Inspection method for all-solid battery and manufacturing method for all-solid battery

Abstract

To provide a novel technique capable of inspecting an all-solid battery.SOLUTION: An inspection method includes a process of irradiating an all-solid battery or an object to be inspected as an intermediate product thereof with X rays from a fluorescent X-ray analysis device to inspect it.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for inspecting an all-solid-state battery and a method for manufacturing an all-solid-state battery.

Background Art

[0002] An all-solid-state battery is a secondary battery in which an electrolyte layer and an electrode layer are substantially solid. For example, Patent Document 1 describes an invention related to a method for manufacturing an all-solid-state secondary battery. Specifically, it is a method for manufacturing an all-solid-state secondary battery in which a solid electrolyte is disposed between a positive electrode material and a negative electrode material, and current collectors are respectively disposed on the outer surfaces of these electrode materials. After sealing a laminate formed by laminating a positive electrode current collector, a positive electrode material, a solid electrolyte, a negative electrode material, and a negative electrode current collector in a bag-shaped container, a method for manufacturing an all-solid-state secondary battery is characterized by performing preliminary charge and discharge at least once under a predetermined pressure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to put an all-solid-state battery into practical use, it is necessary to establish an inspection technique. That is, it is necessary to inspect an all-solid-state battery during manufacturing and select good products and defective products.

[0005] Therefore, an object of the present invention is to provide a new technique capable of inspecting an all-solid-state battery.

Means for Solving the Problems

[0006] In one aspect, an inspection method according to the present invention includes a step of inspecting an all-solid-state battery or an object to be inspected which is an intermediate thereof by irradiating the object to be inspected with X-rays from a fluorescent X-ray analyzer.

[0007] In one aspect, the method for manufacturing an all-solid-state battery according to the present invention includes a step of inspecting an object to be inspected using the above-described inspection method, and a step of selecting the object to be inspected based on the inspection result of the inspection step.

Advantages of the Invention

[0008] According to the present invention, a new technology capable of inspecting an all-solid-state battery is provided.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] In this specification, the "all-solid-state battery" means a secondary battery in which the electrolyte layer and the electrode layers (the positive electrode layer and the negative electrode layer) are substantially solid. Note that each layer only needs to be something that can be called "substantially" solid, and a small amount of liquid substance may be used even if it is a small amount.

[0011] In this specification, the "intermediate body" of the all-solid-state battery means a structure obtained during the manufacturing process of the all-solid-state battery.

[0012] (1) Outline The inventors of the present invention have studied various methods for the inspection method of all-solid-state batteries. As a result, it has been found that by using X-ray fluorescence analysis, an all-solid-state battery or its intermediate body can be inspected. That is, the inspection method according to the present embodiment includes a step of irradiating an object to be inspected, which is an all-solid-state battery or its intermediate body, with X-rays from an X-ray fluorescence analyzer for inspection.

[0013] In particular, by using X-ray fluorescence analysis, it is possible to know whether the electrode layer, the solid electrolyte layer, and the negative electrode intermediate layer (details will be described later) are formed normally. Therefore, by selecting a structure including the electrode layer, the solid electrolyte layer, or the negative electrode intermediate layer as the object to be inspected and measuring the elemental composition of the portion including the electrode layer, the solid electrolyte layer, or the negative electrode intermediate layer, it is possible to know whether the object to be inspected is a good product.

[0014] The above is the outline of the present embodiment. Subsequently, the inspection method according to the present embodiment will be described while giving an example of an all-solid-state battery.

[0015] (2) All-solid-state battery First, the configuration of the all-solid-state battery will be described. FIG. 1 is a schematic cross-sectional view showing the main part of the all-solid-state battery 1. FIG. 1 shows the configuration in the discharged state (or immediately after manufacturing). As shown in FIG. 1, the all-solid-state battery 1 has a positive electrode current collector foil 2, a positive electrode layer 3, an insulating layer 9, a solid electrolyte layer 4, a negative electrode intermediate layer 5, and a negative electrode current collector foil 8. Specifically, the positive electrode layer 3 and the insulating layer 9 are disposed on the positive electrode current collector foil 2. The solid electrolyte layer 4 is disposed on the positive electrode layer 3. The negative electrode intermediate layer 5 is disposed on the solid electrolyte layer 4. The negative electrode current collector foil 8 is disposed on the negative electrode intermediate layer 5.

[0016] The all-solid-state battery 1 shown in FIG. 1 is a deposition type all-solid-state battery. A deposition type all-solid-state battery is an all-solid-state battery configured such that metallic lithium is deposited between the solid electrolyte layer and the negative electrode current collector foil during charging. In such an all-solid-state battery, the metallic lithium deposited during charging functions as a negative electrode active material. During discharging, the metallic lithium as the negative electrode active material moves to the positive electrode side as lithium ions. Therefore, in the discharged state, as shown in FIG. 1, there may be almost no negative electrode active material between the solid electrolyte layer 4 and the negative electrode current collector foil 8.

[0017] As the positive electrode current collector foil 2, for example, a metal foil is used. For reasons described later, it is preferable that the positive electrode current collector foil 2 does not contain an element having an atomic weight of Ag or more. As the positive electrode current collector foil 2, for example, an aluminum foil or the like can be used. The thickness of the positive electrode current collector foil 2 is, for example, 5 to 50 μm, preferably 8 to 20 μm.

[0018] The positive electrode layer 3 is configured to occlude lithium during discharging and release lithium as lithium ions during charging. For reasons described later, it is preferable that the positive electrode layer 3 does not contain an element having an atomic weight of Ag or more. The positive electrode layer 3 is formed of, for example, a material containing a resin binder and a positive electrode active material dispersed in the resin binder. As the positive electrode active material, for example, layered rock salt type active materials such as LiCoO2, LiMnO2, LiNiO2, LiVO2, Li(Ni-Mn-Co)O2, Li(Ni-Co-Al)O2, LiMn2O4, LiNi 0.5Mn 1.5 Spinel-type active materials such as MnO4, olivine-type active materials such as LiFePO4 and LiMnPO4, Si-containing active materials such as Li2FeSiO4 and Li2MnSiO4, etc. can be mentioned. Or, Li4Ti5O 12 etc. can also be mentioned. Among them, composite oxides containing lithium and nickel are preferably used, and more preferably Li(Ni-Mn-Co)O2 (hereinafter, also simply referred to as "NMC composite oxide") or Li(Ni-Co-Al)O2 (hereinafter, also simply referred to as "NCA composite oxide") and those in which a part of these transition metals is substituted by other elements are used, and particularly preferably NMC composite oxide is used. Also, the positive electrode layer may contain a positive electrode auxiliary agent. Examples of the positive electrode auxiliary agent include metals such as aluminum, alloys or metal oxides containing these metals; carbon such as carbon fiber, carbon nanotube, carbon black, etc., but are not limited thereto. The thickness of the positive electrode layer is, for example, 10 to 1000 μm, preferably 30 to 500 μm.

[0019] The insulating layer 9 is provided for protecting the end portion of the positive electrode layer 3 etc. The insulating layer 9 is arranged in a frame shape so as to surround the outer peripheral end of the positive electrode layer 3. The insulating layer 9 can be formed of, for example, the same material as the solid electrolyte layer 4.

[0020] The solid electrolyte layer 4 is solid and functions as the electrolyte layer in the secondary battery. For reasons described later, it is preferable that the solid electrolyte layer 4 does not contain elements having an atomic weight of Ag or more. The solid electrolyte layer 4 includes, for example, a resin binder and a solid electrolyte dispersed in the resin binder. Examples of the solid electrolyte include a sulfide solid electrolyte and an oxide solid electrolyte. Preferably, it is a sulfide solid electrolyte. Examples of the sulfide solid electrolyte include LiI-Li2S-SiS2, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li2S-P2S5, LiI-Li3PS4, LiI-LiBr-Li3PS4, Li3PS4, 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-ZmSn (where m and n are positive numbers and Z is any one of Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-LixMOy (where x and y are positive numbers and M is any one of P, Si, Ge, B, Al, and Ga), etc. The thickness of the solid electrolyte layer 4 is, for example, 5 to 100 μm.

[0021] The negative electrode intermediate layer 5 is provided for protecting the solid electrolyte layer 4. As described above, during charging, metallic lithium as the negative electrode active material precipitates between the solid electrolyte layer 4 and the negative electrode current collector foil 8. At this time, if metallic lithium precipitates directly on the solid electrolyte layer 4, the solid electrolyte layer 4 may be damaged. Therefore, the negative electrode intermediate layer 5 is provided for protecting the solid electrolyte layer 4. Metallic lithium precipitates between the negative electrode intermediate layer 5 and the negative electrode current collector foil 8. The precipitated metallic lithium does not directly contact the solid electrolyte layer 4. Therefore, damage to the solid electrolyte layer 4 is prevented.

[0022] The negative electrode intermediate layer 5 is formed of a material containing, for example, Ag and C. The thickness of the negative electrode intermediate layer 5 is not particularly limited. Usually, the negative electrode intermediate layer 5 is thinner than the solid electrolyte layer 4. The thickness of the negative electrode intermediate layer 5 is, for example, 5 to 9 μm.

[0023] As the negative electrode current collector foil 8, for example, a metal foil is used. As the negative electrode current collector foil 8, for example, SUS, copper foil, etc. can be used. The thickness of the negative electrode current collector foil 8 is, for example, 5 to 50 μm, preferably 8 to 20 μm.

[0024] (3) Manufacturing method of all-solid-state battery Subsequently, an example of the manufacturing method of the all-solid-state battery 1 will be described. FIGS. 2 to 4 are schematic diagrams showing an example of the manufacturing method of the all-solid-state battery 1.

[0025] First, as shown in FIG. 2(a), a slurry for forming the positive electrode layer 3 is prepared. Next, as shown in FIG. 2(b), the slurry is applied onto the positive electrode current collector foil 2 and dried. Thereby, the positive electrode layer 3 is formed. Next, as shown in FIG. 2(c), a slurry for forming the insulating layer 9 is applied onto the positive electrode current collector foil 2. Then, as shown in FIG. 2(d), the obtained structure is pressed by a roll.

[0026] Subsequently, as shown in FIG. 3(a), a slurry for forming the solid electrolyte layer 4 is applied onto the positive electrode layer 3 and dried. Next, the obtained structure is pressed by a roll as shown in FIG. 3(b). Subsequently, as shown in FIG. 3(c), the negative electrode intermediate layer 5 is laminated onto the solid electrolyte layer 4. The negative electrode intermediate layer 5 can be laminated, for example, by a transfer method using a transfer sheet. Subsequently, as shown in FIG. 3(d), the obtained laminate is cut to a desired size. Thereby, the positive electrode side laminate 10 is obtained.

[0027] Subsequently, as shown in FIG. 4(a), the positive electrode side laminate 10 and a separately prepared negative electrode current collector foil 8 are laminated. When the all-solid-state battery 1 includes a plurality of cells, the plurality of positive electrode side laminates 10 and the plurality of negative electrode current collector foils 8 are laminated so as to alternate with each other. Subsequently, as shown in FIG. 4(b), tabs 11 are joined to the current collector foils. Subsequently, as shown in FIG. 4(c), the obtained structure is sealed with a laminate film 12. Subsequently, as shown in FIG. 4(d), a charge-discharge test is performed, and good products are selected. Thereby, the all-solid-state battery 1 is obtained.

[0028] (4) Inspection method for all-solid-state battery As described above, the all-solid-state battery 1 is manufactured through a number of processes. However, defects may occur in the all-solid-state battery 1 during the manufacturing process. FIG. 5 is a schematic cross-sectional view showing an example of a defective portion of the all-solid-state battery 1. For example, metal foreign substances or the like may be mixed into the positive electrode layer 3 and the solid electrolyte layer 4, and contamination 14 may be formed. In addition, since the solid electrolyte layer 4 and the negative electrode intermediate layer 5 are often relatively thin, pinholes 13 may occur during manufacturing. Alternatively, when the upper layer is laminated on the underlying layer, the position of the upper layer may deviate from the desired position.

[0029] Therefore, in the present embodiment, by using fluorescent X-ray analysis, defects as described above are detected. That is, an intermediate or a finished product including the positive electrode layer, the solid electrolyte layer, or the negative electrode intermediate layer is selected as the object to be inspected. Then, the elemental composition of the portion including the positive electrode layer, the solid electrolyte layer, or the negative electrode intermediate layer is measured by fluorescent X-ray analysis. As shown in the examples described later, the measurement results of the elemental composition by fluorescent X-ray analysis are different between defective products and good products. Therefore, by analyzing the elemental composition by fluorescent X-ray analysis, good products and defective products can be sorted.

[0030] In addition, according to fluorescent X-ray analysis, the elemental composition of a solid structure can be measured non-destructively for the object to be inspected. Therefore, the all-solid-state battery or its intermediate can be inspected without sacrificing the yield.

[0031] Fluorescent X-ray analysis can be carried out using a commercially available fluorescent X-ray analyzer. As the fluorescent X-ray analyzer, both a handy type device and a non-handy type device are commercially available. Using a handy type fluorescent X-ray analyzer makes it easy to perform inspections at multiple stages in the manufacturing process, which is preferable.

[0032] The timing of the inspection by fluorescent X-ray analysis is not particularly limited. For example, if it is after the formation of the positive electrode layer 3 shown in Fig. 2(b), a structure after any process can be used as the object to be inspected. For example, after the coating and drying processes shown in Figs. 2(b) and 3(a), an inspection by fluorescent X-ray analysis can be carried out. Alternatively, after the pressing processes shown in Figs. 2(d), 3(b), and 3(c), an inspection by fluorescent X-ray analysis can be carried out. Alternatively, after the cutting process shown in Fig. 3(d), an inspection by fluorescent X-ray analysis can be carried out. Alternatively, after the lamination process shown in Fig. 4(a), an inspection by fluorescent X-ray analysis can be carried out. Alternatively, after the tab bonding process shown in Fig. 4(b), an inspection by fluorescent X-ray analysis can be carried out. Alternatively, after the sealing process of the laminate film shown in Fig. 4(c), an inspection by fluorescent X-ray analysis can be carried out.

[0033] In other words, examples of the "intermediate body" to be inspected include the following structures (1) to (7). (1) A structure including the positive electrode current collector foil 2 and the positive electrode layer 3 formed thereon, as shown in Fig. 2(b). (2) A structure including the positive electrode current collector foil 2, the positive electrode layer 3 formed thereon, and a frame member arranged so as to surround the positive electrode layer, as shown in Figs. 2(c) and 2(d). (3) A structure including the positive electrode current collector foil 2, the positive electrode layer 3 formed thereon, and the solid electrolyte layer 4 formed on the positive electrode layer 3, as shown in Figs. 3(a) and (b). (4) A structure including the positive electrode current collector foil 2, the positive electrode layer 3 formed thereon, the solid electrolyte layer 4 formed on the positive electrode layer 3, and the negative electrode intermediate layer formed on the solid electrolyte layer 4, as shown in Figs. 3(c) and (d). (5) As shown in Fig. 4(a), a structure in which a plurality of positive electrode side laminates 10 and a negative electrode current collector foil 8 are laminated. (6) As shown in Fig. 4(b), a laminate in which a plurality of positive electrode side laminates 10 and a negative electrode current collector foil 8 are laminated, and tabs are joined to each positive electrode current collector foil and each negative electrode current collector foil. (7) As shown in Fig. 4(c), a structure having a laminate in which a plurality of positive electrode side laminates 10 and a negative electrode current collector foil 8 are laminated, and a laminate film 12 for sealing the laminate.

[0034] Preferably, the inspection by X-ray fluorescence analysis is carried out at least twice in the manufacturing process of the all-solid-state battery. More preferably, the inspection by X-ray fluorescence analysis is carried out twice with some process in between. Thereby, it is possible to find out in which process a defect has occurred.

[0035] In the case where an inspection is carried out after the lamination of the negative electrode intermediate layer 5 and the negative electrode intermediate layer 5 contains Ag, it is preferable to irradiate X-rays from the side opposite to the negative electrode intermediate layer 5. In other words, when the object to be inspected includes a solid electrolyte layer, a positive electrode layer, and a negative electrode intermediate layer containing Ag, it is preferable to irradiate the object to be inspected with X-rays from the positive electrode layer 3 side rather than from the negative electrode intermediate layer 5 side. Ag absorbs a large amount of X-ray energy. Therefore, when irradiating X-rays from the negative electrode intermediate layer 5 side when the negative electrode intermediate layer 5 contains Ag, it is likely to be difficult to analyze the accurate elemental composition. On the other hand, accurate inspection becomes possible by irradiating X-rays from the positive electrode layer side.

[0036] Regarding elements having an atomic weight larger than that of Ag, like Ag, they also absorb a large amount of X-ray energy. Therefore, even when the negative electrode intermediate layer 5 contains an element having an atomic weight larger than that of Ag, it is preferable to irradiate X-rays from the positive electrode layer side as in the case where Ag is contained.

[0037] In addition, as described above, in order to perform an accurate inspection by irradiating X-rays from the positive electrode side, it is preferable that the positive electrode layer, the solid electrolyte layer, and the positive electrode current collector foil do not contain elements having an atomic weight equal to or greater than Ag.

[0038] Next, an example of suitable X-ray fluorescence analysis will be described. FIG. 6 is a schematic cross-sectional view showing a suitable example of X-ray fluorescence analysis. In this example, an elastic body 16 is disposed on the object to be inspected. Then, X-rays are irradiated from the X-ray fluorescence analyzer 15 to the object to be inspected through the elastic body 16. According to this example, the presence of the elastic body 16 prevents stress concentration when the X-ray fluorescence analyzer 15 is brought close to the object to be inspected. Thereby, the generation of cracks in the object to be inspected is prevented.

[0039] As the elastic body 16, for example, a sheet having a thickness of 0.1 mm or less can be used. Further, as the elastic body 16, for example, one having a Young's modulus of 0.3 GPa or less can be used.

[0040] The embodiments of the present invention have been described above. As described above, according to this embodiment, by using X-ray fluorescence analysis, inspection of all-solid-state batteries can be performed.

[0041] In this embodiment, the case where the all-solid-state battery 1 is a "deposited type all-solid-state battery" has been described as an example. In particular, the inspection method for a deposited type all-solid-state battery having a negative electrode intermediate layer has been described. However, the inspection method according to this embodiment is not limited to all-solid-state batteries having such a specific configuration. For example, instead of the negative electrode intermediate layer 5, a negative electrode layer containing a normal negative electrode active material may be formed during manufacturing. In such a case, a structure including the negative electrode layer may be used as the object to be inspected, and the composition of the portion including the negative electrode layer may be inspected by X-ray fluorescence analysis.

Example

[0042] Hereinafter, experimental examples conducted by the present inventors will be described.

[0043] (Experimental Example 1) As a reference sample (NMC), a sample with a positive electrode layer formed on a positive electrode current collector foil was prepared. As the positive electrode layer, one containing a resin binder, an NMC-based positive electrode active material, etc. was used. On the other hand, as a contaminated sample (Cu), a sample with Cu deliberately mixed into the positive electrode layer was prepared. Then, for each of the reference sample and the contaminated sample, fluorescence X-ray analysis was performed to measure the elemental composition.

[0044] The results are shown in Fig. 7. As shown in Fig. 7, Cu was not detected in the reference sample, whereas Cu was detected in the contaminated sample. The peak intensities of other elements were also different. From this result, it can be understood that the presence or absence of metal foreign substances such as Cu in the positive electrode layer can be inspected by fluorescence X-ray analysis.

[0045] (Experimental Example 2) As a reference sample (NMC / SE), a sample with a positive electrode layer and a solid electrolyte layer laminated on a positive electrode current collector foil was prepared. As the positive electrode layer, one containing an NMC-based positive electrode active material was used in the same manner as in Experimental Example 1. On the other hand, as a contaminated sample (Cu), a sample prepared in the same manner as the reference sample except that Cu was deliberately mixed into the positive electrode layer was prepared. Then, for each of the reference sample and the contaminated sample, fluorescence X-ray analysis was performed to measure the elemental composition.

[0046] The results are shown in Fig. 8. As shown in Fig. 8, Cu was not detected in the reference sample, whereas Cu was detected in the contaminated sample. From this result, it can be understood that even after the formation of the positive electrode layer and the solid electrolyte layer, the presence or absence of metal foreign substances in the positive electrode layer can be inspected by performing fluorescence X-ray analysis.

[0047] (Experimental Example 3) As a reference sample (NMC), the same one as in Experimental Example 1 was prepared. On the other hand, as a pinhole sample, one with pinholes formed in the positive electrode layer was prepared. Then, for each of the reference sample (NMC) and the pinhole sample, fluorescence X-ray analysis was performed to measure the elemental composition.

[0048] The results are shown in Fig. 9. As shown in Fig. 9, the intensities of Ni etc. were significantly different between the reference product and the pinhole product. From this, it can be understood that the presence or absence of pinholes in the positive electrode layer can be inspected by X-ray fluorescence analysis.

[0049] (Experimental Example 4) As the reference product (NMC), the same one as in Experimental Example 1 was prepared. On the other hand, as the composition-abnormal product, one in which the amount of the resin binder in the positive electrode layer was 20% more than that of the reference product was prepared. Then, X-ray fluorescence analysis was performed on each of the reference product (NMC) and the composition-abnormal product, and the elemental composition was measured.

[0050] The results are shown in Fig. 10. As shown in Fig. 10, the intensities of Ni etc. were significantly different between the reference product and the composition-abnormal product. From this, it can be understood that it is possible to inspect whether the composition of the positive electrode layer is the desired composition by X-ray fluorescence analysis.

[0051] (Experimental Example 5) As the reference product (NMC811), a sample in which a positive electrode layer was formed on a positive electrode current collector foil was prepared. As the positive electrode layer, one containing a resin binder, an NMC-based positive electrode active material, etc. was used. As the NMC-based positive electrode active material, one in which the ratio of Ni:Mn:Co was 8:1:1 was used. On the other hand, as the composition-abnormal product (NMC811+MNC532), one formed by the same method as the reference product (NMC811) except that an NMC-based positive electrode active material in which the ratio of Ni:Mn:Co was 5:3:2 was further contained was prepared. Then, X-ray fluorescence analysis was performed on each of the reference product (NMC811) and the composition-abnormal product (NMC811+MNC532), and the elemental composition was measured.

[0052] The results are shown in Fig. 11. As shown in Fig. 11, the intensities of Ni etc. were different between the reference product and the composition-abnormal product (NMC811+MNC532). From this, it was found that it is possible to inspect whether the metal composition of the positive electrode layer is the desired composition by X-ray fluorescence analysis.

[0053] (Experimental Example 6) As a reference sample (NMC / SE), a sample was prepared in which a positive electrode layer and a solid electrolyte layer were formed on a positive electrode current collector foil. On the other hand, as a laminated defective product, a sample in which the position of the solid electrolyte layer with respect to the positive electrode layer was shifted was prepared. Then, for each of the reference sample (NMC / SE) and the laminated defective product, fluorescence X-ray analysis was performed to measure the elemental composition.

[0054] The results are shown in FIG. 12. As shown in FIG. 12, the intensities of a plurality of elements were different between the reference sample (NMC / SE) and the laminated defective product. From this, it was found that the presence or absence of misalignment during lamination can be inspected by fluorescence X-ray analysis.

[0055] (Experimental Example 7) A sample in which a positive electrode layer, a solid electrolyte layer, and a negative electrode intermediate layer were formed in this order on a positive electrode current collector foil was prepared. As the negative electrode intermediate layer, one containing Ag was used. Then, the elemental composition of the sample was measured by fluorescence X-ray analysis. At this time, it was observed whether there was a difference in the results between the case where X-rays were irradiated from the positive electrode layer side and the case where X-rays were irradiated from the negative electrode intermediate layer side.

[0056] The results are shown in FIG. 13. As shown in FIG. 13, the intensities of each element were different between the case where X-rays were irradiated from the positive electrode side and the case where X-rays were irradiated from the negative electrode intermediate layer side. And when X-rays were irradiated from the positive electrode layer side, the intensity of the element that should exist in the positive electrode layer was clearly readable, and an accurate elemental composition could be obtained. From this, it was found that when a negative electrode intermediate layer containing an element with a large atomic weight such as Ag exists, the inspection can be accurately performed by irradiating X-rays from the positive electrode layer side.

[0057] [Supplementary Note] The representative configurations and their effects disclosed in the present application are summarized below as supplementary notes.

[0058] (Supplementary Note 1) An inspection method including a step of inspecting an all-solid-state battery or an object to be inspected which is an intermediate thereof by fluorescence X-ray analysis.

[0059] According to this method, good and defective products of all-solid-state batteries or their intermediates can be discriminated by X-ray fluorescence analysis.

[0060] (Appendix 2) An inspection method described in Appendix 1, wherein the object to be inspected includes an electrode layer, a solid electrolyte layer, or a negative electrode intermediate layer, and the inspection process includes a process of measuring the elemental composition of a portion including the electrode layer, the solid electrolyte layer, or the negative electrode intermediate layer.

[0061] According to this method, the presence or absence of defects in the electrode layer, the solid electrolyte layer, or the negative electrode intermediate layer can be inspected.

[0062] (Appendix 3) An inspection method described in Appendix 1 or 2, wherein the inspection process includes a process of disposing an elastic body on the object to be inspected and a process of irradiating the object to be inspected with X-rays from an X-ray fluorescence analyzer through the elastic body.

[0063] According to this method, damage to the object to be inspected due to contact between the X-ray fluorescence analyzer and the object to be inspected can be prevented.

[0064] (Appendix 4) An inspection method described in Appendix 3, wherein the thickness of the elastic body is 0.1 mm or less.

[0065] According to this method, damage to the object to be inspected due to contact between the X-ray fluorescence analyzer and the object to be inspected can be more reliably prevented.

[0066] (Appendix 5) An inspection method described in Appendix 3 or 4, wherein the Young's modulus of the elastic body is 0.3 GPa or less.

[0067] According to this method, damage to the object to be inspected due to contact between the X-ray fluorescence analyzer and the object to be inspected can be more reliably prevented.

[0068] (Appendix 6) The inspection method according to any one of Supplementary Notes 1 to 5, wherein the object to be inspected includes a solid electrolyte layer, a positive electrode layer and a negative electrode intermediate layer disposed so as to sandwich the solid electrolyte layer, the negative electrode intermediate layer contains Ag or an element having an atomic weight larger than that of Ag, and the inspection step includes a step of irradiating the object to be inspected with X-rays from the positive electrode layer side.

[0069] According to this method, since it is difficult for the energy of X-rays to be absorbed by Ag, accurate inspection can be performed.

[0070] (Supplementary Note 7) The manufacturing method according to any one of Supplementary Notes 1 to 6, wherein the inspection step is carried out at least twice in the manufacturing process of the all-solid-state battery.

[0071] According to this method, it is possible to identify in which process a defect has occurred.

[0072] (Supplementary Note 8) A method for manufacturing an all-solid-state battery, comprising a step of inspecting an object to be inspected using the inspection method according to any one of Supplementary Notes 1 to 6, and a step of sorting the object to be inspected based on the inspection result of the inspection step.

[0073] According to this method, good products of all-solid-state batteries can be sorted efficiently.

Explanation of Reference Numerals

[0074] 1...All-solid-state battery, 2...Positive electrode current collector foil, 3...Positive electrode layer, 4...Solid electrolyte layer, 5...Negative electrode intermediate layer, 8...Negative electrode current collector foil, 9...Insulating layer, 10...Positive electrode side laminate, 11...Tab, 12...Laminated film, 13...Pinhole, 14...Contamination, 15...X-ray fluorescence analyzer, 16...Elastomer

Claims

1. A step of inspecting a solid-state battery or a test object which is an intermediate thereof by irradiating the test object with X-rays from a fluorescent X-ray analyzer. Inspection method.

2. The inspection method according to Claim 1, wherein the test object includes an electrode layer, a solid electrolyte layer, or a negative electrode intermediate layer, and the inspection step includes a step of measuring the elemental composition of a portion including the electrode layer, the solid electrolyte layer, or the negative electrode intermediate layer. Inspection method.

3. The inspection method according to Claim 1, wherein the inspection step includes a step of disposing an elastic body on the test object, and a step of irradiating the test object with X-rays from a fluorescent X-ray analyzer through the elastic body. The inspection method comprises the above steps. Inspection method.

4. The inspection method according to Claim 3, wherein the thickness of the elastic body is 0.1 mm or less. Inspection method.

5. The inspection method according to Claim 3, wherein the Young's modulus of the elastic body is 0.3 GPa or less. Inspection method.

6. The inspection method according to Claim 1, wherein the test object includes a solid electrolyte layer, a positive electrode layer and a negative electrode intermediate layer disposed so as to sandwich the solid electrolyte layer, the negative electrode intermediate layer contains Ag or an element having an atomic weight larger than that of Ag, and the inspection step includes a step of irradiating the test object with X-rays from the positive electrode layer side. Inspection method.

7. The inspection method according to Claim 1, wherein the inspection step is carried out at least twice in the manufacturing process of the solid-state battery. Inspection method.

8. A step of inspecting the test object using the inspection method according to Claim 1, and a step of sorting the test object based on the inspection result of the inspection step. The manufacturing method of the solid-state battery comprises the above steps. Manufacturing method of a solid-state battery.

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