difficult to align the laminated electrodes.

[0035] Therefore, the inventors of this invention, We discovered that the aforementioned problems can be solved when manufacturing an all-solid-state battery by alternately folding two bending substrates, each containing multiple electrodes spaced apart in the width direction on a current collector, so that positive and negative electrodes are alternately stacked, and thus completed the present invention.

[0036] This invention relates to a method for manufacturing an all-solid-state battery, and more specifically, (1) The current collector includes a plurality of first electrodes spaced apart from each other in the width direction, and the first electrode active material is applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single (1) A step to prepare a first electrode bending substrate which is a double-sided electrode in which electrode active material of the same polarity is applied to both sides of the current collector, excluding the surface electrode; (2) A current collector which includes a plurality of second electrodes spaced apart from each other in the width direction, wherein the second electrode active material is applied to only one side of the current collector at one end of the current collector single A surface electrode is formed, single (3) The electrode excluding the surface electrode is a double-sided electrode in which electrode active material of the same polarity is coated on both sides of the current collector, and a second electrode bending substrate is prepared; (3) one end of the first electrode bending substrate single The process may include (4) a step of stacking the double-sided electrodes of one end of the second electrode bending substrate on the surface electrode, then alternately folding the first electrode bending substrate and the second electrode bending substrate to manufacture an electrode laminate so that the first electrode and the second electrode are alternately stacked; and (4) a step of pressurizing the outermost part of the electrode laminate at a high temperature.

[0037] The present invention relates to an all-solid-state battery manufactured by the above manufacturing method, The electrode laminate includes a first electrode bending substrate containing a plurality of first electrodes spaced apart from each other in the width direction on a current collector, and a second electrode bending substrate containing a plurality of second electrodes spaced apart from each other in the width direction on a current collector, which are alternately folded, and the first electrodes and the second electrodes are alternately stacked. The first electrode bending substrate has the first electrode active material applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single The electrodes, excluding the surface electrodes, are double-sided electrodes in which electrode active material of the same polarity is coated on both sides of the current collector. The second electrode bending substrate has the second electrode active material applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single The electrodes, excluding the surface electrodes, are double-sided electrodes in which electrode active material of the same polarity is coated on both sides of the current collector. This invention relates to an all-solid-state battery in which a solid electrolyte layer covering the entire electrode is formed on at least one of the first electrode bending substrate and the second electrode bending substrate, so that the first electrode and the second electrode do not come into contact with each other.

[0038] Step (1) above is the step of preparing the first electrode bending substrate. The first electrode bending substrate will be described in detail below with reference to Figure 1. In Figure 1, the negative electrode is merely described as a specific example, and if the first electrode is a negative electrode, the second electrode described later may be a positive electrode, and if the first electrode is a positive electrode, the second electrode described later may be a negative electrode. The first electrode bending substrate includes a plurality of first electrodes spaced apart from each other in the width direction on the current collector. The plurality of first electrodes are coated with the first electrode active material on only one surface of the current collector. single The electrode may be a surface electrode, or a double-sided electrode in which the same polarity electrode active material is applied to both sides of the current collector. In the present invention, at one end of the current collector, the first electrode active material is applied to only one side of the current collector. single A surface electrode is formed, single The electrodes other than the surface electrodes may be double-sided electrodes in which electrode active material of the same polarity is coated on both sides of the current collector. Through this, a single positive or negative electrode may be provided on the outermost layer of the electrode laminate manufactured by stacking electrode bending substrates on top of each other in step (3) described below.

[0039] The first electrode bending substrate is single The distance between a surface electrode and its adjacent double-sided electrode is the longest, and the distance between adjacent double-sided electrodes may gradually decrease. As shown in the upper left of Figure 1, the rightmost... singleThe distance d between the surface negative electrode and the double-sided negative electrode is the longest, the distance c between the double-sided negative electrodes to the left of that is also long, and thus the distance a between the leftmost double-sided negative electrodes is the shortest. By creating this difference in separation distance, it becomes possible to correct for differences caused by changes in the thickness and curvature of the electrode stack when the first electrode bending substrate and the second electrode bending substrate are alternately folded in step (3) described later, thereby achieving accurate stacking. However, the separation distances between adjacent electrodes may be the same, so distances d and c may be the same, distances c and b may be the same, and distances b and a may be the same. In the end, the relationship between distances a, b, c, and d can satisfy the relationship (a ≤ b ≤ c ≤ d). In this case, the mathematical distances a, b, c, and d may all be the same, but at least the value of d may be greater than the value of a.

[0040] Furthermore, the first electrode bending substrate can form a solid electrolyte layer that covers the entire electrode. The solid electrolyte layer is a double-sided electrode made of a negative electrode active material, as disclosed in Figure 1 or single The entire surface electrode can be covered. In this way, because the solid electrolyte layer covers the entire electrode, during the bending process described later, the solid electrolyte layer is positioned between the first electrode and the second electrode, thereby preventing the first electrode and the second electrode from coming into contact with each other.

[0041] The solid electrolyte in the solid electrolyte layer may preferably contain a sulfide-based solid electrolyte.

[0042] The sulfide-based solid electrolyte contains sulfur (S) and has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and may include Li-PS glass or Li-PS glass ceramic. Non-restrictive examples of such sulfide-based solid electrolytes include Li2S-P2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2S5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, Li2S-GeS2-ZnS, and may include one or more of these. However, it is not particularly limited to these.

[0043] The method for forming the solid electrolyte layer is not particularly limited as long as it is used in the industry. For example, it may involve mixing solid electrolyte powder with a binder and a solvent to produce a slurry containing a sulfide-based solid electrolyte, then applying the slurry to a current collector on which electrodes are formed, and finally drying and rolling it. The binder and solvent can be used without particular limitation as long as they are materials that do not react with sulfur in the solid electrolyte.

[0044] The above step (2) is the step of preparing the second electrode bending substrate. The second electrode bending substrate will be described in detail below with reference to Figure 2. In Figure 2, the positive electrode is described as a specific example, but when the second electrode is the positive electrode, the above-mentioned first electrode may be the negative electrode, and when the second electrode is the negative electrode, the above-mentioned first electrode may be the positive electrode. The second electrode bending substrate includes a plurality of second electrodes spaced apart from each other in the width direction on the current collector. The plurality of second electrodes are coated with the second electrode active material on only one surface of the current collector. single The electrode may be a surface electrode, or a double-sided electrode in which the same polarity electrode active material is applied to both sides of the current collector. In the present invention, at one end of the current collector, the second electrode active material is applied to only one side of the current collector. single A surface electrode is formed, singleThe electrodes other than the surface electrodes may be double-sided electrodes in which electrode active material of the same polarity is coated on both sides of the current collector. Through this, a single positive or negative electrode may be provided on the outermost layer of the electrode laminate manufactured by stacking electrode bending substrates on top of each other in step (3) described below.

[0045] In other words, the step of preparing the second electrode bending substrate can be done in the same way as the step of preparing the first electrode bending substrate, with only the type of electrode being different.

[0046] The first electrode bending substrate is single The distance between a surface electrode and its adjacent double-sided electrode is shortest, and the distance between adjacent double-sided electrodes gradually increases. As shown in the upper left of Figure 2, the length d, which is the distance between the rightmost double-sided positive electrode and double-sided negative electrode, is the longest, and the length c, which is the distance between the double-sided positive electrodes to its left, is also long. single The length 'a', which is the distance between the surface positive electrode and the double-sided positive electrode, may be the shortest. By creating this difference in separation distance, the difference caused by changes in the thickness and curvature of the electrode laminate can be corrected when the first electrode bending substrate and the second electrode bending substrate are alternately folded in step (3) described later, thereby enabling accurate lamination. However, even in the second electrode bending substrate, the separation distance between adjacent electrodes may be the same, so that distance D and distance C may be the same, distance C and distance B may be the same, and distance B and distance A may be the same. In the end, the relationship between distances A, B, C, and D can satisfy the relationship (A ≤ B ≤ C ≤ D). In this case, the mathematical distances A, B, C, and D may all be the same, but at least the value of D may be greater than the value of A. Furthermore, the separation distance between electrodes in the second electrode bending substrate can be adjusted to match the separation distance between electrodes in the first electrode bending substrate.

[0047] Furthermore, the second electrode bending substrate can also form a solid electrolyte layer that covers the entire electrode. The solid electrolyte layer is a double-sided electrode made of a positive electrode active material, as disclosed in Figure 2 or single It can cover the entire surface electrode.

[0048] Thus, the role, material, and formation method of the solid electrolyte layer in the second electrode bending substrate are the same as those described above for the first electrode bending substrate.

[0049] In the method for manufacturing an all-solid-state battery of the present invention, a solid electrolyte layer covering the entire electrode can be formed on at least one of the first electrode bending substrate and the second electrode bending substrate. That is, a solid electrolyte layer may be formed on both the first electrode bending substrate and the second electrode bending substrate, but even if the solid electrolyte layer is formed on at least one of them, the first electrode and the second electrode can be prevented from coming into contact with each other.

[0050] Next, in step (3), the electrode laminate is manufactured. Specifically, one end of the first electrode bending substrate single After placing the double-sided electrodes of one end of the second electrode bending substrate onto the surface electrode, the first electrode bending substrate and the second electrode bending substrate are alternately folded to manufacture an electrode laminate in which the first electrode and the second electrode are alternately stacked.

[0051] Specifically, the manufacturing method of the electrode laminate in step (3) above will be explained with reference to Figure 3. Figure 3 assumes that a solid electrolyte layer is formed on both the first electrode bending substrate and the second electrode bending substrate, but as mentioned above, it is also acceptable for a solid electrolyte layer to be formed on only one of the two. First, to explain the first step in Figure 3, the first bending substrate with the negative electrode formed on the current collector is prepared in the lateral direction, and the first bending substrate with the positive electrode formed on the current collector is prepared in the vertical direction. Subsequently, in the second step, the second bending substrate singleThe double-sided negative electrodes of the first bending substrate are positioned above the positive electrode. In the third step, the second bending substrate on the bottom is folded so that the second bending substrate is positioned above the first bending substrate. Subsequently, in the fourth step, the first bending substrate is folded horizontally so that it is positioned above the second bending substrate. Repeating this process from the fifth to the ninth step results in the bottom layer being as shown in Figure 4. single The positive electrode is located at the top. single A surface negative electrode is formed, and double-sided negative electrodes and double-sided positive electrodes are alternately stacked between them. A solid electrolyte layer is formed between the positive and negative electrodes, making it possible to manufacture an electrode laminate with a structure that prevents contact between the positive and negative electrodes.

[0052] As shown in Figure 4, the uppermost and lowermost electrodes of the electrode stack manufactured by the manufacturing method in step (3) above have electrode active material applied to only one surface of the current collector. single It can also be a surface electrode.

[0053] At this time, the uppermost and lowermost single The surface electrodes may have different polarities from each other. That is, the bottom single When the surface electrode is the positive electrode, the topmost single The surface electrode becomes the negative electrode, and at the bottom single When the surface electrode is the negative electrode, the top single The surface electrode may also be the positive electrode.

[0054] Also, the above single Electrodes other than surface electrodes may be double-sided electrodes in which electrode active materials of the same polarity are coated on both sides of the current collector.

[0055] The process may further include a step of joining lead tabs to the outermost parts on both sides of the electrode stack. Specifically, as shown in the 10 steps of Figure 3, electrode lead tabs are formed on the uppermost and lowermost parts of the electrode stack. For example, a negative electrode lead tab can be formed on the current collector of the uppermost part, and a positive electrode lead tab can be formed on the current collector of the lowermost part of the electrode stack. An electrode stack manufactured in this way will have a structure as shown in Figure 4.

[0056] Then, in step (4), the outermost layer of the electrode stack is pressurized at a high temperature. At this time, high-temperature pressurization is carried out using CIP, WIP, or upper and lower plates, which allows the interlayer interface of the solid electrolyte to be tightly bonded and ensure ionic conductivity. The pressurization conditions are not particularly limited, and pressurization conditions used in the manufacture of all-solid-state batteries can be used. Preferably, pressurization is carried out at 60 to 100°C and a pressure of 300 to 500 MPa for 10 to 60 minutes, and the thickness of the solid electrolyte layer after pressurization can be manufactured to 20 to 100 μm. For example, pressurization is carried out at 80°C and a pressure of 500 MPa for 30 minutes, and the thickness of the solid electrolyte layer after pressurization can be manufactured to 50 μm.

[0057] According to the present invention, an all-solid-state battery manufactured by the above-described manufacturing method is provided.

[0058] Specifically, the electrode laminate includes a first electrode bending substrate containing a plurality of first electrodes spaced apart from each other in the width direction on a current collector, and a second electrode bending substrate containing a plurality of second electrodes spaced apart from each other in the width direction on a current collector, which are alternately folded, and the first electrodes and the second electrodes are alternately stacked. The first electrode bending substrate has the first electrode active material applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single The electrodes, excluding the surface electrodes, are double-sided electrodes in which electrode active material of the same polarity is coated on both sides of the current collector. The second electrode bending substrate has the second electrode active material applied to only one surface of the current collector at one end of the current collector. single A surface electrode is formed, single The electrodes, excluding the surface electrodes, are double-sided electrodes in which electrode active material of the same polarity is coated on both sides of the current collector. The present invention provides an all-solid-state battery in which a solid electrolyte layer covering the entire electrode is formed on at least one of the first electrode bending substrate and the second electrode bending substrate, so that the first electrode and the second electrode do not come into contact with each other.

[0059] The descriptions of each component of the all-solid-state battery are the same as those described in the manufacturing method of the all-solid-state battery described above.

[0060] An all-solid-state battery according to one embodiment of the present invention is a lithium secondary battery, and there are no restrictions on whether it is a positive or negative electrode; it may be a lithium-air battery, a lithium oxide battery, a lithium-sulfur battery, or a lithium metal battery.

[0061] In one embodiment of the present invention, when the electrode of the first electrode bending substrate or the second electrode bending substrate is the positive electrode, the positive electrode current collector included in the bending substrate is for supporting the positive electrode active material and is not particularly limited as long as it has excellent conductivity and is electrochemically stable in the voltage range of the lithium secondary battery. For example, the positive electrode current collector may be any one metal selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof, and the stainless steel may be surface-treated with carbon, nickel, titanium, or silver, and as the alloy, an aluminum-cadmium alloy may preferably be used, but other materials such as calcined carbon, a non-conductive polymer surface-treated with a conductive material, or a conductive polymer may also be used.

[0062] The positive electrode current collector can have fine irregularities formed on its surface to strengthen the bonding force with the positive electrode active material, and may be used in various forms such as film, sheet, foil, mesh, net, porous material, foam, or nonwoven fabric.

[0063] The positive electrode active material may selectively include a conductive material and a binder in addition to the positive electrode active material.

[0064] The positive electrode active material may vary depending on the type of all-solid-state battery. For example, the positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; chemical formula Li 1+x Mn 2-xLithium manganese oxides such as O4(0≦x≦0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; chemical formula LiNi 1-x M x Ni-site type lithium nickel oxides represented by O2 (M = Co, Mn, Al, Cu, Fe, Mg, B or Ga; 0.01≦x≦0.3); chemical formula LiMn 2-x M x Lithium manganese composite oxides represented by O2 (M = Co, Ni, Fe, Cr, Zn or Ta; 0.01≦x≦0.1) or Li2Mn3MO8 (M = Fe, Co, Ni, Cu or Zn); LiNi x Mn 2-x Spinel-structured lithium manganese composite oxides represented by O4; LiCoPO4; LiFePO4; sulfur element (Elemental sulfur, S8); Li2S n (n = 1), organic sulfur compounds or carbon-sulfur polymers ((C2S x ) n :x = 2.5~50, n = 2), etc. Sulfur series compounds such as these may be included, but are not limited thereto.

[0065] The conductive material serves as a substance that electrically connects the electrolyte and the positive electrode active material and provides a path for electrons to move from the current collector to the positive electrode active material. As long as it does not undergo a chemical change in the lithium secondary battery and has porosity and conductivity, it can be used without limitation.

[0066] For example, as the conductive material, porous carbon-based substances can be used. Such carbon-based substances include carbon black, graphite, graphene, activated carbon, carbon fiber, etc., metallic fibers such as metal meshes; metallic powders such as copper, silver, nickel, aluminum, etc.; or organic conductive materials such as polyphenylene derivatives. The conductive materials can be used alone or in combination.

[0067] Currently, commercially available conductive materials include the acetylene black series (products from Chevron Chemical Company or Gulf Oil Company, etc.), the Ketjen Black EC series (products from Armak Company), Vulcan XC-72 (products from Cabot Company), and Super P (products from MMM). Examples include acetylene black, carbon black, and graphite.

[0068] Furthermore, the positive electrode may further include a binder, the binder which enhances the bonding force between the components constituting the positive electrode and between them and the current collector, and any binder known in the industry can be used.

[0069] For example, the binder may be one, a mixture of two or more, or a copolymer selected from the group consisting of: fluororesin binders containing polyvinylidene fluoride (PVdF) or polytetrafluoroethylene (PTFE); rubber binders containing styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber, or styrene-isoprene rubber; cellulose binders containing carboxyl methyl cellulose (CMC), starch, hydroxypropyl cellulose, or regenerated cellulose; polyalcohol binders; polyolefin binders containing polyethylene or polypropylene; polyimide binders; polyester binders; and silane binders.

[0070] In one embodiment of the present invention, when the electrode of the first electrode bending substrate or the second electrode bending substrate is a negative electrode, the negative electrode included in the bending substrate may, as necessary, contain a conductive material and a binder, similar to the positive electrode. In this case, the negative electrode current collector, conductive material, and binder can be those normally used for negative electrodes, as described above.

[0071] The negative electrode active material in one embodiment of the present invention may be lithium metal, a lithium alloy, or in a negative electrode-free form.

[0072] The aforementioned negative electrode-free configuration may include only a negative electrode current collector, or a structure in which a carbon layer containing a binder is coated on the negative electrode current collector.

[0073] A method for manufacturing an all-solid-state battery according to one embodiment of the present invention has the advantage of a simple manufacturing process because it involves repeatedly folding and stacking electrodes so that they do not come into contact with each other. Furthermore, while conventional methods required pressurization at each stage of stacking the positive electrode, negative electrode, and all-solid-state electrolyte layer sheet, this method allows for pressurization of the manufactured all-solid-state battery at once, which also simplifies the manufacturing process. In addition, it allows for stacking more electrode layers in various sizes, and by positioning the positive and negative electrodes at specified locations on the all-solid-state electrolyte layer sheet, alignment of the positive and negative electrodes is facilitated.

[0074] In the art related to this embodiment, a person of ordinary skill will understand that the invention can be embodied in modified forms that do not deviate from the essential properties of the aforementioned substrate. Accordingly, the disclosed method should be considered in an explanatory rather than restrictive view. The scope of the invention is shown in the claims, not in the foregoing description, and all differences within an equivalent scope should be construed as being included in the invention.

Claims

1. (1) A step of preparing a first electrode bending substrate, which includes a plurality of first electrodes spaced apart from each other in the width direction on a current collector, wherein a single-sided electrode is formed at one end of the current collector, with the first electrode active material applied to only one surface of the current collector, and the first electrodes excluding the single-sided electrode are double-sided electrodes with the same polarity electrode active material applied to both surfaces of the current collector; (2) A step of preparing a second electrode bending substrate, which includes a plurality of second electrodes spaced apart from each other in the width direction on a current collector, wherein a single-sided electrode is formed at one end of the current collector, with the second electrode active material applied to only one surface of the current collector, and the second electrodes excluding the single-sided electrode are double-sided electrodes with the same polarity electrode active material applied to both surfaces of the current collector; (3) The step of manufacturing an electrode laminate by stacking the double-sided electrode on one end of the second electrode bending substrate on the single-sided electrode on one end of the first electrode bending substrate, and then alternately folding the first electrode bending substrate and the second electrode bending substrate so that the first electrode and the second electrode are alternately stacked; and (4) The step of pressurizing the outermost part of the electrode stack at a high temperature of 60°C to 100°C; A solid electrolyte layer is formed on at least one of the first electrode bending substrate and the second electrode bending substrate, covering the entire electrode and the entire current collector between the electrodes, so that the first electrode and the second electrode do not come into contact with each other. The first electrode bending substrate has the longest separation distance between a single electrode and its adjacent double-sided electrode, and the separation distance between adjacent double-sided electrodes gradually decreases. A method for manufacturing an all-solid-state battery, characterized in that the second electrode bending substrate has the shortest separation distance between a single electrode and its adjacent double-sided electrode, and the separation distance between adjacent double-sided electrodes gradually increases.

2. The method for manufacturing an all-solid-state battery according to claim 1, further comprising the step of joining lead tabs to the outermost surfaces on both sides of the electrode stack.

3. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that step (4) involves pressurizing at a pressure of 300 MPa to 500 MPa for 10 to 60 minutes.

4. A method for manufacturing an all-solid-state battery according to claim 1, characterized in that when the first electrode is a negative electrode, the second electrode is a positive electrode, and when the first electrode is a positive electrode, the second electrode is a negative electrode.

5. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that the uppermost and lowermost electrodes of the electrode stack are single-sided electrodes in which an electrode active material is coated on only one surface of the current collector.

6. The method for manufacturing an all-solid-state battery according to claim 5, characterized in that the uppermost and lowermost single-sided electrodes have different polarities.

7. The method for manufacturing an all-solid-state battery according to claim 6, characterized in that the electrodes other than the single-sided electrode are double-sided electrodes in which an electrode active material of the same polarity is coated on both sides of the current collector.

8. A method for manufacturing an all-solid-state battery according to any one of claims 1 to 7, characterized in that the solid electrolyte layer contains a sulfide-based solid electrolyte.

9. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that the solid electrolyte layer further comprises a binder and a solvent.

10. The method for manufacturing an all-solid-state battery according to claim 1, characterized in that, when the first electrode or the second electrode is a negative electrode, the negative electrode active material is lithium metal or a lithium alloy.

11. The electrode laminate includes a first electrode bending substrate containing a plurality of first electrodes spaced apart from each other in the width direction on a current collector, and a second electrode bending substrate containing a plurality of second electrodes spaced apart from each other in the width direction on a current collector, which are alternately folded, and the first electrodes and the second electrodes are alternately stacked. The first electrode bending substrate has a single-sided electrode formed at one end of the current collector, with the first electrode active material applied to only one surface of the current collector, and the electrodes other than the single-sided electrode are double-sided electrodes with electrode active material of the same polarity applied to both surfaces of the current collector. The second electrode bending substrate has a single-sided electrode formed at one end of the current collector, with the second electrode active material applied to only one surface of the current collector, and the electrodes other than the single-sided electrode are double-sided electrodes with the same polarity electrode active material applied to both surfaces of the current collector. A solid electrolyte layer is formed on at least one of the first electrode bending substrate and the second electrode bending substrate, covering the entire electrode and the entire current collector between the electrodes, so that the first electrode and the second electrode do not come into contact with each other. The first electrode bending substrate has the longest separation distance between a single electrode and its adjacent double-sided electrode, and the separation distance between adjacent double-sided electrodes gradually decreases. The second electrode bending substrate is characterized in that the separation distance between a single electrode and its adjacent double-sided electrode is shortest, and the separation distance between adjacent double-sided electrodes gradually increases, thus providing an all-solid-state battery.

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