Method for manufacturing a laminated electrode body

Abstract

To provide a manufacturing method of a laminated electrode that has increased battery capacity due to a thin solid electrolyte layer covering a periphery side surface of a positive electrode layer and a periphery side surface of a negative electrode layer, and that is capable of suppressing generation of internal shot circuits.SOLUTION: A laminated electrode 1 comprises a positive electrode layer 2, a negative electrode layer 3, a solid electrolyte layer 4, and a solid electrolyte layer 5. The solid electrolyte layer 4 and the solid electrolyte layer 5 are relatively thin, and thus battery capacity is increased. The solid electrolyte layer 5 covers a periphery side surface of the positive electrode layer 2 or the negative electrode layer 3, and thus generation of internal short circuits is suppressed. The laminated electrode 1 is made from the negative electrode layer 3 formed by filling a powdery electrode material X in a mortar hole, the thin solid electrolyte layer 4 and a thin solid electrolyte layer 5 formed by splaying a powdery solid electrolyte material W onto a top face of the negative electrode layer 3 and an inner peripheral surface of the motor hole, and the positive electrode layer 2 formed by filling a powdery electrode material Y to a space surrounded by the solid electrolyte layer 4 and the solid electrolyte layer 5.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a laminated electrode body housed in an all-solid-state battery.

Background Art

[0002] An all-solid-state battery is assembled by housing a laminated electrode body in which a solid electrolyte layer is disposed between a positive electrode layer and a negative electrode layer in a battery container. The laminated electrode body is formed by pressing a powdery electrode material for forming the positive electrode layer, a powdery electrode material for forming the negative electrode layer, and a powdery solid electrolyte material.

[0003] The solid electrolyte layer of the laminated electrode body is preferably relatively thin in order to improve the battery capacity. However, when attempting to form the solid electrolyte layer thinly, the laminated electrode body is likely to crack during pressure molding. Also, the solid electrolyte layer is more likely to have unevenness even when pressure molded compared to when it is formed relatively thick. Therefore, it is difficult to make the thickness of the solid electrolyte layer uniform. Cracking of the laminated electrode body and unevenness in the thickness of the solid electrolyte layer deteriorate the battery performance of the all-solid-state battery.

[0004] Also, when the laminated electrode body is housed in the battery container, there is a gap between the outer peripheral surface of the laminated electrode body and the inner peripheral surface of the battery container. Therefore, when positive electrode active material particles are detached from the positive electrode layer, or when negative electrode active material particles are detached from the negative electrode layer, an internal short circuit may occur if they come into contact with the electrode layer of the counter electrode, respectively.

[0005] Japanese Unexamined Patent Application Publication No. 2009-64644 discloses an all-solid-state lithium secondary battery including a lithium ion conductive solid electrolyte layer having a shape covering at least one of the positive electrode and the negative electrode (Patent Document 1). The all-solid-state lithium secondary battery includes a lithium ion conductive solid electrolyte layer covering the peripheral side surface of the electrode, thereby suppressing the occurrence of an internal short circuit due to the detachment of positive electrode active material particles or negative electrode active material particles.

[0006] Japanese Patent Application Laid-Open No. 2010-282803 discloses a method for manufacturing an all-solid-state lithium-ion secondary battery in which a powder material of an electrode material and a powder material of a solid electrolyte are charged and sprayed onto the surface of a current collector (Patent Document 2). By this method, in the method for manufacturing an all-solid-state lithium-ion secondary battery, a powder layer can be formed with a uniform thickness, and since the pressure during the forming process is applied to the whole, cracking during the pressure forming can be suppressed. Therefore, according to the method for manufacturing an all-solid-state lithium-ion secondary battery, a solid electrolyte layer disposed between a positive electrode layer and a negative electrode layer can be formed thinly.

[0007] Further, Japanese Patent Application Laid-Open No. 2019-21428 discloses a coin-shaped battery in which a solid electrolyte layer of a laminate has an average thickness of 5 μm or more and 100 μm or less (Patent Document 3). The laminate of the coin-shaped battery is formed by charging a powder, which is a forming material of the solid electrolyte layer, by brushing it onto each screen and attaching it to an object to be printed. Thereby, a solid electrolyte layer disposed between a positive electrode layer and a negative electrode layer can be formed thinly.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, among the solid electrolyte layers of the all-solid-state lithium secondary battery described in Patent Document 1, the side solid electrolyte layer that covers the side surface of the electrode is formed by pressing the upper surface of the cylindrical solid electrolyte layer with a mold having a convex portion for forming a space portion for electrode filling. Therefore, when attempting to thinly form the side solid electrolyte layer in the radial direction by making the diameter of the convex portion of the mold slightly smaller than the diameter of the upper surface of the solid electrolyte layer, the side solid electrolyte layer cannot be properly formed and collapses. Thus, it has been difficult to thinly form the side solid electrolyte layer in the all-solid-state lithium secondary battery.

[0010] Further, although the all-solid-state lithium-ion secondary battery described in Patent Document 2 and the coin-shaped battery described in Patent Document 3 can thinly form the solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, it has been difficult to thinly form the solid electrolyte layer that covers the peripheral side surfaces of the positive electrode layer and the negative electrode layer simply by spraying or adhering the powder for forming the solid electrolyte layer from above. Also, although the coin-shaped battery includes a solid electrolyte layer that covers the peripheral side surface of the positive electrode layer, it has been difficult to adjust the thickness of the solid electrolyte layer on the peripheral side surface during pressure molding after spraying or adhering. Moreover, the bonding property between the peripheral side surface of the positive electrode layer and the solid electrolyte layer on the peripheral side surface, or the bonding property between the peripheral side surface of the negative electrode layer and the solid electrolyte layer on the peripheral side surface is poor, and there is a possibility that the solid electrolyte layer on the peripheral side surface peels off from the positive electrode layer or the negative electrode layer.

[0011] Therefore, an object of the present disclosure is to provide a method for manufacturing a high-capacity and highly reliable laminated electrode body that can increase the battery capacity by thinning the thickness of the solid electrolyte layer that covers the peripheral side surfaces of the positive electrode layer and the negative electrode layer and can suppress internal short circuits.

Means for Solving the Problems

[0012] To solve the above problems, the present disclosure is configured as follows. That is, the method for manufacturing a laminated electrode body according to the present disclosure may include a step of preparing a pressing device including a die having a mortar hole penetrating vertically, a lower pestle inserted from below the mortar hole and sliding within the mortar hole, and an upper pestle inserted from above the mortar hole and sliding within the mortar hole. The method may include a step of forming a first electrode layer of one of the positive electrode layer and the negative electrode layer by filling the mortar hole with a first electrode material in a state where the opening below the mortar hole is closed by the lower pestle. The method may include a step of forming a first solid electrolyte layer on the upper surface of the first electrode layer and a second solid electrolyte layer on the inner peripheral surface of the mortar hole by attaching a solid electrolyte material to the upper surface of the first electrode layer and the inner peripheral surface of the mortar hole from above the mortar hole. The method may include a step of forming a second electrode layer of the other of the positive electrode layer and the negative electrode layer by filling the space surrounded by the first solid electrolyte layer and the second solid electrolyte layer with a second electrode material. The method may include a step of forming a laminated electrode body by pressing the first electrode layer, the second electrode layer, the first solid electrolyte layer, and the second solid electrolyte layer with the lower pestle and the upper pestle. The method may include a step of taking out the laminated electrode body from the mortar hole by relatively moving at least one of the upper pestle and the lower pestle and the die.

[0013] Preferably, further, after forming the first electrode layer by filling the mortar hole with the first electrode material, the method may include a step of pressing the first electrode layer with the upper pestle and the lower pestle before attaching the solid electrolyte material.

[0014] Preferably, in the step of forming the first solid electrolyte layer and the second solid electrolyte layer, the solid electrolyte material may be previously attached to the lower surface of the upper pestle facing the upper surface of the first electrode layer. The first solid electrolyte layer may be formed on the upper surface of the first electrode layer by moving the upper pestle toward the upper surface of the first electrode layer and pressing. The second solid electrolyte layer may be formed by attaching the solid electrolyte material to the inner peripheral surface of the mortar hole.

[0015] Preferably, further, before filling the first electrode material into the mortar hole, with the opening below the mortar hole closed by the first lower pestle, by attaching a solid electrolyte material, a second solid electrolyte layer on the first electrode layer side is formed on the inner peripheral surface of the mortar hole, and a step of forming a third solid electrolyte layer on the upper surface of the first lower pestle may be included. Removing the first lower pestle from below the mortar hole together with the third solid electrolyte layer, and inserting the second lower pestle from below the mortar hole so as to contact the lower end of the second solid electrolyte layer on the first electrode layer side may be included. In the step of filling the first electrode material into the mortar hole, the first electrode layer may be formed by filling the first electrode material into the space surrounded by the second solid electrolyte layer on the inner peripheral surface of the mortar hole and the upper surface of the second lower pestle. Before forming the first solid electrolyte layer and the second solid electrolyte layer on the second electrode layer side, a step of forming a space for attaching the solid electrolyte material on the inner peripheral surface of the mortar hole and the upper surface of the first electrode layer may be included.

Effect of the Invention

[0016] According to the method for manufacturing a laminated electrode body according to the present disclosure, it is possible to provide a laminated electrode body that can increase the battery capacity by reducing the radial thickness of the solid electrolyte layer that covers at least one of the peripheral side surfaces of the positive electrode layer and the negative electrode layer, and can suppress internal short circuits.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0018] Hereinafter, the manufacturing method of the laminated electrode body 1 according to the present disclosure will be specifically described with reference to FIGS. 1 to 13. First, the all-solid-state battery 10 according to the present disclosure and the laminated electrode body 1 included in the all-solid-state battery 10 will be specifically described with reference to FIGS. 1 and 2. As shown in FIG. 1, the all-solid-state battery 10 includes an outer can 20, a sealing can 30, a laminated electrode body 1, and a gasket 40. The all-solid-state battery 10 is a flat battery.

[0019] The outer can 20 includes a circular bottom portion 21 and a cylindrical peripheral wall portion 22 continuously formed from the outer periphery of the bottom portion 21. The peripheral wall portion 22 is provided so as to extend substantially perpendicular to the bottom portion 21 in a longitudinal sectional view. The outer can 20 is formed of a metal material such as stainless steel, nickel, or iron. Note that the shape of the outer can 20 is not limited to a cylindrical shape having a circular bottom portion 21. For example, the shape of the outer can 20 may be formed such that the bottom portion 21 is formed in a polygonal shape such as a square shape, and the peripheral wall portion 22 is formed in a polygonal cylindrical shape such as a square cylindrical shape corresponding to the shape of the bottom portion 21, and can be variously changed according to the size and shape of the all-solid-state battery 10. Therefore, the shape of the peripheral wall portion 22 includes not only a cylindrical shape but also a polygonal cylindrical shape such as a square cylindrical shape.

[0020] The sealed can 30 includes a circular planar portion 31 and a cylindrical peripheral wall portion 32 formed continuously from the outer periphery of the planar portion 31. The opening of the sealed can 30 faces the opening of the outer can 20. The sealed can 30 is formed of a metal material such as stainless steel. Note that the shape of the sealed can 30 is not limited to a cylindrical shape with a circular planar portion 31. For example, the shape of the sealed can 30 may be formed such that the planar portion 31 is polygonal such as square, and the peripheral wall portion 32 is formed into a polygonal cylindrical shape such as a square cylindrical shape according to the shape of the planar portion 31, and can be variously changed according to the size and shape of the all-solid-state battery 10. Therefore, the shape of the peripheral wall portion 32 includes not only a cylindrical shape but also a polygonal cylindrical shape such as a square cylindrical shape.

[0021] The peripheral wall portion 32 of the sealed can 30 has a base end portion 32a on the planar portion 31 side, a diameter-expanded portion 32b on the opening end side formed larger than the outer diameter of the base end portion 32a, and a stepped portion 32c between the base end portion 32a and the diameter-expanded portion 32b. Therefore, the peripheral wall portion 32 is formed in a stepped shape where the diameter-expanded portion 32b is wider outward than the base end portion 32a.

[0022] After the laminated electrode body 1 is housed in the internal space, the outer can 20 and the sealed can 30 are caulked via a gasket 40 between the peripheral wall portion 22 of the outer can 20 and the peripheral wall portion 32 of the sealed can 30. Specifically, the outer can 20 and the sealed can 30 are caulked via a gasket 40 after opposing the openings of the outer can 20 and the sealed can 30 to each other and inserting the peripheral wall portion 32 of the sealed can 30 inside the peripheral wall portion 22 of the outer can 20. The edge end portion of the peripheral wall portion 22 is caulked so as to face inward in the direction of the stepped portion 32c of the peripheral wall portion 32. Therefore, the edge end portion of the peripheral wall portion 22 can be sufficiently caulked in a direction substantially perpendicular to the radial direction of the cylindrical side wall portion 22, that is, in the longitudinal direction. In this way, a battery container is constituted by the outer can 20 and the sealed can 30.

[0023] The gasket 40 is formed of a low moisture permeability resin such as polypropylene resin, polyphenylene sulfide resin, or PFA resin. The gasket 40 is formed in a cylindrical shape along the inner peripheral surface of the peripheral wall portion 22 of the outer can 20 and is disposed between the peripheral wall portion 22 of the outer can 20 and the peripheral wall portion 32 of the sealed can 30. The gasket 40 is not particularly limited as long as it can insulate the outer can 20 and the sealed can 30, but from the viewpoints of moisture permeability and heat resistance, polyphenylene sulfide resin or a fluororesin such as PFA resin is preferably used.

[0024] As shown in FIGS. 1 and 2, the laminated electrode body 1 includes a positive electrode layer (electrode layer) 2, a negative electrode layer (electrode layer) 3, a solid electrolyte layer 4 disposed between the positive electrode layer 2 and the negative electrode layer 3, and a solid electrolyte layer 5 extending from the peripheral edge of the solid electrolyte layer 4 along the peripheral side surface of the positive electrode layer 2. The positive electrode layer 2, the negative electrode layer 3, and the solid electrolyte layer 4 are substantially similar circular shapes in plan view, and are laminated in the order of the positive electrode layer 2, the solid electrolyte layer 4, and the negative electrode layer 3 from the bottom surface 21 side of the positive electrode can 20 from the lower side shown in the figure. That is, the laminated electrode body 1 has a cylindrical shape. The positive electrode layer 2 of the laminated electrode body 1 is disposed on the upper surface of the bottom portion 21 of the outer can 20. Therefore, the outer can 20 functions as a positive electrode can. Further, the negative electrode layer 3 of the laminated electrode body 1 faces the lower surface of the flat portion 31 of the sealed can 30. Therefore, the sealed can 30 functions as a negative electrode can. Note that the laminated electrode body 1 is not limited to a cylindrical shape and can be variously changed according to the size and shape of the all-solid-state battery 10, such as a rectangular parallelepiped shape or a polygonal prism shape. Further, the laminated electrode body 1 may be arranged such that the negative electrode layer 3 is positioned on the outer can 20 side and the positive electrode layer 2 is positioned on the sealed can 30 side. In that case, the outer can 20 functions as a negative electrode can and the sealed can 30 functions as a positive electrode can.

[0025] The positive electrode layer 2 is, for example, lithium cobaltate having an average particle diameter of 5 μm as a positive electrode active material used in a lithium ion secondary battery, and a sulfide-based solid electrolyte (Li 6 PS 5The positive electrode mixture contains 92 mg of a positive electrode mixture containing (Cl) and carbon nanotubes as a conductive aid in a mass ratio of 70:26:4, which is placed in a mold with a diameter of 8 mm and formed into a cylindrical positive electrode pellet. The positive electrode layer 2 is not particularly limited as long as it can function as the positive electrode layer 2 of the laminated electrode body 1. For example, it may be lithium cobaltate, lithium nickelate, lithium manganate, spinel-type manganese composite oxide, olivine-type composite oxide, etc., or a mixture thereof as appropriate. Also, the size and shape of the positive electrode layer 2 are not limited to a cylindrical shape and can be variously changed according to the size and shape of the all-solid-state battery 1.

[0026] The negative electrode layer 3 is, for example, LTO (Li 4 Ti 5 O 12 , lithium titanate), a sulfide-based solid electrolyte (Li 6 PS 5 Cl), and a negative electrode pellet formed by shaping 129 mg of a negative electrode mixture containing carbon nanotubes in a weight ratio of 50:41:9 into a cylindrical shape. The negative electrode layer 3 is not particularly limited as long as it can function as the negative electrode layer 3 of the laminated electrode body 1. For example, it may be a metal material such as metallic lithium or a lithium alloy, a carbon material such as graphite or low-crystalline carbon, SiO, LTO (Li 4 Ti 5 O 12 , lithium titanate), etc., or a mixture thereof as appropriate. Also, the size and shape of the negative electrode layer 3 are not limited to a cylindrical shape and can be variously changed according to the size and shape of the all-solid-state battery 1.

[0027] The solid electrolyte layer 4 and the solid electrolyte layer 5 are, for example, 1 mg of a sulfide-based solid electrolyte (Li 6 PS 5Cl) is formed into a cylindrical shape. The solid electrolyte layers 4 and 5 are not particularly limited, but may be other sulfide-based solid electrolytes such as other argyrodite types from the viewpoint of ion conductivity. When using a sulfide-based solid electrolyte, it is preferable to coat the surface of the positive electrode active material with niobium oxide in order to prevent reaction with the positive electrode active material. Further, the solid electrolyte layers 4 and 5 may be hydride-based solid electrolytes, oxide-based solid electrolytes, or the like. Further, the size and shape of the solid electrolyte layer 4 are not limited to a cylindrical shape, and can be variously changed according to the size and shape of the all-solid-state battery 1.

[0028] The solid electrolyte layer 4 is disposed between the positive electrode layer 2 and the negative electrode layer 3. As shown in FIG. 2, the thickness t1 of the solid electrolyte layer 4 is 5 μm to 180 μm. The thickness t1 of the solid electrolyte layer 4 is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 20 μm or more in order to form the solid electrolyte layer 4 with a uniform thickness and prevent short circuit occurring between the positive electrode layer and the negative electrode layer. On the other hand, if the solid electrolyte layer 4 becomes too thick, the ratio of the positive electrode layer 2 and the negative electrode layer 3 in the entire laminated electrode body 1 decreases, and the battery capacity per volume of the laminated electrode body 1 decreases. Further, the discharge characteristics deteriorate due to an increase in resistance caused by the solid electrolyte layer 4. Therefore, the thickness t1 of the solid electrolyte layer 4 is preferably 180 μm or less, more preferably 100 μm or less, and still more preferably 50 μm or less.

[0029] The solid electrolyte layer 5 only needs to extend from the peripheral edge of the solid electrolyte layer 4 along at least one of the peripheral side surfaces of the positive electrode layer 2 and the negative electrode layer 3. As shown in FIG. 2, when the solid electrolyte layer 5 is provided on the peripheral side surface of the positive electrode layer 2, in a plan view, the radial size of the negative electrode layer 3 can be made larger than that of the positive electrode layer 2. That is, the solid electrolyte layer 5 can also be extended from the peripheral edge of the solid electrolyte layer 4 along the peripheral side surface of the positive electrode layer 2 so that the combined radial size of the positive electrode layer 2 and the solid electrolyte layer 5 is the same as the radial size of the negative electrode layer 3. As shown in FIG. 2, the solid electrolyte layer 4 and the solid electrolyte layer 5 have a substantially U-shaped cross section in a longitudinal sectional view. The solid electrolyte layer 5 is cylindrical and covers the peripheral side surface of the positive electrode layer 2. Thereby, it is possible to suppress a short circuit that may occur when positive electrode active material particles desorb from the peripheral side surface of the positive electrode layer 2 and come into contact with the peripheral side surface of the negative electrode layer 3. The radial thickness t2 of the solid electrolyte layer 5 is preferably 1 μm or more, more preferably 5 μm or more, and still more preferably 10 μm or more in order to prevent the desorption of active material particles from the positive electrode layer 2 or the negative electrode layer 3. On the other hand, if the solid electrolyte layer 5 becomes too thick, the ratio of the positive electrode layer 2 and the negative electrode layer 3 in the entire laminated electrode body 1 decreases, and the battery capacity per unit volume of the laminated electrode body 1 decreases. Therefore, the radial thickness t2 of the solid electrolyte layer 5 is preferably 180 μm or less, more preferably 50 μm or less, and still more preferably 30 μm or less. Note that the solid electrolyte layer 5 does not necessarily have to be composed only of a solid electrolyte. For example, even if the active material of the electrode layer on which the solid electrolyte layer 5 is formed is slightly mixed, its function can be exhibited.

[0030] The ratio R of the thickness t1 of the solid electrolyte layer 4 to the thickness t3 of the positive electrode layer 2 (t1 / t3) is preferably 0.03 or more. The positive electrode layer 2 is pressed during molding so as to have a packing density of a certain level or more. The pressure applied to the positive electrode layer 2 increases as the thickness t3 of the positive electrode layer 2 increases. Therefore, if the thickness t3 of the positive electrode layer 2 is too thick, that is, if the ratio R becomes too small, when the positive electrode layer 2 and the solid electrolyte layer 4 are pressed together, an excessive pressure is applied to the solid electrolyte layer 4. Then, the positive electrode active material particles of the positive electrode layer 2 bite into the solid electrolyte layer 4, increasing the risk of a short circuit occurring between the positive electrode layer 2 and the negative electrode layer 3. Therefore, the ratio R is preferably 0.03 or more, and preferably 0.1 or more. On the other hand, if the thickness t1 of the solid electrolyte layer 4 is too thick, that is, if the ratio R becomes too large, the proportion of the positive electrode layer 2 and the negative electrode layer 3 in the entire laminated electrode body 1 decreases, and the battery capacity per unit volume of the laminated electrode body 1 decreases. Also, the discharge characteristics deteriorate due to an increase in the resistance of the solid electrolyte layer 4. Therefore, the ratio R is preferably 0.3 or less, and preferably 0.2 or less.

[0031] As shown in FIG. 1, the peripheral wall portion 32 of the sealed can 30 is located inside the peripheral wall portion 22 of the outer can 20. The solid electrolyte layer 5 is formed along the peripheral side surface of the positive electrode layer 2. That is, the solid electrolyte layer 5 covers the peripheral side surface of the positive electrode layer 2. Thereby, it is possible to suppress a short circuit that may occur when positive electrode active material particles detach from the positive electrode layer 2 and come into contact with the sealed can 30. On the other hand, when the laminated electrode body 1 is arranged such that the negative electrode layer 3 is positioned on the outer can 20 side and the positive electrode layer 2 is positioned on the sealed can 30 side, the solid electrolyte layer 5 may be formed along the peripheral side surface of the negative electrode layer 3. In this way, by covering the peripheral side surface of either the positive electrode layer 2 or the negative electrode layer 3 arranged on the outer can 20 side with the solid electrolyte layer 5, an internal short circuit due to contact between the sealed can 2 and the active material particles can be suppressed.

[0032] Next, the manufacturing method of the laminated electrode body 1 will be specifically described with reference to FIGS. 3 to 7.

[0033] First, as shown in FIG. 3, a pressing device 100 is prepared. The pressing device 100 includes a die 101 having a mortise hole 101a penetrating vertically, a lower pestle 102 inserted from below the mortise hole 101a and sliding within the mortise hole 101a, and an upper pestle 103 inserted from above the mortise hole 101a and sliding within the mortise hole 101a. The die 101 is formed in a plate shape. The mortise hole 101a is formed to open in a cylindrical shape from the upper surface to the lower surface of the die 101. The lower pestle 102 and the upper pestle 103 are each formed in a cylindrical shape along the opening shape of the mortar pestle. The pressing device 100 presses the material filled in the mortise hole 101a by sliding the lower pestle 102 and the upper pestle 103 in the vertical direction.

[0034] Next, as shown in FIG. 4, with the lower pestle 102 inserted into the mortise hole 101a and the opening below the mortise hole 101a closed by the lower pestle 102, the electrode material X is filled from above the mortise hole 101a. Thereby, the negative electrode layer 3 before molding is formed. In this manufacturing method, the electrode material X is a powdery negative electrode compounding agent for forming the negative electrode layer 3. Although not particularly shown, the powdery electrode material X is filled into the mortise hole 101a from a hopper that moves parallel to the upper surface of the die 101. The hopper moves above the mortise hole 101a when filling the electrode material X and waits at a location other than above the mortise hole 101a when not filling the electrode material X. The electrode material X filled in the mortise hole 101a is pressed by the upper pestle 103 from above. The electrode material X may be powdery or may be a pellet that has been pre-pressed and has an outer diameter substantially the same as the inner diameter of the mortise hole 101a. When the electrode material X is a pellet, the electrode material X may or may not be pressed by the upper pestle 103 from above. Also, even if the electrode material X is powdery, it may not be pressed here, and as will be described later, after further inserting the solid electrolyte material W and the electrode material Y into the mortise hole 101a, the electrode material X, the solid electrolyte material W, and the electrode material Y may be pressed together.

[0035] In addition, in FIG. 4, the negative electrode layer 3 is formed using the space above the mortar hole 101a. However, in reality, it is preferable to form the negative electrode layer 3 using the space below the mortar hole 101a. At this time, the upper surface of the lower pestle 102 is positioned along the lower surface of the die 101, for example, on the lower opening side of the mortar hole 101a. After forming the negative electrode layer 3 in the space below the mortar hole 101a, the solid electrolyte layer 4, the solid electrolyte layer 5, and the positive electrode layer 2 are formed using the space above the negative electrode layer 3 (the portion where the negative electrode layer 3 is formed in FIG. 4). Thereby, the step of disposing the negative electrode layer 3 above the mortar hole 101a, which will be described later, on the lower side can be omitted, and the manufacturing process of the laminated electrode body 1 can be simplified.

[0036] In addition, as shown in FIG. 4, when the negative electrode layer 3 is formed using the space above the mortar hole 101a, next, the negative electrode layer 3 (the molded body or the filler before molding) is moved to the lower side of the mortar hole 101a by the upper pestle 103 or in a state of being sandwiched between the upper pestle 103 and the lower pestle 102, and a space for producing the solid electrolyte layer 4, the solid electrolyte layer 5, and the positive electrode layer 2 is formed above the mortar hole 101a as shown in FIG. 5 below. Alternatively, after removing the lower pestle 102 from below the mortar hole 101a, the die 101 may be inverted and the negative electrode layer 3 may be disposed on the lower side of the mortar hole 101a to form the space. That is, after forming the negative electrode layer 3, it is sufficient to form a space in the mortar hole 101a where the solid electrolyte material W can be injected onto the inner peripheral surface of the mortar hole 101a and the upper surface of the negative electrode layer 3.

[0037] Next, as shown in FIG. 5, a powdery solid electrolyte material W is injected from above the mortar hole 101a onto the negative electrode layer 3 and the inner peripheral surface of the mortar hole 101a by an injection device 104. The injection device 104 moves parallel to the upper surface of the die 101, similar to the above-described hopper. The injection device 104 moves above the mortar hole 101a when injecting the solid electrolyte material W, and waits at a location other than above the mortar hole 101a when not injecting the solid electrolyte material W. The injection device 104 is provided with an electrostatic generation electrode (not shown) having a needle-like or tapered tip. By applying a DC high voltage of about -20 kV to the electrode, the solid electrolyte material W can be negatively charged by the electric field formed at the tip of the electrode. The die 101 and the lower pestle 102 are charged with the opposite polarity to the charged solid electrolyte material W, thereby forming an adhesion layer of the solid electrolyte material W. By adjusting the adhesion amount of the solid electrolyte material W in the solid electrolyte layer 4 and the solid electrolyte layer 5, the thicknesses of the solid electrolyte layer 4 and the solid electrolyte layer 5 can be adjusted. After molding, the solid electrolyte layer 4 can be thinly and uniformly formed on the upper surface of the electrode material X, and the solid electrolyte layer 5 can be thinly and uniformly formed on the inner peripheral surface of the mortar hole 101a.

[0038] In addition, when it is difficult to adjust the thickness of the solid electrolyte layer 4, that is, the adhesion amount of the solid electrolyte material W in the solid electrolyte layer 4 by the above method, the solid electrolyte layer 5 may be formed after the solid electrolyte layer 4 is formed. That is, although not shown, the negatively charged solid electrolyte material W is adhered to the lower surface of the upper pestle 103 charged with the opposite polarity, and further, the electrode material X is pressed from above by the upper pestle 103, thereby fixing the solid electrolyte material W to the upper surface of the negative electrode layer 3 to form the solid electrolyte layer 4. Next, the charged solid electrolyte material W is injected into the mortar hole 101a to adhere the solid electrolyte material W to the inner peripheral surface of the mortar hole 101a, thereby forming the solid electrolyte layer 5.

[0039] Next, as shown in FIG. 6, the space surrounded by the solid electrolyte layer 4 and the solid electrolyte layer 5 is filled with the electrode material Y. Thereby, the positive electrode layer 2 before molding is formed. In this manufacturing method, the electrode material Y is a powdery positive electrode mixture for forming the positive electrode layer 2. Although not particularly shown, the powdery electrode material Y is filled into the mortar hole 101a from a hopper that moves parallel to the upper surface of the die 101. The hopper moves above the mortar hole 101a when filling the electrode material Y, and waits at a location other than above the mortar hole 101a when not filling the electrode material Y. Note that the pressing device 100 includes a hopper for filling the electrode material X and a hopper for filling the electrode material Y, respectively. The filled electrode material Y is pressed by the upper pestle 103 from above. Thereby, a molded body of the laminated electrode body 1 is formed.

[0040] When the filled electrode material Y is pressed from above, the above-described negative electrode layer 3, solid electrolyte layer 4, and solid electrolyte layer 5 are also pressed together. At this time, the movement of the solid electrolyte layer 5 in the radial direction is suppressed by the inner peripheral surface of the mortar hole 101a, and the downward movement of the laminated electrode body 1 is also suppressed by the lower pestle 102. Therefore, when the pressure from above by the upper pestle 103 is applied to the laminated electrode body 1, the outer peripheral surface of the positive electrode layer 2 presses the solid electrolyte layer 5 against the inner peripheral surface of the mortar hole 101a in the radial direction. Thereby, the molding of the solid electrolyte layer 5 by pressing can be sufficiently performed. In addition, the bonding property between the positive electrode layer 2 and the solid electrolyte layer 5 can be improved, and thereby, the peeling of the solid electrolyte layer 5 from the positive electrode layer 2 can be suppressed, so that the thickness of the solid electrolyte layer 5 after molding can be made thinner.

[0041] Finally, as shown in FIG. 7, by relatively moving the die 101 and the lower pestle 102, the laminated electrode body 1 can be taken out from the mortar hole 101a. Then, as shown in FIG. 1, the laminated electrode body 1 is accommodated between the outer can 20 and the sealing can 30, and the all-solid-state battery 10 is assembled. Note that, to take out the laminated electrode body 1 from the mortar hole 101a, the die 101 and the upper pestle 103 may be relatively moved. Further, with the laminated electrode body 1 sandwiched therebetween, the upper pestle 103 and the lower pestle 102 are relatively moved with respect to the die 101 so that the laminated electrode body 1 is taken out from the mortar hole 101a, which is preferable because cracking and chipping of the laminated electrode body 1 can be prevented. Note that, depending on the material of the solid electrolyte layer 5, it can be expected that the solid electrolyte acts as a lubricant and the removal of the laminated electrode body 1 from the die 101 becomes easier.

[0042] Thus, according to the manufacturing method of the laminated electrode body 1, the solid electrolyte layer 4 and the solid electrolyte layer 5 can be formed thinly and uniformly, and the thickness of the solid electrolyte layer 5 can be adjusted. Further, the bonding property between the peripheral side surface of the positive electrode layer 2 and the solid electrolyte layer 5 can be improved. As a result, the battery capacity of the all-solid-state battery 1 can be increased. Further, the detachment of the positive electrode active material particles from the positive electrode layer 2 can be more surely suppressed, and an internal short circuit due to the contact between the positive electrode active material particles and the negative electrode layer 3 or the negative electrode can 30 can be suppressed. That is, according to the laminated electrode body 1 obtained by this manufacturing method, an all-solid-state battery 1 with high capacity and high reliability can be provided.

[0043] In this manufacturing method, the electrode material X forms the negative electrode layer 3 and the electrode material Y forms the positive electrode layer 2, but it is also possible to make the electrode material X form the positive electrode layer 2 and the electrode material Y form the negative electrode layer 3.

[0044] Next, another laminated electrode body 1 will be specifically described with reference to FIG. 8. Another laminated electrode body 1 has the same basic configuration as the above-described laminated electrode body 1. Therefore, the configuration different from the above-described laminated electrode body 1 will be described.

[0045] As shown in Fig. 8, the other laminated electrode body 1 has a solid electrolyte layer 5 extending from the peripheral edge of the solid electrolyte layer 4 along the peripheral side surfaces of the positive electrode layer 2 and the negative electrode layer 3. The radial thickness of the solid electrolyte layer 5 is the same as that of the above-described solid electrolyte layer 5 shown in Fig. 2. The solid electrolyte layer 4 and the solid electrolyte layer 5 have a substantially H-shaped cross-section in a longitudinal sectional view. Thereby, it is possible to suppress the desorption of active material particles from both the positive electrode layer 2 and the negative electrode layer 3, and it is possible to more reliably suppress an internal short circuit. As a result, according to the other laminated electrode body 1, the battery capacity can be increased, and a more reliable all-solid-state battery 1 can be provided. In particular, in a bipolar battery in which a plurality of laminated electrode bodies 1 are laminated in series, since the negative electrode layer 3 of one laminated electrode body 1 and the positive electrode layer 2 of the other laminated electrode body 1 adjacent to each other are adjacent, an internal short circuit between adjacent laminated electrode bodies 1 can be suppressed.

[0046] Another manufacturing method of the laminated electrode body 1 will be described with reference to Figs. 9 to 13.

[0047] First, as in the above-described manufacturing method, a pressing device 100 is prepared. In this manufacturing method, a replaceable lower pestle 105 shown in Fig. 9 is inserted from below the mortar hole 101a instead of the lower pestle 102.

[0048] Next, as shown in Fig. 9, a powdery solid electrolyte material W is sprayed from above the mortar hole 101a onto the upper surface of the replaceable lower pestle 105 and the inner peripheral surface of the mortar hole 101a by an injection device 104. The solid electrolyte material W is negatively charged. The die 101 and the replaceable lower pestle 105 are charged with the opposite polarity to the charged solid electrolyte material W. Thereby, an adhesion layer of the solid electrolyte material W is formed, and the solid electrolyte layer 5 can be thinly formed on the inner peripheral surface of the mortar hole 101a. On the other hand, since the solid electrolyte layer 6 formed on the upper surface of the replaceable lower pestle 105 is not used for manufacturing the laminated electrode body 1, as shown in Fig. 10, the replaceable lower pestle 105 together with the solid electrolyte layer 6 is removed from below the mortar hole 101a. After that, a lower pestle 102 different from the lower pestle 105 is inserted from below the mortar hole 101a. The upper surface end of the lower pestle 102 can be inserted into the mortar hole 101a so as to contact the lower end of the solid electrolyte layer 5.

[0049] Next, as shown in FIG. 11, the space surrounded by the solid electrolyte layer 5 and the upper surface of the lower pestle 102 is filled with the electrode material X. Thereby, the negative electrode layer 3 before molding is formed. In this manufacturing method, the electrode material X is a powdery negative electrode mixture for forming the negative electrode layer 3. Although not particularly shown, the powdery electrode material X is filled into the mortar hole 101a by a hopper similar to the above. The electrode material X filled in the mortar hole 101a and the solid electrolyte layer 5 are pressed from above by the upper pestle 103, and a molded body of the negative electrode layer 3 and the solid electrolyte layer 5 disposed on the peripheral side surface of the negative electrode layer 3 is formed. Note that the negative electrode layer 3 and the solid electrolyte layer 5 may not be pressed here, and after further putting the solid electrolyte material W and the electrode material Y into the mortar hole 101a, they may be pressed together.

[0050] Next, the negative electrode layer 3 and the solid electrolyte layer 5 (molded body or filling before molding) are moved to the lower side of the mortar hole 101a while being sandwiched by the upper pestle 103 or between the upper pestle 103 and the lower pestle 102, and a space for producing the solid electrolyte layer 4 and the solid electrolyte layer 5 shown in FIG. 12 below and the positive electrode layer 2 shown in FIG. 13 is formed above the mortar hole 101a. Alternatively, after removing the lower pestle 102 from below the mortar hole 101a, the die 101 may be inverted and the negative electrode layer 3 may be disposed on the lower side of the mortar hole 101a to form the space. That is, after forming the negative electrode layer 3 and the solid electrolyte layer 5 on the negative electrode layer 3 side, it is only necessary to form a space in the mortar hole 101a where the solid electrolyte material W can be sprayed onto the inner peripheral surface of the mortar hole 101a and the upper surface of the negative electrode layer 3.

[0051] Next, as shown in FIG. 12, in the above-described space, the powdery solid electrolyte material W is sprayed onto the negative electrode layer 3 and the inner peripheral surface of the mortar hole 101a from above the mortar hole 101a by the spraying device 104, or after fixing the solid electrolyte material W to the upper surface of the negative electrode layer 3 by the upper pestle 103, the powdery solid electrolyte material W is sprayed by the spraying device 104 to form the solid electrolyte layer 4 and the solid electrolyte layer 5 on the positive electrode layer 2 side. This process is the same as that described above, and a detailed description thereof is omitted.

[0052] Next, as shown in FIG. 13, the electrode material Y is filled into the space surrounded by the solid electrolyte layer 4 and the solid electrolyte layer 5. Thereby, the positive electrode layer 2 before molding is formed. The filled electrode material Y is pressed by the upper punch 103 from above. At this time, the above-described negative electrode layer 3, solid electrolyte layer 4, and solid electrolyte layer 5 are also pressed together. Thereby, a molded body of the laminated electrode body 1 is formed. This process is the same as the one described above, and detailed description thereof is omitted. Note that the solid electrolyte layer 5 formed on the peripheral side surface of the negative electrode layer 3 and the solid electrolyte layer 5 formed on the peripheral side surface of the positive electrode layer 2 may have different thicknesses.

[0053] Finally, by relatively moving the die 101 and the lower punch 102, the laminated electrode body 1 can be taken out from the die hole 101a. Note that, in order to take out the laminated electrode body 1 from the die hole 101a, the die 101 and the upper punch 103 may be relatively moved. Further, in a state where the laminated electrode body 1 is sandwiched, if the upper punch 103 and the lower punch 102 are relatively moved with respect to the die 101 so as to take out the laminated electrode body 1 from the die hole 101a, it is preferable because cracking and chipping of the laminated electrode body 1 can be prevented. According to the laminated electrode body 1 obtained by this manufacturing method, a short circuit can be more reliably prevented, and a more reliable all-solid-state battery 1 can be provided. Note that, also in this manufacturing method, the electrode material X may form the positive electrode layer 2 and the electrode material Y may form the negative electrode layer 3.

[0054] As described above, the embodiments have been described. However, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit thereof.

[0055] Next, a test was conducted on the thickness of the solid electrolyte layer 4 or 5 of the laminated electrode body 1 and the presence or absence of an internal short circuit in the all-solid-state battery 10 (flat battery) that houses the laminated electrode body 1.

[0056] (Example 1) Using a commercially available powder compression molding machine for tablet molding, a laminated electrode body was produced by the following method. Note that the production of the electrode body was performed in an atmosphere with sufficiently reduced humidity.

[0057] <Formation of negative electrode layer and solid electrolyte layer> Lithium titanate powder with an average particle diameter of 2 μm: 50 parts by mass, carbon nanotubes: 9 parts by mass, sulfide-based solid electrolyte (Li 6 PS 5 Cl): 41 parts by mass were mixed to prepare a negative electrode mixture. The negative electrode mixture was set in a powder supply mechanism (hopper) provided in a powder compression molding machine, and 129 mg of the negative electrode mixture was filled into the mortar hole of a die having a mortar hole with a diameter of 8 mm with the lower opening closed by a pestle.

[0058] Next, a sulfide-based solid electrolyte material (Li 6 PS 5 Cl) was set in an injection device equipped with an electrostatic generation electrode having a needle-shaped tip, and was sprayed onto the lower surface of the pestle charged to the opposite polarity with a DC high voltage of about -20 kV applied to the electrode, and the solid electrolyte material was adhered. The adhesion amount of the solid electrolyte material at this time was about 2 mg.

[0059] Furthermore, the negative electrode mixture in the mortar hole was pressed by the pestle with the solid electrolyte material adhered to the lower surface, and a negative electrode layer and a solid electrolyte layer (solid electrolyte layer 4) were formed.

[0060] <Formation of laminated electrode body> Inside the mortar hole in which the negative electrode layer and the solid electrolyte layer 4 were formed, a negatively charged sulfide-based solid electrolyte material was sprayed from the injection device, and the solid electrolyte material was adhered to the inner peripheral surface of the mortar hole charged to the opposite polarity, thereby forming a solid electrolyte layer (solid electrolyte layer 5).

[0061] Next, lithium cobalt oxide powder with an average particle diameter of 5 μm: 70 parts by mass, carbon nanotubes: 4 parts by mass, sulfide-based solid electrolyte with an average particle diameter of 3 μm (Li 6 PS 5 Cl): 26 parts by mass were mixed to prepare a positive electrode mixture. The positive electrode mixture was set in a hopper, and the positive electrode mixture was filled into the mortar hole with the solid electrolyte material adhered to the inner peripheral surface, thereby forming a laminated electrode body.

[0062] Furthermore, the laminated electrode body was pressed with an upper pestle to produce a molded body of the laminated electrode body. The thicknesses of the negative electrode layer, positive electrode layer, solid electrolyte layer 4, and solid electrolyte layer 5 of the laminated electrode body were confirmed by electron microscopic observation of the cross section. The thickness of the negative electrode layer was 1.3 mm, the thickness of the positive electrode layer was 0.7 mm, the thickness of the solid electrolyte layer 4 was 25 μm, and the thickness of the solid electrolyte layer 5 was 20 μm.

[0063] (Comparative Example 1) 129 mg of the negative electrode mixture prepared in Example 1 was placed in a powder molding die with a diameter of 8 mm, and pressure molding was performed using a press to form a negative electrode layer. Next, 2 mg of a sulfide-based solid electrolyte material (Li 6 PS 5 Cl) was put on the upper surface of the negative electrode layer and pressure molded to form a solid electrolyte layer on the upper surface of the negative electrode layer. Furthermore, 92 mg of the positive electrode mixture prepared in Example 1 was put on the upper surface of the solid electrolyte layer and pressure molded to produce a molded body of the laminated electrode body. The thickness of the negative electrode layer of the laminated electrode body was 1.3 mm, and the thickness of the positive electrode layer was 0.7 mm. On the other hand, the thickness of the solid electrolyte layer was non-uniform, and there were portions where the negative electrode layer and the positive electrode layer were in contact and short-circuited.

[0064] (Comparative Example 2) 129 mg of the negative electrode mixture prepared in Example 1 was placed in a powder molding die with a diameter of 8 mm, and pressure molding was performed using a press to form a negative electrode layer. Next, 16 mg of a sulfide-based solid electrolyte (Li 6 PS 5 Cl) was put on the upper surface of the negative electrode layer and pressure molded to form a solid electrolyte layer on the upper surface of the negative electrode layer. Furthermore, 92 mg of the positive electrode mixture prepared in Example 1 was put on the upper surface of the solid electrolyte layer and pressure molded to produce a molded body of the laminated electrode body. The thickness of the negative electrode layer of the laminated electrode body was 1.3 mm, the thickness of the positive electrode layer was 0.7 mm, and the thickness of the solid electrolyte layer was 0.2 mm.

[0065] In the laminated electrode body of Example 1 produced by the manufacturing method of the present invention using a charged solid electrolyte material, both the solid electrolyte layer 4 and the solid electrolyte layer 5 could be formed with a thin and uniform thickness. On the other hand, in the laminated electrode body of the comparative example produced by the conventional method, in the laminated electrode body of Comparative Example 1 in which an attempt was made to form a thin solid electrolyte layer, the thickness became non-uniform, and a problem occurred in that the insulation between the negative electrode layer and the positive electrode layer became insufficient.

[0066] Next, the laminated electrode bodies of Example 1 and Comparative Example 2 were enclosed in a battery container composed of a stainless steel exterior can and a sealed can and a gasket made of polyphenylene sulfide resin with current collectors made of expanded graphite sheets arranged on the negative electrode layer side and the positive electrode layer side, respectively, to assemble coin-shaped batteries. In addition, the thickness of the expanded graphite sheet arranged on the laminated electrode body of Example 1 was made 0.18 mm thicker in total than that of Comparative Example 2 so that the difference in thickness between the laminated electrode body of Example 1 (2.025 mm) and the laminated electrode body of Comparative Example 2 (2.2 mm) could be eliminated.

[0067] Ten flat batteries each containing the laminated electrode body of Example 1 and ten flat batteries each containing the laminated electrode body of Comparative Example 2 were assembled and charged and discharged, the discharge capacity was confirmed, and the presence or absence of internal short circuits was examined. As a result, short circuits could not be recognized in all ten of the flat batteries containing the laminated electrode body of Example 1. On the other hand, short circuits were recognized in nine out of ten of the flat batteries containing the laminated electrode body of Comparative Example 2. That is, in the flat battery containing the laminated electrode body of Comparative Example 2, defects due to short circuits occurred at a rate of 90%.

[0068] This is because in the flat battery containing the laminated electrode body of Example 1, the solid electrolyte layer 5 formed on the peripheral side surface of the positive electrode layer can prevent the positive electrode layer from falling off, and in the flat battery containing the laminated electrode body of Comparative Example 2, no solid electrolyte layer is formed on the peripheral side surface of the positive electrode layer, resulting in the positive electrode layer falling off.

Explanation of Reference Numerals

[0069] 1 Stacked electrode body, 2 Positive electrode layer, 3 Negative electrode layer, 4 Solid electrolyte layer, 5 Solid electrolyte layer, 6 Solid electrolyte layer 10 All-solid-state battery, 20 Outer can, 21 Bottom part, 22 Peripheral wall part, 30 Sealed can, 31 Flat part, 32 Peripheral wall part, 40 Gasket 100 Pressing device, 101 Die, 101a Mortar hole, 102 Lower pestle, 103 Upper pestle, 104 Injection device, 105 Lower pestle, X Electrode material, Y Electrode material, W Solid electrolyte material

Claims

1. A step of preparing a pressurizing device including a die having a die hole penetrating vertically, a lower punch inserted into the die hole from below and sliding within the die hole, and an upper punch inserted into the die hole from above and sliding within the die hole; filling the die hole with a first electrode material while closing a lower opening of the die hole with the lower punch, thereby forming a first electrode layer which is one of a positive electrode layer and a negative electrode layer; a step of depositing a solid electrolyte material onto an upper surface of the first electrode layer and an inner peripheral surface of the die hole from above the die hole to form a first solid electrolyte layer on the upper surface of the first electrode layer and a second solid electrolyte layer on the inner peripheral surface of the die hole; filling a space surrounded by the first solid electrolyte layer and the second solid electrolyte layer with a second electrode material to form a second electrode layer which is the other of the positive electrode layer and the negative electrode layer; forming a laminated electrode body by applying pressure to the first electrode layer, the second electrode layer, the first solid electrolyte layer, and the second solid electrolyte layer with the lower punch and the upper punch; and removing the laminated electrode body from the die hole by moving at least one of the upper punch and the lower punch relative to the die.

2. The method for producing a laminated electrode body according to claim 1, further comprising: a step of forming the first electrode layer by filling the die hole with the first electrode material, and then pressing the first electrode layer with an upper punch and a lower punch before attaching a solid electrolyte material.

3. A method for producing the laminated electrode body according to claim 1, comprising the steps of: a second solid electrolyte layer formed on the inner circumferential surface of the die hole by applying pressure to the inner circumferential surface of the die hole, the second solid electrolyte layer being formed on the inner circumferential surface of the die hole by applying pressure to ...

4. The method for producing a laminated electrode body according to claim 1, further comprising: a step of depositing a solid electrolyte material in a state in which a lower opening of the die hole is closed by a first lower punch before filling the die hole with the first electrode material, thereby forming a second solid electrolyte layer on the inner peripheral surface of the die hole on the side of the first electrode layer, and forming a third solid electrolyte layer on an upper surface of the first lower punch; removing the first lower punch together with the third solid electrolyte layer from below the die hole, and inserting a second lower punch from below the die hole so as to contact a lower end of the second solid electrolyte layer on the first electrode layer side; In the step of filling the first electrode material into the die hole, the first electrode material is filled into a space surrounded by the second solid electrolyte layer on the inner circumferential surface of the die hole and an upper surface of a second lower punch, thereby forming the first electrode layer; forming a space in the die hole for adhering a solid electrolyte material to an inner peripheral surface of the die hole and to an upper surface of the first electrode layer before forming the first solid electrolyte layer and a second solid electrolyte layer on the second electrode layer side.

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