All-solid-state battery qualified product sorting method

Abstract

The invention provides a method for determining qualification or disqualification of an all-solid-state battery, which comprises the following steps of: stacking and pressing a cathode, an anode and a solid electrolyte layer, measuring the resistance of a battery cell in a high-frequency region and an ultrahigh-frequency region, and sorting the battery cell based on a measured value. Specific frequency windows (e.g., about 2-4 kHz or 30-70 kHz) and digital thresholds (e.g., resistance of 100-150 m [Omega] for high frequency regions, or resistance of 80-200 m [Omega] for ultrahigh frequency regions) are used as criteria for determining whether the battery complies with qualified requirements. A qualified cell may also exhibit an initial capacity that is at least 90% of its design capacity. The method may also include discarding or reworking unqualified pressed structures, and performing a further battery manufacturing step only on qualified cells to improve production efficiency and ensure a high quality final product.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0110815, filed with the Korean Intellectual Property Office on August 19, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a method for sorting qualified solid-state batteries, which can effectively sort qualified solid-state batteries in the assembly process steps including pressing and cell stacking processes during the manufacturing process of solid-state batteries. Background Technology

[0004] To overcome the limitations of lithium-ion batteries in terms of capacity, stability, power output, and size (whether increasing or decreasing), various battery technologies have been researched and explored. Among these, all-solid-state batteries refer to batteries with a solid electrolyte instead of the liquid electrolyte used in traditional lithium-ion batteries. According to all-solid-state batteries, since flammable solvents are not used internally, the risk of fire or explosion caused by the decomposition reactions of traditional electrolytes is eliminated, thus significantly improving stability.

[0005] All-solid-state batteries comprise a three-stage stacked structure, including a cathode composite layer bonded to the cathode current collector, an anode composite layer bonded to the anode current collector, and a solid electrolyte disposed between the cathode and anode. All-solid-state batteries are manufactured through electrode fabrication, assembly, and activation processes. Specifically, the assembly process includes electrode stamping, electrode stacking, pressing, cell stacking, tab welding, and packaging.

[0006] Furthermore, due to the different characteristics of all-solid-state batteries compared to traditional lithium-ion batteries, different standards must be used to sort qualified all-solid-state batteries during their manufacturing process. In traditional lithium-ion batteries, the local resistance of the battery is measured at high frequencies during the wetting process after electrolyte injection to determine conductivity faults or the magnitude of local resistance. However, since all-solid-state batteries do not use liquid electrolytes, an electrolyte injection step is not employed in their manufacturing process. Moreover, because all-solid-state batteries use solid electrolytes, the resistance at grain boundaries and interlayer interfaces must be considered to determine whether an all-solid-state battery is qualified. Therefore, the standards for determining the quality of traditional lithium-ion batteries are not entirely applicable to all-solid-state batteries.

[0007] Therefore, a new qualified product sorting method is needed, which is best suited for, and limited to, all-solid-state batteries. Summary of the Invention

[0008] The present invention aims to solve the aforementioned problems in the prior art while retaining the advantages achieved by the prior art.

[0009] One aspect of the present invention provides a method for sorting qualified all-solid-state batteries.

[0010] More specifically, this invention provides a method for sorting qualified all-solid-state batteries. By using two resistors measured in the high-frequency and ultra-high-frequency regions, the resistivity characteristics at grain boundaries and interlayer interfaces caused by the structural characteristics of the all-solid-state battery are determined, thereby easily sorting out defective batteries from the assembly process. Therefore, the yield of the final stage product can be improved, and the quality of the final stage all-solid-state batteries can be enhanced.

[0011] The technical problems to be solved by this invention are not limited to those described above. Any other technical problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

[0012] To achieve this objective, the present invention provides a method for sorting qualified all-solid-state batteries.

[0013] More specifically, (1) the present invention provides a method for sorting qualified all-solid-state batteries, including measuring the resistance of the battery cell in the high-frequency region and the ultra-high-frequency region after pressing the battery cell having a cathode, a solid electrolyte layer and an anode (S1), and determining whether the battery cell is qualified based on the resistance of the battery cell measured in the high-frequency region and the ultra-high-frequency region (S2).

[0014] (2) The present invention provides a method for sorting qualified solid-state batteries, wherein in (1), the high frequency region is the frequency range of 0.01 kHz to 10 kHz.

[0015] (3) The present invention provides a method for sorting qualified solid-state batteries, wherein in (1) or (2), the high frequency region is the frequency region from 2kHz to 4kHz.

[0016] (4) The present invention provides a method for sorting qualified solid-state batteries, wherein in any one of (1) to (3), the ultra-high frequency region is a frequency range of 10kHz to 100kHz.

[0017] (5) The present invention provides a method for sorting qualified solid-state batteries, wherein in any one of (1) to (4), the ultra-high frequency region is a frequency range of 30 kHz to 70 kHz.

[0018] (6) The present invention provides a method for sorting qualified all-solid-state batteries, wherein in any one of (1) to (5), if the high-frequency resistance in S2 is 100mΩ to 150mΩ, the battery cell is determined to be qualified.

[0019] (7) The present invention provides a method for sorting qualified all-solid-state batteries, wherein in any one of (1) to (6), if the resistance in the ultra-high frequency region in S2 is 80mΩ to 200mΩ, the battery cell is determined to be qualified.

[0020] (8) The present invention provides a method for sorting qualified products of all-solid-state batteries, wherein in any one of (1) to (7), if the ultra-high frequency region resistance of the cell is greater than the high frequency region resistance in S2, the cell is determined to be a qualified product.

[0021] (9) The present invention provides a method for sorting qualified solid-state batteries, wherein in any one of (1) to (8), if the ratio of ultra-high frequency region resistance to high frequency region resistance is 1.2 to 2.0, the battery cell is determined to be qualified.

[0022] (10) The present invention provides a method for sorting qualified all-solid-state batteries, wherein in any one of (1) to (9), the initial capacity of the battery cell determined to be qualified is at least 90% of the design capacity of the battery cell.

[0023] In some embodiments, a method for sorting qualified all-solid-state batteries includes: stacking a cathode, a solid electrolyte layer, and an anode to form a cell; pressing the cell; measuring the resistance of the pressed cell in the high-frequency region and the resistance of the pressed cell in the ultra-high-frequency region; and determining whether the pressed cell is qualified based on the measured resistance in the high-frequency region and the ultra-high-frequency region.

[0024] The high-frequency region can be the frequency range from about 2 kHz to about 4 kHz.

[0025] The ultra-high frequency range can be the frequency range from about 30 kHz to about 70 kHz.

[0026] When the high-frequency resistance of the pressed battery cell is approximately 100mΩ to approximately 150mΩ, the pressed battery cell can be determined to be qualified.

[0027] When the ultra-high frequency resistance of the pressed battery cell is about 80mΩ to about 200mΩ, the pressed battery cell can be determined to be qualified.

[0028] When the measured resistance in the ultra-high frequency region is greater than the measured resistance in the high frequency region, the pressed battery cell can be determined to be qualified.

[0029] When the ratio of the ultra-high frequency region resistance to the high frequency region resistance is approximately 1.2 to approximately 2.0, the pressed battery cell can be determined to be qualified.

[0030] In some embodiments, a method for manufacturing an all-solid-state battery includes: stacking a cathode, a solid electrolyte layer, and an anode to form a stacked structure; pressing the stacked structure; measuring the resistance of the pressed stacked structure in the high-frequency region and the resistance of the pressed stacked structure in the ultra-high-frequency region; sorting the pressed stacked structures into qualified or unqualified products based on the measured resistance in the high-frequency region and the ultra-high-frequency region; and performing one or more subsequent battery manufacturing steps on the pressed stacked structures that are sorted into qualified products.

[0031] Pressing can be carried out at a pressure of about 450 MPa and a temperature of about 100°C.

[0032] Any pressed stacked structure that is identified as defective may be discarded or reworked before proceeding to one or more subsequent battery manufacturing steps.

[0033] As discussed, the method and system appropriately include the use of a controller or processor. Detailed Implementation

[0034] The invention will be described in more detail below.

[0035] The terms or words used in this specification and claims should not be interpreted as having their usual dictionary meanings, but rather as relating to the technical scope of the invention, since the inventors may appropriately define the concepts of the terms to best interpret the invention.

[0036] The term “all-solid-state battery” as used in this article refers to a battery that uses a solid electrolyte instead of a traditional liquid electrolyte, thereby greatly reducing or eliminating the risk of leakage and combustion associated with liquid electrolytes.

[0037] As used in this article, the term "cell" refers to an electrochemical cell comprising at least one cathode, an anode, and a solid electrolyte layer disposed between the cathode and the anode, which may be repeatedly stacked or combined to form a larger battery assembly.

[0038] The term “grain boundary” as used in this article refers to the interface within a solid electrolyte (or electrode) material where two adjacent grains meet, which may affect ion conduction characteristics and overall battery performance.

[0039] As used herein, the term "pressing" or "pressing process" refers to applying physical pressure (optionally controlled by heat) to stacked cathode, anode, and solid electrolyte layers to improve interfacial contact and reduce voids between layers.

[0040] The term “initial capacity” as used in this article refers to the measured capacity or stored charge of a battery at the start of its service life (e.g., after final assembly and the first activation cycle), which can be compared to the theoretical or “design capacity”.

[0041] The term “design capacity” as used in this article refers to the theoretical or target capacity of a battery cell based on electrode load, material formulation, and other design parameters determined before manufacturing.

[0042] As used in this article, “qualified product” refers to a battery or cell that meets or exceeds predetermined electrical and structural quality standards (such as a specific resistance threshold or a required initial capacity level).

[0043] The term “micro-short circuit” as used in this article refers to a partial or localized short circuit within a battery layer, which is usually caused by improper contact or defects and may lead to unwanted self-discharge or capacity loss.

[0044] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. These terms are used only to distinguish one component from another, and the terms do not limit the nature, order, or sequence of the constituent components. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude 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 stated otherwise, the word “comprising” and variations such as “including” or “containing” should be understood to imply inclusion of the stated elements but not exclude any other elements. Furthermore, the terms “unit,” “component,” “device,” and “module” described in the specification refer to a unit for performing at least one function and operation and can be implemented by hardware components or software components and combinations thereof.

[0045] Although exemplary embodiments are described as using multiple units to perform exemplary processes, it should be understood that exemplary processes can also be performed by one or more modules. Additionally, 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 modules, and the processor is specifically configured to execute said modules to perform one or more processes further described below.

[0046] Furthermore, the control logic of this invention can be embodied in a non-transitory computer-readable medium containing executable program instructions that are executed by a processor, controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable medium can also be distributed across a network-connected computer system, enabling it to be stored and executed in a distributed manner, for example, via a telematics server or a controller area network (CAN).

[0047] Unless otherwise specified or obvious from the context, as used herein, the term “about” should be understood as being within the normal tolerance range in the field, such as within 2 standard deviations of the mean. “About” can be understood as being within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the specified value. Unless otherwise explicitly stated in the context, all numerical values ​​provided herein are modified by the term “about”.

[0048] The structure of an all-solid-state battery differs from that of a conventional lithium-ion battery, which consists of a solid electrolyte layer between the cathode and anode, rather than a separator and electrolyte solution. Therefore, sorting methods used for lithium-ion battery products may not yield effective results when applied to all-solid-state batteries. Thus, a novel all-solid-state battery product sorting method is needed, taking into full account the material and system characteristics of all-solid-state batteries. To this end, this invention provides an all-solid-state battery product sorting method that uses high-frequency and ultra-high-frequency resistance to determine the quality of all-solid-state batteries. These resistances are measured for cells of all-solid-state batteries formed through a pressing process after stacking the cathode, solid electrolyte layer, and anode.

[0049] The following will describe in detail the method for sorting qualified all-solid-state batteries according to the present invention.

[0050] Sorting method for qualified solid-state batteries

[0051] The present invention provides a method for sorting qualified all-solid-state batteries, comprising: pressing a battery cell having a cathode, a solid electrolyte layer and an anode stacked together, and measuring the resistance of the battery cell in the high frequency region and the ultra-high frequency region (S1); and determining whether the battery cell is qualified based on the resistance measured in the high frequency region and the ultra-high frequency region (S2).

[0052] For a battery cell, the resistances obtained in different frequency regions can represent the resistance of the cell components and the resistance at the interface between the solid electrolyte layer and the electrodes, respectively. Based on these two resistances, the final stage determines whether the all-solid-state battery is a qualified product.

[0053] Furthermore, according to the present invention, the cathode, anode, and solid electrolyte layer of the cell, which are the subject of the qualified product determination, can be the cathode, anode, and solid electrolyte layer used in conventional all-solid-state batteries. More preferably, the cathode may include a cathode layer formed on a cathode current collector, and the cathode layer may include a cathode active material and a solid electrolyte. The anode may include an anode layer formed on an anode current collector, and the anode layer may include an anode active material and a solid electrolyte. The solid electrolyte that may be included in the solid electrolyte layer, cathode, and anode may be a sulfide-based solid electrolyte.

[0054] The sorting method for qualified all-solid-state batteries will be described step by step below.

[0055] Resistance measurement (S1)

[0056] To sort qualified all-solid-state batteries, it is necessary to measure the cell resistance in the high-frequency and ultra-high-frequency regions. In this step, the cell whose resistance is to be measured can have a structure including a cathode, an anode, and a solid electrolyte layer disposed between the cathode and anode. The cell resistance can be measured by performing a pressing process on the stacked structure after stacking the cathode, solid electrolyte layer, and anode. If the resistance is measured before the pressing process and then the pressing process is performed, the measured resistance will not adequately reflect the quality of the all-solid-state battery as the final product.

[0057] The device used to measure resistance in this step can be a conventional resistance measuring device. For example, a conventional resistance measuring device such as Hioki's IM3590 can be used. When using this device to measure resistance, the measurement temperature conditions can be from -30°C to 60°C. Preferably, the measurement temperature conditions can be at least -30°C, at least -20°C, at least -10°C, at least 0°C, at least 10°C, or at least 20°C, and at most 60°C, at most 50°C, at most 40°C, or at most 30°C.

[0058] Simultaneously, in this step, the high-frequency range for resistance measurement conditions can be from 0.01 kHz to 10 kHz. Preferably, the high-frequency range can be at least 0.01 kHz, at least 0.1 kHz, at least 0.5 kHz, at least 1 kHz, or at least 2 kHz, and at most 10 kHz, at most 8 kHz, at most 6 kHz, or at most 4 kHz. Additionally, the ultra-high frequency range for resistance measurement conditions can be from 10 kHz to 100 kHz. Preferably, the ultra-high frequency range can be at least 10 kHz, at least 15 kHz, at least 20 kHz, or at least 30 kHz, and at most 100 kHz, at most 90 kHz, at most 80 kHz, or at most 70 kHz. The resistance measured in the high-frequency and ultra-high-frequency ranges is highly correlated with whether the final all-solid-state battery is a qualified product. More specifically, the resistance measured in the high-frequency range can be an indicator of the resistance of the cell components, and the resistance measured in the ultra-high-frequency range can be an indicator of the resistance at the interface of the all-solid-state battery cell.

[0059] Determine if the battery cell is a qualified product (S2)

[0060] After measuring the resistance of the cell in the high-frequency and ultra-high-frequency regions in "S1" above, the all-solid-state battery is determined to be a qualified product based on the measured resistance of the cell.

[0061] More specifically, the resistance of the battery cell can be estimated based on the resistance measured in the high-frequency region, and the resistance at the interface can be estimated based on the resistance measured in the ultra-high-frequency region. All-solid-state batteries whose cell resistance and interface resistance meet specific conditions can be identified as qualified products.

[0062] More specifically, in S2, cells with a high-frequency resistance of 100mΩ to 150mΩ can be identified as qualified. In S2, cells with an ultra-high-frequency resistance of 80mΩ to 200mΩ can be identified as qualified. When the high-frequency resistance is within the above range, the cell resistance of the all-solid-state battery can be identified as indicating qualified. When the high-frequency resistance is too low, it can indicate a short-circuit fault. When the high-frequency resistance is too high, it can indicate a fault in the ion conduction or electron conduction of the all-solid-state battery, resulting in a decrease in capacity and power. When the ultra-high-frequency resistance is within the above range, the resistance at the interface of the all-solid-state battery can be identified as indicating qualified. When the ultra-high-frequency resistance is too high, it can indicate poor contact at the interface. When the ultra-high-frequency resistance is too low, it can indicate a fault caused by a cathode / anode short circuit.

[0063] Furthermore, in S2, cells with a high-frequency resistance greater than an ultra-high-frequency resistance can be identified as qualified products. Specifically, when the ratio of ultra-high-frequency resistance to high-frequency resistance is 1.2 to 2.0, the quality of all-solid-state batteries that are considered qualified products can be particularly excellent.

[0064] According to the present invention, the initial capacity of a cell determined to be qualified can be at least 90% of the cell's design capacity. Preferably, the initial capacity of the cell can be at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, or at least 98% of the cell's design capacity. A cell determined to be qualified substantially exhibits an initial capacity very close to the initial capacity expected at the time of design, which indicates excellent cell performance.

[0065] In the following sections, exemplary embodiments of the present invention will be described in more detail. However, these embodiments are for illustrative purposes only, and the scope of the present invention is not limited to them.

[0066] Example Implementation

[0067] For three different types of all-solid-state battery cells, the all-solid-state battery quality sorting method of this invention is used to determine qualified products. The cathode, solid electrolyte layer, and anode are stacked sequentially, and the stacked structure is packaged in a bag. A pressing process is performed on the stacked structure using a WIP board, and then the resistance of each cell is measured using a Hiokki IM3590 resistance measuring device. For resistance measurement, the high-frequency region is set in the range of 1kHz to 10kHz, and the ultra-high-frequency region is set in the range of 10kHz to 100kHz. If the high-frequency region resistance is in the range of 100mΩ to 150mΩ and the ultra-high-frequency region resistance is in the range of 80mΩ to 200mΩ, the cell with these high-frequency and ultra-high-frequency resistances is determined to be a qualified product.

[0068] The results of the qualified product determination are summarized in Table 1.

[0069] Table 1

[0070] Cell #1 Cell #2 Cell #3 High-frequency resistance (mΩ) 147.3 102.8 93.1 Ultra-high frequency resistor (mΩ) 345.3 154.6 40.4 Qualified or not Unqualified qualified products Unqualified Initial capacity (%) compared to design capacity 95.1 98.5 82.3

[0071] Additionally, in Table 1, the initial capacity (%) compared to the design capacity can be calculated by multiplying the measured capacity by the theoretical cell capacity by 100%. Furthermore, when there are design limitations at the cathode, the theoretical cell capacity can be calculated by subtracting the irreversible cathode capacity from the cathode charge. When there are design limitations at the anode, the theoretical cell capacity can be calculated by subtracting the irreversible cathode capacity from the anode charge.

[0072] As shown in Table 1, cell #2, sorted as a qualified cell using the all-solid-state battery qualification sorting method of the present invention, has an initial capacity of approximately 98.5% of its design capacity, indicating that the initial capacity of cell #2 is close to the actual design capacity. Meanwhile, cell #1, identified as a defective cell, exhibits significantly higher resistance at ultra-high frequencies, indicating very low ion conductivity. Like cell #1, cell #3, identified as a defective cell, has an initial capacity significantly lower than its design capacity, which is attributed to micro-short circuits and self-discharge due to the inability to ensure insulation characteristics. More specifically, the ultra-high frequency resistance of cell #3 is significantly higher than that of cell #2, which can be an indicator of interface resistance. Accordingly, it can be inferred that poor contact has occurred at the solid interface inside the cell. Since cell #3 has lower high-frequency resistance, an indicator of cell component resistance, it can be inferred that a short circuit fault has occurred inside the battery.

[0073] Therefore, when using the all-solid-state battery qualification sorting method of the present invention, it is not necessary to calculate the initial capacity compared with the actual design capacity, but the all-solid-state battery can be easily determined as a qualified product by simply measuring the resistance of the cells after the pressing process.

[0074] The technical significance of this invention lies in providing a method for sorting qualified solid-state batteries, which is specifically designed for solid-state batteries, rather than for traditional lithium-ion batteries. When using this method, the fault conditions of the solid-state batteries can be easily determined, thereby ensuring that the final obtained solid-state batteries are of uniform and excellent quality.

[0075] Although the invention has been described above with reference to exemplary embodiments, the invention is not limited thereto, and various modifications and alterations can be made by those skilled in the art without departing from the spirit and scope of the invention as claimed in the claims.

Claims

1. A method for sorting qualified all-solid-state batteries, the method comprising the following steps: After pressing a battery cell with a stacked cathode, solid electrolyte layer, and anode, the resistance of the battery cell in the high-frequency region and the resistance of the battery cell in the ultra-high-frequency region were measured; and Based on the resistance of the battery cell measured in the high-frequency region and the ultra-high-frequency region, it is determined whether the battery cell is a qualified product.

2. The method according to claim 1, wherein, The high-frequency region is the frequency range from 0.01 kHz to 10 kHz.

3. The method according to claim 1, wherein, The high-frequency region is the frequency range of 2kHz to 4kHz.

4. The method according to claim 1, wherein, The ultra-high frequency range is the frequency range from 10 kHz to 100 kHz.

5. The method according to claim 1, wherein, The ultra-high frequency range is the frequency range from 30kHz to 70kHz.

6. The method according to claim 1, wherein, When the resistance of the battery cell measured in the high-frequency region is between 100mΩ and 150mΩ, the battery cell is determined to be a qualified product.

7. The method according to claim 1, wherein, When the resistance of the battery cell measured in the ultra-high frequency region is between 80mΩ and 200mΩ, the battery cell is determined to be a qualified product.

8. The method according to claim 1, wherein, When the resistance of the battery cell measured in the ultra-high frequency region is greater than the resistance of the battery cell measured in the high frequency region, the battery cell is determined to be a qualified product.

9. The method according to claim 1, wherein, The cell is deemed a qualified product when the ratio of the resistance measured in the ultra-high frequency region to the resistance measured in the high frequency region is between 1.2 and 2.

0.

10. The method according to claim 1, wherein, The initial capacity of the battery cell that is determined to be qualified is at least 90% of the design capacity of the battery cell.

11. A method for sorting qualified all-solid-state batteries, the method comprising the following steps: Stacking a cathode, a solid electrolyte layer, and an anode to form a battery cell; Press the battery cell; Measure the resistance of the pressed battery cell in the high-frequency region and the resistance of the pressed battery cell in the ultra-high-frequency region; and The quality of the pressed battery cell is determined based on the resistance measured in the high-frequency region and the ultra-high-frequency region.

12. The method according to claim 11, wherein, The high-frequency region is the frequency range of 2kHz to 4kHz.

13. The method according to claim 11, wherein, The ultra-high frequency range is the frequency range from 30kHz to 70kHz.

14. The method according to claim 11, wherein, When the resistance of the pressed battery cell in the high-frequency region is 100mΩ to 150mΩ, the pressed battery cell is determined to be a qualified product.

15. The method according to claim 11, wherein, When the resistance of the pressed battery cell in the ultra-high frequency region is between 80mΩ and 200mΩ, the pressed battery cell is determined to be a qualified product.

16. The method according to claim 11, wherein, When the resistance measured in the ultra-high frequency region is greater than the resistance measured in the high frequency region, the pressed battery cell is determined to be a qualified product.

17. The method according to claim 11, wherein, When the ratio of the resistance in the ultra-high frequency region to the resistance in the high frequency region is 1.2 to 2.0, the pressed battery cell is determined to be a qualified product.

18. A method for manufacturing an all-solid-state battery, the method comprising the following steps: a) Stacking the cathode, solid electrolyte layer, and anode to form a stacked structure; b) Press down the stacked structure; c) Measure the resistance of the pressed stacked structure in the high-frequency region and the resistance of the pressed stacked structure in the ultra-high-frequency region. d) Based on the resistance measured in the high-frequency region and the ultra-high-frequency region, the pressed stacked structures are sorted into qualified or unqualified products; and e) Perform one or more subsequent battery manufacturing steps on the pressed stacked structures that have been sorted as qualified products.

19. The method according to claim 18, wherein, The pressing was carried out at a pressure of approximately 450 MPa and a temperature of approximately 100°C.

20. The method of claim 18, further comprising the step of: Pressed stacked structures that are sorted as defective products are discarded or reworked before proceeding with one or more subsequent battery manufacturing steps.