Method of making all-solid-state battery including silicon-based anode active material, method of operating same, and method of testing same

Abstract

The invention relates to a preparation method, an operation method and a testing method of an all-solid-state battery comprising a silicon-based anode active material. A method of preparing an all-solid-state battery includes preparing a battery including a cathode layer, an anode layer, and a solid electrolyte layer disposed between the cathode layer and the anode layer; and activating the battery by charging and discharging while applying a pressure of about 4.5 MPa or more to the battery.

Description

Technical Field

[0001] The present disclosure relates to a method for preparing a all-solid-state battery including a silicon-based anode active material, and a method for operating and testing the all-solid-state battery prepared by the preparation method. Background Art

[0002] Compared with existing carbon-based anode active materials such as graphite, silicon-based anode active materials have the advantage of high theoretical capacity. However, the silicon-based anode active material undergoes a large volume expansion during charging and discharging, which causes cracking of the solid electrolyte and the electrode.

[0003] For the purpose of solving this problem, a method of inserting the battery into a fixed-pressure fixture and applying a high pressure from the outside during charging and discharging of the battery has been proposed. However, during charging and discharging, the battery undergoes repeated expansion and contraction, while the pressure fixture is fixed, so there is a problem that the pressure applied to the battery varies according to the SoC (state of charge). The uneven pressure change can cause cracking of the solid electrolyte and the electrode.

[0004] A variable-pressure fixture capable of controlling the pressure applied from the outside can be applied, but the manufacturing cost of the battery increases, and the volume of the battery also increases, which can lead to a loss of energy density. Summary of the Invention

[0005] An object of the present disclosure is to provide a method for preparing an all-solid-state battery with a low operating pressure.

[0006] The object of the present disclosure is not limited to the foregoing. Through the following description, the object of the present disclosure will be clearly understood and achieved by the manner described in the present invention.

[0007] An exemplary embodiment of the present disclosure provides a method for preparing an all-solid-state battery, including: preparing a battery including a cathode layer, an anode layer, and a solid electrolyte layer disposed between the cathode layer and the anode layer, and activating the battery by charging and discharging under predetermined conditions while applying a pressure of 4.5 MPa or higher to the battery.

[0008] The anode layer may include a silicon-based anode active material.

[0009] The anode layer may include 60 wt% to 80 wt% of a silicon-based anode active material, 10 wt% to 35 wt% of a solid electrolyte, and 1 wt% to 10 wt% of a binder.

[0010] The battery may have an N / P ratio of 2.0 or less but greater than 1.1.

[0011] Activating a battery may include charging and discharging while applying pressure to the battery at a voltage of 2.0 V to 4.25 V and a temperature of 30 °C to 50 °C.

[0012] Activating a battery may include subjecting the battery to 3 to 10 charge and discharge cycles.

[0013] Activating a battery may include applying a pressure of 10 MPa or less to the battery.

[0014] Another exemplary embodiment of the present disclosure provides a method of operating a all-solid-state battery, including: preparing a all-solid-state battery including a cathode layer, an anode layer, and a solid electrolyte layer interposed between the cathode layer and the anode layer, activating the all-solid-state battery by charging and discharging while applying a pressure of 4.5 MPa or more to the all-solid-state battery, and operating the activated all-solid-state battery while applying a pressure of 4.5 MPa or less to the activated all-solid-state battery.

[0015] Operating the activated all-solid-state battery may include charging and discharging while applying a pressure of 2.5 MPa to 4.5 MPa to the activated all-solid-state battery.

[0016] Another exemplary embodiment of the present disclosure provides a method of testing a all-solid-state battery, including: preparing a all-solid-state battery including a cathode layer, an anode layer, and a solid electrolyte layer interposed between the cathode layer and the anode layer, activating the all-solid-state battery by charging and discharging while applying a pressure of 4.5 MPa or more to the all-solid-state battery, operating the activated all-solid-state battery while applying a pressure of 4.5 MPa or less to the activated all-solid-state battery, and determining whether the all-solid-state battery is defective by measuring the DC-IR (direct current internal resistance) value of the operated all-solid-state battery.

[0017] When determining whether the all-solid-state battery is defective, if the DC-IR value in the first cycle discharge after operating the activated all-solid-state battery is 50 Ω or more, it may be determined that the activated all-solid-state battery is defective. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other features of the present disclosure will now be described in detail with reference to certain exemplary embodiments of the present disclosure shown in the drawings, which are illustrated below by way of example only, and thus do not limit the present disclosure, and wherein:

[0019] Figure 1 A all-solid-state battery according to the present disclosure is shown;

[0020] Figure 2 Evaluation results of the lifetimes of all-solid-state batteries according to Example 1, Example 2, and Comparative Example 1 are shown;

[0021] Figure 3 Shows the evaluation results of the lifetimes of all-solid-state batteries according to Example 1, Example 3, and Comparative Example 2; and

[0022] Figure 4 Shows the evaluation results of the lifetimes of all-solid-state batteries according to Example 1, Example 4, and Comparative Example 3. Detailed implementation manners

[0023] From the following preferred implementation manners in conjunction with the accompanying drawings, the above and other objects, features, and advantages of the present disclosure will be more clearly understood. However, the present disclosure is not limited to the implementation manners disclosed herein and can be modified into different forms. These implementation manners are provided to thoroughly explain the present disclosure and fully convey the spirit of the present disclosure to those skilled in the art.

[0024] Throughout the drawings, the same reference numerals will indicate the same or similar elements. For the sake of clarity of the present disclosure, the dimensions of the structures are depicted as larger than their actual dimensions. It will be understood that although terms such as "first", "second", etc. may be used herein to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present disclosure, the "first" element discussed below can be referred to as the "second" element. Similarly, the "second" element can also be referred to as the "first" element. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form.

[0025] It will be further understood that when the terms "comprise", "include", "have", etc. are used in this specification, they specify the presence of the described features, wholes, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, or combinations thereof. Also, it will be understood that when an element such as a layer, film, region, or sheet is referred to as being "on" another element, it can be directly on the other element, or there may be intervening elements therebetween. Similarly, when an element such as a layer, film, region, or sheet is referred to as being "under" another element, it can be directly under the other element, or there may be intervening elements therebetween.

[0026] The terms used in this specification are for the purpose of describing particular embodiments only and are not intended to limit the present disclosure. As used herein, unless the context clearly dictates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms as well. These terms are only intended to distinguish one component from another, and these terms do not limit the nature, order or sequence of the components. It should also be understood that when the terms "comprises" and / or "comprising" are used in this specification, they specify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Throughout the specification, unless explicitly described to the contrary, the word "comprises" and variations such as "comprising" or "containing" will be understood to imply the inclusion of the stated element but not the exclusion of any other element. In addition, the terms "unit", "device", "component" and "module" described in the specification mean a unit for processing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0027] Although the exemplary embodiments are described as using multiple units to perform the exemplary processing, it should be understood that the exemplary processing can also be performed by one or more modules. In addition, it should be understood that the term controller / control unit refers to a hardware device that includes a memory and a processor and is specifically programmed to perform the processes described herein. The memory is configured to store the modules, and the processor is specifically configured to execute the modules to perform one or more of the processes described further below.

[0028] In addition, the control logic of the present disclosure can be embodied as a non-volatile computer-readable medium on a computer-readable medium that contains executable program instructions executed by a processor, a controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, compact disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable medium can also be distributed in a network-coupled computer system such that the computer-readable medium is stored and executed in a distributed manner, such as by a telematics server or a controller area network (CAN).

[0029] Unless specifically stated or obvious from the context, as used herein, the term "about" should be understood to be within the normal tolerances in the art, e.g., within 2 standard deviations of the mean. "About" can be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the stated value. Unless the context clearly dictates otherwise, all numerical values provided herein are modified by the term "about".

[0030] In this specification, when a range is described for a variable, it will be understood that the variable includes all values including the endpoints described within the said range. For example, a range of "5 to 10" should be understood to include any sub-ranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., as well as the individual values of 5, 6, 7, 8, 9, and 10, and should also be understood to include any values between the valid integers within the said range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, 6.5 to 9, etc. Further, for example, a range of "10% to 30%" will be understood to include sub-ranges such as 10% to 15%, 12% to 18%, 20% to 30%, etc., as well as all integers including the values of 10%, 11%, 12%, 13%, etc. up to 30%, and will also be understood to include any values between the valid integers within the said range, such as 10.5%, 15.5%, 25.5%, etc.

[0031] As used herein, the term "adhesive" refers to a resin or polymeric material that can be polymerized or cured to form a polymeric matrix. The adhesive can be cured (polymerized) or partially cured during a curing process such as heating, UV radiation, electron beam treatment, chemical polymerization using additives, etc.

[0032] The term "all-solid-state battery" as used herein refers to a rechargeable secondary battery that includes a solid electrolyte (e.g., a gel or polymer (cured)), which can include an ionomer and other electrolytic components for transferring ions between the electrodes of the battery.

[0033] Unless otherwise specified, all numerical values, values, and / or representations used herein to denote amounts of components, reaction conditions, polymer compositions, and mixtures should be considered approximate values, including the various uncertainties affecting measurements that inherently occur in obtaining such values, etc., and should therefore in all cases be understood to be modified by the term "about". Further, when a numerical range is disclosed in this specification, the range is continuous and includes all values from the minimum value of the said range to its maximum value, unless otherwise indicated. Further, when such a range relates to integer values, all integers from the minimum value to the maximum value are included, unless otherwise indicated.

[0034] Figure 1 An all-solid-state battery according to the present disclosure is shown. Hereinafter, "battery" and "all-solid-state battery" may refer to an object having a layered structure including a cathode layer 10, an anode layer 20, and a solid electrolyte layer 30 disposed between the cathode layer 10 and the anode layer 20, as Figure 1 shown. Considering the context of each term, the meanings of "battery" and "all-solid-state battery" will be clearly understood.

[0035] A method for preparing a all-solid-state battery may include preparing a battery including a cathode layer 10, an anode layer 20, and a solid electrolyte layer 30 disposed between the cathode layer 10 and the anode layer 20, and activating the battery by pressing the battery under high pressure and charging and discharging it under predetermined conditions.

[0036] In the present disclosure, when activating a battery including an anode layer 20 containing a silicon-based anode active material that undergoes large volume expansion during charging and discharging, the battery is pressed at a higher pressure than before. Since there is a large volume change in the activation step corresponding to the early charging and discharging, a high pressure can be applied to the battery to prevent cracking. Since the volume change is small in the operation steps after activation, the battery can be stably driven even at a lower pressure than in the activation step.

[0037] Even when a high pressure is applied in the activation step, due to the large volume change when the utilization rate of the anode active material is high, there is a high possibility of cracking in the operation steps. Therefore, the present disclosure is characterized in that the N / P ratio of the battery is appropriately adjusted so that the battery can be driven more stably.

[0038] The cathode layer 10 may include a cathode active material, a solid electrolyte, a conductive material, and a binder.

[0039] The cathode active material may include a lithium transition metal oxide capable of storing and releasing lithium.

[0040] The lithium transition metal oxide may include any material common in the technical field to which the present disclosure pertains. For example, the lithium transition metal oxide may include LiNi x1 Co x2 Mn x3 O2 (0.65 ≤ x1 ≤ 0.85, 0.05 < x2 < 0.25, 0.03 < x3 < 0.2 and x1 + x2 + x3 = 1).

[0041] The average particle size D50 of the cathode active material is not particularly limited and may be, for example, 1 μm to 20 μm. The average particle size D50 of the cathode active material can be measured using a commercially available laser diffraction scattering type particle size distribution analyzer, such as a Microtrac particle size distribution analyzer. Alternatively, 200 particles can be randomly extracted from an electron micrograph and their average particle size can be calculated.

[0042] The cathode active material may be coated with an alkali metal oxide.

[0043] The alkali metal oxide may include an alkali metal element, a transition metal element, and a substitution element.

[0044] The alkali metal element may include at least one selected from the group consisting of lithium (Li), sodium (Na), potassium (K), and combinations thereof. Preferably, the alkali metal element includes lithium (Li).

[0045] The transition metal element may include any transition metal contained in common alkali metal oxides in the technical field to which the present disclosure pertains. For example, the transition metal element may include at least one selected from the group consisting of niobium (Nb), tantalum (Ta), zirconium (Zr), and combinations thereof.

[0046] The solid electrolyte may facilitate the movement of lithium ions in the cathode layer 10.

[0047] The solid electrolyte may include at least one selected from the group consisting of oxide-based solid electrolytes, sulfide-based solid electrolytes, and combinations thereof. Moreover, the solid electrolyte may be crystalline, amorphous, or in a mixed state thereof.

[0048] Examples of the oxide-based solid electrolyte may include perovskite-type LLTO (Li 3x La 2 / 3-x TiO3), phosphate-based NASICON-type LATP (Li 1+x Al x Ti 2-x (PO4)3), etc.

[0049] Examples of the sulfide-based solid electrolyte may include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is any one selected from Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is any one selected from P, Si, Ge, B, Al, Ga, and In), Li 10 GeP2S 12 etc.

[0050] Preferably, the solid electrolyte may include a sulfide-based solid electrolyte having a thio-LISICON crystal structure. The sulfide-based solid electrolyte having a thio-LISICON crystal structure may include at least one selected from the group consisting of Li 7-y PS 6-y Ha y (where Ha includes Cl, Br, or I and y satisfies 0 < y ≤ 2), Li 7-z PS 6-z (Ha1 1-b Ha2 b ) z (where Ha1 and Ha2 are different from each other, each independently includes Cl, Br, or I, and b and z satisfy 0 < b < 1 and 0 < z ≤ 2) and combinations thereof.

[0051] Examples of the conductive material may include carbon black, conductive graphite, ethylene black, graphene, carbon nanotubes, carbon nanofibers, vapor-grown carbon fibers, and the like.

[0052] Examples of the binder may include butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), and the like. The binder may be present in the cathode layer 10 in the form of particles or wires.

[0053] The cathode layer 10 may include 70 wt% to 90 wt% of the cathode active material, 10 wt% to 15 wt% of the solid electrolyte, 1 wt% to 5 wt% of the conductive material, and 1 wt% to 5 wt% of the binder. Here, the amount of each component may be appropriately adjusted in consideration of the capacity, efficiency, etc. of the all-solid-state battery.

[0054] The thickness of the cathode layer 10 is not particularly limited, but may be 1 μm to 100 μm. The thickness of the cathode layer 10 may represent the average value measured at 5 points when measuring the measurement target. In addition, the thickness of the cathode layer 10 may represent the thickness after discharging of the all-solid-state battery.

[0055] The anode layer 20 may include an anode active material, a solid electrolyte, and a binder.

[0056] The anode active material may include a silicon-based anode active material. The silicon-based anode active material may include at least one selected from the group consisting of Si, SiO x (0 < x < 2), Si-containing alloys, and combinations thereof. The Si-containing alloy may include an alloy of Si and any metal selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, transition metals, rare earth elements, and combinations thereof.

[0057] The anode active material may include a silicon-based anode active material and a carbon-based anode active material. The carbon-based anode active material may include graphite such as mesocarbon microbeads (MCMB), highly oriented pyrolytic graphite (HOPG), etc., or amorphous carbon such as hard carbon and soft carbon.

[0058] The anode active material may be a composite of a carbon active material and a metal active material. For example, the surface of the carbon active material may be coated with a metal active material, or the surface of the metal active material may be coated with a carbon active material.

[0059] The solid electrolyte may be the same as or different from the solid electrolyte of the cathode layer 10. The solid electrolyte may include at least one selected from the group consisting of oxide-based solid electrolytes, sulfide-based solid electrolytes, and combinations thereof. Moreover, the solid electrolyte may be crystalline, amorphous, or in a mixed state thereof.

[0060] Examples of oxide-based solid electrolytes may include perovskite-type LLTO (Li 3x La 2 / 3-x TiO3), phosphate-based NASICON-type LATP (Li 1+x Al x Ti 2-x (PO4)3), etc.

[0061] Examples of sulfide-based solid electrolytes may include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is any one selected from Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is any one selected from P, Si, Ge, B, Al, Ga, and In), Li 10 GeP2S 12 etc.

[0062] Preferably, the solid electrolyte may include a sulfide-based solid electrolyte having a thiogermanate crystal structure. The sulfide-based solid electrolyte having a thiogermanate crystal structure may include those selected from the group consisting of Li7-y PS 6-y Ha y (wherein Ha includes Cl, Br, or I and y satisfies 0 < y ≤ 2), Li 7-z PS 6-z (Ha1 1-b Ha2 b ) z (wherein Ha1 and Ha2 are different from each other, each independently includes Cl, Br, or I, and b and z satisfy 0 < b < 1 and 0 < z ≤ 2) and at least one selected from the group consisting of combinations thereof.

[0063] The binder can be the same as or different from the binder of the cathode layer 10. Examples of the binder may include butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), etc. The binder can be present in the anode layer 20 in the form of particles or threads.

[0064] The anode layer 20 can include 60 wt% to 80 wt% of a silicon-based anode active material, 10 wt% to 35 wt% of a solid electrolyte, and 1 wt% to 10 wt% of a binder.

[0065] The thickness of the anode layer 20 is not particularly limited, but can be 1 μm to 100 μm. The thickness of the anode layer 20 can represent the average value when measured at 5 points of the measurement target. In addition, the thickness of the anode layer 20 can indicate the thickness after the all-solid-state battery is discharged.

[0066] The solid electrolyte layer 30 can have a sheet shape having at least two opposite main surfaces. Each of the two main surfaces can include not only a mathematical plane but also partially include a certain curved surface, and can have irregularities generated during the formation of the solid electrolyte layer 30. In this sense, the sheet shape is not limited to a relatively thin rectangular parallelepiped.

[0067] In the sheet-shaped solid electrolyte layer 30, the distance between the two opposite main surfaces can be the thickness of the solid electrolyte layer 30. The length of the solid electrolyte layer 30 in a first direction (e.g., the width direction) perpendicular to the thickness direction is greater than the thickness. In addition, the length of the solid electrolyte layer 30 in a second direction (e.g., the length direction) perpendicular to the thickness direction and the first direction is greater than the thickness.

[0068] The thickness of the solid electrolyte layer 30 is not particularly limited, but can be 1 μm to 100 μm. The thickness of the solid electrolyte layer 30 can represent the average value when measured at 5 points of the measurement target.

[0069] The solid electrolyte layer 30 can include a solid electrolyte having lithium ion conductivity and a binder.

[0070] The solid electrolyte may be the same as or different from the solid electrolyte of the cathode layer 10 and / or the anode layer 20. The solid electrolyte may include at least one selected from the group consisting of oxide-based solid electrolytes, sulfide-based solid electrolytes, and combinations thereof. Moreover, the solid electrolyte may be crystalline, amorphous, or in a mixed state thereof.

[0071] Examples of oxide-based solid electrolytes may include perovskite-type LLTO (Li 3x La 2 / 3-x TiO3), phosphate-based NASICON-type LATP (Li 1+x Al x Ti 2-x (PO4)3), etc.

[0072] Examples of sulfide-based solid electrolytes may include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is any one selected from Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is any one selected from P, Si, Ge, B, Al, Ga, and In), Li 10 GeP2S 12 etc.

[0073] Preferably, the solid electrolyte may include a sulfide-based solid electrolyte having a thiogermanate crystal structure. The sulfide-based solid electrolyte having a thiogermanate crystal structure may include those selected from the group consisting of Li 7-y PS 6-y Ha y (where Ha includes Cl, Br, or I and y satisfies 0 < y ≤ 2), Li 7-z PS 6-z (Ha1 1-b Ha2 b ) zAt least one selected from the group consisting of (wherein Ha1 and Ha2 are different from each other and each independently includes Cl, Br, or I, and b and z satisfy 0 < b < 1 and 0 < z ≤ 2) and combinations thereof.

[0074] The binder may be the same as or different from the binder of the cathode layer 10 and / or the anode layer 20. Examples of the binder may include butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), etc. The binder may be present in the solid electrolyte layer 30 in the form of particles or threads.

[0075] The battery may have an N / P ratio of 2.0 or less but greater than 1.1. The N / P ratio may represent a value obtained by dividing the total capacity of the anode layer 20 by the total capacity of the cathode layer 10. If the N / P ratio is 1.1 or less, due to the high utilization rate of the silicon-based anode active material, the volume change may become large, so even after activation at high voltage, the all-solid-state battery may rupture during operation. On the other hand, if the N / P ratio exceeds 2.0, the battery resistance and energy density loss may increase.

[0076] The method for preparing the battery is not particularly limited. For example, each layer may be formed by a wet method, a dry method, etc. In the wet method, a slurry containing the components of each layer is coated on a substrate and dried, and in the dry method, powders containing the components of each layer are pressed. Moreover, each layer may be formed simultaneously or at different times. For example, the solid electrolyte layer 30 and the cathode layer 10 may be formed by directly applying them on the anode layer 20, or each layer may be prepared separately and then assembled into Figure 1 the structure shown.

[0077] The method for preparing the all-solid-state battery according to the present disclosure may include activating the battery prepared as described above by pressing, charging, and discharging under high pressure.

[0078] The activation step may include applying a pressure of 4.5 MPa to 10 MPa to the battery and charging and discharging under predetermined conditions. If the pressure applied in the activation step is less than 4.5 MPa, the volume change of the silicon-based anode active material cannot be suppressed, and if it exceeds 10 MPa, the pressure will be too high and the battery will rupture.

[0079] The activation step may include charging and discharging the battery at a voltage of 2.0 V to 4.25 V and a temperature of 30 °C to 50 °C. In addition, the activation step may include subjecting the battery to 3 to 10 charge and discharge cycles.

[0080] Because the volume change of the silicon-based anode active material is controlled, the all-solid-state battery prepared as described above can achieve stable charging and discharging even at low voltages during actual operation.

[0081] The method for operating a all-solid-state battery according to the present disclosure may include: preparing a all-solid-state battery including a cathode layer 10, an anode layer 20, and a solid electrolyte layer 30 interposed between the cathode layer 10 and the anode layer 20; activating the all-solid-state battery by charging and discharging while applying a pressure of 4.5 MPa or higher to the all-solid-state battery; and operating the activated all-solid-state battery while applying a pressure of 4.5 MPa or lower to the activated all-solid-state battery.

[0082] The preparation and activation of the all-solid-state battery are as described above, and their detailed descriptions will be omitted below.

[0083] Operating the all-solid-state battery may include applying a pressure of 2.5 MPa to 4.5 MPa to the activated all-solid-state battery and charging and discharging. If the pressure applied during the operating step is less than 2.5 MPa, the volume change of the silicon-based anode active material occurring during operation cannot be effectively suppressed.

[0084] The method for testing a all-solid-state battery according to the present disclosure may include: preparing a all-solid-state battery including a cathode layer 10, an anode layer 20, and a solid electrolyte layer 30 interposed between the cathode layer 10 and the anode layer 20, activating the all-solid-state battery by charging and discharging while applying a pressure of 4.5 MPa or higher to the all-solid-state battery, operating the activated all-solid-state battery while applying a pressure of 4.5 MPa or lower to the activated all-solid-state battery, and determining whether the all-solid-state battery is defective by measuring the DC-IR (direct current internal resistance) value of the operated all-solid-state battery.

[0085] The preparation, activation, and operation of the all-solid-state battery are as described above, and their detailed descriptions will be omitted below.

[0086] When determining whether the all-solid-state battery is defective, if the DC-IR value is 50 Ω or greater in the first cycle discharge after operating the activated all-solid-state battery, it can be determined that the activated all-solid-state battery is defective. If the pressure is insufficient or the number of charge and discharge cycles is insufficient when activating the all-solid-state battery, electrode volume expansion can occur significantly during the operating step, causing electrode defects and shortening the life of the all-solid-state battery.

[0087] A better understanding of the present disclosure can be obtained through the following examples. These examples are only illustrative of the present disclosure and should not be construed as limiting the scope of the present disclosure.

[0088] Example 1

[0089] Prepare a battery as Figure 1 shown, including an anode layer, a cathode layer, and a solid electrolyte layer containing a silicon-based anode active material. Adjust the N / P ratio of the battery to approximately 1.3.

[0090] While applying a pressure of 4.5 MPa to the battery, the battery is activated by performing 5 charge and discharge cycles in the voltage range of about 2.0 V to 4.25 V under the condition of 0.2C.

[0091] While applying a pressure of 2.5 MPa to the activated battery, the life is measured by charging and discharging in the voltage range of about 2.0 V to 4.25 V under the condition of 0.2C. The results are shown in Figure 2 .

[0092] Example 2

[0093] The life is measured in the same manner as in Example 1, except that a pressure of 4.5 MPa is applied to the activated battery. The results are shown in Figure 2 .

[0094] Comparative Example 1

[0095] The life is measured in the same manner as in Example 1, except that the battery is activated while applying a pressure of 2.5 MPa, and a pressure of 2.5 MPa is applied to the activated battery. The results are shown in Figure 2 .

[0096] Reference Figure 2 , the life of Examples 1 and 2 activated under high pressure is much longer than that of Comparative Example 1 activated under low pressure.

[0097] Example 3

[0098] The life is measured in the same manner as in Example 1, except that the N / P ratio of the battery is adjusted to 2.0. The results are shown in Figure 3 .

[0099] Comparative Example 2

[0100] The life is measured in the same manner as in Example 1, except that the N / P ratio of the battery is adjusted to 1.1. The results are shown in Figure 3 .

[0101] Reference Figure 3 , if the N / P ratio of the battery is 1.1 or less, the capacity retention rate is low even when activated under high pressure. Examples 1 and 3 in which the N / P ratio of the battery is 2.0 or less but greater than 1.1 show a capacity retention rate of about 80% even after 15 charge and discharge cycles.

[0102] Example 4

[0103] The lifetime was measured in the same manner as in Example 1, except that while applying a pressure of 4.5 MPa, the battery was activated by performing 3 charge and discharge cycles in the voltage range of about 2.0 V to 4.25 V under the condition of 0.2 C. The results are shown in Figure 4 .

[0104] Comparative Example 3

[0105] The lifetime was measured in the same manner as in Example 1, except that while applying a pressure of 4.5 MPa, the battery was activated by performing 1 charge and discharge cycle in the voltage range of about 2.0 V to 4.25 V under the condition of 0.2 C. The results are shown in Figure 4 .

[0106] Figure 4 The evaluation results of the lifetimes of the all-solid-state batteries according to Example 1 and 4 and Comparative Example 3 are shown. Moreover, Table 1 below shows the measurement results of the DC-IR values in the first-cycle discharge during operation in the all-solid-state batteries according to Example 1 and 4 and Comparative Example 3. The DC-IR was measured under the conditions of 50% SoC and a discharge time period of 10 seconds.

[0107] [Table 1]

[0108]

[0109]

[0110] Reference Figure 4 and Table 1, in Comparative Example 3, the number of charge and discharge cycles during activation was insufficient, resulting in a DC-IR value of 50 Ω or more in the first-cycle discharge during operation, and thus its capacity retention rate was much lower than those of Example 1 and Example 4. Therefore, it is determined whether the activation step is sufficiently performed based on the DC-IR value, and based on the result, it is determined whether the all-solid-state battery is defective.

[0111] According to the present disclosure, an all-solid-state battery with a low operating pressure can be obtained.

[0112] The effects of the present disclosure are not limited to the above effects. It should be understood that the effects of the present disclosure include all effects that can be inferred from the description of the present disclosure.

[0113] Since the embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited to the above embodiments, and various modifications and changes made by those skilled in the art using the basic concept of the present disclosure in the appended claims are also within the scope of the present disclosure.

Claims

1. A method for preparing a all - solid - state battery, the method comprising: Preparing a battery comprising a cathode layer, an anode layer, and a solid electrolyte layer disposed between the cathode layer and the anode layer; And Activating the battery by charging and discharging while applying a pressure of 4.5 MPa or higher to the battery.

2. The method according to claim 1, wherein the anode layer comprises: 60 wt% to 80 wt% of a silicon - based anode active material, 10 wt% to 35 wt% of a solid electrolyte, and 1 wt% to 10 wt% of a binder.

3. The method according to claim 1, wherein the battery has an N / P ratio of 2.0 or less but greater than 1.

1.

4. The method according to claim 1, wherein activating the battery comprises applying a pressure to the battery and charging and discharging at a voltage of 2.0 V to 4.25 V and a temperature of 30 °C to 50 °C.

5. The method according to claim 1, wherein activating the battery comprises subjecting the battery to 3 to 10 charge - and - discharge cycles.

6. The method according to claim 1, wherein activating the battery comprises applying a pressure of 10 MPa or lower to the battery.

7. A method for operating a all - solid - state battery, the method comprising: Preparing a all - solid - state battery comprising a cathode layer, an anode layer, and a solid electrolyte layer interposed between the cathode layer and the anode layer; Activating the all - solid - state battery by charging and discharging while applying a pressure of 4.5 MPa or higher to the battery; And Operating the activated all - solid - state battery while applying a pressure of 4.5 MPa or lower to the activated all - solid - state battery.

8. The method according to claim 7, wherein the anode layer comprises: 60 wt% to 80 wt% of a silicon - based anode active material, 10 wt% to 35 wt% of a solid electrolyte, and 1 wt% to 10 wt% of a binder.

9. The method according to claim 7, wherein the all - solid - state battery has an N / P ratio of 2.0 or less but greater than 1.

1.

10. The method according to claim 7, wherein activating the all - solid - state battery comprises applying a pressure to the all - solid - state battery and charging and discharging at a voltage of 2.0 V to 4.25 V and a temperature of 30 °C to 50 °C.

11. The method according to claim 7, wherein activating the all - solid - state battery comprises subjecting the all - solid - state battery to 3 to 10 charge - and - discharge cycles.

12. The method according to claim 7, wherein activating the all - solid - state battery comprises applying a pressure of 10 MPa or lower to the all - solid - state battery.

13. The method according to claim 7, wherein operating the activated all - solid - state battery comprises charging and discharging while applying a pressure of 2.5 MPa to 4.5 MPa to the activated all - solid - state battery.

14. A method for testing a all - solid - state battery, the method comprising: Preparing a all - solid - state battery comprising a cathode layer, an anode layer, and a solid electrolyte layer interposed between the cathode layer and the anode layer; Activating the all-solid-state battery by performing charging and discharging while applying a pressure of 4.5 MPa or higher to the all-solid-state battery; Operating the activated all-solid-state battery while applying a pressure of 4.5 MPa or lower to the activated all-solid-state battery; And Determining whether the all-solid-state battery is defective by measuring a direct current internal resistance value of the operated all-solid-state battery.

15. The method according to claim 14, wherein the anode layer comprises: 60 wt% to 80 wt% of a silicon-based anode active material, 10 wt% to 35 wt% of a solid electrolyte, and 1 wt% to 10 wt% of a binder.

16. The method according to claim 14, wherein the all-solid-state battery has an N / P ratio of 2.0 or less but greater than 1.

1.

17. The method according to claim 14, wherein activating the all-solid-state battery comprises applying a pressure to the all-solid-state battery and performing charging and discharging at a voltage of 2.0 V to 4.25 V and a temperature of 30 °C to 50 °C.

18. The method according to claim 14, wherein activating the all-solid-state battery comprises applying a pressure of 10 MPa or lower to the all-solid-state battery and subjecting the all-solid-state battery to 3 to 10 charge and discharge cycles.

19. The method according to claim 14, wherein operating the activated all-solid-state battery comprises performing charging and discharging while applying a pressure of 2.5 MPa to 4.5 MPa to the activated all-solid-state battery.

20. The method according to claim 14, wherein if the direct current internal resistance value is 50 Ω or greater in the first cycle discharge after operating the activated all-solid-state battery, it is determined that the activated all-solid-state battery is defective.

Images