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

Abstract

Provided are an all-solid-state secondary battery and a method for manufacturing the all-solid-state secondary battery, the all-solid-state secondary battery having a battery element member including one or more groups of battery cells in which at least a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer are laminated in this order, wherein the battery element member has, at an end portion thereof, an insulating coating body that coats at least a side surface of the battery element member, and the insulating coating body is configured from a mixture of a resin material that melts in a temperature region of 300 DEG C or less and insulating inorganic particles that do not melt at 350 DEG C; the method for manufacturing the all-solid-state secondary battery includes: a step for disposing a mixture of a resin material that melts in a temperature region of 300 DEG C or less and insulating inorganic particles that do not melt at 350 DEG C at an end portion of the battery element member; and a step for heating the mixture at a temperature at which the resin material melts and pressurizing the mixture toward the inside of the battery element member.

Description

Technical Field

[0001] The present invention relates to an all-solid-state secondary battery and a method for manufacturing the same. Background Art

[0002] An all-solid-state secondary battery has a battery cell formed by sequentially laminating a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer as a battery element component. In addition to a normal (single-layer type) all-solid-state secondary battery having one set of such battery cells, in recent years, for the purpose of achieving high energy density, a laminated all-solid-state secondary battery formed by laminating two or more battery cells is also being developed towards practical use.

[0003] An all-solid-state secondary battery is usually formed by sequentially laminating a positive electrode active material layer and a negative electrode active material layer via a solid electrolyte layer. Therefore, there is a problem that the ends of the battery cell formed by laminating constituent layers such as a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer are likely to come into contact. That is, even when laminated via a solid electrolyte layer, the ends of the positive electrode active material layer and the negative electrode active material layer are likely to come into contact with each other and cause a short circuit.

[0004] An all-solid-state secondary battery has been proposed to address the problem of short circuit occurrence at such ends.

[0005] For example, Patent Document 1 describes an electrochemical element including an electrode body for an electrochemical element. "The electrode body for an electrochemical element has a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode. The electrode body for an electrochemical element is characterized in that the solid electrolyte layer contains a sulfide-based solid electrolyte, and an insulating layer is formed on the side surface of the electrode body. The insulating layer contains a filler containing a resin having a melting point or a thermal decomposition temperature of 150°C or higher and a binder."

[0006] Moreover, Patent Document 2 describes "an all-solid-state lithium battery including: an oriented positive electrode plate composed of an oriented polycrystal formed by orienting a plurality of lithium transition metal oxide particles; a solid electrolyte layer provided on the oriented positive electrode plate and composed of a lithium ion conductive material; a negative electrode layer provided on the solid electrolyte layer; and an end insulating portion for insulatingly coating the end of the oriented positive electrode plate. The surface on the solid electrolyte layer side of the end insulating portion constitutes a continuous surface with the surface on the solid electrolyte layer side of the oriented positive electrode plate. Thus, there is no step difference between the end insulating portion and the surface on the solid electrolyte layer side of the oriented positive electrode plate, or it is a discontinuous surface where the surface on the solid electrolyte layer side of the end insulating portion is lower than the surface on the solid electrolyte layer side of the oriented positive electrode plate, but the step difference between the end insulating portion and the surface on the solid electrolyte layer side of the oriented positive electrode plate is smaller than the thickness of the solid electrolyte layer."

[0007] Previous technical literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2019-175736

[0010] Patent Document 2: International Publication No. 2016 / 152565 Summary of the invention

[0011] Technical issues to be solved by the invention

[0012] The constituent layers constituting the battery cell are formed by various methods such as a film-making method (a method of coating and drying the constituent layer forming material) using a constituent layer forming material containing solid particles such as an inorganic solid electrolyte, an active material, and a conductive auxiliary agent, and a method of sputtering or evaporating an active material. At this time, regardless of the manufacturing method, the thickness of the end of the constituent layer formed is easy to become thinner, and it is easy to cause poor adhesion, inducing the occurrence of a short circuit at the end of the battery element component (battery cell, constituent layer). In addition, if the all-solid-state secondary battery (battery cell) is pressurized in the stacking direction during manufacturing and use in order to improve battery performance, there is a problem that the end of the constituent layer is deformed due to the pressurized stress, and defects (cracks, cracks, gaps, etc.) are generated due to the adhesion collapse of the solid particles, which ultimately leads to a short circuit. In this way, in addition to the short circuit caused by the stacking of the above-mentioned constituent layers (contact of the constituent layers), the all-solid-state secondary battery also has the problem of a short circuit at the end of the battery element component due to the end formation of the constituent layer and pressurization. Such problems of short circuit at the end and deformation or defect at the end occur significantly in all-solid-state secondary batteries that include a solid electrolyte layer formed of a soft and fragile sulfide-based inorganic solid electrolyte and in stacked all-solid-state secondary batteries that widely use a technology that reduces the size (main surface area) of the positive electrode active material layer more than the negative electrode active material layer in order to suppress the occurrence of short circuits caused by stacking deviations of the constituent layers.

[0013] However, the all-solid-state secondary battery of Patent Document 1 only prevents the occurrence of short circuits that may occur when stacking the constituent layers by providing an insulating layer on the side of the electrode body, and the all-solid-state secondary battery of Patent Document 2 prevents short circuits caused by the step difference generated when using the oriented positive electrode plate by providing an end coating portion that insulates the end of the oriented positive electrode plate. In both Patent Documents 1 and 2, no research was conducted from the perspective of the end formability of the constituent layer and the deformation or defect occurrence of the end. In the all-solid-state secondary battery of Patent Document 2 using an oriented positive electrode plate, there is no problem of deformation or defect occurrence of the end of the constituent layer.

[0014] An object of the present invention is to provide an all-solid-state secondary battery and a method for manufacturing the same, which can suppress the occurrence of short circuits by preventing deformation and defects while maintaining the insulation of the end portions of battery element components.

[0015] Means for Solving the Technical Problem

[0016] As a result of repeated various studies by the present inventors, it has been found that: an insulating coating body that covers from the outside of the side surface is provided at the end portion (at least the side surface) of a battery element component of a battery unit including laminated constituent layers, and the insulating coating body is formed of a mixture of a resin material that melts in a temperature range of 300°C or lower and insulating inorganic particles that do not melt at 350°C. Thereby, it is possible to prevent the occurrence of deformation and defects while maintaining the insulation of the end portion of the battery element component. Based on these findings, further studies were repeated until the present invention was completed.

[0017] That is, the above problems are solved by the following solutions.

[0018] <1> An all-solid-state secondary battery having a battery element component, wherein

[0019] the battery element component includes one or more sets of battery units, and each battery unit is formed by laminating at least a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in this order.

[0020] at the end portion of the battery element component, there is an insulating coating body that covers at least the side surface of the battery element component from the outside of the side surface.

[0021] the insulating coating body is composed of a mixture of a resin material that melts in a temperature range of 300°C or lower and insulating inorganic particles that do not melt at 350°C.

[0022] <2> The all-solid-state secondary battery according to <1>, wherein

[0023] each battery unit is a battery unit formed by laminating a negative electrode current collector, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector in this order.

[0024] the positive electrode current collector has a positive electrode current collecting portion laminated adjacent to the positive electrode active material layer and a positive electrode tab extending in a manner protruding from one end thereof, and the positive electrode tab protrudes from the insulating coating body.

[0025] <3> The all-solid-state secondary battery according to <1> or <2>, wherein

[0026] each battery unit is a battery unit formed by laminating a negative electrode current collector, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector in this order.

[0027] The above-mentioned negative electrode current collector has a negative electrode current collecting portion laminated adjacent to the negative electrode active material layer and a negative electrode tab extending in a manner protruding from one end thereof, and the negative electrode tab protrudes from the insulating coating body.

[0028] <4> The all-solid-state secondary battery according to any one of <1> to <3>, wherein

[0029] The insulating coating body is composed of a molten solid of a resin material that melts in a temperature range below 200 °C and insulating solid particles that do not melt at 250 °C.

[0030] <5> The all-solid-state secondary battery according to any one of <1> to <4>, wherein

[0031] An insulating coating body containing insulating inorganic particles is filled in the recess, and the recess is formed at the end of the battery element member due to the size difference between the positive electrode active material layer and the negative electrode active material layer and is adjacent to the outside in the plane direction of the positive electrode active material layer or the negative electrode active material layer.

[0032] <6> The all-solid-state secondary battery according to any one of <1> to <5>, wherein

[0033] At least one interface between adjacent laminated layers in the battery element member has a coating intrusion region where an insulating coating body containing at least one insulating inorganic particle intrudes from the end of the battery element member toward the inside.

[0034] <7> The all-solid-state secondary battery according to <6>, wherein

[0035] The solid electrolyte layer in contact with the coating intrusion region does not have cracks.

[0036] <8> A method for manufacturing an all-solid-state secondary battery, comprising the following steps:

[0037] A step of disposing a mixture of a resin material that melts in a temperature range below 300 °C and insulating inorganic particles that do not melt at 350 °C at the end of a battery element member including one or more laminated units, the laminated unit being formed by sequentially laminating a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer; and

[0038] A step of heating the mixture while applying pressure in the inward direction of the battery element member at the temperature at which the resin material melts.

[0039] <9> The manufacturing method according to <8>, wherein

[0040] The pressing step is performed in a state where the battery element member is pressed in the lamination direction.

[0041] <10>According to the manufacturing method described in <8> or <9>, wherein,

[0042] In the above pressurizing step, the mixture disposed at the end of the battery element component is heated to the temperature, while preventing the flow in the stacking direction, and making it flow in the inward direction.

[0043] Advantages of the Invention

[0044] The all-solid-state secondary battery of the present invention can maintain the insulation of the end by preventing the contact of the constituent layers at the end of the battery element component, and can strengthen the end to prevent the occurrence of deformation and defects, thereby being able to suppress the occurrence of short circuits. Moreover, the manufacturing method of the all-solid-state secondary battery of the present invention can manufacture an all-solid-state secondary battery in which the occurrence of the above short circuit is suppressed.

[0045] Regarding the above features, other features and advantages of the present invention, they should become clearer by appropriately referring to the drawings and according to the following description. Description of the Drawings

[0046] Figure 1 It is a longitudinal sectional view schematically showing the basic structure of a general all-solid-state secondary battery.

[0047] Figure 2 It is a partial schematic cross-sectional view schematically showing the end in a preferred embodiment of the all-solid-state secondary battery of the present invention.

[0048] Figure 3 It is a partial schematic cross-sectional view schematically showing the end in another preferred embodiment of the all-solid-state secondary battery of the present invention.

[0049] Figure 4 It is a partial schematic cross-sectional view schematically showing the other end in another preferred embodiment of the all-solid-state secondary battery of the present invention.

[0050] Figure 5 It is a partial schematic cross-sectional view schematically showing yet another end in another preferred embodiment of the all-solid-state secondary battery of the present invention.

[0051] Figure 6A It is a top schematic view showing an embodiment of a positive electrode plate that can be used in a preferred manufacturing method of a battery element component.

[0052] Figure 6B It is a top schematic view showing an embodiment of a negative electrode plate with an electrolyte layer that can be used in a preferred manufacturing method of a battery element component.

[0053] Figure 7It is a schematic top view showing a state in which a plurality of electrode plates are accommodated in an accommodation space of a frame and temporarily positioned in a preferred manufacturing method of a battery element component using a preferred manufacturing apparatus.

[0054] FIG. 8(A) is a schematic cross-sectional view showing an initial state of a process of performing final positioning in a preferred manufacturing method of a battery element component using a preferred manufacturing apparatus, and shows a cut surface on a plane perpendicular to the longitudinal direction of the frame and passing through the center of the pin receiving portion.

[0055] FIG. 8(B) is a schematic cross-sectional view showing a completed state of a process of performing final positioning in a preferred manufacturing method of a battery element component using a preferred manufacturing apparatus, and shows a cut surface on a plane perpendicular to the longitudinal direction of the frame and passing through the center of the pin receiving portion.

[0056] Figure 9 It is a schematic cross-sectional view showing a state in which a battery element component that has been finally positioned is pressure-constrained in the stacking direction in a preferred manufacturing method of a laminated all-solid-state secondary battery using a preferred manufacturing apparatus, and shows a cut surface on a plane perpendicular to the longitudinal direction of the frame and passing through the center of the pin receiving portion.

[0057] Figure 10 It is a schematic cross-sectional view showing a state in which a battery element component that has been finally positioned is pressure-constrained in the stacking direction in a preferred manufacturing method of a laminated all-solid-state secondary battery using a preferred manufacturing apparatus, and shows a cut surface on a plane perpendicular to the longitudinal direction of the frame and at a substantially central portion in the longitudinal direction.

[0058] Figure 11 It is a schematic cross-sectional view illustrating a method of forming an insulating coating at an end portion by disposing a rod-shaped molding body near the end portion of a battery element component and applying pressure in a preferred manufacturing method of a laminated all-solid-state secondary battery using a preferred manufacturing apparatus. Detailed Description

[0059] In the present invention, the "main surface" refers to a surface perpendicular to the thickness direction in a flat body such as a layer, and generally refers to a surface having the largest surface area. And, the "plane direction" refers to the in-plane direction of the main surface, specifically, the longitudinal direction and the lateral direction.

[0060] In the present invention, "insulating" means having electrical insulation, that is, a property of not allowing electrons to pass through. And, in the present invention, when referred to as "insulating", "insulativity", or "electrical insulation", the conductivity is preferably 10 -9 Siemens / cm or less at a measurement temperature of 25°C.

[0061] In the present invention, "cracks", "cracks", and "notches" that may occur in the constituent layer are all defects caused by the bonding collapse of solid particles. Specifically, "cracks" refer to cracks that continuously extend along the grain boundaries of at least one solid particle in the depth direction or the plane direction of the constituent layer. For example, when observed with an electron microscope or the like, they are considered to be cracks that expand along the grain boundaries of at least one solid particle. Generally, once a crack occurs, stress will concentrate at the tip of the crack, so the crack will expand linearly and will not follow the grain boundaries of solid particles. On the other hand, "cracks" refer to a state in which the crack penetrates in the depth direction and the plane direction and the constituent layer loses its integrity (separates into multiple parts), and "notches" refer to a state in which a part of the constituent layer is locally peeled off or missing (defective) (except for the state with cracks).

[0062] In the present invention, when a numerical range is described regarding the content of components, physical properties, etc., when the upper limit value and the lower limit value of the numerical range are described separately, any upper limit value and lower limit value can be appropriately combined to form a specific numerical range. On the other hand, when multiple numerical ranges represented by "~" are set for description, the upper limit value and the lower limit value that form the numerical range are not limited to the specific combination described before and after "~" as a specific numerical range, and can be set as a numerical range that appropriately combines the upper limit value and the lower limit value of each numerical range. In addition, in the present invention, the numerical range represented by "~" means a range that includes the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0063] Hereinafter, regarding the all-solid-state secondary battery and its manufacturing method of the present invention, the preferred embodiments thereof will be specifically described, but the present invention is not limited to the preferred embodiments described below.

[0064] [All-solid-state secondary battery]

[0065] In the all-solid-state secondary battery of the present invention, the ends of the battery element components are covered with an insulating coating. Through this insulating coating, the insulation of the ends of the battery element components (battery cells, constituent layers) can be maintained, and the strength of the ends of the constituent layers can be enhanced to prevent deformation and the occurrence of defects. As a result, the occurrence of short circuits can be suppressed. In particular, even for an all-solid-state secondary battery having battery element components that use a consolidation layer that requires pressure for densification or a composite material layer that requires restraint during use as a constituent layer, by integrally covering the ends of the battery element components, the insulation of the ends can be maintained, and the strength of the composite material layer can be enhanced. Thus, the all-solid-state secondary battery of the present invention has high reliability whether it is a single-layer type or a stacked type.

[0066] In the present invention, the end portion of the battery element member refers to a region that at least includes the side surface (end surface) of the battery element member. In the case where there is a dimensional difference between the positive electrode active material layer and the negative electrode active material layer, it refers to a region that includes a recess formed due to this dimensional difference (in other words, a region formed by a straight line connecting the outer side surfaces of the battery element member and a straight line connecting the inner surface of the recess).

[0067] When the solid electrolyte layer is transferred or laminated and coated in a manner that covers the end portion (side surface) of the negative electrode active material layer, the insulating coating does not directly contact the end portion (side surface) of the negative electrode active material layer, but this manner is also included in the present invention as one manner of the end portion of the battery element member. In this manner, the compressive pressure directed toward the inner direction of the battery element member is transmitted to the end portion (side surface) of the negative electrode active material layer via the solid electrolyte layer.

[0068] In the all-solid-state secondary battery of the present invention, the end portion of the battery element member is covered by an insulating coating, and other structures are not particularly limited, the same as in known all-solid-state secondary batteries.

[0069] The all-solid-state secondary battery of the present invention includes at least the following two manners: a manner of an all-solid-state secondary battery having a battery unit (laminated unit) formed by laminating a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in sequence (sometimes referred to as a single-layer type all-solid-state secondary battery); and a manner of an all-solid-state secondary battery having two or more battery units (sometimes referred to as a laminated type all-solid-state secondary battery). The battery units included in the laminated type all-solid-state secondary battery are not particularly limited as long as there are two or more, and for example, can be set to 2 to 500 groups, preferably 60 to 100 groups.

[0070] The shape of the all-solid-state secondary battery of the present invention is not particularly limited and can be appropriately set according to the use and the like. For example, it can be set to be circular or rectangular in a top view. In the present invention, "rectangle" refers to a quadrilateral including a square and a rectangle, but is not limited to a geometrically accurate quadrilateral, and can be a roughly quadrilateral shape as long as it is based on the use, required characteristics, etc., and can also be a shape with chamfered corners. The external dimensions of the all-solid-state secondary battery can be appropriately set according to the use and the like.

[0071] <Structure of all-solid-state secondary battery>

[0072] In Figure 1 shows the basic structure (battery unit) of a general all-solid-state secondary battery.

[0073] As Figure 1As shown, the all-solid-state secondary battery 10 has a structure in which a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5 are stacked in this order when viewed from the negative electrode side. Adjacent layers in each layer are in direct contact with each other.

[0074] According to the above structure, during charging, electrons (e - ) are supplied to the negative electrode side. At the same time, the alkali metal or alkaline earth metal constituting the positive electrode active material is ionized. The ionized ions move through the (conductive) solid electrolyte layer 3 and accumulate in the negative electrode. For example, in a lithium-ion secondary battery, lithium ions (Li + ) accumulate in the negative electrode.

[0075] During discharging, the above-mentioned alkali metal ions or alkaline earth metal ions accumulated in the negative electrode return to the positive electrode side and supply electrons to the working part 6. In the illustrated example, a light bulb is used as the working part 6 and is lit by discharging.

[0076] The single-layer all-solid-state secondary battery of the present invention includes a battery cell formed by stacking a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in this order as a battery element component. Preferably, it further includes a Figure 1 shown basic structure in which a negative electrode current collector and a positive electrode current collector are stacked.

[0077] In Figure 2 , for the cross-section along the stacking direction in a preferred embodiment of the all-solid-state secondary battery (single-layer type) of the present invention, the whole of its end portion and the vicinity of the interface between the solid electrolyte layer and the positive electrode active material layer (the region indicated by R1 in Figure 2 ) are schematically shown.

[0078] The all-solid-state secondary battery 30 is a single-layer all-solid-state secondary battery 30 having a battery element component 21 composed of a set of battery cells having the Figure 1 shown layer structure as a basic unit. That is, the all-solid-state secondary battery 30 has a battery element component 21, and the battery element component 21 is composed of a set of battery cells 21 stacked in this order as a negative electrode current collector 1A, a negative electrode active material layer 2A, a solid electrolyte layer 3A, a positive electrode active material layer 4A, and a positive electrode current collector 5A when viewed from the negative electrode side. In the all-solid-state secondary battery 30, the main surface areas of the negative electrode current collector 1A, the negative electrode active material layer 2A, the solid electrolyte layer 3A, the positive electrode active material layer 4A, and the positive electrode current collector 5A are all the same.

[0079] The battery element component 21 has an insulating coating body 22 that covers at least the side surface from the outside of the side surface at its end portion 21A. As Figure 2As shown, the insulating coating body 22 integrally and entirely coats and seals the peripheral side surface of the battery element component 21 without any gap. The insulating coating body 22 is preferably coated in a compressed state from the outside of the side surface of the end portion 21A toward the inside. The insulating coating body 22 is disposed on the outside in contact with the side surface of the battery element component 21, and in addition to the side surface of the battery element component 21, it also coats the main surfaces near the edges of the negative electrode current collector 1A and the positive electrode current collector 5A. The coating amount of the insulating coating body 22 on the main surface near the edge (the length (average coating thickness) L of the insulating coating body 22 in the surface direction on the main surface near the edge) is not particularly limited, and can be set to 0.1 mm or more, preferably 0.5 to 2 mm for example.

[0080] As described above, if the insulating coating body 22 is provided at the end portion 21A of the battery element component 21, it is possible to maintain the insulation of the end portion 21A of the battery element component 21 (battery cell, constituent layer) while preventing the occurrence of deformation and defects (collapse, breakage). As a result, the all-solid-state secondary battery 30 can suppress the occurrence of short circuits and exhibit high reliability.

[0081] In the all-solid-state secondary battery, as Figure 2 shown in the enlarged region R1 (the slashes are omitted for easy visual recognition) in, there is a coating body intrusion region 23 formed by the insulating coating body 22 containing at least one insulating inorganic particle 24 invading from the end portion 21A (side surface) of the battery element component 21 toward the inside (inside the main surface) at the interface between the adjacent stacked solid electrolyte layer 3A and the positive electrode active material layer 4A. Moreover, in the intrusion region toward the interface, the coating body intrusion region 23 has at least one insulating inorganic particle 24 in the resin material 25 described later. By having such a coating body intrusion region 23, even if the layer thicknesses of the ends of the positive electrode active material layer 4A and the solid electrolyte layer 3A become thin, it is possible to strengthen their strength and make them firm, and it is possible to highly suppress the deformation of the end portion 21A of the battery element component 21 and the occurrence of defects in the constituent layers, especially the solid electrolyte layer 3A. Usually, defects are likely to occur at the end of the solid electrolyte layer 3A, but the occurrence of defects such as cracks and notches, especially cracks, in the solid electrolyte layer 3A in contact with the coating body intrusion region 23 is suppressed, and a defect-free state can be maintained.

[0082] As long as the number of the insulating inorganic particles 24 contained in the inclusion intrusion region 23 is one or more, there is no particular limitation, and it can be appropriately set according to the size of the insulating inorganic particles 24, the intrusion amount of the inclusion intrusion region 23, etc., rather than being uniquely set. For example, regarding the number of the insulating inorganic particles 24 present in the inclusion intrusion region 23, it is preferable to fill in a plurality of insulating inorganic particles 24, and for example, it can be set to 10 or more. Its upper limit is not particularly limited, and is actually 50 or less.

[0083] As long as the inclusion intrusion region 23 exists at the above interface, its intrusion amount (the intrusion length from the side surface of the positive electrode active material layer 4A toward the inner side: depth), the average thickness in the stacking direction, etc. can be appropriately determined. For example, the intrusion amount also depends on the size of the positive electrode active material layer 4A, and for example, it can be set to 0.05 mm or more, preferably 0.1 to 0.5 mm. The average thickness of the inclusion intrusion region 23 also depends on the layer thicknesses of the solid electrolyte layer 3A and the positive electrode active material layer 4A, and for example, it can be set to 200 μm or less, preferably 20 to 60 μm.

[0084] The presence, intrusion amount and thickness of the inclusion intrusion region 23, and the presence and number of the insulating inorganic particles can be confirmed or measured, for example, by observation based on a scanning electron microscope (SEM).

[0085] In addition, in Figure 2 Although not shown in the figure, the positive electrode current collector 5A has a positive electrode tab electrically connected thereto, and the negative electrode current collector 1A has a negative electrode tab electrically connected thereto.

[0086] In the case where the end portion of the single-layer type all-solid-state secondary battery 30 provided with the positive electrode tab or the negative electrode tab is covered with an insulating coating body, each end portion is the same as the above end portion 21A except that the positive electrode tab or the negative electrode tab penetrates through the insulating coating body and protrudes outward from the outer surface of the insulating coating body. In this case, it can also be said that a part of the positive electrode current collector side or the negative electrode current collector side of the positive electrode tab or the negative electrode tab is covered or buried by the insulating coating body. The forming method of this end portion is basically the same as that of the above end portion 21A, and the forming method of the end portion provided with the positive electrode tab or the negative electrode tab in the stacked type all-solid-state secondary battery described later can also be applied. The above end portion of the single-layer type all-solid-state secondary battery 30 can be formed, for example, by arranging a mixture in a manner of sandwiching the positive electrode tab or the negative electrode tab in the vertical direction in the stacking direction and applying pressure toward the inner direction of the battery element components.

[0087] The stacked type all-solid-state secondary battery of the present invention includes two or more battery units formed by sequentially stacking a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer as battery element components, and preferably each battery unit further includes a Figure 1The basic structure shown. In this method, adjacent battery cells share a negative current collector or a positive current collector.

[0088] In Figure 3 For the cross-section along the stacking direction in a preferred embodiment of the all-solid-state secondary battery (laminated type) of the present invention, the entire end portion (the end portion where no positive electrode tab and negative electrode tab are disposed) and the vicinity of the interface between the solid electrolyte layer and the positive electrode active material layer (the region represented by R2 in Figure 3 ) are schematically shown.

[0089] In this all-solid-state secondary battery 50, a plurality of positive electrode active material layers 4B and a plurality of negative electrode active material layers 2B are alternately stacked via a solid electrolyte layer 3B, and a battery element component 41 is provided which is composed of 5 sets of battery cells 42 having the layer structure shown as a basic unit. That is, as Figure 1 shown, the all-solid-state secondary battery 50 has a battery element component 41 in which 5 sets of battery cells 42 are stacked in an alternately opposite manner in the stacking order of the constituent layers. When viewed from the negative electrode side, each battery cell 42 is stacked in the order of a negative current collector 1B, a negative electrode active material layer 2B, a solid electrolyte layer 3B, a positive electrode active material layer 4B, and a positive current collector 5B. Among them, adjacent two battery cells 42 share one current collector. That is, it is in the following manner: negative electrode active material layers 2B are provided on two main surfaces of one negative current collector 1B, and positive electrode active material layers 4B are provided on two main surfaces of one positive current collector 5B. As Figure 3 shown, the stacking order of the constituent layers in this laminated all-solid-state secondary battery 50 is a stacking order of positive current collector 5B - positive electrode active material layer 4B - solid electrolyte layer 3B - negative electrode active material layer 2B - negative current collector 1B - negative electrode active material layer 2B - solid electrolyte layer 3B - positive electrode active material layer 4B -... Figure 3 Although not clearly shown in

[0090] In Figure 3 , it can be clearly understood from Figure 4 and Figure 5 that, as will be described later, the current collector of the all-solid-state secondary battery 50 has a current collecting portion laminated adjacent to the active material layer and a tab connected and provided so as to protrude from one end thereof. Moreover, in the battery element component 41, the positive current collectors are stacked such that the positive electrode tabs are located on the same end side, and the negative current collectors are stacked such that the negative electrode tabs are located on the end portion different from the end portion where the positive electrode tabs are located (usually the opposite end portion) side.

[0091] As Figure 3As shown, in the laminated all-solid-state secondary battery 50, the main surface area of the positive electrode active material layer 4B is set to be smaller than the main surface area of the negative electrode active material layer 2B. Generally, in a laminated all-solid-state secondary battery, in order to prevent short circuits caused by lamination misalignment, the main surface area of the positive electrode active material layer is set to be smaller than the main surface area of the negative electrode active material layer. In the laminated all-solid-state secondary battery 50, at the edge (end portion) of the positive electrode where no positive electrode tab is provided, the positive electrode current collector 5B and the positive electrode active material layer 4B have the same end face by punching the coating sheet or the like. At the edge (end portion) of the negative electrode where no negative electrode tab is provided, the negative electrode current collector 1B and the negative electrode active material layer 2B have the same end face by punching the coating sheet or the like. The solid electrolyte layer 3B is transferred onto the negative electrode active material layer, and thus has the same end face as the negative electrode current collector 1B and the negative electrode active material layer 2B. Therefore, due to the size difference between the positive electrode active material layer 4B and the negative electrode active material layer 2B, a recess 43 adjacent to the outside in the plane direction of the positive electrode active material layer 4B is formed at the end portion 41A of the battery element member 41 (the end portion where no positive electrode tab and negative electrode tab are disposed). More specifically, as Figure 3 shown, at the end portion 41A of the battery element member 41, adjacent to the outside in the plane direction of the positive electrode active material layer 4B, a recess 43 is formed by the side faces of the positive electrode plate (two positive electrode active material layers 4B and the positive electrode current collector 5B) and the two solid electrolyte layers 3B sandwiching the positive electrode plate. In a normal laminated all-solid-state secondary battery having such a recess, short circuits are likely to occur at the end portion of the battery element member, and deformation and defects are also likely to occur. However, in the present invention, since the laminated all-solid-state secondary battery 50 has the insulating coating body 44, the occurrence of short circuits and deformation and the like can be highly suppressed at the end portion 41A of the battery element member 41. As a result, the positive electrode active material layer 4B can be set to be smaller than the negative electrode active material layer 2B, and not only the occurrence of short circuits caused by insufficient reliability of the end portion 41A can be highly suppressed, but also the occurrence of short circuits caused by lamination misalignment can be highly suppressed.

[0092] The battery element member 41 has an insulating coating body 44 that covers at least the side face from the outside of the side face at its end portion 41A. As Figure 3As shown, the insulating coating 44 integrally and entirely coats and seals the peripheral side surface of the battery element component 41 (five sets of battery cells 42) without any gaps. The insulating coating 44 is preferably coated in a compressed state from the outside of the side surfaces of each end toward the inside. The insulating coating 44 is disposed in a region that contacts the side surfaces of each constituent layer starting from a position more outside than the side surfaces of the outermost constituent layer in the plane direction. Moreover, in the insulating coating 44, the recess 43 formed due to the dimensional difference between the positive electrode active material layer 4B and the negative electrode active material layer 2B is also filled without any gaps with the insulating coating 44 containing the insulating inorganic particles 46. Further, the insulating coating 44 also coats the main surfaces near the edges of the negative electrode current collector 1B on the outermost side in the stacking direction (the lowermost layer in Figure 3 ), and the positive electrode current collector 5B on the outermost side (the uppermost layer in Figure 3 ). The coating amount coated by the insulating coating 44 on the main surfaces near the edges (the length (average coating thickness) L of the insulating coating in the plane direction on the main surfaces near the edges) is not particularly limited, and can be set to 0.1 mm or more, preferably 0.5 to 2 mm, for example. Here, as Figure 3 shown, the length L of the insulating coating in the plane direction in the laminated all-solid-state secondary battery refers to the average length from the side surfaces of the negative electrode active material layer 2B and the solid electrolyte layer 3B to the outer surface in the plane direction of the outermost constituent layer in the plane direction in the battery element component 41.

[0093] As described above, if the insulating coating 44 is provided at the end 41A of the battery element component 41, even in the laminated all-solid-state secondary battery 50 in which the positive electrode active material layer 4B is set to be small, it is possible to maintain the insulation of the end 41A of the battery element component 41 (the battery cells 42, the constituent layers) while preventing the occurrence of deformation and defects (collapse, breakage). As a result, the all-solid-state secondary battery 50 can suppress the occurrence of short circuits and exhibit high reliability.

[0094] In the all-solid-state secondary battery, as Figure 3As shown in the enlarged view of region R2 (the slashes are omitted for easy visual recognition), at least one interface between the adjacent stacked solid electrolyte layer 3B and the positive electrode active material layer 4B has an insulating coating body 44 containing at least one insulating inorganic particle 46 that penetrates from the end 41A of the battery element component 41 into the interior (inside the main surface) of the interface to form a coating body intrusion region 45. The interface having this coating body intrusion region 45 exists within the recess 43. Moreover, in the intrusion region into the interface, the coating body intrusion region 45 has at least one insulating inorganic particle 46 in the resin material 47 described later. By having such a coating body intrusion region 45, even if the layer thickness at the ends of the positive electrode active material layer 4B and the solid electrolyte layer 3B becomes thin, its strength can be enhanced to make it firm, and deformation of the end 41A of the battery element component 41 and the occurrence of defects in the constituent layers, particularly in the solid electrolyte layer 3B, can be highly suppressed. Usually, defects are likely to occur at the ends of the solid electrolyte layer 3B, but the occurrence of defects such as cracks and notches, particularly cracks, in the solid electrolyte layer 3B in contact with the coating body intrusion region 45 is suppressed, and a defect-free state can be maintained.

[0095] Although not shown in Figure 3 FIG. 5, in the all-solid-state secondary battery 50, the coating body intrusion region 45 exists at all interfaces between the adjacent stacked solid electrolyte layer 3B and the positive electrode active material layer 4B, but as described later, it may not exist at all interfaces.

[0096] The number of insulating inorganic particles 46 contained in the coating body intrusion region 45 is not particularly limited as long as it is one or more, and can be appropriately set according to the size of the insulating inorganic particles 46, the intrusion amount of the coating body intrusion region 45, etc., rather than being uniquely set. For example, regarding the number of insulating inorganic particles 46 present in the coating body intrusion region 45, it is preferable to fill in a plurality of insulating inorganic particles 46, and for example, it can be set to 10 or more. Its upper limit is not particularly limited, and is actually 50 or less.

[0097] The intrusion amount (the intrusion length from the side surface of the positive electrode active material layer 4B toward the inner side: the depth), the average thickness in the stacking direction, etc. of the coating body intrusion region 45 can be appropriately determined. For example, the intrusion amount also depends on the size of the positive electrode active material layer 4B, and can be set to 0.01 mm or more, preferably 0.02 - 0.1 mm. The average thickness of the coating body intrusion region 45 also depends on the layer thicknesses of the solid electrolyte layer 3B and the positive electrode active material layer 4B, and can be set to 200 μm or less, preferably 20 - 60 μm.

[0098] The presence, intrusion amount and thickness of the coating body intrusion region 45, and the presence and number of insulating inorganic particles can be confirmed or measured in the above manner.

[0099] The laminated all-solid-state secondary battery 50 has positive electrode tabs electrically connected to respective positive electrode current collectors 5B, and the positive electrode tabs are electrically connected to each other outside the laminated all-solid-state secondary battery 50. Further, the laminated all-solid-state secondary battery 50 has negative electrode tabs electrically connected to respective negative electrode current collectors 1B, and the negative electrode tabs are electrically connected to each other outside the laminated all-solid-state secondary battery 50. Therefore, although not shown in Figure 3 , the laminated all-solid-state secondary battery 50 has a rectangular shape in plan view with four end portions including two end portions 41A where no positive electrode tab and negative electrode tab are disposed, an end portion 41B where the positive electrode tab is disposed, and an end portion 41C where the negative electrode tab is disposed.

[0100] When the end portions of the laminated all-solid-state secondary battery 50 where the positive electrode tab or the negative electrode tab is disposed are covered with an insulating coating, as shown in Figure 4 or Figure 5 , each of the end portions 41B or 41C is the same as the above-described end portion 41A except that a plurality of positive electrode tabs or a plurality of negative electrode tabs penetrate the insulating coating 44B or 44C and protrude outward from the outer surface of the insulating coating. In this case, it can also be said that a part of the positive electrode tab or the negative electrode tab on the positive electrode current collector side or the negative electrode current collector side is covered or buried by the insulating coating 44B or 44C.

[0101] Figure 4 is a partial schematic cross-sectional view schematically showing the end portion 41B where the positive electrode tab 5b is disposed in a cross-section along the lamination direction in a preferred embodiment (laminated all-solid-state secondary battery 50) of the all-solid-state secondary battery (laminated type) of the present invention. Figure 5 is a partial schematic cross-sectional view schematically showing the end portion 41C where the negative electrode tab 1b is disposed in a cross-section along the lamination direction in a preferred embodiment (laminated all-solid-state secondary battery 50) of the all-solid-state secondary battery (laminated type) of the present invention.

[0102] As shown in Figure 4 , the laminated all-solid-state secondary battery 50 includes a battery element component 41, and the battery element component 41 includes at least one set of battery cells 42 laminated in sequence including a negative electrode current collector 1B, a negative electrode active material layer 2B, a solid electrolyte layer 3B, a positive electrode active material layer 4B, and a positive electrode current collector 5B. Here, as will be described later, the positive electrode current collector 5B has a positive electrode current collector portion 5a laminated adjacent to the positive electrode active material layer 4B and a positive electrode tab (positive terminal) 5b connected and provided so as to protrude from one end thereof. Further, in the battery element component 41, the positive electrode current collectors 5B are laminated such that the positive electrode tabs 5b are located on the same end side, and the negative electrode current collectors 1B are laminated such that the negative electrode tabs 1b are located on an end portion different from the end portion where the positive electrode tabs 5b are located (usually the opposite end portion) side.

[0103] In the stacked all-solid-state secondary battery 50, at the end portion 41B of the battery element member 41 where the positive electrode tab 5b is disposed, there is an insulating coating body 44B that covers at least the side surface of the battery element member 41 from the outside of the side surface. The positive electrode tab 5b penetrates the insulating coating body 44B and protrudes outward from the outer surface of the insulating coating body 44B. The insulating coating body 44B is formed of a mixture described later. Thus, if the end portion 41B has the insulating coating body 44B, even if there is a positive electrode tab 5b, it is possible to maintain the insulation of the end portion 41B while preventing the occurrence of deformation and defects (collapse, breakage). As a result, this all-solid-state secondary battery 50 can suppress the occurrence of short circuits and exhibits high reliability.

[0104] As Figure 4 shown, a recess 43B is formed in the end portion 41B of the battery element member 41 where the positive electrode tab 5b is disposed, adjacent to the outside in the plane direction of the positive electrode active material layer 4B. More specifically, in the end portion 41B of the battery element member 41, adjacent to the outside in the plane direction of the positive electrode active material layer 4B, a recess 43B is formed by the positive electrode tab 5b, the side surface of the positive electrode active material layer 4B, and the solid electrolyte layer 3B. In other words, the end portion 41B has a recess 43B formed by dividing the recess 43 of the above-mentioned end portion 41A into two by the positive electrode tab 5b. Similar to the above-mentioned end portion 41A, the end portion 41B also has an insulating coating body 44B in the recess 43B, so that the occurrence of short circuits caused by contact between the positive electrode tab 5b and the respective ends of the negative electrode current collector 1B or the negative electrode active material layer 2B can be highly suppressed.

[0105] As Figure 4 shown, a plurality of positive electrode tabs 5b protrude outward from the stacked all-solid-state secondary battery 50, that is, outside the insulating coating body 44B, and are led out. At this time, as long as the plurality of positive electrode tabs 5b do not contact the negative electrode current collector 1B and the negative electrode active material layer 2B inside the all-solid-state secondary battery 50, they can contact each other inside the insulating coating body 44B, but it is preferably not to contact each other. The protruding portions of the positive electrode tabs 5b are not covered by the insulating coating body 44B, and are disposed along the surface of the insulating coating body 44B, and are electrically connected to each other by welding or the like to form a single body. Here, the covering amount of the positive electrode tab 5b covered by the insulating coating body 44B (the length in the plane direction of the positive electrode tab 5b buried in the insulating coating body 44B from the connecting portion with the positive electrode current collecting portion 5a) is not particularly limited, and can be set to 0.1 mm or more, preferably 0.5 to 2 mm.

[0106] As Figure 5 shown, the stacked all-solid-state secondary battery 50 includes Figure 4The above-described battery element component 41 shown. Here, as will be described later, the negative electrode current collector 1B has a negative electrode current collecting portion 1a laminated adjacent to the negative electrode active material layer 2B and a negative electrode tab (negative electrode terminal) 1b connected and provided so as to protrude from one end thereof. Further, in the battery element component 41, as described above, the negative electrode current collector 1B is laminated such that the negative electrode tab 1b is located on the same end side.

[0107] In the laminated all-solid-state secondary battery 50, at the end portion 41C of the battery element component 41 where the negative electrode tab 1b is disposed, there is an insulating coating body 44C that at least covers the side surface of the battery element component 41 from the outside of the side surface. The negative electrode tab 1b penetrates the insulating coating body 44C and protrudes outward from the outer surface of the insulating coating body 44C. The insulating coating body 44C is formed of a mixture described later. Thus, if the end portion 41C has the insulating coating body 44C, even if there is a negative electrode tab 1b, it is possible to maintain the insulation of the end portion 41C while preventing the occurrence of deformation and defects (collapse, breakage). As a result, this all-solid-state secondary battery 50 can suppress the occurrence of short circuits and exhibit high reliability.

[0108] As Figure 5 shown, a concave portion 43C is formed at the end portion 41C of the battery element component 41 where the negative electrode tab 1b is disposed, adjacent to the outside in the plane direction of the positive electrode active material layer 4B. More specifically, at the end portion 41C of the battery element component 41, adjacent to the outside in the plane direction of the positive electrode active material layer 4B, a concave portion 43C is formed by the side surfaces of the positive electrode plate (two positive electrode active material layers 4B and the positive electrode current collector 5B) and the two solid electrolyte layers 3B sandwiching the positive electrode plate. The concave portion 43C is the same as the concave portion 43 of the above-described end portion 41A. Similar to the above-described end portion 41A, the end portion 41C also has an insulating coating body 44C in the concave portion 43C, and thus can highly suppress short circuits caused by contact between the negative electrode tab and the respective ends of the positive electrode current collector or the positive electrode active material layer.

[0109] As Figure 5As shown, a plurality of negative electrode tabs 1b, similar to a plurality of positive electrode tabs 5b, protrude to the outside of the laminated all-solid-state secondary battery 50, i.e., the outside of the insulating coating 44C, and are led out. At this time, as long as the plurality of negative electrode tabs 1b do not contact the positive electrode current collector 5B and the positive electrode active material layer 4B within the all-solid-state secondary battery 50, they may contact each other inside the insulating coating 44C, but it is preferably that they do not contact each other. The protruding portions of the negative electrode tabs 1b are not covered by the insulating coating 44C, and are arranged, for example, along the surface of the insulating coating 44C, and are electrically connected to each other by welding or the like to form a single body. Here, the covering amount of the negative electrode tabs 1b covered by the insulating coating 44C (the length in the plane direction of the negative electrode tabs 1b buried in the insulating coating 44C starting from the connecting portion with the negative electrode current collecting portion 1a) is not particularly limited, and can be set to, for example, 0.1 mm or more, preferably 0.5 - 2 mm.

[0110] The single-layer all-solid-state secondary battery and the laminated all-solid-state secondary battery of the present invention are not limited to the above structures, and can be appropriately changed within the range that does not damage the effects of the present invention.

[0111] For example, in the present invention, the insulating coating does not need to integrally surround (enclose) the peripheral side surface of the end portion of the battery element component for covering, and it is sufficient to cover at least one end portion of the battery element component (for example, the end portion of the battery element component that is prone to short circuit, deformation, or defect). And, in the present invention, the insulating coating does not need to cover the main surface near the edge of the negative electrode current collector and the positive electrode current collector, and it is sufficient to cover at least the side surface of the battery element component. And, in the present invention, in the positive electrode current collector provided with the positive electrode tab, as Figure 4 shown, the insulating coating preferably covers the main surface near the edge (buries a part of the positive electrode tab 5b). Similarly, in the negative electrode current collector provided with the negative electrode tab, as Figure 5 shown, it is preferable to cover the main surface near the edge.

[0112] In the present invention, the inclusion intrusion region preferably exists at at least one interface between adjacent stacked constituent layers in the battery element components in both the single-layer type all-solid-state secondary battery and the stacked type all-solid-state secondary battery. More preferably, it exists at at least one interface at at least one end, and still more preferably, it exists at at least one interface at each end. For example, in the present invention, the interface where the inclusion intrusion region is located is not limited to the interface between the adjacent stacked solid electrolyte layer and the positive electrode active material layer, and any interface between adjacent stacked constituent layers is acceptable. For example, it can be the interface between the solid electrolyte layer and the negative electrode active material layer. The inclusion intrusion region generally tends to preferentially exist at an interface with a weak interfacial adhesion force between adjacent stacked constituent layers. For example, when manufacturing an all-solid-state secondary battery, it can be formed at the interface between constituent layers that are stacked adjacent to each other in an unpressurized state or at the interface between constituent layers that are pressure-bonded with a relatively weak applied pressure. Moreover, the inclusion intrusion region can exist at multiple interfaces, but it does not need to exist at all interfaces. For example, in the single-layer type all-solid-state secondary battery and the stacked type all-solid-state secondary battery, at one end, the proportion of the number of interfaces having an inclusion intrusion region among all the interfaces between adjacent stacked constituent layers can be set to 5% or more, and can also be set to 10 - 90%. And in the stacked type all-solid-state secondary battery, at one end, the proportion of the number of interfaces having an inclusion intrusion region among all the interfaces between the same adjacent stacked constituent layers (for example, all the interfaces between the solid electrolyte layer and the positive electrode active material layer) can be set to 10% or more, and can also be set to 50 - 100%. In the stacked type all-solid-state secondary battery, the interface where the inclusion intrusion region is located is not limited to the interface of the constituent layer forming the concave portion, and can also be the interface between constituent layers with a relatively large main surface area and without forming a concave portion.

[0113] Moreover, in the present invention, the single-layer type all-solid-state secondary battery does not need to have a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer with the same main surface area, and the positive electrode active material layer and the negative electrode active material layer can also have a size difference in the main surface area. In this case, similar to the stacked type all-solid-state secondary battery 50, the insulating inclusion is filled in the concave portion formed by the solid electrolyte layer and the current collector due to the size difference.

[0114] The main surface area of the positive electrode active material layer of the stacked all-solid-state secondary battery is usually set to be smaller than that of the negative electrode active material layer. However, in the present invention, the main surface area of the negative electrode active material layer can also be set to be smaller than that of the positive electrode active material layer, and the positive electrode active material layer and the negative electrode active material layer do not need to have a size difference in the main surface area and can have the same main surface area. When the main surface area of the negative electrode active material layer is set to be smaller than that of the positive electrode active material layer, the end portion of the stacked all-solid-state secondary battery has a concave portion adjacent to the outer side in the plane direction of the negative electrode active material layer.

[0115] And, as Figure 3 shown, the stacked all-solid-state secondary battery is not limited to the manner of stacking battery cells in such a way that the stacking order of the constituent layers is alternately reversed, and can also be the manner of stacking battery cells in such a way that the stacking order of the constituent layers is the same.

[0116] The above-mentioned insulating coating is formed of a mixture having a resin material and insulating inorganic particles.

[0117] (Resin material)

[0118] The resin material is a resin material having physical properties of melting in a temperature range below 300 °C. In the present invention, "thermally melting in a temperature range below 300 °C" means thermally melting in a temperature range below 300 °C under 1 atmosphere pressure, and means being in a molten state at least at a temperature of 300 °C.

[0119] By using this resin material in combination with the insulating inorganic particles described later, while maintaining the particle form of the insulating inorganic particles, the mixture can be heated to the temperature at which the resin material melts. By this heating, the mixture melts and deforms in a manner of covering the end portions of the battery element components according to the pressure while maintaining the mixed state with the insulating inorganic particles. At the same time, it penetrates into the gaps between the battery element components and also flows into the above-mentioned concave portion to bury the concave portion, so that the end portions including the gaps and the concave portion can be sealed or filled. Then, by cooling, the resin material is cured to form an insulating coating formed of the re-cured mixture, so that a state of covering along the end portions of the battery element components with almost no gaps can be formed. Moreover, the molten resin material can penetrate into the constituent layers and can also strengthen the constituent layers (the bonding state of the solid particles). Moreover, it can penetrate into the interface between the constituent layers while maintaining the mixed state with the insulating inorganic particles to form a coating intrusion region including the insulating inorganic particles. In this way, the end portions of the battery element components are covered and strengthened by the insulating coating.

[0120] The resin material has electrical insulation and can maintain the insulation of the end portions of the battery element components.

[0121] The resin material has physical properties of being thermally melted in a temperature range below 300 °C (preferably in a temperature range below 200 °C, more preferably in a temperature range below 150 °C). Herein, based on having a softening point where the complex viscosity drops by more than one digit within a temperature change range of 40 °C in the following shear test using a viscoelasticity measuring device, it can be confirmed that the resin material melts. Therefore, the resin material having the physical property of being hot-melted in a temperature range below XXX °C means that the above softening point (maximum temperature change range of 40 °C) is included in the temperature range below XXX °C. Herein, XXX °C represents 300 °C, 200 °C, or 150 °C.

[0122] <Measurement Conditions>

[0123] When performing vibration measurement using a viscoelasticity measuring device MCR302 (trade name, manufactured by Anton Paar) and parallel plates, the measurement conditions are as follows.

[0124] Angular frequency: 6.28 rad / s

[0125] Measurement mode: Temperature dependence mode

[0126] Temperature: Heating from 25 °C to 200 °C

[0127] Heating rate: Heating from 25 °C to 190 °C over 400 seconds, and then heating to 200 °C over 200 seconds

[0128] The complex viscosity of the resin material at 190 °C is preferably 10 Pa·s or more and 100000 Pa·s or less. The complex viscosity at 190 °C is set to the value measured under the above <Measurement Conditions>.

[0129] The resin material has the physical property of becoming a solid state and coating the end portion after being cooled after melting. For example, it preferably becomes a solid state at 60 °C.

[0130] For the resin material, various resins that satisfy the above melting characteristics can be used. For example, thermoplastic resins, thermoplastic elastomers, and thermosetting resins can be cited, and thermoplastic resins or thermoplastic elastomers are preferred.

[0131] As thermoplastic resins and thermoplastic elastomers, well-known resins, etc. can be used. For example, polyolefin-based thermoplastic elastomers containing polyethylene, polypropylene, etc. as hard segments, polystyrene-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, polybutadiene-based thermoplastic elastomers, ethylene-vinyl acetate-based thermoplastic elastomers (EVA), etc. can be cited.

[0132] Among them, from the viewpoint of having few side reactions with lithium-ion battery materials, polyolefin-based thermoplastic elastomers containing polyethylene, polypropylene, etc. as hard segments are preferred. On the other hand, from the viewpoint of easily forming an intrusion region of the coating containing insulating inorganic particles, EVA is preferred. In the case of EVA, the vinyl acetate content contained in EVA is preferably 11 to 28% by mass, the softening point is preferably in the range of 70 to 115 °C, and a hot melt adhesive composition having a complex viscosity of 10 to 100 cps at 190 °C is preferably used.

[0133] The resin material contained in the mixture may be one kind or two or more kinds. As the weight average molecular weight of the whole resin material contained in the mixture, at the stage of forming the insulating coating, it is preferably 8000 or more and 100000 or less.

[0134] In the present invention, the resin material only needs to become a resin (polymer) when forming the insulating coating. When contained in the mixture, it may be a resin or a polymerizable compound (monomer) that forms a resin. And additives such as a polymerization initiator may be contained.

[0135] (Insulating inorganic particles)

[0136] The insulating inorganic particles have electrical insulation and maintain the end insulation of the battery element components.

[0137] The insulating inorganic particles have physical properties that do not melt at 350 °C. And the insulating inorganic particles are not easily deformed even under pressure during the manufacture and use of the all-solid-state secondary battery and maintain the particle state, and function as an aggregate that resists pressure in the insulating coating.

[0138] By using such insulating inorganic particles in combination with the above resin material, as described above, while maintaining the particle form of the insulating inorganic particles, the mixture can be heated to the temperature at which the resin material melts, and a state of substantially gapless coating along the end of the battery element component can be formed, so that it can function as an aggregate in the insulating coating to prevent deformation and occurrence of defects at the end of the battery element component.

[0139] The insulating inorganic particles preferably have physical properties that do not melt at the temperature at which the resin material melts, for example, preferably have physical properties that do not melt at 250 °C. Here, it can be simply confirmed that the insulating inorganic particles do not melt according to not having the above softening point in the shear measurement test using a viscoelasticity measuring device. In the measurement, a vertical load of 50 N is applied to the parallel plates.

[0140] <Measurement conditions>

[0141] When performing vibration measurement using a viscoelasticity measuring device MCR302 (trade name, manufactured by Anton Paar) and parallel plates, the measurement conditions are as follows.

[0142] Apply a load of 50 N to the parallel plates

[0143] Angular frequency: 6.28 rad / s

[0144] Measurement mode: Temperature dependence mode

[0145] Temperature: Heat from 25°C to 250°C

[0146] Heating rate: Heat from 25°C to 190°C over 400 seconds, and then heat to 250°C over 200 seconds

[0147] Various inorganic particles can be used as the insulating inorganic particles. For example, metal oxides, metal nitrides, metal carbides, metal carbonates, etc. can be cited. From the viewpoint of high hardness and being able to be produced inexpensively by calcination in the atmosphere, metal oxide particles are preferred.

[0148] The metal oxide is not particularly limited. For example, alumina, zirconia, silica, zeolite, ceria, calcium oxide, magnesium oxide, etc. can be cited. Among them, from the viewpoint of being able to produce hard and uniform-sized particles inexpensively, alumina and silica are preferred.

[0149] The metal nitride, metal carbide, and metal carbonate are not particularly limited. For example, nitrides, carbides, and carbonates of aluminum, zirconium, silicon, cerium, calcium, magnesium, etc. can be cited.

[0150] The insulating inorganic particles contained in the mixture can be one kind or two or more kinds.

[0151] The shape of the insulating inorganic particles is not particularly limited and can be spherical, granular, flat, amorphous, etc.

[0152] The particle size of the insulating inorganic particles is not particularly limited and is usually set to be smaller than the layer thickness of the constituent layer, preferably set to be smaller than the average layer thickness of the positive electrode active material layer. Here, the particle size of the insulating inorganic particles is set to D measured by a particle size distribution measuring device (MT3300 (trade name), Microtrac) based on the laser diffraction / scattering method 90 Diameter (the diameter below which 90% of the total is). On the other hand, the lower limit of the particle size of the insulating inorganic particles is not particularly limited and is usually set to be larger than the solid particles forming the constituent layer. Specifically, the particle size (D 90 Diameter) of the insulating inorganic particles can be set to 0.01 - 100 μm, preferably 0.5 - 60 μm.

[0153] The content rate of the resin material in the mixture is preferably 6 to 50% by mass, more preferably 8 to 40% by mass, and still more preferably 10 to 30% by mass.

[0154] The content rate of the insulating inorganic particles in the mixture is preferably 50 to 94% by mass, more preferably 60 to 92% by mass, and still more preferably 70 to 90% by mass.

[0155] In the mixture, the ratio of the content rate of the insulating inorganic particles to the content rate of the resin material [content rate of insulating inorganic particles / content rate of resin material] is not particularly limited, and is preferably 1 to 15.6, more preferably 1.5 to 11.5, and still more preferably 2.3 to 9.

[0156] In addition, for the insulating coating, the above-mentioned respective content rates and the content rate ratio are also the same.

[0157] The mixture is a mixture of a resin material and insulating inorganic particles, including a mixture of a resin and insulating inorganic particles, a mixture of a polymerizable compound and insulating inorganic particles, and a mixture of a resin and insulating inorganic particles is preferred. The mixture is preferably a molten solid obtained by previously melt-mixing a mixture of a resin material and insulating inorganic particles and then curing it, and more preferably a molten solid of a resin material and insulating inorganic particles. The molten solid may be a molten solid of a mixture of a resin material that melts in a temperature range of 300°C or lower and insulating inorganic particles that do not melt at 350°C, and is preferably a molten solid of a mixture of a resin material that melts in a temperature range of 200°C or lower and insulating solid particles that do not melt at 250°C.

[0158] The mixture preferably does not contain an insulating inorganic material having the following physical properties: having electronic insulation and being solid at 100°C (i.e., having a melting point exceeding 100°C) and thermally melting in a temperature range of 200°C or lower. Examples of such an insulating inorganic material include sulfur (monomeric sulfur) and / or modified sulfur, iodine, a mixture of iodine and sulfur, etc. In the present invention, the mixture not containing an insulating inorganic material means that the content of the insulating inorganic material in the mixture is less than 5% by mass, preferably 1% by mass or less.

[0159] <Solid electrolyte layer>

[0160] The solid electrolyte layer is an electronically insulating electrolyte layer, and a layer used as a solid electrolyte layer of an all-solid-state secondary battery can be used without particular limitation.

[0161] The solid electrolyte layer contains an inorganic solid electrolyte. The inorganic solid electrolyte is not particularly limited, and common components can be used. For example, sulfide-based inorganic solid electrolytes and oxide-based inorganic solid electrolytes can be cited. In the present invention, a soft and fragile sulfide-based inorganic solid electrolyte can be used because it can improve the reliability of the ends of battery element components, thereby enabling a all-solid-state secondary battery with high ionic conductivity to be realized. The shape of the inorganic solid electrolyte is not particularly limited and can be spherical, granular, flat, amorphous, etc. The particle size of the inorganic solid electrolyte is not particularly limited. From the viewpoint of strengthening the constituent layer with the above-mentioned insulating inorganic particles, it is preferably smaller than the particle size of the insulating inorganic particles. For example, it can be set to 0.5 to 20 μm. Here, the particle size of the inorganic solid electrolyte is set to D 90 measured in the same manner as the particle size of the above-mentioned insulating inorganic particles. The diameter. The content rate of the inorganic solid electrolyte in the solid electrolyte layer is not particularly limited. For example, it can be set to 90 to 99% by mass.

[0162] The solid electrolyte layer may appropriately contain a binder and other additives. These binder and additives are not particularly limited, and common components used in all-solid-state secondary batteries can be used.

[0163] The size (main surface area) of the solid electrolyte layer is not particularly limited and can be appropriately set. Usually, it is set to the same size as the negative electrode active material layer. The thickness of the solid electrolyte layer is not particularly limited and can be appropriately determined according to the type of all-solid-state secondary battery (number of battery cells), use, required characteristics, etc. The thickness of the solid electrolyte layer can be set to 5 to 300 μm, for example, or can also be set to 30 to 50 μm.

[0164] The solid electrolyte layer can be used alone or as a plate electrode laminated on the active material layer of the current collector.

[0165] <Negative electrode active material layer>

[0166] The negative electrode active material layer is at least an ion-conductive layer, and a layer used as the negative electrode active material layer of an all-solid-state secondary battery can be used without particular limitation.

[0167] The negative electrode active material layer can be a composite layer formed by binding solid particles containing the above-mentioned inorganic solid electrolyte and the negative electrode active material. The negative electrode active material is not particularly limited, and carbonaceous materials, metal oxides, metal composite oxides, etc. can be used. The shape of the negative electrode active material is not particularly limited, and it can be spherical, granular, flat, amorphous, etc. The particle size of the negative electrode active material is not particularly limited, and from the viewpoint of strengthening the negative electrode active material layer with the above-mentioned insulating inorganic particles, etc., it is preferably smaller than the particle size of the insulating inorganic particles, and can be set to 0.5 to 55 μm, for example. Here, the particle size of the negative electrode active material is set as D 90 measured in the same manner as the particle size of the above-mentioned insulating inorganic particles. The content rate of the negative electrode active material in the negative electrode active material layer is not particularly limited, and can be set to 30 to 70% by mass, for example. And, the content rate of the inorganic solid electrolyte in the negative electrode active material layer is not particularly limited, and can be set to 30 to 70% by mass, for example. The negative electrode active material layer can contain commonly used conductive aids, binders, and other additives.

[0168] The size (main surface area) of the negative electrode active material layer is not particularly limited, and can be appropriately set. It can be set to the same size as the positive electrode active material layer, or can be set to a size larger than the positive electrode active material layer. In a laminated all-solid-state secondary battery, the size of the negative electrode active material layer is usually set to a size larger than the positive electrode active material layer. The size difference between the negative electrode active material layer and the positive electrode active material layer is not particularly limited and can be appropriately set. The thickness of the negative electrode active material layer is not particularly limited, and can be appropriately determined according to the type of all-solid-state secondary battery (number of battery cells), use, required characteristics, etc. The thickness of the negative electrode active material layer can be set to 5 to 300 μm, for example, or can also be set to 30 to 50 μm.

[0169] The negative electrode active material layer can be used alone or as a negative electrode plate laminated on a negative electrode current collector described later.

[0170] <Positive electrode active material layer>

[0171] The positive electrode active material layer is at least an ion-conductive layer, and a layer used as the positive electrode active material layer of an all-solid-state secondary battery can be used without particular limitation.

[0172] The positive electrode active material layer can be a composite layer formed by bonding solid particles containing the above-mentioned inorganic solid electrolyte and positive electrode active material. The positive electrode active material is not particularly limited, and transition metal oxides, etc. can be used. The shape of the positive electrode active material is not particularly limited, and can be spherical, granular, flat, amorphous, etc. The particle size of the positive electrode active material is not particularly limited, and from the viewpoint of strengthening the positive electrode active material layer with the above-mentioned insulating inorganic particles, etc., it is preferably smaller than the particle size of the insulating inorganic particles, and can be set to 0.5 to 55 μm, for example. Here, the particle size of the positive electrode active material is set to D 90 measured in the same manner as the particle size of the above-mentioned insulating inorganic particles. The content rate of the positive electrode active material in the positive electrode active material layer is not particularly limited, and can be set to 50 to 90% by mass, for example. The content rate of the inorganic solid electrolyte in the positive electrode active material layer is not particularly limited, and can be set to 10 to 50% by mass, for example. The positive electrode active material layer can contain commonly used conductive aids, binders, and other additives.

[0173] The size (main surface area) of the positive electrode active material layer is not particularly limited and can be set appropriately. The thickness of the positive electrode active material layer is not particularly limited and can be appropriately determined according to the type of all-solid-state secondary battery (number of battery cells), use, required characteristics, etc. The thickness of the positive electrode active material layer can be set to 5 to 300 μm, for example, or can also be set to 30 to 50 μm.

[0174] The positive electrode active material layer can be used alone or as a positive electrode plate laminated on the following positive electrode current collector.

[0175] <Negative electrode current collector and positive electrode current collector>

[0176] The negative electrode current collector and the positive electrode current collector (hereinafter, sometimes collectively referred to as "current collector" or "substrate") can each be used without particular limitation as a current collector for an all-solid-state secondary battery, and metal plates (foils) such as aluminum, aluminum alloy, copper, copper alloy, stainless steel, nickel, iron, and titanium are usually used.

[0177] As the current collector, a thin plate-shaped current collector having a current collecting portion laminated adjacent to the active material layer and a tab connected and provided so as to protrude from one end thereof can be used. From the viewpoint of being able to maintain high lamination accuracy and shorten the lamination time to manufacture battery cells or battery element components, it is preferably provided with at least one positioning hole. The tab usually does not contact the active material layer, and for example, an insulating portion or the like is provided between the connection portion with the current collecting portion or the end portion of the active material layer.

[0178] The shape of the current collector is not particularly limited and can be appropriately determined according to the shape of the all-solid-state secondary battery, etc. The current collecting portion of the current collector is preferably in the shape of a thin plate that is rectangular (usually rectangular) in plan view.

[0179] As a preferred mode of the current collector, a thin plate-shaped current collector having a current collecting portion, a tab connected in a manner protruding from one end thereof, and a base material extending portion connected in a manner protruding from the other end of the current collecting portion (preferably, the end edge on the opposite side of the current collecting portion with respect to the above-mentioned one end) can be cited. As such a preferred current collector, the positive current collector 5C corresponding to the positive electrode plate 8 shown in Figure 6A and the negative current collector 1C corresponding to the negative electrode plate 9 shown in Figure 6B can be cited. In addition, Figure 6A The positive electrode plate 8 in which the positive electrode active material layer 4B is formed in the positive electrode current collecting portion 5a is shown. Figure 6B The negative electrode plate (also referred to as a negative electrode plate with an electrolyte layer) 9 in which the negative electrode active material layer 2B (not shown) and the solid electrolyte layer 3B are sequentially formed in the negative electrode current collecting portion 1a is shown.

[0180] As Figure 6A shown, the positive current collector 5C has: a positive current collecting portion 5a that is rectangular in plan view; a pair of base material extending portions 5c extending in a manner protruding substantially rectangularly from both ends (long side edge) near one short side edge thereof; and one positive tab 5b extending in a manner protruding substantially rectangularly from substantially the center of the other short side edge. In addition, regions for preventing short circuit by contacting the positive current collecting portion 5a are provided between the pair of base material extending portions 5c and at the positive tab 5b side edge of the positive current collecting portion 5a, respectively. Similarly, as Figure 6B shown, the negative current collector 1C has: a negative current collecting portion 1a that is rectangular in plan view; a pair of base material extending portions 1c extending in a manner protruding substantially rectangularly from both ends (long side edge) near one short side edge thereof; and one negative tab (also referred to as a lead portion) 1b extending in a manner protruding substantially rectangularly from substantially the center of the other short side edge.

[0181] The positive current collecting portion 5a and the negative current collecting portion 1a are regions adjacent to the active material layer and are regions in which the positive electrode active material layer 4B or the negative electrode active material layer 2B is formed, respectively.

[0182] The positive electrode tab 5b and the negative electrode tab 1b (hereinafter sometimes collectively referred to as tabs) are components that serve as lead tabs in all-solid-state secondary batteries, and each has a circular positioning hole 5d or 1d formed therethrough inside thereof (e.g., at approximately the central portion). One circular positioning hole 5d or 1d is respectively formed through the inside (e.g., at approximately the central portion) of a pair of substrate extension portions 5c and 1c. In addition, the dimensions of the substrate extension portions 5c and 1c and the tabs can be appropriately determined respectively. When using a current collector provided with tabs or substrate extension portions, if a mixture of the ends of the current collector not provided with tabs or substrate extension portions (usually the two ends on the long side) and the ends of the current collector provided with tabs or substrate extension portions (usually the two ends on the short side) is pressed and caused to flow inward to fill the recesses of the battery element components, it is necessary to remove the mixture adhering to the tabs or substrate extension portions before welding. In order to avoid such cumbersome operations, as in Example C described later, the tabs can also be lengthened so that the mixture does not adhere to the welded portion.

[0183] As Figure 6A and Figure 6B shown, the region including the positioning hole on the current collecting portion side of the tab, the entire surface of the substrate extension portion, and further preferably the region for preventing the above-mentioned short circuit are preferably coated with an insulating material such as an insulating resin, and more preferably coated with the mixture (molten solidified body) described later. For example, as described later, a strip-shaped molded body (molten solidified body) 5e or 1e formed by molding the mixture into a strip shape is attached. By being coated with an insulating material, especially by the mixture, when co-positioning using the positioning hole in a preferred manufacturing method of the battery element components described later, deformation, breakage, etc. of the tab and the substrate extension portion can be effectively suppressed. As a result, high overlapping accuracy can be maintained, and the battery element components or battery cells can be manufactured with a shortened lamination time. Also, when coated with the mixture, an insulating coating body can be formed by the manufacturing method described later.

[0184] The shapes of the positioning holes 1d and 5d are preferably similar to the cross-sectional shape perpendicular to the axis of the positioning pin described later. For example, they can be circular, elliptical, polygonal, or star-shaped, and are preferably circular. The inner diameter of the positioning hole is not particularly limited and can be appropriately determined according to the dimensions of the battery element components, etc. As an example, it can be set to 1.0 to 6.0 mm, for instance.

[0185] The current collectors, for example, can be the same or different in terms of shape and positioning holes. The positive electrode current collector and the negative electrode current collector are preferably the same respectively.

[0186] The size of the current collector (the longitudinal length and the lateral length of the main surface) is not particularly limited and can be appropriately determined according to the use, required characteristics, etc. Usually, it is preferable that the portions other than the tab and the substrate extension portion (the current collection portion and the short-circuit prevention region) have the same shape with substantially the same size. However, regarding the current collection portion, it is further preferable that the main surface surface area of the positive current collection portion 5a is smaller than that of the negative current collection portion 1a. The thickness of the current collector is also not particularly limited and can be appropriately determined according to the type of the all-solid-state secondary battery (the number of battery cells), use, required characteristics, strength, etc. The thickness of the current collector can be set to, for example, 5 to 30 μm.

[0187] <Other structures>

[0188] In the present invention, a functional layer can be provided between adjacent constituent layers, and a protective member such as a frame or a film can be provided outside the all-solid-state secondary battery. Further, the constituent layer can be composed of a single layer or multiple layers.

[0189] [Method for manufacturing an all-solid-state secondary battery]

[0190] The method for manufacturing the all-solid-state secondary battery of the present invention (sometimes simply referred to as the manufacturing method of the present invention) at least includes the following steps: a step of disposing a mixture of a resin material melted in a temperature region of 300°C or lower and insulating inorganic particles that do not melt at 350°C at an end portion of a battery element member including a lamination unit in which one or more sets of a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer are sequentially laminated; and a step of heating the mixture at a temperature at which the resin material melts while applying pressure in the inner direction of the battery element member.

[0191] According to the manufacturing method of the present invention including the above steps, the above-mentioned insulating coating can be filled in the end portion of the battery element member without a gap, and thus an all-solid-state secondary battery that maintains the insulation of the end portion of the constituent layer and is not easily deformed or defective can be manufactured.

[0192] In the manufacturing method of the present invention, for each of the steps of disposing the mixture and the pressing step, the steps can be performed together for all the end portions of the battery element member, or can be performed sequentially for each end portion, and can be performed multiple times for one end portion. For example, in the case of using a current collector having a rectangular current collection portion, the steps can also be performed for one end portion of two sets of opposed end portions and then for the other end portion. In the case where each step is performed multiple times and in the case of performing sequentially, the steps performed multiple times can be the same or different. For example, as the step of disposing the mixture, there can be mentioned a step of previously disposing the mixture on the tab of the current collector, etc., and a step of disposing the mixture after manufacturing the battery element member. And, as the heating step, there can be mentioned the steps described later.

[0193] In the manufacturing method of the present invention, the step of disposing the above-described mixture can also be carried out in a state where the battery element components are pressurized in the stacking direction, that is, the following steps can be carried out in sequence: a step of pressurizing the battery element components including a stacking unit formed by laminating at least a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in this order in one or more groups in the stacking direction; and a step of disposing the above-described mixture at the end of the battery element components pressurized in the stacking direction.

[0194] In the manufacturing method of the present invention, it is preferable that the above-described pressurizing step is carried out in a state where the battery element components are pressurized in the stacking direction, that is, it is preferable to carry out the following steps in sequence: a step of pressurizing the battery element components including a stacking unit formed by laminating at least a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in this order in one or more groups in the stacking direction; a step of disposing the above-described mixture at the end of the battery element components pressurized in the stacking direction; and a step of pressurizing the battery element components pressurized in the stacking direction in the inner direction of the battery element components while heating the mixture at a temperature at which the resin material melts. According to the preferable method of pressurizing the battery element components in the stacking direction, the battery element components are pressurized in the stacking direction before the mixture is pressurized at the end of the battery element components or during the pressurization of the mixture, and thus the intrusion of the mixture caused by pressurizing the mixture in the inner direction of the battery element components can be restricted to the end region of the constituent layer with uneven layer thickness, and the intrusion of the mixture into the central region of the constituent layer with uniform layer thickness can be effectively suppressed, thereby preventing a decrease in battery capacity caused by an insulating mixture being interposed between the constituent layers. In addition, the change in the stacking state of the battery element components caused by the load acting when the mixture is pressurized in the inner direction of the battery element components can be prevented.

[0195] In the manufacturing method of the present invention, in the above-mentioned pressing step, the mixture disposed at the end of the battery element component is pressed in the inward direction of the battery element component to cause it to deform and flow. At this time, for example, it is preferable to press the battery element component in the stacking direction to press the mixture in the stacking direction to prevent deformation and flow in this direction, while causing it to deform and flow in the inward direction of the battery element component. The deformation and flow of such a mixture are preferably carried out, for example, by the following steps in sequence: a step of disposing the mixture at the end of the battery element component including a stacking unit formed by laminating at least one set of a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in sequence; and a step of heating the mixture at a temperature at which the resin material melts, restricting the deformation and flow of the battery element component in the stacking direction, and pressing it in the inward direction to cause it to deform and flow. In this method, from the viewpoint of easily achieving deformation and flow in the inward direction, it is preferable that the mixture has a layer thickness thicker than the thickness of the end of the battery element component (preferably the thickness of the active material) adjacent to the mixture. Also, in this method, before or after the step of disposing the mixture, a step of disposing flow restricting members for pressing the battery element component in the stacking direction to restrict the deformation and flow of the mixture in this direction can be carried out in front of and behind the battery element component in the stacking direction. In the manufacturing method having this step, the above-mentioned pressing step can also be carried out. As the above-mentioned pressing step, it is preferable to heat the mixture while moving the flow restricting member in the stacking direction to press the battery element component (indirectly pressing) to cause the mixture to deform and flow toward the inward direction. In this manufacturing method, the step of disposing the mixture and the pressing step can also be carried out in multiple times. According to this manufacturing method, it is easy to cause the mixture to deform and flow toward the inward direction of the battery element component, so that the mixture penetrates into the end of the constituent layer, especially the end of the constituent layer with uneven layer thickness, and in addition to ensuring insulation, the end can also be strengthened. This method is particularly effective in the method of previously disposing the mixture on the current collector.

[0196] <Manufacturing or preparing a battery element component>

[0197] In the manufacturing method of the present invention, first, a battery element component is manufactured or prepared.

[0198] In the case of manufacturing a single-layer all-solid-state secondary battery, a battery element component having Figure 1The battery element component of the layer structure shown. The manufacturing method is not particularly limited, and examples thereof include a film-forming method or a molding method using a composition containing solid particles. For example, it can be manufactured through the following steps: preparing a positive electrode composition containing a positive electrode active material and an inorganic solid electrolyte, an electrolyte composition containing an inorganic solid electrolyte, and a negative electrode composition containing a negative electrode active material and an inorganic solid electrolyte, sequentially coating the negative electrode composition, the electrolyte composition, and the positive electrode composition on a negative electrode current collector and drying them, and then placing a positive electrode current collector. The coating method and drying conditions of each composition can be appropriately determined.

[0199] In the case of manufacturing a laminated all-solid-state secondary battery, each constituent layer can be formed in the same manner as the above-mentioned single-layer all-solid-state secondary battery, but a method of manufacturing a plate electrode having active material layers formed on two main surfaces of a current collector and laminating them via a solid electrolyte layer is preferred. For example, a negative electrode plate having negative electrode active material layers on two main surfaces of a negative electrode current collector and a positive electrode plate having positive electrode active material layers on two main surfaces of a positive electrode current collector are manufactured. A specified number of negative electrode plates with an electrolyte layer and positive electrode plates having solid electrolyte layers transferred to the surfaces of the negative electrode active material layers are alternately laminated to manufacture a battery element component. Here, the battery element component can be pressurized in the laminating direction to make it denser. In addition, each constituent layer can be formed in the same manner as the single-layer all-solid-state secondary battery.

[0200] In the manufacturing method of the present invention, from the viewpoint of being able to maintain high overlapping accuracy and positioning a plurality of plate electrodes together to shorten the manufacturing time (laminating time), and thus being able to manufacture a battery element component with high productivity, it is preferred to laminate a specified number of plate electrodes formed using the current collector having the above-mentioned positioning holes and position them together (sometimes referred to as a preferred manufacturing method of the battery element component). Specifically, it is preferred to alternately laminate a plurality of negative electrode plates with an electrolyte layer having negative electrode active material layers and solid electrolyte layers on two main surfaces of a negative electrode current collector having the above-mentioned positioning holes and a plurality of positive electrode plates having positive electrode active material layers on two main surfaces of a positive electrode current collector having the above-mentioned positioning holes, position them together using the positioning holes, and for example, insert a positioning pin described later into the positioning holes communicating in the laminating direction of the plate electrodes to manufacture a battery element component. At this time, the tabs and the substrate extension portions of each current collector are covered with an insulating material (preferably the mixture described later), so that deformation, breakage, etc. of the tabs and the substrate extension portions can be effectively suppressed during the positioning together using the positioning holes.

[0201] The preferred manufacturing method of the battery element component has the following steps 1 and 2.

[0202] Step 1: A step of alternately stacking a rectangular positive electrode plate and a rectangular negative electrode plate having positioning holes via a solid electrolyte layer and performing temporary positioning, thereby obtaining a temporarily stacked electrode plate group in which the positioning holes communicate with each other in the stacking direction

[0203] Step 2: A step of inserting a positioning pin through the above-mentioned communication holes that appear in the step of obtaining the temporarily stacked electrode plate group until it protrudes from one opening side to the other opening side to perform formal positioning on the rectangular positive electrode plate and the rectangular negative electrode plate constituting the temporarily stacked electrode plate group

[0204] In Step 2, it is preferable to insert the positioning pin while restricting the variation in the stacking direction of one opening side of the communication hole (for example, the area where the positioning holes are provided in the electrode plate).

[0205] Here, the communication hole means that a plurality of positioning holes arranged on a line in the stacking direction of a plurality of stacked electrode plates as shown in Figure 7 and FIG. 8(A) overlap when viewed from above, so that it is possible to visually recognize from the uppermost positioning hole through the lowermost positioning hole.

[0206] The preferred manufacturing method of the above battery element components can be carried out using an appropriate device. For example, from the viewpoint of being able to manufacture battery element components and form an insulating coating, it is preferably carried out using a manufacturing device having a cell stack accommodating frame, a positioning jig, and a restricting member. The cell stack accommodating frame is a frame for temporarily stacking a plurality of electrode plates in such a way that communication holes are formed by communicating positioning holes with each other, and is preferably the following cell stack accommodating frame. The positioning jig is a jig provided with a positioning pin inserted through the communication hole for positioning the electrode plate, and is preferably the following positioning jig. The restricting member is a member that restricts the variation in the stacking direction of one opening side of the communication hole, and is preferably the following restricting member.

[0207] Cell stack accommodating frame: It is a cell stack accommodating frame having an accommodating space for accommodating a rectangular positive electrode plate and a rectangular negative electrode plate having positioning holes in a state of being alternately stacked via a solid electrolyte layer. The rectangular positive electrode plate and the rectangular negative electrode plate are accommodated in the accommodating space and temporarily positioned, thereby becoming a temporarily stacked electrode plate group in which the positioning holes communicate with each other

[0208] Positioning jig: It is a positioning jig that is set to be movable relatively in front of or behind the temporarily stacked electrode plate group in the stacking direction and is provided with a positioning pin inserted through the positioning hole

[0209] Restricting member: A restricting member that is configured to be able to move relatively to the opposing position of the positioning jig (positioning pin) with the frame body interposed between the electrode plate groups and to be able to move relatively closer to or away from the positioning jig, and has: a restricting portion that restricts variations in the stacking direction on one opening side of the communication hole formed by the positioning holes communicating with each other; and a pin receiving portion that is provided on the restricting portion and receives the positioning pin (coming through the positioning holes).

[0210] Reference Figures 7 - 11 , a manufacturing apparatus 70 as an embodiment of the above-described manufacturing apparatus, a battery element component using the manufacturing apparatus 70, and a preferred manufacturing method of the laminated all-solid-state secondary battery will be described.

[0211] Figure 7 It is a schematic plan view showing a state in which a plurality of electrode plates are accommodated in the accommodation space 71c of the frame body 71 and temporarily positioned in a preferred manufacturing method of a battery element component using the preferred manufacturing apparatus 70.

[0212] FIG. 8(A) is a schematic cross-sectional view illustrating an initial state in the process of performing formal positioning in a preferred manufacturing method of a battery element component using the preferred manufacturing apparatus 70, showing a cut surface on a plane perpendicular to the length direction of the frame body 71 and passing through the center of the pin receiving portion 73a. FIG. 8(B) is a schematic cross-sectional view illustrating a completed state in the process of performing formal positioning in a preferred manufacturing method of a battery element component using the preferred manufacturing apparatus 70, showing a cut surface on a plane perpendicular to the length direction of the frame body 71 and passing through the center of the pin receiving portion 73a. In FIGS. 8(A) and 8(B) (collectively referred to as FIG. 8), only the vicinity of the communication holes of the electrode plates in the formal positioning process is shown. In addition, in FIG. 8, in order to ensure visual recognition, the number of electrode plates accommodated in the accommodation space is different from the number of electrode plates used in Example D and is shown less.

[0213] Figure 9 It is a schematic cross-sectional view showing a state in which the formally positioned battery element components are pressure-constrained in the stacking direction in a preferred manufacturing method of the laminated all-solid-state secondary battery using the preferred manufacturing apparatus 70, showing a cut surface on a plane perpendicular to the length direction of the frame body 71 and passing through the center of the pin receiving portion 73a.

[0214] Figure 10 It is a schematic cross-sectional view showing a state in which the formally positioned battery element components are pressure-constrained in the stacking direction in a preferred manufacturing method of the laminated all-solid-state secondary battery using the preferred manufacturing apparatus 70, showing a cut surface on a plane perpendicular to the length direction of the frame body 71 and at a substantially central portion in the length direction.

[0215] Figure 11This is a schematic cross-sectional view showing a method of forming an insulating coating at an end portion by disposing a rod-shaped molding body near the end portion of a battery element component and applying pressure in a preferred manufacturing method of a laminated all-solid-state secondary battery using a preferred manufacturing apparatus 70.

[0216] In addition, in FIGS. 8 to Figure 11 the number of laminated sheets of the electrode plates in the battery element component also varies, but this is a difference in the drawings, and of course they are the same in the actual manufacturing method.

[0217] The manufacturing apparatus 70 only needs to include the above-described electrode plate group accommodation frame 71, positioning jig 72, and restricting member 73, and may appropriately include other constituent devices (mechanisms), such as a conveying device for conveying the electrode plates to the accommodation space, a device for carrying the electrode plate group accommodation frame or the positioning jig, and other constituent devices.

[0218] In the manufacturing apparatus 70, the lamination direction (gravity direction) of the electrode plates is referred to as the vertical direction, and the advancing direction of the positioning pin 72a in this direction is referred to as the downward direction. In the present invention, the "electrode plate" refers to either or both of the positive electrode plate and the negative electrode plate.

[0219] As Figure 7 shown in FIGS. and 8, the electrode plate group accommodation frame (sometimes simply referred to as the frame) 71 is, for example, a box body (single-sided open frame) having a rectangular bottom 71a and side walls (peripheral walls) 71b erected from the bottom 71a, and has an accommodation space 71c surrounded by them. The accommodation space 71c accommodates a plurality (predetermined number) of electrode plates (here, the negative electrode plate 9 with an electrolyte layer and the positive electrode plate 8) in a state of being alternately laminated via the solid electrolyte layer, and is thus set to have a shape and size such that the positioning holes formed in the base material extension portion and the electrode tabs in the lamination direction communicate with each other. The shape and size of such an accommodation space 71c are determined according to the shape or size of the electrode plates, the piercing positions, numbers, shapes, or sizes of the positioning holes, and the stacking speed, etc. Usually, it is rectangular in plan view like the electrode plates, and the depth can be appropriately determined according to the thickness and number of the laminated electrode plates. As Figure 7 shown, the internal dimensions of the frame 71 (the dimensions of the accommodation space 71c) are preferably set to be relatively large with respect to the dimensions of the electrode plates (the larger dimension when the dimensions of the negative electrode plate 9 with an electrolyte layer and the positive electrode plate 8 are different) so as to form communication holes in the positioning holes.

[0220] The side walls on the long side of the side walls 71b erected from the bottom 71a are each provided on the bottom and the side walls on the short side in a manner that they can be detached from the bottom and the side walls on the short side or can approach and separate from each other. If the side walls on the long side are provided in this way, in addition to being able to manufacture the battery element component, an insulating coating can also be provided at the end portion on the long side of the battery element component.

[0221] At a position on the bottom 71a corresponding to the positioning pin 72a of the positioning jig 72 to be vertically provided as described later, a hole 71d through which the positioning pin passes is provided (refer to FIG. 8).

[0222] As Figure 9 shown, the positioning jig 72 may be a component having a positioning pin 72a vertically provided on a flat base (not shown in FIGS. and FIG. 8). The axis vertical sectional shape, vertically provided position, configuration, etc. of the positioning pin 72a can be determined corresponding to the shape, piercing position, configuration, etc. of the positioning holes in the electrode plates 8 and 9. In addition, in the present invention, as the positioning jig, the positioning pin can also be used alone without having a flat base. Figure 7 The shape of the positioning pin 72a is not particularly limited as long as it can be inserted into the positioning hole and position the electrode plate. Generally, as

[0223] shown, it preferably has a pin main body portion (also referred to as a trunk portion) with a diameter smaller than the inner diameter of the positioning hole and a tip portion (also referred to as a tapered portion) extending from one end of the pin main body portion. The axis vertical sectional shape of the tip portion and the pin main body portion is not particularly limited, and can be, for example, circular, elliptical, polygonal, star-shaped, and is preferably circular. As described later, the tip portion functions to guide the positioning pin 72a to be inserted into the communication hole on the gradually expanding circumferential side surface, and to assist in the overlapping position adjustment function of the pin main body portion. And the pin main body portion functions as follows: by sequentially inserting from the front end of the tip portion into the communication hole, the electrode plate whose overlapping position is shifted by the contact between the outer peripheral surface and the inner periphery (inner surface) of the positioning hole is adjusted to a specified overlapping position. If such a tip portion is provided, it is easy to insert the positioning pin 72a into the communication hole that appears in the temporarily laminated electrode plate group, and while preventing damage, impairment, etc. of the substrate extension portion caused by the insertion of the positioning pin 72a, high-precision positioning of the electrode plate can be achieved. Figure 9 shown, it preferably has a pin main body portion (also referred to as a trunk portion) with a diameter smaller than the inner diameter of the positioning hole and a tip portion (also referred to as a tapered portion) extending from one end of the pin main body portion. The axis vertical sectional shape of the tip portion and the pin main body portion is not particularly limited, and can be, for example, circular, elliptical, polygonal, star-shaped, and is preferably circular. As described later, the tip portion functions to guide the positioning pin 72a to be inserted into the communication hole on the gradually expanding circumferential side surface, and to assist in the overlapping position adjustment function of the pin main body portion. And the pin main body portion functions as follows: by sequentially inserting from the front end of the tip portion into the communication hole, the electrode plate whose overlapping position is shifted by the contact between the outer peripheral surface and the inner periphery (inner surface) of the positioning hole is adjusted to a specified overlapping position. If such a tip portion is provided, it is easy to insert the positioning pin 72a into the communication hole that appears in the temporarily laminated electrode plate group, and while preventing damage, impairment, etc. of the substrate extension portion caused by the insertion of the positioning pin 72a, high-precision positioning of the electrode plate can be achieved.

[0224] The outer diameter of the pin main body portion can be appropriately determined according to the inner diameter of the positioning hole, etc. The length of the pin main body portion can be appropriately determined as long as it is the length that penetrates the positioning hole of the temporarily laminated electrode plate group.

[0225] The restricting member 73 may be a component having a restricting portion and a pin receiving portion (pin receiving hole) formed in the flat base. In the manufacturing apparatus 70, the bottom 71a of the frame 71 also serves as the restricting member 73. The surface of the bottom 71a (the bottom surface of the accommodation space 71c) functions as a restricting portion that restricts the displacement of the tab or the substrate extension portion during formal positioning (when inserting the positioning pin 72a), that is, restricts the displacement of the communication hole H that appears.

[0226] The position and arrangement of the pin receiving portion 73a (hole 71d) can be determined in correspondence with the upright position and arrangement of the positioning pin 72a. The pin receiving portion 73a only needs to be formed so that the positioning pin 72a can be inserted, and can be determined to an appropriate size according to the outer diameter and insertion amount of the pin receiving portion 73a.

[0227] The manufacturing device 70 preferably includes a correction member 74 for correcting the electrode plates 8 and 9 stacked in the storage space 71c to be flat. Examples of such correction member 74 include plate-shaped members or block-shaped members having a flat surface, and a press machine or the like can also be used. In the manufacturing device 70, the correction member 74 only needs to have a size that can correct the electrode plates in the stacking direction, and for example, it is formed to have the same size as the main surface size of the storage space 71c of the frame 71, such as Figure 9 As shown in the figures, it is arranged side by side with the storage space side surface of the cover of the frame body 71.

[0228] From the viewpoint of preventing the mixed body from deforming and flowing in the stacking direction and causing it to deform and flow in the inner direction in the pressurizing process described later, the correction member 74 is preferably configured as follows: Figure 9 As shown, the temporary stacked electrode group (battery element component) accommodated in the accommodation space 71c and formally positioned is pressed in the stacking direction, thereby limiting the deformation and flow of the mixture in the stacking direction. The pressing limiting component plays a role (also serving as a pressing limiting component). In the case where the correction component 74 also serves as the pressing limiting component, the correction component 74 has a thickness that can press in the stacking direction of the temporary stacked electrode group that has been formally positioned together with the limiting component 73. In the present invention, from the viewpoint of limiting deformation and flow, the pressing limiting component can also be referred to as a flow limiting component. In addition, in the present invention, the correction component 74 and the pressing limiting component can also be provided separately, and sometimes the above-mentioned limiting component and the pressing limiting component are collectively referred to as a flow limiting component.

[0229] Each device constituting the manufacturing device 70 may be formed of any appropriate material. The portion of the transport device and the like that comes into contact with the active material layer is preferably formed of resin, rubber, or the like to prevent damage to the active material layer.

[0230] Hereinafter, a preferred method for producing battery element components will be described by taking an embodiment using the production apparatus 70 as an example.

[0231] (Process 1)

[0232] In a preferred method for manufacturing a battery element component, a rectangular positive electrode plate and a rectangular negative electrode plate (sometimes simply referred to as a positive electrode plate or a negative electrode plate) are used as the electrode plate. Therefore, in the present invention, when referred to as a "electrode plate", it refers to a general term for a positive electrode plate and a negative electrode plate unless otherwise specified.

[0233] First, makeFigure 6A the positive electrode plate 8 shown and Figure 6B the negative electrode plate 9 with an electrolyte layer shown.

[0234] The positive electrode current collector 5C constituting the positive electrode plate 8 is as described above. The positive electrode plate 8 is produced by forming a positive electrode active material layer 4B on the surface of the positive electrode current collecting portion 5a of the positive electrode current collector 5C by an appropriate method. On the other hand, the negative electrode plate 9 with an electrolyte layer is produced by sequentially laminating and forming a negative electrode active material layer 2B and a solid electrolyte layer 3B on the surface of the negative electrode current collecting portion 1a of the negative electrode current collector 1C constituting the same by an appropriate method. As Figure 6A and Figure 6B shown, in the positive electrode plate 8 and the negative electrode plate 9, the region including the positioning hole on the current collecting portion side of the tab, the entire surface of the base material extension portion, and the region for preventing the above short circuit are all coated with a mixture (molten solid) described later. The method of coating with the mixture is as described above.

[0235] Next, as Figure 7 shown, in the accommodation space 71c of the housing 71, a plurality of (a specified number of) negative electrode plates 9 and positive electrode plates 8 are accommodated in a state of being alternately laminated with their main surfaces in contact with each other across the solid electrolyte layer, and temporary positioning is performed. For example, it is preferable to laminate a plurality of negative electrode plates (refer to Figure 6B .) 9 having a negative electrode active material layer 2B and a solid electrolyte layer 3B on two main surfaces of the negative electrode current collector 1C having the above positioning hole 1d and a plurality of positive electrode plates (refer to Figure 6A .) 8 having a positive electrode active material layer 4B on two main surfaces of the positive electrode current collector 5C having the above positioning hole 5d alternately. At this time, the orientation of laminating a plurality of bipolar plates and the position of arranging the tabs are not particularly limited and can be on the same side. In the present invention, it is preferable as follows: as Figure 7 shown, in a plurality of bipolar plates, for the same-polarity plates, they are laminated with the base material extension portion and the tab located on the same side in the long side direction of the same-polarity plate, and the negative electrode plate 9 and the positive electrode plate 8 are laminated with the base material extension portion and the tab located on opposite sides in the long side direction of the plate. That is, it is preferable that the positive electrode tab 5b and the negative electrode tab 1b are laminated in opposite directions so as not to overlap in the lamination direction of the plates.

[0236] Here, the electrode plates 8 and 9 placed (accommodated) in the accommodation space 71c are temporarily positioned by the accommodation space 71c. In the same-polarity electrode plate group, the positioning holes connected in the stacking direction do not completely shift from other positioning holes in the plane direction, but at least partially overlap. As a result, the positioning holes 1d of the negative electrode plate 9 communicate with each other (in the overlapping area) at intervals in the stacking direction (the direction of gravity), so that communication holes H appear inside each positioning hole 1d. Also, similarly for the positioning holes 5d of the positive electrode plate 8, the positioning holes 5d communicate with each other at intervals in the stacking direction, so that communication holes H appear inside each positioning hole 5d. Thus, a temporarily stacked electrode plate group is formed in which the positioning holes provided in the same electrode plate communicate with each other.

[0237] In a preferred manufacturing method of the present invention, it is also possible to press or apply pressure to the temporarily stacked electrode plate group in the stacking direction to flatten it or make the electrode plates closely adhere to each other. Thereby, the appearance of the communication holes H can be assisted or the size of the communication holes can be increased.

[0238] (Process 2)

[0239] In a preferred manufacturing method of the battery element component, next, a formal positioning process is performed.

[0240] As shown in FIG. 8, the positioning pins 72a of the positioning jig 72 are inserted through the respective communication holes H that appear in Process 1. At this time, as shown in FIG. 8(A), the tip portion of the positioning pin 72a first enters the communication hole H. As shown in FIG. 8(B), then the pin main body portion enters the communication hole H, and finally it is inserted (inserted until it protrudes from the other opening side of the communication hole to one opening side) into the appeared communication hole H. Here, the tip portion that first enters the communication hole H guides the pin main body portion into the communication hole H on the gradually expanding circumferential surface and assists in adjusting the overlapping position of the pin main body portion. Then, as the pin main body portion enters the communication hole H, the tip portion enters the communication hole H, and thus the electrode plate whose overlapping position is shifted due to the contact between its outer peripheral surface and the inner peripheral surface of the positioning hole moves in its plane direction (horizontal direction), so that it can be positioned at a specified overlapping position. Here, the displacement of the positioning pin 72a in the advancing direction is restricted by the restricting member 73 for the substrate extending portion and the ear, that is, the appeared communication hole H, so the insertion is quickly completed. Moreover, as described above, the substrate extending portion and the ear are strengthened by being coated with an insulating material (preferably a mixture), so when inserting the positioning pin 72a, the substrate extending portion and the ear, especially the positioning hole, will not be damaged, and the insertion is quickly completed. In the example shown in FIG. 8, the positive electrode plate 8 and the negative electrode plate 9 are respectively positioned by three positioning pins 72a.

[0241] Thus, the pin main body part functions to adjust the overlapping position. As a result, while preventing breakage, damage, etc. of the base material extension part and the tab, particularly the positioning hole H, the plurality of electrode plates are moved in the surface direction thereof (the direction perpendicular to the insertion direction of the positioning pin) to accurately adjust the overlapping position of the electrode plates, thereby precisely performing formal positioning on the temporarily stacked electrode plate group that is temporarily positioned.

[0242] In a preferred manufacturing method of the battery element component, the battery element component 41 can be simply manufactured in the above-described manner.

[0243] Hereinafter, taking the method of using the manufacturing apparatus 70 as an example, the manufacturing method of the laminated all-solid-state secondary battery will be described. In addition, the manufacturing method of the single-layer all-solid-state secondary battery is the same as the manufacturing method of the laminated all-solid-state secondary battery except that one set of battery cells is used as the battery element component.

[0244] <Preparation or production of the mixture>

[0245] In the manufacturing method of the present invention, a mixture of a resin material that melts in a temperature range of 300°C or lower and insulating inorganic particles that do not melt at 350°C is produced or prepared. The mixture can be prepared by mixing the resin material and the insulating inorganic particles, but it is preferably prepared by pre-melting and mixing at a temperature above the melting temperature of the resin material and then cooling to obtain a molten solid. The mixture and the molten solid are as described above. The mixing method is not particularly limited, and an appropriate method can be adopted. The mixing temperature can also be appropriately set in consideration of the melting temperature of the resin material and the like.

[0246] <Step of disposing the mixture>

[0247] In the manufacturing method of the present invention, the mixture is disposed at the end of the battery element component produced or prepared in the above-described manner. Here, in the subsequent heating and pressing step, the mixture is disposed at positions and in amounts that cover the entire range in the stacking direction of the end (side surface) of the battery element component. As described above, the end at which the mixture is disposed does not need to be the entire circumferential side surface of the end of the battery element component, and it is sufficient if it is at least one end of the battery element component. Also, the mixture only needs to be disposed at the end of the battery element component, and in addition to the end, it can also be disposed on the outermost main surface side or the main surface in the stacking direction. The disposition position of the mixture at the end is usually disposed at a position more outside than the side surface of the battery element component, and it can also be disposed at an interval from the end (side surface) of the battery element component, but from the viewpoint of being able to fill the battery element component and the insulating coating without gaps, it is preferably disposed in contact with the end (side surface). The usage amount of the mixture can be appropriately set in consideration of the end to be covered, the thickness of the insulating coating, the pressing force in the heating and pressing step, etc.

[0248] Regarding the end portion provided with the tab, from the viewpoint of being able to form an insulating coating without gaps at the end portion (end face and recess) of the battery element component, the arrangement position of the mixture is preferably arranged in contact with the end portion (side face) of the active material layer of the tab of the electrode plate. And, from the viewpoint of being able to substantially cover the end portion (end face and recess) of the battery element component with the insulating coating without gaps, the mixture is preferably arranged between two tabs that are spaced apart in the stacking direction. The arrangement method of such a mixture is not particularly limited, and the mixture can also be arranged after manufacturing the battery element component. However, as described above, a method of previously providing a strip-shaped molded body of the mixture on the main surface of the tab of the electrode plate used is preferred. Specifically, the mixture can be processed into a strip with the same layer thickness as the active material layer in advance using a hot roll press or the like, for example, and the strip-shaped molded body (melted and solidified body) of the mixture can be welded to the main surface of the tab in a state adjacent to the active material layer using a hot iron or the like. By previously providing the strip-shaped molded body of the mixture in this way, the narrow-gap end portion, particularly the recess 43B, of the positive electrode tab 5b can be reliably filled with the insulating coating 44B.

[0249] As a method of arranging the mixture on the main surface of the tab, from the viewpoint of being able to arrange the layer thickness and width with high precision, a method of heating the strip-shaped molded body of the mixture to a temperature above the melting temperature of the resin material contained in the mixture and locally transferring and attaching it to a specified area of the tab is preferred. Moreover, in this case, by covering the main surface of the tab with the mixture, it is possible to effectively suppress damage to the tab and the positioning hole when positioning the temporarily stacked electrode plate group. Also, when drilling the positioning hole, burrs generated on the inner periphery of the positioning hole are suppressed, the inner peripheral shape of the positioning hole is stabilized, and the positioning accuracy of the formal positioning is improved. Therefore, it is preferred when setting the positioning hole. As another method, for example, a method of locally arranging the mixture on a specified area of the tab using a hot melt adhesive machine can be cited. In this method, the mixture can be arranged in a specified area by a simple method.

[0250] Regarding the end portion provided with the base material extension portion, similar to the end portion provided with the tab, it is preferred to arrange the mixture on the main surface of the base material extension portion of the electrode plate. The arrangement position and arrangement method of the mixture are the same as those in the end portion provided with the tab.

[0251] In addition, in the present invention, in addition to the end portion provided with the tab, other base material extension portions can be provided and a strip-shaped molded body of the mixture can be previously provided. For example, in the case where the electrode plate has a rectangular shape, as Figure 6A and Figure 6BAs shown, it is preferable to preliminarily provide a strip-shaped molded body of the mixture at the tab provided at the short-side edge of the electrode plate and the base material extension provided at the short-side edge facing the edge. More preferably, positioning holes are provided in the tab or the base material extension to improve the positioning accuracy of the battery element components. Here, as a method for improving the positioning accuracy of the battery element components, the preferred manufacturing method of the above battery element components is preferred, and particularly preferred is the preferred manufacturing method of the above battery element components using the above manufacturing apparatus 70.

[0252] <Pressurization step>

[0253] In the manufacturing method of the present invention, in the above-described manner, while heating the mixture at the temperature at which the resin material in the mixture melts in a state where the mixture is disposed at the end of the battery element component, pressurization is performed in the inward direction of the battery element component. By this step, as described above, the mixture melts and deforms in a manner of covering the end of the battery element component while maintaining the mixed state with the insulating inorganic particles. At the same time, it penetrates into the gaps of the battery element component and, in the case of having the above-described recess, also flows into the recess to fill the recess. Further, the molten resin material penetrates into the constituent layers. Moreover, it is preferable to penetrate into the interface between the constituent layers while maintaining the mixed state with the insulating inorganic particles. Then, the resin material is cured by cooling to form an insulating coating formed of the re-cured mixture, so that a state of covering along the shape of the end of the battery element component with substantially no gap can be formed. In addition, it is preferable to form a coating intrusion region.

[0254] Further, in the case of using a mixture of a polymerizable compound and insulating inorganic particles as the mixture, the mixture undergoes a polymerization reaction to become a resin while deforming in a manner of covering the end.

[0255] Regarding the heating temperature, considering the melting temperature of the resin material and the temperature at which the particle state of the insulating inorganic particles can be maintained, it can be set to a temperature range above the melting temperature of the resin material, for example, above the melting temperature of the resin material and below the thermal decomposition temperature of the resin material, and preferably set to above the melting temperature of the resin material and below the melting temperature + 150°C.

[0256] As a pressing method, any method that can actually fill the mixture without gaps along the end shape of the battery element component is acceptable. For example, a method of arranging the battery element component and the mixture on a hot plate and pressing the mixture with a pressing component while heating, a method of heating and pressing using an isostatic pressing device such as a hot isostatic pressing device (HIP) or a warm isostatic pressing device (WIP), etc., can be cited. In the case where the battery element component is pre-pressed and densified in the stacking direction, the above method using a hot plate can be preferably applied. On the other hand, the above method using an isostatic pressing device can simultaneously perform the densification of the battery element component and the formation of the insulating coating, and can highly strengthen while maintaining the insulation of the end of the battery element component.

[0257] The pressing force when pressing the mixture can be appropriately set considering the heating temperature, the melt viscosity of the resin material, etc. The pressing force based on the isostatic pressing device can be set to 10 - 1000 MPa, preferably 20 - 600 MPa. In the present invention, from the viewpoint of being able to fill the mixture without gaps along the end shape of the battery element component and also being able to densify (improve battery performance), it is preferred to first press the mixture arranged at the end of the battery element component with a pressure of 1 - 10 MPa, and then press with the above pressure using an isostatic pressing device or the like.

[0258] When pressing the mixture, for example, in the case of using a hot plate, from the viewpoint of being able to suppress the stacking offset of the electrode plates even when the mixture is pressed into the interior direction of the battery element component, it is preferred to press the battery element component in the stacking direction. The pressing force at this time is preferably in the range that can suppress the stacking offset of the electrode plates and does not cause damage in the active material layer, and can generally be set to 1 - 50 MPa.

[0259] In the manufacturing method of the present invention, after the above method using a hot plate, a method of heating and pressing using an isostatic pressing device can also be performed. In particular, in the case of using a positive electrode active material layer and a negative electrode active material layer having a size difference, it is preferred to first press the mixture into the concave portion of the battery element component by the above method using a hot plate, and then, by the method of heating and pressing using an isostatic pressing device, form an insulating coating while densifying each battery element component. In this method, the heating temperature based on the hot plate can be set to a temperature lower than the heating temperature based on the isostatic pressing device. If this heating and pressing process is divided into two stages, the mixture can be filled into the concave portion of the battery element component practically without gaps, and a coating intrusion region can be formed at the interface, so that high strengthening can be achieved while maintaining the insulation of the end of the battery element component. As a result, densification of the battery element component at higher temperature and higher pressure can be achieved, thereby improving battery performance.

[0260] In the manufacturing method of the present invention, the step of disposing the mixture and the pressing step can be carried out using the battery element components taken out from the above-mentioned manufacturing apparatus 70, or can be carried out in a state of being accommodated in the housing 71 of the manufacturing apparatus 70.

[0261] When the manufacturing method of the present invention is carried out using the above-mentioned manufacturing apparatus 70, the following steps can be carried out in sequence to manufacture a laminated all-solid-state secondary battery: a step of previously disposing a mixture at the tab or the substrate extension portion and pressing the end portion provided with the tab or the substrate extension portion; then, a step of disposing a mixture at the end portion where the tab and the substrate extension portion are not provided and heating it. In addition, in this manufacturing method, the above-mentioned manufacturing apparatus 70 further includes a pressing plate 75 for pressing the mixture into the end portion of the battery element component in addition to the above-mentioned constituent components.

[0262] That is, before taking out the battery element component manufactured in the accommodation space 71c of the housing 71 from the housing 71, the battery element component together with the housing 71 is heated to a temperature higher than the melting temperature of the resin material in the mixture, so that the strip-shaped molded body of the mixture previously provided on the electrode plate is melted, and the two short-side portions of the battery element component are fixed and filled with the mixture (molten mixture). For example, as Figure 9 and Figure 10 shown, in a state where the positioning jig 72 is inserted through the pressing restriction member 74, the battery element component is heated by, for example, a hot plate. In this way, the battery element component is pressed and restricted by the pressing restriction member 74 and the restriction member 73 in the stacking direction, so that the strip-shaped molded body provided on the tab and the substrate extension portion does not deform or flow in the stacking direction, but deforms and flows at least in the inward direction in a balanced manner. In this way, the strip-shaped molded body provided on the tab and the substrate extension portion can be filled in a state of being in contact with the end face of the active material layer with almost no gap, and an inclusion intrusion region can be formed at the interface.

[0263] Next, with respect to the long-side portion of the battery element component, the side wall on the long-side portion is removed in a state where the battery element component is pressed and constrained in the vertical direction, a rod-shaped or strip-shaped molded body of the mixture is disposed at the end portion on the long-side portion, and then, it is heated and melted and pressed into the end face and the recess. For example, as Figure 11As shown, in a state where the battery element part is pressed in the stacking direction by the pressing restriction part 74 and the restriction part 73, on the long side end part of the exposed battery element part near the side wall 71b on the long side of the disassembling frame 71, a mixture is arranged, for example, a strip-shaped molded body or a rod-shaped molded body 76 is arranged. Then, while maintaining this state, heating is performed together with the frame 71 using a hot plate or the like, and at the same time, the press-in plate 75 arranged outside the mixture is moved toward the long side end part, so that the mixture deforms and flows in the inward direction. In this way, the mixture can be filled in the long side end part of the battery element part with virtually no gap, and an inclusion intrusion area can be formed at the interface.

[0264] In the case of manufacturing a laminated all-solid-state secondary battery, before or after the above heating and pressing process, as Figure 4 shown, leads are provided by connecting the negative electrode tabs of the negative electrode current collectors to each other by welding or the like (refer to Figure 5 .). And leads are provided by connecting the positive electrode tabs of the positive electrode current collectors to each other by welding or the like.

[0265] Moreover, normal assembly processes such as enclosing the all-solid-state secondary battery with an end portion covered with an insulating coating in a frame can be performed.

[0266] In this way, single-layer and laminated all-solid-state secondary batteries in which the end portions of the battery element parts are covered with an insulating coating can be manufactured.

[0267] Examples

[0268] Hereinafter, the present invention will be described in further detail based on examples, but the present invention is not limited thereto and is not to be construed as such. In the following examples, unless otherwise specified, "parts" and "%" indicating composition are based on mass. In the present invention, "room temperature" means 25°C.

[0269] In the examples, unless otherwise specified, operations are performed in an argon atmosphere or a dry atmosphere with a dew point of -60°C or lower.

[0270] [Example A]

[0271] In Examples A-1 to A-6 and Comparative Examples A-1 to A-3, laminated all-solid-state secondary batteries including a positive electrode active material layer and a negative electrode active material layer having a size difference were manufactured and evaluated.

[0272] In addition, Examples A-1 to A-6 and Comparative Examples A-1 to A-3 were basically set to have the same structure except for the content shown in Table 1, and one of the differences was the presence or absence or composition of the insulating coating (mixture).

[0273] <Fabrication of negative electrode plate>

[0274] 53% by mass of mixed natural graphite, 45% by mass of argyrodite sulfide solid electrolyte (Li 6 PS 5 Cl), 2% by mass of a rubber-based binder (in terms of solid content), and a mixed solvent of tetralin - anisole were used to prepare a negative electrode mixture paste. Subsequently, the obtained negative electrode mixture paste was coated on both sides of a stainless steel (SUS) negative electrode current collector so that the film thickness after coating and drying became 130 μm, and then dried to produce a negative electrode plate having negative electrode active material layers on both sides.

[0275] In addition, the main surface size of the negative electrode active material layer was set to 2.5 cm × 2.5 cm.

[0276] In Examples A-1 to A-6 and Comparative Example A-3, it was confirmed that the particle size (D 90 ) of natural graphite particles in the negative electrode active material layer was smaller than the particle size (D 90 ) of alumina particles or PMMA particles in the mixture (molten solid) described later.

[0277] <Fabrication of Solid Electrolyte Sheet for Transfer>

[0278] 98% by mass of argyrodite sulfide solid electrolyte (Li 6 PS 5 Cl), 2% by mass of a rubber-based binder (in terms of solid content), and a mixed solvent of tetralin - anisole were used to prepare a paste containing a solid electrolyte. Subsequently, the obtained paste containing a solid electrolyte was coated on one side of a 10-μm-thick stainless steel foil so that the film thickness after coating and drying became 120 μm, and then dried to produce a solid electrolyte sheet for transfer.

[0279] In addition, the main surface size of the solid electrolyte layer was set to 2.5 cm × 2.5 cm.

[0280] In Examples A-1 to A-6 and Comparative Example A-3, it was confirmed that the particle size (D 90 ) of solid electrolyte particles in the solid electrolyte layer was smaller than the particle size (D 90 ) of alumina particles or PMMA particles in the mixture (molten solid) described later.

[0281] <Fabrication of Solid Electrolyte Layer - Stacked Negative Electrode Plate>

[0282] After overlapping the solid electrolyte layer of the solid electrolyte sheet for transfer on each negative electrode active material layer of the fabricated negative electrode plate and performing a pressing process, the stainless steel foil was peeled off from the solid electrolyte layer to produce a solid electrolyte layer - stacked negative electrode plate (having the same meaning as a negative electrode with an electrolyte layer).

[0283] In addition, the weight per unit area (mass per unit area) of the negative electrode active material layer and the solid electrolyte layer did not change (decrease) due to the pressing treatment.

[0284] <Fabrication of the positive electrode plate>

[0285] The positive electrode mixture paste was prepared by mixing 66 mass% of the positive electrode active material NCM523 (a material obtained by coating the surface of LiNi 3 Coated with LiNi 0.5 Co 0.2 Mn 0.3 Particles), 30 mass% of the argyrodite sulfide solid electrolyte (Li 6 PS 5 Cl), 3 mass% of VGCF (carbon fiber manufactured by SHOWA DENKO K.K.) as a conductive aid, a total of 1 mass% (in terms of solid component conversion value) of a rubber-based binder and a cellulose-based binder, and a tetralin - anisole mixed solvent. Subsequently, the obtained positive electrode mixture paste was coated on both sides of an aluminum (Al) positive electrode current collector so that the film thickness after coating and drying became 90 μm, and then dried to fabricate a positive electrode plate having positive electrode active material layers on both sides.

[0286] In addition, the main surface size of the positive electrode active material layer was set to 2.0 cm × 2.0 cm.

[0287] In Examples A-1 to A-6 and Comparative Example A-3, it was confirmed that the particle diameter (D 90 ) of the NCM523 particles in the positive electrode active material layer was smaller than the particle diameter (D 90 ) of the alumina particles or PMMA particles in the mixture (molten solidified body) described later.

[0288] <Fabrication of battery element components>

[0289] The battery element components including 10 sets of battery cells were fabricated by laminating 6 solid electrolyte layer - laminated negative electrode plates and 5 positive electrode plates alternately in order from the negative electrode plate.

[0290] In addition, a negative electrode tab was provided on one of the four sides of each negative electrode plate (each negative electrode current collector), a positive electrode tab was provided on one of the four sides of each positive electrode plate (each positive electrode current collector), and after forming an insulating coating on the end portion of the battery element components, the tabs of the same polarity were welded to each other. Regarding the lamination direction of the solid electrolyte layer - laminated negative electrode plate and the positive electrode plate, they were laminated so that the negative electrode tab and the positive electrode tab were in opposite directions.

[0291] As Figure 3As shown, in the fabricated battery element component, a recess 43 is formed by the side surface of the positive electrode plate and two solid electrolyte layers sandwiching the positive electrode plate in a manner adjacent to the outer side in the plane direction of the positive electrode active material layer. On the side where the positive electrode tab is provided (the end of the battery element component), as Figure 4 shown, a recess 43B is formed by the positive electrode tab, the side surface of the positive electrode active material layer, and the solid electrolyte layer. On the side where the negative electrode tab is provided (the end of the battery element component), as Figure 5 shown, a recess 43C is formed by the side surface of the positive electrode plate and two solid electrolyte layers sandwiching the positive electrode plate.

[0292] <Preparation of the Mixture (Molten Solidified Body)>

[0293] Polyvinyl acetate (EVA, manufactured by BOSCH) and alumina particles (D based on the above method 90 with a diameter of 50 μm) were put into a glass bottle, placed on a hot plate, heated to 140 °C and melt-kneaded with a silicone spatula, and then cooled to room temperature to prepare molten solidified bodies A1 to A4. In addition, the mixing ratio (content rate) of EVA and alumina particles was set to the value shown in the "Mass Ratio (Resin Material / Insulating Inorganic Particles)" column of Table 1.

[0294] Furthermore, a mixed resin with a mass ratio of 4:1 of polypropylene resin (PP) or polyethylene resin (PE) and EVA (manufactured by BOSCH) (hereinafter referred to as "PE / EVA mixed resin") and alumina particles (D based on the above method 90 with a diameter of 50 μm) were put into a glass bottle, placed on a hot plate, heated to 210 °C (PP) or 175 °C (PE / EVA mixed resin), and melt-kneaded with a silicone spatula, and then cooled to room temperature to prepare molten solidified bodies A5 and A6, respectively. In addition, the mixing ratio (content rate) of PP or PE / EVA mixed resin and alumina particles was set to the value shown in the "Mass Ratio (Resin Material / Insulating Inorganic Particles)" column of Table 1.

[0295] Moreover, EVA (manufactured by BOSCH) and particles of polymethyl methacrylate (referred to as PMMA particles. D based on the above method 90 with a diameter of 53 μm, manufactured by COREFRONT) were put into a glass bottle, placed on a hot plate, heated to 140 °C and melt-kneaded with a silicone spatula, and then cooled to room temperature to prepare molten solidified body A7. In addition, the mixing ratio (content rate) of EVA and PMMA particles was set to the value shown in the "Mass Ratio (Resin Material / Insulating Inorganic Particles)" column of Table 1.

[0296] The softening points and complex viscosities of EVA, PP, PE / EVA blended resin, and alumina particles were confirmed according to the above-mentioned shear tests. As a result, the softening point of EVA was 80 to 90 °C, and the complex viscosity at 190 °C was 30 Pa·s. The softening point of PP was 160 °C, and the complex viscosity at 190 °C was 1000 Pa·s. The softening point of the PE / EVA blended resin was 130 °C, and the complex viscosity at 190 °C was 1000 Pa·s. Also, it was confirmed that the alumina particles did not have a softening point in the temperature range up to 350 °C and did not melt at 350 °C and 250 °C. The softening point of PMMA particles was 100 to 110 °C.

[0297] The vinyl acetate content, complex viscosity at 190 °C, and weight-average molecular weight of EVA were within the above ranges. Also, the weight-average molecular weights of PP and the PE / EVA blended resin were within the above ranges.

[0298] <Manufacture of laminated all-solid-state secondary battery>

[0299] Heat-resistant films (made of polyphenylene sulfide (PPS)) that were 1 cm larger on each side than the size of the battery element part (2.5 cm × 2.5 cm) were arranged below and above the produced battery element parts, and a molten solid (amount capable of entirely covering the end part and the circumferential side surface: 2 g) was arranged between the two films arranged above and below the battery element part and near the end part of the battery element part (throughout the entire circumference). The compositions of the molten solids A1 to A7 used in Examples A-1 to A-6 and Comparative Example A-3 are shown in the "Insulating coating body (molten solid)" column of Table 1. Additionally, no molten solid was arranged in Comparative Example A-1, and only EVA resin was arranged in place of the molten solid in Comparative Example A-2.

[0300] Next, while maintaining this state, the molten solid was melted on a hot plate set to the following temperature, and the melt was pressed from above in a state sealed by the two films so that it flowed toward the end part (inside) and flowed into the recess of the battery element part. Then, cooling was performed. The battery element part (temporary laminated battery) into which the insulating coating body had flowed into the recess thus obtained was wrapped with a laminated film, and further warm isostatic pressing was performed for 1 minute under the conditions of a temperature of 190 °C and a pressure of 588 MPa, filling the insulating coating body into the recess of the battery element part to form an insulating coating body at the end part of the battery element part and densifying each battery element part.

[0301] Here, the melting temperature of the molten solid (set temperature of the hot plate) was set to the melting point of the resin material used + 50 °C. Specifically, it was set to 140 °C in Examples A-1 to A-4 and Comparative Examples A-1 to A-3, 210 °C in Example A-5, and 180 °C in Example A-6.

[0302] Thus, the laminated all-solid-state secondary batteries of each example and each comparative example were manufactured separately.

[0303] [Evaluation 1: Confirming the state of the end portion of the solid electrolyte layer]

[0304] For each of the manufactured laminated all-solid-state secondary batteries, using a scanning electron microscope (model: Hitachitabletop SEM TM4000Plus, manufactured by Hitachi High-Tech Corporation), five sites near an arbitrary interface between the positive electrode active material layer and the solid electrolyte layer in the end portion cross-section of the battery element components obtained by fracture and ion beam cross-section polishing (Cross Section Polisher) were observed at a magnification of 200 times. In the obtained SEM photographs, the state (presence or absence of deformation and presence or absence of defects) of the end portion of the solid electrolyte layer was visually confirmed. The results are shown in the column of "State of the end portion of the SE layer" in Table 1.

[0305] Among all the observed sites, the sites where no deformation or defect occurred at the end portion of the solid electrolyte layer were designated as "〇" (qualified). On the other hand, the cases where deformation or defect occurred at the end portion of the solid electrolyte layer at even one site were designated as "×" (unqualified), and the state (crack generation, crack, etc.) was also recorded.

[0306] [Evaluation 2: Confirming the presence or absence of an inclusion intrusion region]

[0307] In the SEM photographs obtained in the above Evaluation 1, whether there was an inclusion intrusion region at the interface between the positive electrode active material layer and the solid electrolyte layer was checked. And in the case where there was an inclusion intrusion region, the number of insulating inorganic particles contained in the inclusion intrusion region was counted and the average value was obtained. In the case where there was an inclusion intrusion region at even one site at the interface between the positive electrode active material layer and the solid electrolyte layer, it was recorded as "Yes" in the column of "Presence or absence of an inclusion intrusion region" in Table 1, and the average value of the number of insulating inorganic particles was shown in the column of "Number of insulating inorganic particles in the inclusion intrusion region" in Table 1. On the other hand, in the case where there was no inclusion intrusion region at even one site at the interface between the positive electrode active material layer and the solid electrolyte layer, it was recorded as "No" in the column of "Presence or absence of an inclusion intrusion region" in Table 1.

[0308] In addition, the intrusion amount and average thickness of the inclusion intrusion region were measured from the SEM photographs, and the obtained average values were shown in Table 1.

[0309] [Evaluation 3: Confirming the occurrence of a short circuit]

[0310] For the fabricated laminated all-solid-state secondary battery, a charge-discharge cycle in which it was charged at a constant current / constant voltage (CCCV) of 1.3 mA up to 4.35 V and discharged at 1.3 mA down to 3.0 V was defined as one cycle, and it was repeated 3 times at 25°C using a charge-discharge evaluation device TOSCAT (trade name, manufactured by TOYO SYSTEM Co., Ltd.). At this time, the horizontal axis was set as the charge capacity (current × time) and the vertical axis was set as the charge voltage to obtain a charge curve.

[0311] In the evaluation, during the charge-discharge of 3 cycles, if the charge voltage reached 4.35 V all 3 times, it was regarded as no short circuit occurred and marked as "〇" (qualified). On the other hand, during the charge-discharge of 3 cycles, if the charge voltage did not reach 4.35 V even once and charging was impossible (judged as a short circuit occurred), it was marked as "×" (unqualified). The results are shown in the column of "Confirmation of short circuit occurrence" in Table 1.

[0312] [Evaluation 4: Ratio of discharge capacity]

[0313] In the above [Evaluation 3: Confirmation of short circuit occurrence], taking the discharge capacity of the 3rd cycle of Example A-4 as the reference, the ratio of the discharge capacities of the 3rd cycle in Examples A-1 to A-6 was calculated, and the results are shown in the column of "Discharge capacity (relative ratio)" in Table 1. In addition, short circuits occurred in Comparative Examples A-1 to A-3, so the ratio of discharge capacities was not evaluated (indicated by "-" in the column of "Discharge capacity (relative ratio)" in Table 1).

[0314] In Table 1 and Table 2 described later, "SE" refers to the solid electrolyte layer. Also, in the "Positive electrode" column, when forming a positive electrode active material layer on the surface of the current collector, the method of setting the positive electrode active material layer on both main surfaces of the current collector is expressed as "double-sided", and the method of setting the positive electrode active material layer on one side (one main surface) of the current collector is expressed as "single-sided". Similarly, in the "SE negative electrode" column, when forming a negative electrode active material layer on the surface of the current collector and transferring the solid electrolyte layer on its surface, the method of setting the negative electrode active material layer and the solid electrolyte layer on both main surfaces of the current collector is expressed as "double-sided", and the method of setting the negative electrode active material layer and the solid electrolyte layer on one side of the current collector is expressed as "single-sided". Moreover, the "bonding interface" refers to the interface that was not pre-pressurized and bonded before manufacturing the battery element components, but was pressurized and bonded by hot isostatic pressing during the manufacturing of the battery element components. As described above, this interface is an interface where the mixture easily intrudes and an inclusion intrusion region is easily formed. In fact, in Examples A-1 to A-6, an inclusion intrusion region was formed at one or more interfaces.

[0315]

[0316] [Example B]

[0317] In Example B-1 and Comparative Example B-1, single-layer all-solid-state secondary batteries including a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer having the same size (the same main surface surface area) were manufactured and evaluated. In addition, Example B-1 and Comparative Example B-1 were basically set to have the same structure except for the contents shown in Table 2, and one of the differences was the presence or absence of an insulating coating (mixture).

[0318] A single-layer all-solid-state secondary battery composed of battery element components of a set of battery cells having the layer structure shown below was manufactured in the following manner. Figure 1 shown layer structure of a set of battery cells

[0319] Specifically, in the same manner as in Example A, a negative electrode plate and a positive electrode plate were respectively produced by providing an active material layer on one main surface of a current collector. By overlapping the transfer solid electrolyte sheet produced in Example A on the negative electrode active material layer of the negative electrode plate and pressing, the solid electrolyte layer was transferred onto the negative electrode active material layer, and a solid electrolyte layer laminated negative electrode plate was produced. The positive electrode active material layer of the positive electrode plate was overlapped on the solid electrolyte layer of the solid electrolyte layer laminated negative electrode plate to produce battery element components including a set of battery cells.

[0320] (Example B-1)

[0321] Next, in the same manner as in Example A-1, near the end of the battery element components, the molten solid (amount capable of entirely coating the end and the peripheral side surface: 1 g) A1 was preformed into a sheet (thickness 250 μm) using a hot roll press. An opening of 2.5 cm × 2.5 cm was made in the sheet, and after the battery element components were embedded and arranged in the opening, warm isostatic pressing was performed to form an insulating coating on the end of the battery element components, and the single-layer all-solid-state secondary battery of Example B-1 was manufactured.

[0322] (Comparative Example B-1)

[0323] The battery element components including a set of battery cells produced in the above manner were used as the all-solid-state secondary battery of Comparative Example B-1.

[0324] In the obtained single-layer all-solid-state secondary battery of Example B-1, the coating amount L covered by the insulating coating on the main surface near the edge of the negative electrode current collector was 0.1 mm.

[0325] For each of the fabricated single-layer all-solid-state secondary batteries, [Evaluation 1] to [Evaluation 3] were conducted in the same manner as in Example A-1. Among them, the observation sites in [Evaluation 1] and [Evaluation 2] were set to one site. An inclusion intrusion region was formed at the "bonding interface" of Example B-1.

[0326] In addition, the layer thicknesses of the positive electrode active material layer and the negative electrode active material layer in each single-layer all-solid-state secondary battery were both 60 μm or more.

[0327] [Table 2]

[0328]

[0329] [Example C]

[0330] In Examples C-1 to C-6 and Comparative Examples C-1 to C-3, laminated all-solid-state secondary batteries including a positive electrode active material layer and a negative electrode active material layer having a size difference were fabricated using current collectors with relatively long tabs, and evaluations thereof were conducted. In addition, in Examples C-1 to C-6 and Comparative Example C-3, molten solids A1 to A7 having the same compositions as in Examples A-1 to A-6 and Comparative Example A-3 were used, respectively. In Comparative Example C-1, no molten solid was disposed, and in Comparative Example C-2, only an EVA resin was disposed instead of the molten solid.

[0331] <Fabrication of negative electrode plate>

[0332] In the fabrication of the negative electrode plate of Example A-1, the negative electrode current collector was changed to the following negative electrode current collector with a tab, and except for this, the negative electrode plate was fabricated in the same manner as in the fabrication of the negative electrode plate of Example A-1. That is, a negative electrode tab having a width of 2.5 cm and a length of 5.5 cm was formed on one of the four sides of the 2.5 cm × 2.5 cm negative electrode current collecting portion to fabricate a negative electrode current collector with a tab.

[0333] Next, in the same manner as the production of the negative electrode plate in Example A-1, a negative electrode active material layer and a solid electrolyte layer were formed on the negative electrode current collector portion of the negative electrode current collector with a tab. Then, using a hot melt adhesive machine (nozzle diameter 1 mm), a molten solid with a width of 2.5 cm × a length of 3 mm × a height of 0.3 mm was attached only to one side of the main surface at a position 1 mm away from the negative electrode active material layer of the negative electrode tab. Thus, a negative electrode plate with a solid electrolyte layer laminated thereon was produced. In addition, in each of the examples and comparative examples, the composition of the molten solid provided on the negative electrode tab was the same as the composition of the molten solid disposed near the end face where no tab was provided as described later. Specifically, as shown in Table 1. For example, in Example C-1, both the molten solid attached to the negative electrode tab and the molten solid disposed near the end face where no tab and the base material extension portion were provided were the same as the molten solid A1 used in Example A-1.

[0334] <Fabrication of the positive electrode plate>

[0335] In the fabrication of the positive electrode plate in Example A-1, the positive electrode current collector was changed to the following positive electrode current collector with a tab, and except for this, a positive electrode plate was fabricated in the same manner as the fabrication of the positive electrode plate in Example A-1. That is, a positive electrode tab with a width of 2.0 cm × a length of 6.0 cm was formed on one of the four sides of the 2.0 cm × 2.0 cm positive electrode current collector portion to fabricate a positive electrode current collector with a tab.

[0336] Next, in the same manner as the fabrication of the positive electrode plate in Example A-1, a positive electrode active material layer was formed on the positive electrode current collector portion of the positive electrode current collector with a tab. Then, using a hot melt adhesive machine (nozzle diameter 1 mm), a molten solid with a width of 2.0 cm × a length of 3 mm × a height of 0.3 mm was attached only to one side of the main surface at a position 3.5 mm away from the positive electrode active material layer of the positive electrode tab. Thus, a positive electrode plate was fabricated. In addition, in each of the examples and comparative examples, the composition of the molten solid provided on the positive electrode tab was the same as the composition of the molten solid disposed near the end face where no tab was provided as described later. Specifically, as shown in Table 1.

[0337] <Fabrication of battery element components>

[0338] The fabricated negative electrode plate with a solid electrolyte layer laminated thereon and the positive electrode plate were used, and they were alternately laminated in sequence from the negative electrode plate in the same manner as in Example A-1 to fabricate a battery element component including 10 sets of battery cells.

[0339] A heat-resistant film (made of PPS) with each side 1 cm larger than the size of the current collector part (2.5 cm × 2.5 cm) is arranged at the lower and upper parts of the produced battery element part. And a molten solidified body prepared in Example A-1 (the amount capable of entirely covering the side surface: 1 g) is arranged between the two films arranged at the upper and lower parts of the current collector part and near the end of the current collector part (only on the side without the tab). Here, the tab protrudes from the heat-resistant film.

[0340] Next, while maintaining this state, the molten solidified body is melted on a hot plate, and the melt is pressed from above in the state of being enclosed between the two films and each tab, so that it flows toward the end (inside) and flows into the recess of the battery element part. Then, cooling is carried out. The battery element part (temporary laminated battery) with the insulating coating body flowing into the recess thus obtained is wrapped with a laminated film, and further warm isostatic pressing is carried out for 1 minute under the conditions of a temperature of 190 °C and a pressure of 588 MPa, so that the insulating coating body is filled in the recess of the battery element part and the insulating coating body is formed at the end of the battery element part, and each battery element part is densified. In addition, the set temperatures of the hot plates in Examples C-1 to C-6 and Comparative Examples C-1 to C-3 are respectively set to the same temperatures as the set temperatures of Examples A-1 to A-6 and Comparative Examples A-1 to A-3.

[0341] In this way, the laminated all-solid-state secondary batteries of Examples C-1 to C-6 and Comparative Examples C-1 to C-3 are respectively manufactured.

[0342] For the laminated all-solid-state secondary batteries of Examples C-1 to C-6 and Comparative Examples C-1 to C-3, the above [Evaluation 1] to [Evaluation 4] were respectively carried out in the same manner as in Example A-1. As a result, the same results as those of the corresponding laminated all-solid-state secondary batteries of Examples A-1 to A-6 and Comparative Examples A-1 to A-3 (Table 1) were obtained. Therefore, the description of the evaluation results of Examples C and Comparative Examples C is omitted.

[0343] [Example D]

[0344] <Examples D-1 to D-6 and Comparative Examples D-1 to D-3>

[0345] In Examples D-1 to D-6 and Comparative Examples D-1 to D-3, a laminated all-solid-state secondary battery was manufactured and evaluated using battery element components that were produced by positioning a plate electrode by a preferred method of manufacturing battery element components using a current collector having a tab with a positioning hole and a substrate extension portion and using the above-described manufacturing apparatus 70. Further, in Examples D-1 to D-6 and Comparative Example D-3, molten solidified bodies A1 to A7 having the same compositions as those in Examples A-1 to A-6 and Comparative Example A-3 were used, respectively. In Comparative Example D-1, no molten solidified body was disposed, and in Comparative Example D-2, only an EVA resin was disposed in place of the molten solidified body.

[0346] The manufacturing apparatus 70 shown in Figures 7 - 11 was prepared.

[0347] <Fabrication of the housing>

[0348] A housing 71 having the following dimensions shown in Figure 7 and FIG. 8 and the like was fabricated using metallic aluminum. Further, six holes 71d (corresponding to the pin receiving portions 73a) penetrating in the thickness direction were formed at positions corresponding to the positioning pins 72a of the positioning jig 72 in the bottom portion 71a (also serving as the restricting member 73). Further, the inner diameter of the hole 71d for the positioning pin 72a having a diameter of 3.0 mm formed in the tab was set to 3.1 mm, and the inner diameter of the hole 71d for the positioning pin 72a having a diameter of 4.0 mm formed in the substrate extension portion was set to 4.1 mm.

[0349] Inner dimensions of the accommodation space 71c: long side (vertical) 151.0 mm, short side (horizontal) 43.0 mm

[0350] <Fabrication of the positioning jig>

[0351] A positioning jig 72 having the following dimensions shown in Figure 9 was fabricated using metallic aluminum.

[0352] One positioning pin 72a having a diameter of 3.0 mm was vertically provided at positions corresponding to the positioning holes formed in the tab on each of the two short sides of a base having appropriate dimensions. Further, two positioning pins 72a having a diameter of 4.0 mm were vertically provided at intervals of 30 mm along the short side at positions corresponding to the positioning holes formed in the substrate extension portion. Thus, a total of six positioning pins 72a were vertically provided on the base.

[0353] <Fabrication of the calibration member>

[0354] As shown in Figure 9As shown, a plate-shaped correction member 74 made of metallic aluminum and having the same internal dimensions as the accommodation space 71c is fabricated and installed on the main surface of a lid body set to an appropriate size. The plate thickness of the correction member 74 is set to a thickness capable of pressing the battery element member in the accommodation space 71c together with the bottom 71a (limiting member 73) (a thickness such that the interval between the correction member 74 and the bottom 71a becomes smaller than the thickness of the battery element member). Further, positioning holes are provided at the same positions on the correction member 74 and the lid body as those of the base of the positioning jig 72.

[0355] Next, a negative electrode plate and a positive electrode plate with an electrolyte layer were fabricated.

[0356] (Fabrication of the negative electrode plate)

[0357] 53 parts by mass of natural graphite, 45 parts by mass of argyrodite sulfide solid electrolyte (Li 6 PS 5 (Cl), 2 parts by mass of a rubber-based binder (in terms of solid component value), and a mixed solvent of tetralin - anisole were mixed to prepare a negative electrode mixture paste.

[0358] The negative electrode mixture paste was coated on the central part in the width direction of both sides of a stainless-steel foil with a width of 180 mm, a length of 200 mm, and a thickness of 10 μm (hereinafter simply referred to as stainless-steel foil) such that the film thickness after coating and drying became 130 μm, and then dried to fabricate a raw plate of the negative electrode plate having uncoated portions of 25.5 mm at both ends of the negative electrode active material layer.

[0359] The obtained raw plate of the negative electrode plate was roughly cut to a width of 44 mm to fabricate a roughly cut negative electrode plate having a long side of 180 mm, a short side of 44 mm, and uncoated portions of 25.5 mm at both the negative electrode active material layer and the end of the negative electrode active material layer.

[0360] (Setting of the strip-shaped molded body of the mixture)

[0361] On the two main surfaces of the negative electrode tab 1b of the roughly cut negative electrode plate within a length of 5.5 mm from the end of the negative electrode active material layer 2B, a strip-shaped molded body 1e obtained by pre-processing the molten solid prepared in Example A-1 into a strip shape (with a thickness 1 - 10 μm thicker than the densified negative electrode active material layer 2B) using a hot roll press was attached with a hot iron. In the same manner, the strip-shaped molded body 1e was attached to the two main surfaces of the substrate extension portion 1c opposed to the negative electrode tab 1b within a length of 10.5 mm from the end of the negative electrode active material layer 2B. After cooling, using a punching tool, a negative electrode current collector 1C including a positioning hole 1d with the strip-shaped molded body 1e and the negative electrode current collector attached was fabricated in the following dimensions.

[0362] (Dimensions of the negative electrode current collector)

[0363] Dimensions of the negative electrode current collecting portion (negative electrode active material layer forming region) 1a: long side 129.0 mm, short side 42.0 mm

[0364] Outer dimensions of the negative electrode current collector 1C including the base material extension portion 1c and the negative electrode tab 1b: long side 150.0 mm, short side 42.0 mm

[0365] Length of the base material extension portion 1c and the negative electrode tab 1b in the long side direction: 10.0 mm

[0366] Width of the base material extension portion 1c and the negative electrode tab 1b in the short side direction: 10.0 mm

[0367] Length of the welding portion of the negative electrode tab 1b: 5.0 mm

[0368] Inner diameter of the positioning hole 1d formed in the base material extension portion 1c: 4.1 mm

[0369] Spacing of the positioning hole 1d formed in the base material extension portion 1c in the short side direction: 30 mm

[0370] Inner diameter of the positioning hole 1d formed on the negative electrode active material layer side of the negative electrode tab 1b: 3.1 mm

[0371] (Fabrication of the solid electrolyte layer)

[0372] A paste containing a solid electrolyte was prepared by mixing 98 parts by mass of argyrodite sulfide solid electrolyte (Li 6 PS 5 Cl), 2 parts by mass of a rubber-based binder (in terms of solid content), and a tetralin - anisole mixed solvent. Then, the obtained paste containing the solid electrolyte was coated on one side of a 10-μm-thick stainless steel foil so that the film thickness after coating and drying became 120 μm and dried. Thus, two laminates of the solid electrolyte layer and the stainless steel foil having the same dimensions as the long side and the short side of the above negative electrode active material layer were fabricated.

[0373] (Fabrication of the negative electrode plate 9 with an electrolyte layer)

[0374] After overlapping the solid electrolyte layer of each laminate on each negative electrode active material layer of the fabricated negative electrode plate and performing a pressing treatment (densification), the stainless steel foil was peeled off from the solid electrolyte layer. Thus, the negative electrode plate 9 with an electrolyte layer was fabricated. In addition, the weight per unit area (mass per unit area) of the negative electrode active material layer and the solid electrolyte layer did not change (decrease) due to the pressing treatment.

[0375] In addition, in each of the examples and comparative examples, the composition of the strip-shaped molded body (molten solid) 1e provided on the negative electrode tab 1b and the substrate extended portion 1c is the same as that of the rod-shaped molded body (molten solid) 76 disposed on the end face where the negative electrode tab 1b or the substrate extended portion 1c is not provided, specifically, as shown in Table 1. For example, in Example D-1, the strip-shaped molded body 1e attached to the negative electrode tab 1b and the substrate extended portion 1c and the rod-shaped molded body 76 disposed near the end face where the negative electrode tab 1b and the substrate extended portion 1c are not provided are both the same as the molten solid A1 used in Example A-1.

[0376] In this way, the negative electrode plate 9 with an electrolyte layer in which the strip-shaped molded body 1e is pre-attached to the negative electrode tab 1b and the substrate extended portion 1c was produced.

[0377] <Fabrication of Positive Electrode Plate>

[0378] 66 parts by mass of a mixed positive electrode active material NCM523 (a substance obtained by coating the surface of LiNi 3 Coated with LiNi 0.5 Co 0.2 Mn 0.3 particles), 30 parts by mass of a thioargentite sulfide solid electrolyte (Li 6 PS 5 Cl), 3 parts by mass of VGCF (carbon fiber manufactured by SHOWA DENKO K.K.) as a conductive aid, 1 part by mass (in terms of solid content) of a rubber-based binder, and a tetrahydronaphthalene - anisole mixed solvent were used to prepare a positive electrode mixture paste.

[0379] The positive electrode mixture paste was coated on the center of the width direction of both sides of an aluminum foil with a width of 180 mm, a length of 200 mm, and a thickness of 20 μm (hereinafter, simply referred to as aluminum foil) so that the film thickness after coating and drying became 90 μm, and then dried to produce a raw plate of a positive electrode plate having uncoated portions of 27.5 mm at the ends of the positive electrode active material layer.

[0380] The obtained raw plate of the positive electrode plate was roughly cut to a width of 44 mm to produce a roughly cut positive electrode plate having a long side of 180 mm, a short side of 44 mm, and uncoated portions of 27.5 mm at both the positive electrode active material layer and the end of the positive electrode active material layer.

[0381] (Setting of Strip-shaped Molded Body of Mixture)

[0382] On the two main surfaces of the positive electrode tab 5b within a length of 7.5 mm from the end of the positive electrode active material layer 4B in the rough-cut positive electrode plate, a strip-shaped molded body 5e obtained by pre-processing the molten solidified body prepared in Example A-1 into a strip shape (with a thickness 1 to 10 μm thicker than the densified positive electrode active material layer 4B) using a hot roll press was attached with a hot iron. In the same manner, the strip-shaped molded body 5e was attached to the two main surfaces of the substrate extension portion 5c opposed to the positive electrode tab 5b within a length of 12.5 mm from the end of the positive electrode active material layer 4B. After cooling, using a blanking tool, a positive electrode current collector including a positioning hole 1d of the following dimensions was produced in a state where the strip-shaped molded body 5e and the positive electrode current collector were attached.

[0383] (Dimensions of the positive electrode current collector)

[0384] Dimensions of the positive electrode current collecting portion (positive electrode active material layer forming region) 5a: long side 125.0 mm, short side 40.0 mm

[0385] External dimensions of the positive electrode current collector 5C including the substrate extension portion 5c and the positive electrode tab 5b: long side 150.0 mm, short side 40.0 mm

[0386] Length of the substrate extension portion 5c and the positive electrode tab 5b in the long side direction: 10.0 mm

[0387] Width of the substrate extension portion 5c and the positive electrode tab 5b in the short side direction: 10.0 mm

[0388] Length of the welding portion of the positive electrode tab 5b: 5.0 mm

[0389] Inner diameter of the positioning hole 5d formed in the substrate extension portion 5c: 4.1 mm

[0390] Interval of the positioning hole 5d formed in the substrate extension portion 5c in the short side direction: 30 mm

[0391] Inner diameter of the positioning hole 5d formed on the positive electrode active material layer side of the positive electrode tab 5b: 3.1 mm

[0392] In addition, in each of the examples and comparative examples, the composition of the strip-shaped molded body (molten solidified body) 5e provided on the positive electrode tab 5b and the substrate extension portion 5c is the same as that of the rod-shaped molded body (mixture) 76 disposed on the end face where the positive electrode tab 5b or the substrate extension portion 5c is not provided, specifically, as shown in Table 1. For example, in Example D-1, the strip-shaped molded body 5e attached to the positive electrode tab 5b and the substrate extension portion 5c and the rod-shaped molded body 76 disposed near the end face where the positive electrode tab 5b and the substrate extension portion 5c are not provided are both the same as the molten solidified body A1 used in Example A-1.

[0393] In this manner, the positive electrode plate 8 in which the strip-shaped molded body 5 e was previously attached to the positive electrode tab 5 b and the base extending portion 5 c was manufactured.

[0394] <Manufacturing of battery components>

[0395] like Figure 7 As shown in FIG8 , six negative plates 9 with electrolyte layers and five positive plates 8 are manually placed one by one in the storage space 71c of the frame 71, and the plates corresponding to 10 battery cells are stacked. Thus, the plates 8 and 9 are temporarily positioned through the storage space 71c, so that the positioning holes on the tabs of the plates 8 and 9 are connected to each other in the stacking direction, and the positioning holes on the substrate extension portions 8B are connected to each other in the stacking direction. In this way, a temporary stacked plate group is obtained.

[0396] Next, a positioning fixture 72 is arranged above the frame 71 that accommodates the obtained temporary stacked electrode plate group via a cover body with a press-limiting component 74. At this time, the vertical movement of the temporary stacked electrode plate group, especially the pole ears and the substrate extension part, in the accommodating space 71c is limited by the limiting component 73 (the bottom 71a of the frame 71). In this state, as shown in FIG8(A), the positioning fixture 72 is manually lowered toward the limiting component 73 at a speed of about 3 cm / min to insert the six positioning pins 72a into the corresponding connecting holes H, and finally, as shown in FIG8(B), it is advanced to the pin receiving portion 73a of the limiting component 73, thereby formally positioning the temporary stacked electrode plate group. Then, as shown in FIG8(B), Figure 9 As shown, in a state where the cover body, the press-limiting member 74 and the positioning jig 72 are stacked on the frame body 71, the cover body is pressed and fixed to the frame body 71 in the stacking direction by screws.

[0397] So, like Figure 9 and Figure 10 As shown in FIG. 1 , a stacked electrode group (battery component) is manufactured in a state where it is accommodated in a manufacturing device 70 and is pressed in the stacking direction by a pressing and limiting member 74 and a limiting member 73. The stacked structure and recessed portion of the manufactured battery component are shown in FIG. Figures 3 - 5 shown.

[0398] <Manufacturing of laminated all-solid-state secondary batteries>

[0399] The frame 71 that houses the produced battery element components is heated to the following heating temperature. When the resin material contained in the strip-shaped molded body melts, the fastening screw is tightened, causing the strip-shaped molded body that is thicker than the densified battery element components to deform and flow in the in-plane direction of the main surface (the first pressing process). The end regions of the constituent layers with uneven layer thicknesses are filled with the molded body that deforms and flows in the in-plane direction by the strip-shaped molded body and that deforms and flows toward the inside of the battery.

[0400] Next, the peripheral walls on the long side of the frame 71 (two peripheral walls shown in cross-section in Figure 10 ) 71b are removed. Then, in a state where the frame 71 is heated to the following heating temperature, a rod-shaped molded body 76 (the amount that can entirely cover the side surface: 5 g) pre-formed into a rod shape is disposed near the ends of the battery element components in the long side direction (the side surfaces of the two sides where no tab and substrate extension portion are provided). In addition, the composition of each rod-shaped molded body (mixture) 76 disposed in Examples D-1 to D-6 and Comparative Example D-3 is the same as the composition shown in Table 1 in the corresponding Examples A-1 to A-6 and Comparative Example A-3. Thus, after the rod-shaped molded body 76 disposed on the long side is melted, as Figure 11 shown, the melt is pressed toward the ends (inside) with a pressing plate 75 disposed at the position of the peripheral wall 71b removed from the frame 71, and is pressed into the ends (end faces and recesses) of the battery element components (the second pressing process). The rod-shaped molded body 76 flows in without bending and deforming the opposed negative electrode plate with a solid electrolyte layer, and thus fills the end regions (end faces and recesses) of the constituent layers with uneven layer thicknesses without gaps. Then, cooling is performed.

[0401] In Examples D-1 to D-6 and Comparative Examples D-1 to D-3, the heating temperatures in the first pressing process and the second pressing process are respectively set to the same temperatures as the set temperatures of the hot plates in Examples A-1 to A-6 and Comparative Examples A-1 to A-3.

[0402] The battery element components (temporary laminated batteries) in which the insulating coating body has flowed into the recesses thus obtained are wrapped with a laminating film, and further, in the same manner as in Example A, warm isostatic pressing is performed at a temperature of 190°C and a pressure of 588 MPa for 1 minute to form the insulating coating body of the recesses of the battery element components and to densify each battery element component.

[0403] For the laminated all-solid-state secondary batteries of Examples D-1 to D-6 and Comparative Examples D-1 to D-3, the above [Evaluation 1] to [Evaluation 4] were carried out in the same manner as in Example A, respectively. As a result, the same results as those of the laminated all-solid-state secondary batteries of the corresponding Examples A-1 to A-6 and Comparative Examples A-1 to A-3 (Table 1) were obtained. Therefore, the description of the evaluation results of Example D and Comparative Example D is omitted.

[0404] <Comparative Example D-4>

[0405] In Example D-1, a negative electrode plate with an electrolyte layer in which a strip-shaped molded body 1e was not previously attached to the negative electrode tab 1b and the substrate extension portion 1c was used instead of the negative electrode plate 9 with an electrolyte layer in which a strip-shaped molded body 1e was previously attached to the negative electrode tab 1b and the substrate extension portion 1c. Except for this, a laminated all-solid-state secondary battery of Comparative Example D-4 was manufactured in the same manner as in Example D-1.

[0406] In the obtained all-solid-state secondary battery, the end portions of the negative electrode active material layer 2B and the solid electrolyte layer 3B were deformed (thinned) in a manner of being bundled toward the end edge direction, and cracks were generated in the solid electrolyte layer 3B near the starting point of the deformation. Therefore, for the laminated all-solid-state secondary battery of Comparative Example D-4, the above [Evaluation 1] to [Evaluation 4] described in Example A were not carried out.

[0407] From Table 1 and Table 2, and the results shown in Examples A to D and Comparative Examples A to D, the following can be known.

[0408] In the laminated all-solid-state secondary batteries of Comparative Examples A-1, C-1, and D-1 and the single-layer all-solid-state secondary battery of Comparative Example B-1, which do not have an insulating coating at the end portions of the battery element components, defects (cracks or fissures) were confirmed at the ends of the solid electrolyte layer, and short circuits occurred, so they could not function as all-solid-state secondary batteries. Also, in the laminated all-solid-state secondary batteries of Comparative Examples A-2, C-2, and D-2, which have an insulating coating composed only of EVA and do not contain insulating inorganic particles, although EVA was filled in the end portions (recesses) of the battery element components, cracks at the ends of the solid electrolyte layer were confirmed, and the occurrence of short circuits could not be suppressed. In Comparative Examples A-3, C-3, and D-3, in which PMMA particles were used as insulating particles, the PMMA particles did not function as aggregates, cracks in the solid electrolyte layer were generated, and short circuits occurred.

[0409] In contrast, in the laminated all-solid-state secondary batteries of Examples A-1 to A-4, C-1 to C-4, and D-1 to D-4 and the single-layer all-solid-state secondary battery of Example B-1, in which the end portion of the battery element member has an insulating coating formed of a molten solid containing EVA and alumina, the insulation of the end portion is ensured, deformation and defects at the end portion of the solid electrolyte layer are not confirmed, and there is a coating intrusion region, capable of highly suppressing the occurrence of short circuits. Even when the resin material is changed to PP with a relatively high melting point (Examples A-5, C-5, and D-5) or a PE / EVA mixed resin (Examples A-6, C-6, and D-6), the results are the same. Moreover, the all-solid-state secondary battery in which the content of the insulating inorganic particles in the mixture is set high shows a high discharge capacity. It is considered that this is because the intrusion of the resin material alone into the interlayer or the constituent layer (expansion of the battery inactive region) is suppressed, thereby forming a coating intrusion region together with the insulating inorganic particles.

[0410] Moreover, in Examples D-1 to D-6 in which the laminated electrode plates 8 and 9 are positioned together using the positioning pins 72a, although the manufacturing time is short, the electrode plates can be laminated with high overlapping accuracy, and damage to the active material layer and the solid electrolyte layer can be effectively prevented, thereby manufacturing the battery element member. Moreover, after manufacturing the battery element member, an insulating coating can be formed as desired to ensure the insulation of the end portion, thereby manufacturing a laminated all-solid-state secondary battery in which the end portion of the solid electrolyte layer has no deformation and defects and the occurrence of short circuits can be highly suppressed.

[0411] Thus, the all-solid-state secondary batteries of Examples A to D have high reliability whether they are single-layer type or laminated type, although they use a composite layer as a constituent layer.

[0412] The present invention has been described together with its embodiments, but unless otherwise specified, none of the details in the description is intended to limit our invention, and it is considered that a broad interpretation can be made without departing from the spirit and scope of the invention shown in the appended claims.

[0413] This application claims the priority of Japanese Patent Application No. 2022-174396 filed in Japan on October 31, 2022, the content of which is incorporated herein by reference as a part of the description of this specification.

[0414] Reference Signs

[0415] 10 - All-solid-state secondary battery, 30 - Single-layer all-solid-state secondary battery, 50 - Stacked all-solid-state secondary battery, 1, 1A, 1B, 1C - Negative electrode current collector, 1a - Negative electrode current collecting portion, 1b - Negative electrode tab, 1c - Substrate extension portion, 1d - Positioning hole, 1e - Strip-shaped molded body, 2, 2A, 2B - Negative electrode active material layer, 3, 3A, 3B - Solid electrolyte layer, 4, 4A, 4B - Positive electrode active material layer, 5, 5A, 5B, 5C - Positive electrode current collector, 5a - Positive electrode current collecting portion, 5b - Positive electrode tab, 5c - Substrate extension portion, 5d - Positioning hole, 5e - Strip-shaped molded body, 6 - Working portion, 8 - Positive electrode plate, 9 - Negative electrode plate (negative electrode plate with electrolyte layer), 21 - Battery element component (battery cell), 41 - Battery element component, 21A, 41A, 41B, 41C - End portion, 22, 44, 44B or 44C - Insulating coating body, 23, 45 - Coating body intrusion area, 24, 46 - Insulating inorganic particles, 25, 47 - Resin material, 42 - Battery cell, 43, 43B, 43C - Recess, 70 - Manufacturing device, 71 - Plate group accommodation frame, 71a - Bottom, 71b - Peripheral wall (side wall), 71c - Accommodation space, 71d - Hole, 72 - Positioning jig, 72a - Positioning pin, 72b - Flat base, 73 - Restricting member, 73a - Pin receiving portion, 74 - Correction member (pressing restricting member), 75 - Pressing plate, 76 - Rod-shaped molded body, H - Communication hole.

Claims

1. A all-solid-state secondary battery having battery element components, wherein, the battery element components include one or more sets of battery cells, and each battery cell is formed by laminating at least a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in sequence, an insulating coating body is provided at an end portion of the battery element components, and the insulating coating body coats at least the side surface of the battery element components starting from a position more outside than the side surface, the insulating coating body is composed of a mixture of a resin material that melts in a temperature range below 300°C and insulating inorganic particles that do not melt at 350°C.

2. The all-solid-state secondary battery according to claim 1, wherein, each battery cell is formed by laminating a negative electrode current collector, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector in sequence, the positive electrode current collector has a positive electrode current collecting portion laminated adjacent to the positive electrode active material layer and a positive electrode tab extending in a manner protruding from one end thereof, and the positive electrode tab protrudes from the insulating coating body.

3. The all-solid-state secondary battery according to claim 1, wherein, each battery cell is formed by laminating a negative electrode current collector, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector in sequence, the negative electrode current collector has a negative electrode current collecting portion laminated adjacent to the negative electrode active material layer and a negative electrode tab extending in a manner protruding from one end thereof, and the negative electrode tab protrudes from the insulating coating body.

4. The all-solid-state secondary battery according to claim 1, wherein, the insulating coating body is composed of a molten solid of a resin material that melts in a temperature range below 200°C and insulating solid particles that do not melt at 250°C.

5. The all-solid-state secondary battery according to claim 1, wherein, at least one interface between adjacent laminated layers in the battery element components has a coating body intrusion region, and the coating body intrusion region is a region where the insulating coating body containing at least one insulating inorganic particle intrudes from the end portion of the battery element components toward the inside.

6. The all-solid-state secondary battery according to claim 1, wherein, an insulating coating body containing the insulating inorganic particles is filled in a recess, and the recess is formed at an end portion of the battery element components due to a size difference between the positive electrode active material layer and the negative electrode active material layer and is adjacent to the outside in the plane direction of the positive electrode active material layer or the negative electrode active material layer.

7. The all-solid-state secondary battery according to claim 6, wherein, at least one interface between adjacent laminated layers in the battery element components has a coating body intrusion region, and the coating body intrusion region is a region where the insulating coating body containing at least one insulating inorganic particle intrudes from the end portion of the battery element components toward the inside.

8. The all-solid-state secondary battery according to claim 5 or 7, wherein, the solid electrolyte layer in contact with the coating body intrusion region does not have cracks.

9. A method for manufacturing an all-solid-state secondary battery, which includes the following steps: A step of disposing a mixture of a resin material that melts in a temperature range below 300°C and insulating inorganic particles that do not melt at 350°C at an end portion of a battery element component, the battery element component including one or more stacked units, the stacked unit being formed by sequentially stacking a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer; and A step of heating the mixture at a temperature at which the resin material melts while applying pressure in the inner direction of the battery element component.

10. The manufacturing method according to claim 9, wherein, The pressing step is performed in a state where the battery element component is pressed in the stacking direction.

11. The manufacturing method according to claim 9, wherein, In the pressing step, the mixture disposed at the end portion of the battery element component is heated to the temperature, and while preventing flow in the stacking direction, it is caused to flow in the inner direction.

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