LAMINATED ALL-SOLID SECONDARY CELL AND METHOD FOR MANUFACTURING SAME

A laminated all-solid-state secondary battery including: a laminated body in which a positive electrode and a negative electrode are laminated with a solid electrolyte layer interposed therebetween and which includes a side surface including a first side surface exposing the positive electrode current collector layer and a second side surface exposing the negative electrode current collector layer; an outer positive electrode attached to the first side surface; and an outer negative electrode attached to the second side surface, wherein the outer positive electrode is electrically connected to the positive electrode current collector layer, a side end portion of the outer positive electrode is located at a position not facing the negative electrode, the outer negative electrode is electrically connected to the negative electrode current collector layer, and a side end portion of the outer negative electrode is located at a position not facing the positive electrode.

TECHNICAL FIELD

The present invention relates to a laminated all-solid-state secondary battery and method for manufacturing the same.

Priority is claimed on Japanese Patent Application No. 2019-045032 filed on Mar. 12, 2019 and Japanese Patent Application No. 2019-045035 filed on Mar. 12, 2019, the content of which is incorporated herein by reference.

BACKGROUND ART

In recent years, electronics technologies have been remarkably developed and portable electronic devices have been made smaller, lighter, thinner, and more multifunctional. Accordingly, there has been a strong demand for cells that are power sources for electronic devices to be smaller, lighter, thinner, and more reliable and an all-solid lithium ion secondary battery that uses solid electrolyte as electrolyte has gained attention.

As the all-solid lithium ion secondary battery, a laminated all-solid lithium ion secondary battery (hereinafter, reoffered to as a laminated all-solid-state secondary battery) in which a positive electrode including a positive electrode current collector layer and a positive electrode active material layer; and a negative electrode including a negative electrode current collector layer and a negative electrode active material layer are alternately laminated with a solid electrolyte layer interposed therebetween is known.

Further, a sintered laminated all-solid lithium ion secondary battery (hereinafter, referred to as a laminated all-solid-state secondary battery) in which a positive electrode and a negative electrode are alternately laminated with a solid electrolyte layer interposed therebetween is known.

In a general laminated all-solid-state secondary battery, a positive electrode current collector layer and a negative electrode current collector layer are exposed to a side surface of a laminated body and the side surface of the laminated body is provided with an outer positive electrode electrically connected to the positive electrode current collector layer and an outer negative electrode electrically connected to the negative electrode current collector layer (Patent Literature 1). Patent Literature 1 discloses the laminated all-solid-state secondary battery in which an end portion of the outer positive electrode is located at a position facing the negative electrode and an end portion of the outer negative electrode is located at a position facing the positive electrode.

Further, in another general laminated all-solid-state secondary battery, a positive electrode current collector layer and a negative electrode current collector layer are exposed to a side surface of a laminated sintered body and the side surface of the laminated body is provided with an outer positive electrode electrically connected to the positive electrode current collector layer and an outer negative electrode electrically connected to the negative electrode current collector layer (Patent Literature 2). In general, this laminated all-solid-state secondary battery is manufactured as below. First, a laminated body is obtained by laminating a positive electrode and a negative electrode with a solid electrolyte layer interposed therebetween. Next, a laminated sintered body is obtained by baking and sintering the obtained laminated body. Then, a conductive material paste is applied to the side surface of the obtained laminated sintered body according to a dip coating method or a printing method and is heated to form an outer positive electrode and an outer negative electrode (Patent Literature 3).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

By the way, in the laminated all-solid-state secondary battery, it is required to have a function of improving the charge and discharge capacity and instantaneously continuously discharging a large current, that is, a function of improving the pulse discharge cycle characteristics with the recent increase in the output of electronic devices. However, the conventional laminated all-solid-state secondary battery has a problem that both the charge and discharge capacity and the pulse discharge cycle characteristics cannot be improved.

The present invention has been made in view of the above-described circumstances and an object of the present invention is to provide a laminated all-solid-state secondary battery having excellent charge and discharge capacity and pulse discharge cycle characteristic.

Further, it is required to improve the charge and discharge capacity and the volumetric energy density in the laminated all-solid-state secondary battery with the recent miniaturization of electronic devices. However, since the laminated all-solid-state secondary battery has a configuration in which the surface of the laminated body is provided with the outer electrode for drawing the positive electrode and the negative electrode to the outside, there is a problem that the volume becomes large and the volumetric energy density becomes small if the outer electrode is provided.

Further, in the laminated sintered body which is obtained at the time of manufacturing the laminated all-solid-state secondary battery, the positive and negative electrode current collector layers contract and the exposure to the side surface may be insufficient. Therefore, since the bondability between the current collector layer and the outer electrode is poor when the outer electrode is applied to the side surface of the laminated sintered body, there is a problem that an excellent charge and discharge capacity cannot be obtained. Furthermore, since a crack is likely to be generated in the bonding surface between the current collector layer and the outer electrode due to the expansion and contraction of the volume with the charge and discharge reaction, there is a problem that excellent cycle characteristics cannot be obtained.

The present invention has been made in view of the above-described circumstances and an object of the present invention is to provide a laminated all-solid-state secondary battery having excellent charge and discharge capacity, volumetric energy density, and cycle characteristics and a method for manufacturing the same.

Solution to Problem

The present inventors have carried out careful examination in order to solve the above-described problems and have found that the charge and discharge capacity and the pulse discharge cycle characteristics are improved by the configuration in which the side end portion of the outer positive electrode of the laminated all-solid-state secondary battery is located at a position not facing the side end portion of the negative electrode and the side end portion of the outer negative electrode is located at a position not facing the side end portion of the positive electrode. The reason for this is not always clear, but it is considered that the generation of the parasitic capacitance (stray capacitance) between the outer positive electrode and the negative electrode or between the outer negative electrode and the positive electrode is suppressed. The parasitic capacitance means a capacitance component not intended by a designer due to the internal physical structure of the electronic component.

That is, the present invention provides the following means in order to solve the above-described problems.

(1) A laminated all-solid-state secondary battery according to a first aspect of the present invention includes: a laminated body in which a positive electrode including a positive electrode current collector layer and a positive electrode active material layer; and a negative electrode including a negative electrode current collector layer and a negative electrode active material layer are laminated with a solid electrolyte layer interposed therebetween and which includes a side surface formed as a surface parallel to a laminating direction, the side surface including a first side surface exposing the positive electrode current collector layer and a second side surface exposing the negative electrode current collector layer; an outer positive electrode which is attached to the first side surface; and an outer negative electrode which is attached to the second side surface, wherein the outer positive electrode is electrically connected to the positive electrode current collector layer, a side end portion of the outer positive electrode is located at a position not facing the negative electrode, the outer negative electrode is electrically connected to the negative electrode current collector layer, and a side end portion of the outer negative electrode is located at a position not facing the positive electrode.

(2) In the laminated all-solid-state secondary battery according to the aspect (1), the laminated body may include an upper surface and a lower surface which are formed as surfaces orthogonal to the laminating direction and each of the outer positive electrode and the outer negative electrode may include a sub-electrode which extends to at least one surface of the upper surface and the lower surface.

(3) In the laminated all-solid-state secondary battery according to the aspect (2), a front end portion of the sub-electrode of the outer positive electrode may be located at a position not facing a major surface of the negative electrode laminated at a position closest to the sub-electrode in the laminating direction.

(4) In the laminated all-solid-state secondary battery according to the aspect (2), a front end portion of the sub-electrode of the outer negative electrode may be located at a position not facing a major surface of the positive electrode laminated at a position closest to the sub-electrode in the laminating direction.

(5) In the laminated all-solid-state secondary battery according to any one of the aspects (1) to (4), the first side surface and the second side surface may be located at a facing position.

(6) In the laminated all-solid-state secondary battery according to the aspect (1), a side surface sub-electrode of the outer positive electrode may be located at a position not facing the side end portion of the negative electrode, the outer negative electrode may be electrically connected to the negative electrode current collector layer, and a side surface sub-electrode of the outer negative electrode may be located at a position not facing the side end portion of the positive electrode.

(7) In the laminated all-solid-state secondary battery according to the aspect (6), the laminated body may include an upper surface and a lower surface which are formed as surfaces orthogonal to the laminating direction and the outer positive electrode and the outer negative electrode may include an upper surface sub-electrode or a lower surface sub-electrode.

(8) In the laminated all-solid-state secondary battery according to the aspect (7), a front end portion of the upper surface sub-electrode or the lower surface sub-electrode of the outer positive electrode may be located at a position not facing a major surface of the negative electrode laminated at a position closest to the upper and lower surface sub-electrodes in the laminating direction.

(9) A front end portion of the upper surface sub-electrode or the lower surface sub-electrode of the outer negative electrode may be located at a position not facing a major surface of the positive electrode laminated at a position closest to the sub-electrode in the laminating direction.

(10) In the laminated all-solid-state secondary battery according to any one of the aspects (6) to (9), the first side surface and the second side surface may be located at a facing position.

Further, the present inventor has carried out careful examination in order to solve the above-described problems and found that the charge and discharge capacity, the volumetric energy density, and the cycle characteristics are improved by forming at least one end portion of the upper end portion and the lower end portion of the outer positive electrode and the outer negative electrode on the inside of the upper end portion or the lower end portion of the laminated body in the laminated all-solid-state secondary battery. The reason for this is not always clear, but the following can be considered.

First, when the positive and outer negative electrodes of the laminated all-solid-state secondary battery are formed on the inside of the laminated body, it is possible to prevent the positive and outer negative electrodes from being formed at the ridge of the laminated body. Thus, the generation of parasitic capacitance (stray capacitance) between the outer positive electrode and the negative electrode at the ridge or between the outer negative electrode and the positive electrode at the ridge is suppressed. Therefore, it is considered that the charge and discharge capacity is improved. Further, the parasitic capacitance means a capacitance component not intended by a designer due to the internal physical structure of the electronic component. Further, since the positive electrode current collector and the negative electrode current collector can be electrically connected to the outer electrodes without increasing the volume of the laminated all-solid-state secondary battery by forming the positive and outer negative electrodes on the inside of the laminated body, it is considered that the volumetric energy density becomes high.

Further, the present inventor forms a groove in the laminated body before baking the laminated body in which the positive electrode and the negative electrode are laminated with the solid electrolyte layer interposed therebetween, that is, at the unbaked stage, exposes the positive electrode current collector and the negative electrode current collector to the side surface of the laminated body, and fills the groove with a conductive material. Next, an unbaked laminated all-solid-state secondary battery in which the conductive material is formed as the outer positive electrode and the outer negative electrode can be manufactured by cutting the groove filled with the conductive material. Thus, it is found that, at the unbaked stage, an unbaked laminated all-solid cell having a good bonded state between the outer positive electrode and the positive electrode current collector and between the outer negative electrode and the negative electrode current collector can be obtained. Thus, since it is possible to obtain good bondability between the outer positive electrode and the positive electrode current collector and between the outer negative electrode and the negative electrode current collector even after the baking even if the laminated body is baked, it is possible to obtain the laminated all-solid-state secondary battery having excellent cycle characteristics.

That is, the present invention provides the following means in order to solve the above-described problems.

(11) A laminated all-solid-state secondary battery according to another aspect of the present invention includes: a laminated sintered body which is obtained by sintering a laminated body, in which a positive electrode including a positive electrode current collector layer and a positive electrode active material layer; and a negative electrode including a negative electrode current collector layer and a negative electrode active material layer are laminated with a solid electrolyte layer interposed therebetween, and includes a side surface formed as a surface parallel to the laminating direction, the side surface including a first side surface exposing the positive electrode current collector layer and a second side surface exposing the negative electrode current collector layer; an outer positive electrode which is attached to the first side surface; and an outer negative electrode which is attached to the second side surface, wherein the outer positive electrode is electrically connected to the positive electrode current collector layer and at least one end portion of an upper end portion and a lower end portion of the outer positive electrode in the laminating direction is located on an inside of an upper end portion or a lower end portion of the laminated sintered body in the laminating direction, and wherein the outer negative electrode is electrically connected to the negative electrode current collector layer and at least one end portion of an upper end portion and a lower end portion of the outer negative electrode in the laminating direction is located on an inside of the upper end portion or the lower end portion of the laminated sintered body in the laminating direction.

(12) In the laminated all-solid-state secondary battery according to the aspect (11), the laminated sintered body may include an upper surface and a lower surface which are formed as surfaces orthogonal to the laminating direction and each of the outer positive electrode and the outer negative electrode may include a sub-electrode which extends to at least one surface of the upper surface and the lower surface.

(13) A method for manufacturing a laminated all-solid-state secondary battery according to another aspect of the present invention includes the steps of: obtaining a unit laminated body by laminating a positive electrode unit in which two or more positive electrodes including a positive electrode current collector layer and a positive electrode active material layer are arranged in parallel with a spacing portion therebetween along a surface direction of the positive electrode and a negative electrode unit in which two or more negative electrodes including a negative electrode current collector layer and a negative electrode active material layer are arranged in parallel with a spacing portion therebetween along a plane direction of the negative electrode so that the spacing portion of the positive electrode unit faces the negative electrode of the negative electrode unit and the spacing portion of the negative electrode unit faces the positive electrode of the positive electrode unit with a solid electrolyte layer interposed therebetween and providing the solid electrolyte layer on both upper and lower surfaces in the laminating direction; providing a first groove passing through the spacing portion of the positive electrode unit and a second groove passing through the spacing portion of the negative electrode unit in the laminating direction from one surface of the unit laminated body in the laminating direction; filling the first groove and the second groove with a conductive material; obtaining a unit laminated body piece by forming a notch penetrating each of the first groove filled with the conductive material and the second groove filled with the conductive material to cut the unit laminated body in the laminating direction; and baking and sintering the unit laminated body piece.

(14) A method for manufacturing a laminated all-solid-state secondary battery according to still another aspect of the present invention includes the steps of: obtaining a unit laminated body by laminating a positive electrode unit in which two or more positive electrodes including a positive electrode current collector layer and a positive electrode active material layer are arranged in parallel with a spacing portion therebetween along a surface direction of the positive electrode and a negative electrode unit in which two or more negative electrodes including a negative electrode current collector layer and a negative electrode active material layer are arranged in parallel with a spacing portion therebetween along a plane direction of the negative electrode so that the spacing portion of the positive electrode unit faces the negative electrode of the negative electrode unit and the spacing portion of the negative electrode unit faces the positive electrode of the positive electrode unit with a solid electrolyte layer interposed therebetween and providing the solid electrolyte layer on one of the upper and lower surfaces in the laminating direction; providing a first groove passing through the spacing portion of the positive electrode unit and a second groove passing through the spacing portion of the negative electrode unit in the laminating direction from a surface on the side opposite to the surface provided with the solid electrolyte layer of the unit laminated body; filling the first groove and the second groove with a conductive material; forming a solid electrolyte layer on a surface on the side opposite to the surface provided with the solid electrolyte layer in the unit laminated body; obtaining a unit laminated body piece by forming a notch penetrating each of the first groove filled with the conductive material and the second groove filled with the conductive material to cut the unit laminated body in the laminating direction; and baking and sintering the unit laminated body piece.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a laminated all-solid-state secondary battery having excellent charge and discharge capacity and pulse discharge cycle characteristics.

Further, it is possible to provide a laminated all-solid-state secondary battery having excellent charge and discharge capacity, volumetric energy density, and cycle characteristics and a method for manufacturing the same.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention will be described in detail by appropriately referring to the drawings. The drawings used in the following description may be enlarged for convenience in order to make the features of the present invention easy to understand. Thus, the dimensional ratios of each component shown in the drawings may differ from the actual ones. The materials, dimensions, and the like exemplified in the following description are examples and the present invention is not limited thereto. The present invention can be appropriately modified and implemented within the range in which the effect is exhibited.

First, a conventional laminated all-solid-state secondary battery will be described.

FIG. 11is a schematic view of the conventional laminated all-solid-state secondary battery, whereFIG. 11(a)is a plan view when viewed from above andFIG. 11(b)is a bottom view when viewed from below.FIG. 12is a cross-sectional view taken along a line XII-XII ofFIG. 11.

In all the plan views and bottom views of the laminated all-solid-state secondary battery in the drawings attached to the specification of the present application, a sufficient side margin is provided between the side surface of the positive electrode or the negative electrode and the side surface of the outer wall of the all-solid-state secondary battery to prevent at least a short circuit. Even if they are drawn as if they are in contact with each other in the drawing, the side margin which is very thin as if it cannot be depicted s provided between them.

As shown inFIGS. 11 and 12, a laminated all-solid-state secondary battery310includes a laminated body320in which a positive electrode330and a negative electrode340are laminated with a solid electrolyte layer350interposed therebetween. The positive electrode330includes a positive electrode current collector layer331and a positive electrode active material layer332. The negative electrode340includes a negative electrode current collector layer341and a negative electrode active material layer342. The laminated body320is a hexahedron and includes four side surfaces (a first side surface321, a second side surface322, a third side surface323, and a fourth side surface324) which are formed as surfaces parallel to the laminating direction, an upper surface325which is formed on the upper side as a surface orthogonal to the laminating direction, and a lower surface326which is formed on the lower side. The positive electrode current collector layer is exposed to the first side surface321and the negative electrode current collector layer is exposed to the second side surface322. The third side surface323is a side surface on the right side when viewed from the first side surface321with the upper surface325facing upward and the fourth side surface324is a side surface on the left side when viewed from the first side surface321with the upper surface325facing upward.

An outer positive electrode360electrically connected to the positive electrode current collector layer331is attached to the first side surface321of the laminated body320. The outer positive electrode360includes a side surface sub-electrode360awhich extends to the third side surface323and the fourth side surface324, an upper surface sub-electrode360bwhich extends to the upper surface325, and a lower surface sub-electrode360cwhich extends to the lower surface326. That is, the outer positive electrode360has a U-shaped cross-section and has five surfaces. The end portion of the side surface sub-electrode360a(the side end portion of the outer positive electrode360) is provided at a position facing the negative electrode340(the side surface of the negative electrode340). Here, the facing position means a position in which the side surface sub-electrode360aoverlaps the negative electrode340when the laminated all-solid-state secondary battery310is viewed through. The end portion of the upper surface sub-electrode360b(the upper end portion of the outer positive electrode360) is located at a position facing the negative electrode340(the upper surface of the negative electrode340). The end portion of the lower surface sub-electrode360c(the lower end portion of the outer positive electrode360) is located at a position facing the negative electrode340(the lower surface of the negative electrode340).

An outer negative electrode370electrically connected to the negative electrode current collector layer341is attached to the second side surface322of the laminated body320. The outer negative electrode370includes a side surface sub-electrode370awhich extends to the third side surface323and the fourth side surface324, an upper surface sub-electrode370bwhich extends to the upper surface325, and a lower surface sub-electrode370cwhich extends to the lower surface326. That is, the outer negative electrode370has a U-shaped cross-section and has five surfaces. The end portion of the side surface sub-electrode370a(the side end portion of the outer negative electrode370) is located at a position facing the positive electrode330(the side surface of the positive electrode330). The end portion of the upper surface sub-electrode370b(the upper end portion of the outer negative electrode370) is located at a position facing the positive electrode330(the upper surface of the positive electrode330). The end portion of the lower surface sub-electrode370c(the lower end portion of the outer negative electrode370) is located at a position facing the positive electrode330(the lower surface of the positive electrode330).

In the laminated all-solid-state secondary battery310, the end portions of the side surface sub-electrode360a, the upper surface sub-electrode360b, and the lower surface sub-electrode360cof the outer positive electrode360extend to a position facing the negative electrode340and the end portions of the side surface sub-electrode370a, the upper surface sub-electrode370b, and the lower surface sub-electrode370cof the outer negative electrode370extend to a position facing the positive electrode330. For this reason, the parasitic capacitance of the negative electrode340is generated at four positions among the outer positive electrode360, the side surface sub-electrode360a, the lower surface sub-electrode360c, and the negative electrode340as indicated by an arrow P. Further, the parasitic capacitance of the positive electrode330is generated at four positions among the outer negative electrode370, the side surface sub-electrode370a, the upper surface sub-electrode370b, and the positive electrode330as indicated by an arrow Q. In order to increase the charge and discharge capacity of the laminated all-solid-state secondary battery310, it is preferable that the facing area between the positive electrode330and the negative electrode340be wide, that is, the gap between the positive electrode330and the second side surface322be narrow and the gap between the negative electrode340and the first side surface321be narrow. However, when the gap between the positive electrode330and the second side surface322is narrow and the gap between the negative electrode340and the first side surface321is narrow, the parasitic capacitance is likely to be generated. When the parasitic capacitance is generated, the current consumption other than the charge and discharge reaction is reduced, so that the continuous discharge characteristics (pulse discharge cycle characteristics) of a large instantaneous current are reduced. Thus, the conventional laminated all-solid-state secondary battery310cannot easily improve both the charge and discharge capacity and the pulse discharge cycle characteristics.

First Embodiment

Next, a laminated all-solid-state secondary battery according to a first embodiment of the present invention will be described.

FIG. 1is a schematic view of the laminated all-solid-state secondary battery according to the first embodiment, whereFIG. 1(a)is a plan view when viewed from above andFIG. 1(b)is a bottom view when viewed from below.FIG. 2is a cross-sectional view taken along a line II-II ofFIG. 1. Further, in the description of the first embodiment, the same reference numerals will be given to the configurations overlapping with the conventional laminated all-solid-state secondary battery310and the description thereof will be omitted.

As shown inFIGS. 1 and 2, in a laminated all-solid-state secondary battery311of this embodiment, an outer positive electrode361is attached to the first side surface321of the laminated body320. An outer negative electrode371is attached to the second side surface322of the laminated body320.

The outer positive electrode361is an electrode having a U-shaped cross-section and including an upper surface sub-electrode361bextending to the upper surface325and a lower surface sub-electrode361cextending to the lower surface326. The end portion of the upper surface sub-electrode361b(the upper end portion of the outer positive electrode361) is located at a position facing the negative electrode340(the upper surface of the negative electrode340). The end portion of the lower surface sub-electrode361c(the lower end portion of the outer positive electrode361) is located at a position facing the negative electrode340(the lower surface of the negative electrode340). The outer positive electrode361does not include a side surface sub-electrode which extends to the third side surface323and the fourth side surface324. However, when the end portion of the side surface sub-electrode (the side end portion of the outer negative electrode371) is located at a position not facing the negative electrode340(the side surface of the negative electrode340), the outer positive electrode361may include the side surface sub-electrode. Here, the non-facing position means a position in which the side surface sub-electrode does not overlap the negative electrode340when the laminated all-solid-state secondary battery311is viewed through. When the outer positive electrode361includes the side surface sub-electrode, the end portion of the side surface sub-electrode is preferably in a range of 10 μm or less from the end portions of the third side surface323and the fourth side surface324on the side of the first side surface321.

The outer negative electrode371is an electrode having a U-shaped cross-section and including an upper surface sub-electrode371bextending to the upper surface325and a lower surface sub-electrode371cextending to the lower surface326. The end portion of the upper surface sub-electrode371b(the upper end portion of the outer negative electrode371) is located at a position facing the positive electrode330(the upper surface of the positive electrode330). The end portion of the lower surface sub-electrode371c(the lower end portion of the outer negative electrode371) is located at a position facing the positive electrode330(the lower surface of the positive electrode330). The outer negative electrode371does not include a side surface sub-electrode which extends to the third side surface323and the fourth side surface324. However, when the end portion of the side surface sub-electrode (the side end portion of the outer positive electrode361) is located at a position not facing the positive electrode330(the side surface of the positive electrode330), the outer negative electrode371may include the side surface sub-electrode. Here, the non-facing position means a position in which the side surface sub-electrode does not overlap the positive electrode330when the laminated all-solid-state secondary battery311is viewed through. When the outer negative electrode371includes the side surface sub-electrode, the end portion of the side surface sub-electrode is preferably in a range of 10 μm or less from the end portions of the third side surface323and the fourth side surface324on the side of the second side surface322.

In the laminated all-solid-state secondary battery311of this embodiment, the parasitic capacitance generating position of the negative electrode340is suppressed at two positions among the outer positive electrode361, a lower surface sub-electrode362c, and the negative electrode340as indicated by an arrow P. Further, the parasitic capacitance generating position of the positive electrode330is suppressed at two positions among the outer negative electrode371, the upper surface sub-electrode371b, and the positive electrode330as indicated by an arrow Q. In this way, in the laminated all-solid-state secondary battery311of this embodiment, the generation of the parasitic capacitance is suppressed compared to the conventional laminated all-solid-state secondary battery310and hence the pulse discharge cycle characteristics are improved. Further, since the generation of the parasitic capacitance is suppressed, the current distribution associated with the charge and discharge reaction becomes uniform and the cell reaction proceeds uniformly. As a result, the charge and discharge capacity is improved.

In the laminated all-solid-state secondary battery311, the materials of the positive electrode current collector layer331, the positive electrode active material layer332, the negative electrode current collector layer341, the negative electrode active material layer342, the solid electrolyte layer350, the outer positive electrode361, and the outer negative electrode371are not particularly limited and known materials used in the conventional laminated all-solid-state secondary battery can be used.

As the materials of the positive electrode current collector layer331and the negative electrode current collector layer341, it is preferable to use a material having a large conductivity. Specifically, metals such as silver, palladium, gold, platinum, aluminum, copper, and nickel can be used. Further, a mixture of the metal and the positive electrode active material may be used as the material of the positive electrode current collector layer331and a mixture of the metal and the negative electrode active material may be used as the material of the negative electrode current collector layer341.

The positive electrode active material layer332and the negative electrode active material layer342include a positive electrode active material and a negative electrode active material that transfer electrons. In addition, a conductive assistant, a binder, or the like may be included. It is preferable that the positive electrode active material and the negative electrode active material can efficiently intercalate and deintercalate lithium ions.

As the positive electrode active material and the negative electrode active material, for example, a transition metal oxide or a transition metal composite oxide is preferably used. Specifically, lithium manganese composite oxide Li2MnaMa1-aO3(0.8≤a≤1, Ma=Co, Ni), lithium cobalt oxide (LiCoO2), lithium nickelate (LiNiO2), lithium manganese spinel (LiMn2O4), composite metal oxide represented by a general formula: LiNixCoyMnzO2(x+y+z=1, 0≤x≤1, 0≤y≤1, 0≤z≤1), lithium vanadium compound (LiV2O5), olivin type LiMbPO4(here, Mb is one or more elements selected from Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, and Zr), lithium vanadium phosphate (Li3V2(PO4)3or LiVOPO4), Li excess solid solution represented by Li2MnO3-LiMcO2(Mc=Mn, Co, Ni), lithium titanate (Li4Ti5O12), composite metal oxide represented by LisNitCouAlvO2(0.9<s<1.3, 0.9<t+u+v<1.1), and the like can be used.

The positive electrode active material and the negative electrode active material may be selected according to the solid electrolyte described later. For example, when Li1+nAlnT2−n(PO4)3(0≤n≤0.6) is used as the solid electrolyte, it is preferable to use one or both of LiVOPO4and Li3V2(PO4)3for the positive electrode active material and the negative electrode active material. In this case, the bonding at the interfaces among the positive electrode active material layer332, the negative electrode active material layer342, and the solid electrolyte layer350becomes strong. Further, the contact area of the interfaces among the positive electrode active material layer332, the negative electrode active material layer342, and the solid electrolyte layer350can be widened.

The solid electrolyte layer350includes solid electrolyte. As the solid electrolyte, it is preferable to use a material having low electron conductivity and high lithium ion conductivity. Specifically, for example, at least one selected from a group consisting of perovskite type compound such as La0.51Li0.34TiO2.94and La0.5Li0.5TiO3, lysicon type compound such as Li14Zn(GeO4)4, garnet type compound such as Li7La3Zr2O12, nasicon type compound such as LiZr2(PO4)3, Li1.3Al0.3Ti1.7(PO4)3, and Li1.5Al0.5Ge1.5(PO4)3, thioricicon type compound such as Li3.2Ge0.25P0.75S4and Li3PS4, glass compound such as 50Li4SiO4.50Li3BO3, Li2S—P2S5, and Li2O—Li3O5—SiO2, phosphoric acid compound such as Li3PO4, Li3.5Si0.5P0.5O4, and Li2.9PO3.3N0.46, amorphous such as Li2.9PO3.3N0.46(LIPON) and Li3.6Si0.6P0.4O4, and glass ceramics such as Li1.07Al0.69Ti1.46(PO4)3and Li1.5Al0.5Ge1.5(PO4)3is preferable.

As the materials of the outer positive electrode361and the outer negative electrode371, it is preferable to use a material having a large conductivity. For example, silver, gold, platinum, aluminum, copper, tin, and nickel can be used.

Next, a method for manufacturing the laminated all-solid-state secondary battery311of this embodiment will be described.

The laminated all-solid-state secondary battery311can be manufactured according to, for example, a method including a paste preparing step of preparing paste of each member constituting the laminated body320, a unit manufacturing step of manufacturing a positive electrode unit and a negative electrode unit using the manufactured paste, a laminating step of manufacturing a laminated structure by alternately laminating the positive electrode unit and the negative electrode unit obtained as described above, a cutting step of cutting the obtained laminated structure into a predetermined shape, a baking step of obtaining the laminated body320by baking the laminated structure, and an outer electrode forming step of forming an outer electrode (the outer positive electrode361and the outer negative electrode371) on the side surface of the obtained laminated body320.

In the paste preparing step, each member of the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode current collector layer, the negative electrode active material layer, the outer electrode is made into paste. The method for making paste is not particularly limited, but for example, paste can be prepared by mixing the powder of each member and the vehicle. As a mixing device for preparing the paste, a conventionally known kneading device such as a bead mill, a planetary paste kneader, an automatic grinder, a three-roll mill, a high-share mixer, and a planetary mixer can be used. Here, the vehicle is a general term for a medium in a liquid phase and includes a solvent, a binder, and the like. The binder included in the paste of each member is not particularly limited, but polyvinyl acetal resin, polyvinyl butyral resin, terpineol resin, ethyl cellulose resin, acrylic resin, urethane resin, vinyl acetate resin, polyvinyl alcohol resin, and the like can be used. One of these resins may be used alone, or two or more of these resins may be used in combination.

Further, the paste of each material may include a plasticizer. The type of plasticizer is not particularly limited, but ester phthalates such as dioctyl phthalate and diisononyl phthalate may be used.

By a related method, paste for the positive electrode current collector layer, paste for the positive electrode active material layer, paste for the solid electrolyte layer, paste for the negative electrode active material layer, and paste for the negative electrode current collector layer are prepared.

The positive electrode unit is a laminated body having a positive electrode in which a positive electrode active material layer, a positive electrode current collector layer, and a positive electrode active material layer are sequentially laminated on a green sheet for a solid electrolyte layer. This positive electrode unit can be manufactured as below.

First, the prepared paste for the solid electrolyte layer is applied on a base such as a polyethylene terephthalate (PET) film to a desired thickness and is dried to manufacture a green sheet for the solid electrolyte layer. A method for applying the paste for the solid electrolyte layer is not particularly limited and known methods such as a doctor blade method, a die coater method, a comma coater method, and a gravure coater method can be adopted. Next, the paste for the positive electrode active material layer, the paste for the positive electrode current collector layer, and the paste for the positive electrode active material layer are laminated in this order on the green sheet for the solid electrolyte layer and are dried to form a positive electrode having the positive electrode active material layer, the positive electrode current collector layer, and the positive electrode active material layer laminated in this order. Further, in order to fill a step between the green sheet for the solid electrolyte layer and the positive electrode, the paste for the solid electrolyte layer is printed on a region (margin) other than the positive electrode by a screen printing method and is dried to form a solid electrolyte layer having a height equivalent to that of the positive electrode. Then, the base is peeled off to obtain a positive electrode unit in which the positive electrode is formed on the green sheet for the solid electrolyte layer.

The negative electrode unit is a laminated body having a negative electrode in which a negative electrode active material layer, a negative electrode current collector layer, and a negative electrode active material layer are laminated in this order on the green sheet for the solid electrolyte layer. This negative electrode unit can be manufactured similarly to the method for manufacturing the positive electrode unit except that the paste for the negative electrode active material layer and the paste for the negative electrode current collector layer are used instead of the paste for the positive electrode current collector layer and the paste for the positive electrode active material layer.

In the laminating step, the positive electrode unit and the negative electrode unit are alternately laminated. Accordingly, a laminated structure including the plurality of positive electrode units and the plurality of negative electrode units is manufactured.

Further, the manufactured laminated structures are collectively pressed and crimped with a die press, a hot water isobaric press (WIP), a cold water isobaric press (CIP), a hydrostatic press, and the like so that the adhesion between the positive electrode unit and the negative electrode unit can be improved. Pressurization is preferably performed in a heated state and can be performed, for example, at 40 to 95° C.

In the cutting step, the manufactured laminated structure is cut in the laminating direction of the laminated structure so that the positive electrode current collector layer of the positive electrode unit and the negative electrode current collector layer of the negative electrode unit are exposed to the side surface of the laminated structure.

As a device for cutting the laminated structure, a dicing blade, a fine laser processing machine, or the like can be used.

In the baking step, the laminated structure is baked and sintered to obtain the laminated body320of the laminated all-solid-state secondary battery311. By baking, the solid electrolyte layer, the electrode layer, and the current collector layer are densified to obtain the desired electrical properties. Baking can be performed in a non-oxidizing atmosphere when the material constituting the current collector layer is not suitable for heat treatment in an oxidizing atmosphere. The baking temperature is, for example, a temperature equal to or higher than 600° C. and equal to or lower than 1000° C. The baking time is, for example, in the range equal to or longer than 0.1 hour and equal to or shorter than 3 hours. The non-oxidizing atmosphere is a nitrogen atmosphere, an argon atmosphere, a nitrogen-hydrogen mixed atmosphere, or the like.

Before the baking step, a debinder treatment can be performed as a step separate from the baking step. By heat-decomposing the binder component included in the laminated structure before baking, it is possible to suppress the rapid decomposition of the binder component in the baking step. The debinder treatment is performed by heating, for example, in a non-oxidizing atmosphere at a temperature equal to or higher than the decomposition temperature of the binder component and lower than the sintering temperature of the laminated structure (usually in the range equal to or higher than 300° C. and equal to or lower than 800° C.) in the range equal to or longer than 0.1 hour and equal to or shorter than 10 hours.

In the outer electrode forming step, an outer electrode is formed on the side surface of the obtained laminated body320using conductive material paste for the outer electrode. Specifically, the outer positive electrode361is formed on the first side surface321of the laminated body320and the outer negative electrode371is formed on the second side surface322to respectively have a predetermined shape and are burned. As a method for molding the outer positive electrode361and the outer negative electrode371, known methods such as a screen printing method, a sputtering method, a dip coating method, and a spray coating method can be used. As a method for forming the outer positive electrode361and the outer negative electrode371into a predetermined shape by using a screen printing method, a sputtering method, a dip coating method, or a spray coating method, for example, a method for masking a region other than the region where an outer electrode is desired to be formed on the side surface of the laminated body320can be used with a masking jig, tape, or the like. The conditions of the burning treatment differ depending on the metal material type of the outer electrode, but the burning treatment can be performed by heating at a temperature equal to or higher than 200° C. and equal to or lower than 600° C. in a reducing atmosphere. Further, the outer electrode may be formed by forming a nickel (Ni) layer, a tin (Sn) layer, or the like on the surface of the outer electrode by a plating method, a sputtering method, or the like in order to improve the wettability with the solder.

Before the outer electrode forming step, the laminated body320may be placed in a cylindrical container together with an abrasive such as alumina and barrel-polished. Accordingly, the corners of the laminated body320can be chamfered. As another method, it may be polished by sandblasting.

Second Embodiment

Next, a laminated all-solid-state secondary battery according to a second embodiment of the present invention will be described.

FIG. 3is a schematic view of the laminated all-solid-state secondary battery according to the second embodiment, whereFIG. 3(a)is a plan view when viewed from above andFIG. 3(b)is a bottom view when viewed from below.FIG. 4is a cross-sectional view taken along a line IV-IV ofFIG. 3. Further, in the description of the second embodiment, the same reference numerals will be given to the configurations overlapping with the laminated all-solid-state secondary battery311of the first embodiment and the description thereof will be omitted.

As shown inFIGS. 3 and 4, in a laminated all-solid-state secondary battery312of this embodiment, an outer positive electrode362is attached to the first side surface321of the laminated body320. An outer negative electrode372is attached to the second side surface322of the laminated body320.

The outer positive electrode362is an electrode having an L-shaped cross-section and including the lower surface sub-electrode362cextending to the lower surface326. The end portion of the lower surface sub-electrode362c(the lower end portion of the outer positive electrode362) is located at a position not facing the negative electrode340(the lower surface of the negative electrode340). The outer positive electrode362does not include the side surface sub-electrode extending to the third side surface323and the fourth side surface324and does not include the upper surface sub-electrode361bin the laminated all-solid-state secondary battery311of the first embodiment.

The outer negative electrode372is an electrode having an L-shaped cross-section and including the lower surface sub-electrode372cextending to the lower surface326. The end portion of the lower surface sub-electrode372c(the lower end portion of the outer negative electrode372) is located at a position facing the positive electrode330(the lower surface of the positive electrode330). The outer negative electrode372does not include the side surface sub-electrode extending to the third side surface323and the fourth side surface324and does not include the upper surface sub-electrode371bin the laminated all-solid-state secondary battery311of the first embodiment.

In the laminated all-solid-state secondary battery312of this embodiment, the parasitic capacitance generating position of the negative electrode340is suppressed at two positions among the outer positive electrode362, the lower surface sub-electrode362c, and the negative electrode340as indicated by an arrow P. Further, the parasitic capacitance of the positive electrode330is suppressed at one position between the outer negative electrode372and the positive electrode330as indicated by an arrow Q. In this way, in the laminated all-solid-state secondary battery312of this embodiment, since the generation of the parasitic capacitance is suppressed compared to the laminated all-solid-state secondary battery311of the first embodiment, the pulse discharge cycle characteristics and the charge and discharge capacity are further improved.

Third Embodiment

Next, a laminated all-solid-state secondary battery according to a third embodiment of the present invention will be described.

FIG. 5is a schematic view of the laminated all-solid-state secondary battery according to the third embodiment, whereFIG. 5(a)is a plan view when viewed from above andFIG. 5(b)is a bottom view when viewed from below.FIG. 6is a cross-sectional view taken along a line VI-VI ofFIG. 5. Further, in the description of the third embodiment, the same reference numerals will be given to the configurations overlapping with the laminated all-solid-state secondary battery311of the first embodiment and the description thereof will be omitted.

As shown inFIGS. 5 and 6, in a laminated all-solid-state secondary battery313of this embodiment, an outer positive electrode363is attached to the first side surface321of the laminated body320. An outer negative electrode373is attached to the second side surface322of the laminated body320.

The outer positive electrode363is an electrode having a U-shaped cross-section, including an upper surface sub-electrode363bextending to the upper surface325and a lower surface sub-electrode363cextending to the lower surface326, and not including the side surface sub-electrode extending to the third side surface323and the fourth side surface324. The end portion of the upper surface sub-electrode363b(the upper end portion of the outer positive electrode363) is located at a position not facing the negative electrode340(the upper surface of the negative electrode340). The end portion of the lower surface sub-electrode363c(the lower end portion of the outer positive electrode363) is located at a position not facing the negative electrode340(the lower surface of the negative electrode340).

The outer negative electrode373is an electrode having a U-shaped cross-section, including an upper surface sub-electrode373bextending to the upper surface325and a lower surface sub-electrode373cextending to the lower surface326, and not including the side surface sub-electrode extending to the third side surface323and the fourth side surface324. The end portion of the upper surface sub-electrode373b(the upper end portion of the outer negative electrode373) is located at a position not facing the positive electrode330(the upper surface of the positive electrode330). The end portion of the lower surface sub-electrode373c(the lower end portion of the outer negative electrode371) is located at a position not facing the positive electrode330(the lower surface of the positive electrode330).

In the laminated all-solid-state secondary battery313of this embodiment, the parasitic capacitance of the negative electrode340is suppressed at one position between the outer positive electrode362and the negative electrode340as indicated by an arrow P. Further, the parasitic capacitance of the positive electrode330is suppressed at one position between the outer negative electrode372and the positive electrode330as indicated by an arrow Q. In this way, in the laminated all-solid-state secondary battery313of this embodiment, since the generation of the parasitic capacitance is further suppressed compared to the laminated all-solid-state secondary battery311of the first embodiment, the pulse discharge cycle characteristics and the charge and discharge capacity are further improved.

Fourth Embodiment

Next, a laminated all-solid-state secondary battery according to a fourth embodiment of the present invention will be described.

FIG. 7is a schematic view of the laminated all-solid-state secondary battery according to the fourth embodiment, whereFIG. 7(a)is a plan view when viewed from above andFIG. 7(b)is a bottom view when viewed from below.FIG. 8is a cross-sectional view taken along a line VIII-VIII ofFIG. 7. Further, in the description of the fourth embodiment, the same reference numerals will be given to the configurations overlapping with the laminated all-solid-state secondary battery311of the first embodiment and the description thereof will be omitted.

As shown inFIGS. 7 and 8, in the laminated all-solid-state secondary battery314of this embodiment, an outer positive electrode364is attached to the first side surface321of the laminated body320. An outer negative electrode374is attached to the second side surface322of the laminated body320.

The outer positive electrode364is an electrode having an L-shaped cross-section and including a lower surface sub-electrode364cextending to the lower surface326. The end portion of the lower surface sub-electrode364c(the lower end portion of the outer positive electrode364) is located at a position not facing the negative electrode340(the lower surface of the negative electrode340). The outer positive electrode364does not include the side surface sub-electrode extending to the third side surface323and the fourth side surface324and does not include the upper surface sub-electrode361bin the laminated all-solid-state secondary battery311of the first embodiment.

The outer negative electrode374is an electrode having an L-shaped cross-section and including a lower surface sub-electrode374cextending to the lower surface326. The end portion of the lower surface sub-electrode374c(the lower end portion of the outer negative electrode374) is located at a position not facing the positive electrode330(the lower surface of the positive electrode330). The outer negative electrode374does not include the side surface sub-electrode extending to the third side surface323and the fourth side surface324and does not include the upper surface sub-electrode371bin the laminated all-solid-state secondary battery311of the first embodiment.

In the laminated all-solid-state secondary battery314of this embodiment, the parasitic capacitance of the negative electrode340is suppressed at one position between the outer positive electrode364and the negative electrode340as indicated by an arrow P. Further, the parasitic capacitance of the positive electrode330is suppressed at one position between the outer negative electrode372and the positive electrode330as indicated by an arrow Q. In this way, in the laminated all-solid-state secondary battery314of this embodiment, since the generation of the parasitic capacitance is suppressed similarly to the laminated all-solid-state secondary battery313of the third embodiment, the pulse discharge cycle characteristics and the charge and discharge capacity are further improved.

Fifth Embodiment

Next, a laminated all-solid-state secondary battery according to a fifth embodiment of the present invention will be described.

FIG. 9is a schematic view of the laminated all-solid-state secondary battery according to the fifth embodiment, whereFIG. 9(a)is a plan view when viewed from above andFIG. 9(b)is a bottom view when viewed from below.FIG. 10is a cross-sectional view taken along a line X-X ofFIG. 9. Further, in the description of the fifth embodiment, the same reference numerals will be given to the configurations overlapping with the laminated all-solid-state secondary battery311of the first embodiment the description thereof will be omitted.

As shown inFIGS. 9 and 10, in a laminated all-solid-state secondary battery315of this embodiment, an outer positive electrode365is attached to the first side surface321of the laminated body320. An outer negative electrode375is attached to the second side surface322of the laminated body320.

The outer positive electrode365is an electrode having an I-shaped cross-section, does not include the side surface sub-electrode extending to the third side surface323and the fourth side surface324, and does not include the upper surface sub-electrode361band the lower surface sub-electrode361cof the laminated all-solid-state secondary battery311of the first embodiment.

The outer negative electrode375is an electrode having an I-shaped cross-section, does not include the side surface sub-electrode extending to the third side surface323and the fourth side surface324, and does not include the upper surface sub-electrode371band the lower surface sub-electrode371cof the laminated all-solid-state secondary battery311of the first embodiment.

In the laminated all-solid-state secondary battery315of this embodiment, the parasitic capacitance of the negative electrode340is suppressed at one position between the outer positive electrode365and the negative electrode340as indicated by an arrow P. Further, the parasitic capacitance of the positive electrode330is suppressed at one position between the outer negative electrode375and the positive electrode330as indicated by an arrow Q. In this way, in the laminated all-solid-state secondary battery315of this embodiment, since the generation of the parasitic capacitance is suppressed similarly to the laminated all-solid-state secondary battery313of the third embodiment, the pulse discharge cycle characteristics and the charge and discharge capacity are further improved.

According to the above-described laminated all-solid-state secondary batteries311to315of this embodiment, since the side end portions of the outer positive electrodes361to365are located at the positions not facing the side end portion of the negative electrode340and the side end portions of the outer negative electrodes371to375are located at the positions not facing the side end portion of the positive electrode330, the generation of the parasitic capacitance between the side end portions of the outer positive electrode361to365and the negative electrode340and the parasitic capacitance between the side end portions of the outer negative electrodes371to375and the positive electrode330can be suppressed. Therefore, the laminated all-solid-state secondary batteries311to315of this embodiment improve the charge and discharge capacity and the pulse discharge cycle characteristics.

First, a conventional laminated all-solid-state secondary battery will be described.

FIG. 32is a schematic view of the conventional laminated all-solid-state secondary battery, whereFIG. 32(a)is a plan view when viewed from above andFIG. 32(b)is a bottom view when viewed from below.FIG. 33is a cross-sectional view taken along a line XVIII-XVIII ofFIG. 32.

As shown inFIGS. 32 and 33, the laminated all-solid-state secondary battery10includes a laminated sintered body20obtained by sintering the laminated body in which the positive electrode30and the negative electrode40are laminated with the solid electrolyte layer50interposed therebetween. The positive electrode30includes a positive electrode current collector layer31and a positive electrode active material layer32. The negative electrode40includes a negative electrode current collector layer41and a negative electrode active material layer42. The laminated sintered body20is a hexahedron and includes four side surfaces (a first side surface21, a second side surface22, a third side surface23, and a fourth side surface24) which are formed as surfaces parallel to the laminating direction, an upper surface25which is formed on the upper side as a surface orthogonal to the laminating direction, and a lower surface26which is formed on the lower side. The positive electrode current collector layer is exposed to the first side surface21and the negative electrode current collector layer is exposed to the second side surface22. The third side surface23is a side surface on the right side when viewed from the first side surface21with the upper surface25facing upward and the fourth side surface24is a side surface on the left side when viewed from the first side surface21with the upper surface25facing upward.

An outer positive electrode60electrically connected to the positive electrode current collector layer31is attached to the first side surface21of the laminated sintered body20. The outer positive electrode60includes a lower surface sub-electrode60awhich extends to the lower surface26, an upper surface sub-electrode60bwhich extends to the upper surface25, and a side surface sub-electrode60cwhich extends to the third side surface23and the fourth side surface24. That is, the outer positive electrode60has a U-shaped cross-section and has five surfaces. The end portion of the lower surface sub-electrode60a(the lower end portion of the outer positive electrode60) is located at a position facing the negative electrode40(the lower surface of the negative electrode40). The end portion of the upper surface sub-electrode60b(the upper end portion of the outer positive electrode60) is located at a position facing the negative electrode40(the upper surface of the negative electrode40). The end portion of the side surface sub-electrode60c(the side end portion of the outer positive electrode60) is located at a position facing the negative electrode40(the side surface of the negative electrode40). Here, for example, in the case of the lower surface sub-electrode60aand the negative electrode40, the facing position means a position in which the lower surface sub-electrode60aoverlaps the negative electrode40when the laminated all-solid-state secondary battery10is viewed through.

An outer negative electrode70electrically connected to the negative electrode current collector layer41is attached to the second side surface22of the laminated sintered body20. The outer negative electrode70includes surfaces of a side surface sub-electrode70cwhich extends to the third side surface23and the fourth side surface24, an upper surface sub-electrode70bwhich extends to the upper surface25, and a lower surface sub-electrode70awhich extends to the lower surface26. That is, the outer negative electrode70has a U-shaped cross-section and has five surfaces. The end portion of the lower surface sub-electrode70a(the lower end portion of the outer negative electrode70) is located at a position facing the positive electrode30(the lower surface of the positive electrode30). The end portion of the upper surface sub-electrode70b(the upper end portion of the outer negative electrode70) is located at a position facing the positive electrode30(the upper surface of the positive electrode30). The end portion of the side surface sub-electrode70c(the side end portion of the outer negative electrode70) is located at a position facing the positive electrode30(the side surface of the positive electrode30).

In the laminated all-solid-state secondary battery10, the parasitic capacitance of the negative electrode40is suppressed at four positions among the outer positive electrode60, the lower surface sub-electrode60a, the side surface sub-electrode60c, and the negative electrode40as indicated by an arrow P. Further, the parasitic capacitance of the positive electrode30is generated at four positions among the outer negative electrode70, the lower surface sub-electrode70a, the side surface sub-electrode70c, and the positive electrode30as indicated by an arrow Q. For this reason, in the laminated all-solid-state secondary battery10, the charge and discharge capacity is likely to decrease. Further, in the laminated all-solid-state secondary battery10, since the outer positive electrode60and the outer negative electrode70are provided on the outer surface of the laminated sintered body20, the volume is larger than that of the laminated sintered body20and the charge and discharge capacity per unit volume decreases.

Sixth Embodiment

Next, a laminated all-solid-state secondary battery according to a sixth embodiment of the present invention will be described.

FIG. 13is a schematic view of the laminated all-solid-state secondary battery according to the sixth embodiment, whereFIG. 13(a)is a plan view when viewed from above andFIG. 13(b)is a bottom view when viewed from below.FIG. 14is a cross-sectional view taken along a line II-II ofFIG. 13. Further, in the description of the sixth embodiment, the same reference numerals will be given to the configurations overlapping with the conventional laminated all-solid-state secondary battery10and the description thereof will be omitted.

As shown inFIGS. 13 and 14, in the laminated all-solid-state secondary battery11of this embodiment, an outer positive electrode61is attached to the first side surface21of the laminated sintered body20. The outer positive electrode61is formed in the recess21aprovided in the first side surface21. An outer negative electrode71is attached to the second side surface22of the laminated sintered body20. The outer negative electrode71is formed in the recess22aprovided in the second side surface22.

The outer positive electrode61is formed as a portion in which the upper end portion (the end portion on the side of the upper surface25of the laminated sintered body20) is in contact with the upper surface of the positive electrode30. That is, the upper end portion of the outer positive electrode61is on the inside (the lower side) of the upper end portion of the laminated sintered body20in the laminating direction and the upper end portion of the outer positive electrode61does not face the negative electrode40(the upper surface of the negative electrode40). Therefore, the parasitic capacitance is less likely to be generated between the upper end portion of the outer positive electrode61and the negative electrode40. Additionally, the upper end portion of the outer positive electrode61may be in the range from a portion which is in contact with the upper surface of the positive electrode30to the upper end portion (the upper surface25) in the laminating direction of the laminated sintered body20.

The outer positive electrode61includes a lower surface sub-electrode61awhich extends to the lower surface26in order to facilitate the connection with the circuit board. That is, the outer positive electrode61has an L-shaped cross-section and has two surfaces. The outer positive electrode61does not include the upper surface sub-electrode60band the side surface sub-electrode60cof the conventional laminated all-solid-state secondary battery10. Additionally, the outer positive electrode61may include the side surface sub-electrode if the end portion of the side surface sub-electrode is located at a position not facing the negative electrode40. Here, the non-facing position means a position in which the side surface sub-electrode does not overlap the negative electrode40when the laminated all-solid-state secondary battery11is viewed through.

The outer negative electrode71is located at a portion in which the upper end portion (the end portion on the side of the upper surface25of the laminated sintered body20) is in contact with the extension line of the upper surface of the positive electrode30. That is, the upper end portion of the outer negative electrode71is located on the inside of the upper end portion of the laminated sintered body20in the laminating direction and the upper end portion of the outer negative electrode71does not face the upper surface of the positive electrode30. Therefore, the parasitic capacitance is less likely to be generated between the upper end portion of the outer negative electrode71and the positive electrode30. Additionally, the upper end portion of the outer negative electrode71may be in the range from a portion contacting the extension line of the upper surface of the positive electrode30to the upper end portion of the laminated sintered body20in the laminating direction.

The outer negative electrode71includes a lower surface sub-electrode71awhich extends to the lower surface26in order to facilitate the connection with the circuit board. That is, the outer negative electrode71has an L-shaped cross-section and two surfaces. The outer negative electrode71does not include the upper surface sub-electrode70band the side surface sub-electrode70cof the laminated all-solid-state secondary battery10. Additionally, the outer negative electrode71may include the side surface sub-electrode if the end portion of the side surface sub-electrode is located at a position not facing the positive electrode30.

In the laminated all-solid-state secondary battery11of this embodiment, since the generation of parasitic capacitance is suppressed and the current consumption other than the charge and discharge reaction is reduced compared to the conventional laminated all-solid-state secondary battery10, the charge and discharge capacity is improved. Further, since the generation of the parasitic capacitance is suppressed, the current distribution associated with the charge and discharge reaction becomes uniform and the cell reaction proceeds uniformly. As a result, the charge and discharge capacity is improved. Further, in the laminated all-solid-state secondary battery11of this embodiment, since the outer positive electrode61and the outer negative electrode71are provided on the inner surface of the laminated sintered body20, the volume is smaller than that of the laminated all-solid-state secondary battery10and the charge and discharge capacity per unit volume increases.

In the laminated all-solid-state secondary battery11, the materials of the positive electrode current collector layer31, the positive electrode active material layer32, the negative electrode current collector layer41, the negative electrode active material layer42, the solid electrolyte layer50, the outer positive electrode61, and the outer negative electrode71are not particularly limited and known materials used in the conventional laminated all-solid-state secondary battery can be used.

As the materials of the positive electrode current collector layer31and the negative electrode current collector layer41, it is preferable to use a material having a large conductivity. Specifically, silver, palladium, gold, platinum, aluminum, copper, nickel, and the like can be used.

The positive electrode active material layer32and the negative electrode active material layer42include a positive electrode active material and a negative electrode active material that transfer electrons. In addition, a conductive assistant, a binder, or the like may be included. It is preferable that the positive electrode active material and the negative electrode active material can efficiently intercalate and deintercalate lithium ions.

As the positive electrode active material and the negative electrode active material, for example, a transition metal oxide or a transition metal composite oxide is preferably used. Specifically, lithium manganese composite oxide Li2MnaMa1-aO3(0.8≤a≤1, Ma=Co, Ni), lithium cobalt oxide (LiCoO2), lithium nickelate (LiNiO2), lithium manganese spinel (LiMn2O4), composite metal oxide represented by a general formula: LiNixCoyMnzO2(x+y+z=1, 0≤x≤1, 0≤y≤1, 0≤z≤1), lithium vanadium compound (LiV2O5), olivin type LiMbPO4(here, Mb is one or more elements selected from Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, and Zr), lithium vanadium phosphate (Li3V2(PO4)3or LiVOPO4), Li excess solid solution represented by Li2MnO3-LiMcO2(Mc=Mn, Co, Ni), lithium titanate (Li4Ti5O12), composite metal oxide represented by LisNitCouAlvO2(0.9<s<1.3, 0.9<t+u+v<1.1), and the like can be used.

The positive electrode active material and the negative electrode active material may be selected according to the solid electrolyte described later. For example, when Li1+nAlnTi2−n(PO4)3(0≤n≤0.6) is used as the solid electrolyte, it is preferable to use one or both of LiVOPO4and Li3V2(PO4)3for the positive electrode active material and the negative electrode active material. The bonding at the interfaces among the positive electrode active material layer32, the negative electrode active material layer42, and the solid electrolyte layer50becomes strong. Further, the contact area of the interfaces among the positive electrode active material layer32, the negative electrode active material layer42, and the solid electrolyte layer50can be widened.

The solid electrolyte layer50includes solid electrolyte. As the solid electrolyte, it is preferable to use a material having low electron conductivity and high lithium ion conductivity. Specifically, for example, at least one selected from a group consisting of perovskite type compound such as La0.51Li0.34TiO2.94and La0.5Li0.5TiO3, lysicon type compound such as Li14Zn(GeO4)4, garnet type compound such as Li7La3Zr2O12, nasicon type compound such as LiZr2(PO4)3, Li1.3Al0.3Ti1.7(PO4)3, and Li1.5Al0.5Ge1.5(PO4)3, thioricicon type compound such as Li3.25Ge0.25P0.75S4and Li3PS4, glass compound such as 50Li4SiO4.50Li3BO3, Li2S—P2S5, and Li2O—Li3O5—SiO2, phosphoric acid compound such as Li3PO4, Li3.5Si0.5P0.5O4, and Li2.9PO3.3N0.46, amorphous such as Li2.9PO3.3N0.46(LIPON) and Li3.6Si0.6P0.4O4, and glass ceramics such as Li1.07Al0.69Ti1.46(PO4)3and Li1.5Al0.5Ge1.5(PO4)3is preferable.

As the materials of the outer positive electrode61and the outer negative electrode71, it is preferable to use a material having a large conductivity. As the conductive material, for example, silver, gold, platinum, aluminum, copper, tin, and nickel can be used.

Next, a method for manufacturing the laminated all-solid-state secondary battery11of this embodiment will be described with reference toFIGS. 15 to 20.FIG. 15is a flowchart of a method for manufacturing the laminated all-solid-state secondary battery according to this embodiment.FIG. 16is a schematic view of the unit laminated body used in the method for manufacturing the laminated all-solid-state secondary battery according to this embodiment, whereFIG. 16(a)is a plan view andFIG. 16(b)is a cross-sectional view taken along a line IVb-IVb ofFIG. 16(a).FIG. 17is a schematic view showing a state in which a groove is provided in the unit laminated body ofFIG. 16, whereFIG. 17(a)is a plan view andFIG. 17(b)is a cross-sectional view taken along a line Vb-Vb ofFIG. 17(a).FIG. 18is a cross-sectional view showing a state in which the groove of the unit laminated body ofFIG. 17is filled with an electrode.FIG. 19is a cross-sectional view showing a filled state in which a sub-electrode is connected to the electrode of the unit laminated body ofFIG. 18. Then,FIG. 20is a cross-sectional view showing a state in which the unit laminated body is cut.

A method for manufacturing the laminated all-solid-state secondary battery11of this embodiment includes, as shown inFIG. 15, a unit laminated body manufacturing step S01, a grooving step S02, a conductive material filling step S03, a sub-electrode forming step S04, a cutting step S05, and a baking step S06.

In the unit laminated body manufacturing step S01, a unit laminated body120shown inFIG. 16is manufactured. The unit laminated body120is a laminated body in which a solid electrolyte layer150a, a negative electrode unit145, a solid electrolyte layer150b, a positive electrode unit135, and a solid electrolyte layer150care laminated in this order from the lower surface126. The unit laminated body120is a hexahedron and includes four side surfaces (a first side surface121, a second side surface122, a third side surface123, and a fourth side surface124) which are formed as surfaces parallel to the laminating direction, an upper surface125which is formed on the upper side as a surface orthogonal to the laminating direction, and a lower surface126which is formed on the lower side. The positive electrode unit135has a configuration in which two or more positive electrodes130including a positive electrode current collector layer131and a positive electrode active material layer132are arranged in parallel with a spacing portion133therebetween along the surface direction of the positive electrode130. The negative electrode unit145has a configuration in which two or more negative electrodes140including a negative electrode current collector layer141and a negative electrode active material layer142are arranged in parallel with a spacing portion143therebetween along the plane direction of the negative electrode140. The unit laminated body120is laminated so that the spacing portion133of the positive electrode unit135faces the negative electrode140of the negative electrode unit145and the spacing portion133of the negative electrode unit145faces the positive electrode130of the positive electrode unit135. The unit laminated body120includes solid electrolyte layers150aand150cwhich are respectively provided on both upper and lower surfaces in the laminating direction.

The unit laminated body120can be manufactured according to, for example, a method including a paste preparing step of preparing paste of each member constituting the unit laminated body120, a unit manufacturing step of manufacturing the positive electrode unit135and the negative electrode unit145using the manufactured paste, and a laminating step of manufacturing a laminated structure by alternately laminating the positive electrode unit135and the negative electrode unit145obtained as described above.

In the paste preparing step, each member of the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode current collector layer, the negative electrode active material layer, the outer electrode is made into paste. The method for making a paste is not particularly limited, but for example, a paste can be prepared by mixing the powder of each member and the vehicle. As a mixing device for preparing the paste, a conventionally known kneading device such as a bead mill, a planetary paste kneader, an automatic grinder, a three-roll mill, a high-share mixer, and a planetary mixer can be used. Here, the vehicle is a general term for a medium in a liquid phase and includes a solvent, a binder, and the like. The binder included in the paste of each member is not particularly limited, but polyvinyl acetal resin, polyvinyl butyral resin, terpineol resin, ethyl cellulose resin, acrylic resin, urethane resin, vinyl acetate resin, polyvinyl alcohol resin, and the like can be used. One of these resins may be used alone, or two or more of these resins may be used in combination.

Further, the paste of each material may include a plasticizer. The type of plasticizer is not particularly limited, but ester phthalates such as dioctyl phthalate and diisononyl phthalate may be used.

By a related method, paste for the positive electrode current collector layer, paste for the positive electrode active material layer, paste for the solid electrolyte layer, paste for the negative electrode active material layer, and paste for the negative electrode current collector layer are prepared.

The positive electrode unit135can be manufactured as below.

First, the prepared paste for the solid electrolyte layer is applied on a base such as a polyethylene terephthalate (PET) film to a desired thickness and is dried to manufacture a green sheet for the solid electrolyte layer. A method for applying the paste for the solid electrolyte layer is not particularly limited and known methods such as a doctor blade method, a die coater method, a comma coater method, and a gravure coater method can be adopted. Next, the paste for the positive electrode active material layer, the paste for the positive electrode current collector layer, and the paste for the positive electrode active material layer are laminated in this order on the green sheet for the solid electrolyte layer and are dried to form the positive electrode130having the positive electrode active material layer132, the positive electrode current collector layer131, and the positive electrode active material layer132laminated in this order. Further, in order to fill a step between the green sheet for the solid electrolyte layer and the positive electrode, the paste for the solid electrolyte layer is printed on a region (margin) other than the positive electrode by a screen printing method and is dried to form a solid electrolyte layer having a height equivalent to that of the positive electrode. Then, the base is peeled off to obtain the positive electrode unit135in which the positive electrode130is formed on the green sheet for the solid electrolyte layer.

The negative electrode unit145can be manufactured similarly to the method for manufacturing the positive electrode unit except that the paste for the negative electrode active material layer and the paste for the negative electrode current collector layer are used instead of the paste for the positive electrode current collector layer and the paste for the positive electrode active material layer.

In the laminating step, the positive electrode unit and the negative electrode unit are alternately laminated. Accordingly, a laminated structure including the plurality of positive electrode units and the plurality of negative electrode units is manufactured.

Further, the manufactured laminated structures are collectively pressed and crimped with a die press, a hot water isobaric press (WIP), a cold water isobaric press (CIP), a hydrostatic press, and the like so that the adhesion between the positive electrode unit and the negative electrode unit can be improved. Pressurization is preferably performed in a heated state and can be performed, for example, at 40 to 95° C.

Next, in the grooving step S02, as shown inFIG. 17, a first groove161cutting the negative electrode140through the spacing portion133of the positive electrode unit135and a second groove162cutting the positive electrode130through the spacing portion of the negative electrode unit145are provided from the side of the lower surface126in the laminating direction of the unit laminated body120.

It is preferable that the first groove161and the second groove162have the same depth. The depths of the first groove161and the second groove162are defined as the depth to the interface in which the positive electrode unit135is in contact with the solid electrolyte layer150con the side of the upper surface125inFIG. 17, but may be the depth exceeding the interface.

As a method for forming the groove in the unit laminated body120, a dicing saw device and a fine laser processing machine can be used.

In the conductive material filling step S03, as shown inFIG. 18, the first groove161and the second groove162are filled with a conductive material163. As a method for filling the first groove161and the second groove162with the conductive material, a method can be used in which the first groove161and the second groove162are filled with the conductive material paste by screen printing and the conductive material paste is heated and dried.

In the sub-electrode forming step S04, as shown inFIG. 19, a sub-electrode164electrically connected to the conductive material163is formed on the surface of the lower surface of the unit laminated body120. It is preferable that the material of the sub-electrode164be the same as the material of the conductive material163.

As a method for forming the sub-electrode164, a method for applying the conductive material paste and heating and drying the conductive material paste can be used.

In the cutting step S05, as shown inFIG. 20, the unit laminated body120is cut in the laminating direction by forming a notch165penetrating the unit laminated body120in the first groove161filled with the conductive material163and the second groove162filled with the conductive material163. As a result, a unit laminated body piece (unbaked laminated all-solid-state secondary battery11) is obtained.

As a method for forming the notch165in the unit laminated body120, a dicing blade and a fine laser processing machine can be used.

In the baking step S06, the unit laminated body piece is baked and sintered to generate the laminated all-solid-state secondary battery11. The baking condition is, for example, a temperature equal to or higher than 600° C. and equal to or lower than 1000° C. in a nitrogen atmosphere. The baking time is, for example, in the range equal to or longer than 0.1 hour and equal to or shorter than 3 hours. If it is a reducing atmosphere, baking may be performed in, for example, an argon atmosphere or a nitrogen-hydrogen mixed atmosphere instead of the nitrogen atmosphere.

Before the baking step, a debinder treatment can be performed as a step separate from the baking step. By heat-decomposing the binder component included in the unit laminated body piece before baking, it is possible to suppress the rapid decomposition of the binder component in the baking step. The debinder treatment is performed, for example, in a nitrogen atmosphere at a temperature in the range equal to or higher than 300° C. and equal to or lower than 800° C. for 0.1 to 10 hours. If it is a reducing atmosphere, for example, the debinder treatment may be performed in an argon atmosphere or a nitrogen-hydrogen mixed atmosphere instead of the nitrogen atmosphere.

Seventh Embodiment

Next, a laminated all-solid-state secondary battery12according to a seventh embodiment of the present invention will be described.

FIG. 26is a cross-sectional view of the laminated all-solid-state secondary battery according to the seventh embodiment, whereFIG. 26(a)is a plan view when viewed from above andFIG. 26(b)is a bottom view when viewed from below.FIG. 27is a cross-sectional view taken along a line II-II of the laminated all-solid-state secondary battery according to the seventh embodiment. Further, in the description of the seventh embodiment, the same reference numerals will be given to the configurations overlapping with the laminated all-solid-state secondary battery11of the sixth embodiment and the description thereof will be omitted.

As shown inFIG. 27, in the laminated all-solid-state secondary battery12of this embodiment, an outer positive electrode62is attached to the first side surface21of the laminated sintered body20and an outer negative electrode72is attached to the second side surface22. The outer positive electrode62and the outer negative electrode72are common to the laminated all-solid-state secondary battery11of the sixth embodiment in that they respectively have a lower surface sub-electrode62aand a lower surface sub-electrode72aand have an L-shaped cross-section. On the other hand, the laminated all-solid-state secondary battery12of this embodiment is different from the laminated all-solid-state secondary battery11of the sixth embodiment in that the lower surface sub-electrode62aand the lower surface sub-electrode72aare embedded in the lower surface26of the laminated sintered body20.

In the laminated all-solid-state secondary battery12of this embodiment, since the lower surface sub-electrode62aof the outer positive electrode62and the lower surface sub-electrode72aof the outer negative electrode72are embedded in the lower surface26of the laminated sintered body20, the volume is smaller than that of the laminated all-solid-state secondary battery11of the sixth embodiment. Therefore, a laminated all-solid-state secondary battery13of this embodiment improves the volumetric energy density.

Eighth Embodiment

Next, a laminated all-solid-state secondary battery13according to an eighth embodiment of the present invention will be described.

FIG. 28is a cross-sectional view of the laminated all-solid-state secondary battery according to the eighth embodiment, whereFIG. 28(a)is a plan view when viewed from above andFIG. 28(b)is a bottom view when viewed from below.FIG. 29is a cross-sectional view taken along a line II-II of the laminated all-solid-state secondary battery according to the eighth embodiment. Further, in the description of the eighth embodiment, the same reference numerals will be given to the configurations overlapping with the laminated all-solid-state secondary battery11of the sixth embodiment and the description thereof will be omitted.

As shown inFIG. 29, the laminated all-solid-state secondary battery13of this embodiment is different from the laminated all-solid-state secondary battery11of the sixth embodiment in that each of the outer positive electrode63and the outer negative electrode73does not include the lower surface sub-electrode.

In the laminated all-solid-state secondary battery13of this embodiment, the parasitic capacitance is less likely to be generated between the lower surface sub-electrode61aof the outer positive electrode63and the lower surface of the negative electrode40. Further, the parasitic capacitance is less likely to be generated between the lower surface sub-electrode71aof the outer negative electrode71and the lower surface of the positive electrode30. Therefore, the laminated all-solid-state secondary battery13of this embodiment improves the charge and discharge capacity.

Ninth Embodiment

Next, a laminated all-solid-state secondary battery14according to a ninth embodiment of the present invention will be described.

FIG. 30is a cross-sectional view of the laminated all-solid-state secondary battery according to the ninth embodiment, whereFIG. 30(a)is a plan view when viewed from above andFIG. 30(b)is a bottom view when viewed from below.FIG. 31is a cross-sectional view taken along a line II-II of the laminated all-solid-state secondary battery according to the ninth embodiment. Further, in the description of the ninth embodiment, the same reference numerals will be given to the configurations overlapping with the laminated all-solid-state secondary battery11of the sixth embodiment and the description thereof will be omitted.

As shown inFIG. 31, the laminated all-solid-state secondary battery14of this embodiment is different from the laminated all-solid-state secondary battery11of the sixth embodiment in that the lower end portion of the outer negative electrode74is formed as a portion which is in contact with the lower surface of the negative electrode40in a portion in which the lower end portion of the outer positive electrode64is in contact with the extension line of the lower surface of the negative electrode40and the lower end portions of the outer positive electrode64and the outer negative electrode74are not exposed to the lower surface of the laminated all-solid-state secondary battery14.

In the laminated all-solid-state secondary battery14of this embodiment, the parasitic capacitance is less likely to be generated between the lower portion of the outer negative electrode74and the positive electrode30. In this way, in the laminated all-solid-state secondary battery14of this embodiment, since the generation of the parasitic capacitance is further suppressed compared to the laminated all-solid-state secondary battery11of the sixth embodiment, the charge and discharge capacity is further improved.

Next, a method for manufacturing the laminated all-solid-state secondary battery14of the ninth embodiment will be described. The method for manufacturing the laminated all-solid-state secondary battery14of this embodiment includes a unit laminated body manufacturing step S11, a grooving step S12, a conductive material filling step S13, a solid electrolyte layer forming step S14, a cutting step S15, and a baking step S16.

In the unit laminated body manufacturing step S11, a unit laminated body220shown inFIG. 21is manufactured. The unit laminated body220is a laminated body in which the solid electrolyte layer150a, the positive electrode unit135, the solid electrolyte layer150b, and the negative electrode unit145are laminated in this order from the lower surface226. The unit laminated body220is a hexahedron and includes four side surfaces which are formed as surfaces parallel to the laminating direction, an upper surface225which is formed on the upper side as a surface orthogonal to the laminating direction, and a lower surface226which is formed on the lower side. The positive electrode unit235has a configuration in which two or more positive electrodes230including a positive electrode current collector layer231and a positive electrode active material layer232are arranged in parallel with a spacing portion233therebetween along the surface direction of the positive electrode130. The negative electrode unit245has a configuration in which two or more negative electrodes140including a negative electrode current collector layer241and a negative electrode active material layer242are arranged in parallel with a spacing portion143therebetween along the plane direction of the negative electrode240. The unit laminated body220is laminated so that the spacing portion233of the positive electrode unit235faces the negative electrode240of the negative electrode unit245and the spacing portion133of the negative electrode unit145faces the positive electrode130of the positive electrode unit135. The unit laminated body220includes a solid electrolyte layer250awhich are provided on the lower surface (the lower surface226) in the laminating direction.

Next, in the grooving step S12, as shown inFIG. 22, a first groove261cutting the negative electrode140through the spacing portion233of the positive electrode unit235and a second groove262cutting the positive electrode130through the spacing portion243of the negative electrode unit245are provided from the surface (the upper surface225) on the side opposite to the surface provided with the solid electrolyte layer250ain the laminating direction of the unit laminated body120.

It is preferable that the first groove261and the second groove262have the same depth. The depths of the first groove261and the second groove262are defined as the depth to the interface in which the negative electrode unit245is in contact with the solid electrolyte layer250aon the side of the lower surface226inFIG. 17, but may be the depth exceeding the interface.

In the conductive material filling step S13, as shown inFIG. 23, the first groove261and the second groove262are filled with a conductive material263.

In the solid electrolyte layer forming step S14, as shown inFIG. 24, a solid electrolyte layer250cis formed on the surface of the upper surface of the unit laminated body220. It is preferable that the material of the solid electrolyte layer250cbe the same as the materials of the solid electrolyte layer250aand the solid electrolyte layer250b.

As a method for forming the solid electrolyte layer250c, a method can be used in which the solid electrolyte paste is applied and the solid electrolyte paste is heated and dried.

In the cutting step S15, as shown inFIG. 25, the unit laminated body220is cut in the laminating direction by forming the notch165penetrating the unit laminated body220in the first groove261filled with the conductive material263and the second groove262filled with the conductive material263. Accordingly, a unit laminated body piece (unbaked laminated all-solid-state secondary battery14) can be obtained.

In the baking step S16, the unit laminated body piece is baked and sintered to generate the laminated all-solid-state secondary battery14.

According to the laminated all-solid-state secondary batteries11to14of the above-described sixth to ninth embodiments, since the outer positive electrodes61,62, and64are on the inside (the lower side) of the upper end portion of the laminated sintered body20in the laminating direction, the parasitic capacitance generated between the upper surface sub-electrode70bof the outer negative electrode70and the positive electrode30in the conventional laminated all-solid-state secondary battery10shown inFIG. 33is avoided in the outer positive electrodes61,62,63, and64. Similarly, the parasitic capacitance generated between the lower surface sub-electrode60aof the outer positive electrode60and the negative electrode40in the conventional laminated all-solid-state secondary battery10shown inFIG. 33is avoided in the outer negative electrodes71,72,73, and74.

Further, according to the laminated all-solid-state secondary batteries of the sixth to ninth embodiments, good bondability can obtained between the outer positive electrode and the positive electrode current collector and between the outer negative electrode and the negative electrode current collector after baking by baking the unbaked laminated all-solid cell in a state in which the outer negative electrode and the negative electrode current collector are well bonded. Accordingly, the cycle characteristics are improved compared to the conventional laminated all-solid-state secondary battery.

Although the embodiments of the present invention have been described in detail with reference to the drawings, each configuration and a combination thereof in each embodiment are examples and the configuration can be added, omitted, replaced, and changed into other forms without departing from the spirit of the present invention.

For example, in the laminated all-solid-state secondary batteries311to315of the first to fifth embodiments, each of the positive electrode330and the negative electrode340is one, but the number of the positive electrodes330and the negative electrodes340is not particularly limited. For example, the plurality of positive electrodes330and the plurality of negative electrodes340may be respectively alternately laminated. When the plurality of positive electrodes330and the plurality of negative electrodes340are laminated, it is preferable that the front end portion of the sub-electrode of the outer positive electrode be located at a position not facing the major surface of the negative electrode laminated at a position closest to the sub-electrode in the laminating direction. Further, it is preferable that the front end portion of the sub-electrode of the outer negative electrode be located at a position not facing the major surface of the positive electrode laminated at a position closest to the sub-electrode in the laminating direction. Accordingly, it is possible to suppress the generation of the parasitic capacitance between the sub-electrode of the outer positive electrode and the negative electrode and the parasitic capacitance between the sub-electrode of the outer negative electrode and the positive electrode.

Further, in the laminated all-solid-state secondary batteries11to14of the sixth to ninth embodiments, each of the positive electrode30and the negative electrode40is one, but the number of the positive electrodes30and the negative electrodes40is not particularly limited. For example, the plurality of positive electrodes30and the number of negative electrodes40may be respectively alternately laminated.

Further, in the laminated all-solid-state secondary batteries11to14of the sixth to ninth embodiments, the upper end portions (the end portions on the side of the upper surface25of the laminated sintered body20) of the outer positive electrodes61,62, and64and the outer negative electrodes71,72, and74are on the inside (the lower side) of the upper end portion of the laminated sintered body20in the laminating direction, but the present invention is not limited thereto. The lower end portions (the end portions on the side of the lower surface26of the laminated sintered body20) of the outer positive electrodes61,62, and64and the outer negative electrodes71,72, and74may be on the inside (the upper side) of the lower end portion of the laminated sintered body20in the laminating direction.

EXAMPLE

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples based on the above-described embodiments, but the present invention is not limited to these examples. In addition, unless otherwise specified, the indication of “parts” of the amount of the material filled in the preparation of the paste means “parts by mass”.

(Preparing of Paste for Solid Electrolyte Layer)

As the solid electrolyte powder, Li1.3Al0.3Ti1.7(PO4)3powder was used. Li1.3Al0.3Ti1.7(PO4)3powder was prepared by the following method.

First, wet mixing was performed with a ball mill using Li2CO3powder, Al2O3powder, TiO2powder, and NH4H2PO4powder as starting materials and then dehydration drying was performed to obtain a powder mixture. Next, the obtained powder mixture was calcined in the air to obtain a calcined powder. The obtained calcined powder was subjected to wet-grinding with a ball mill to obtain Li1.3Al0.3T1.7(PO4)3powder.

100 parts of ethanol and 200 parts of toluene were added to 100 parts of the above Li1.3Al0.3Ti1.7(PO4)3powder as solvents and were wet-mixed with a ball mill. Then, 16 parts of the system binder and 4.8 parts of benzyl butyl phthalate were further added and wet-mixed to prepare paste for a solid electrolyte layer.

(Preparing of Paste for Positive Electrode Active Material Layer and Paste for Negative Electrode Active Material Layer)

Li3V2(PO4)3powder was used as the positive electrode active material powder and the negative electrode active material powder.

Li3V2(PO4)3powder was prepared by the following method.

First, Li2CO3powder, V2O5powder, and NH4H2PO4were used as starting materials, were wet-mixed with a ball mill, and then were dehydrated and dried to obtain a powder mixture. Then, the obtained powder mixture was calcined at 850° C. to obtain a calcined powder. The obtained calcined powder was subjected to wet-grinding with a ball mill to obtain Li3V2(PO4)3powder.

15 parts of a binder and 65 parts of dihydroterpineol as a solvent were added to 100 parts of the Li3V2(PO4)3powder and were kneaded and dispersed to prepare the paste for the positive electrode active material layer and the paste for the negative electrode active material layer.

(Preparing of Paste for Positive Electrode Current Collector Layer and Paste for Negative Electrode Current Collector Layer)

As the materials of the positive electrode current collector layer and the negative electrode current collector layer, 10 parts of a binder and 50 parts of dihydroterpineol as a solvent were added to 100 parts of Cu powder and were kneaded and dispersed to prepare the paste for the positive electrode current collector layer and the paste for the negative electrode current collector layer.

(Preparing of Conductive Material Paste for Outer Electrode)

20 parts of dihydroterpineol was added as a solvent to 100 parts of Cu powder and was kneaded and dispersed to prepare a conductive material paste for an outer electrode.

Using these pastes, a laminated all-solid-state secondary battery was manufactured as follows.

(Manufacturing of Positive Electrode Unit)

The green sheet for the solid electrolyte layer was formed by applying and drying the paste for the solid electrolyte layer on the PET film as the base material by the doctor blade method. Next, the paste for the positive electrode active material layer, the paste for the positive electrode current collector layer, and the paste for the positive electrode active material layer were printed on the green sheet for the solid electrolyte layer in this order according to the screen printing method to form the green sheet for the positive electrode in which the positive electrode active material layer, the positive electrode current collector layer, and the positive electrode active material layer were laminated in this order. Next, the paste for the solid electrolyte layer was printed in a margin other than the positive electrode according to the screen printing method to form and dry the solid electrolyte layer substantially having the same plane height as that of the positive electrode. Then, the obtained laminated body was peeled off from the PET film to manufacture the positive electrode unit.

(Manufacturing of Negative Electrode Unit)

The negative electrode unit was manufactured similarly to the method for manufacturing the positive electrode unit except that the paste for the negative electrode active material layer and the paste for the negative electrode current collector layer were used instead of the paste for the positive electrode current collector layer and the paste for the positive electrode active material layer.

The plurality of positive electrode units and the plurality of negative electrode units were alternately laminated. Next, the green sheet for the solid electrolyte layer was laminated on both major surfaces of the obtained laminated body as a plurality of layers to obtain a laminated structure. The obtained laminated structure was subjected to thermo-compression bonding by mold pressing.

Additionally, the green sheet for the solid electrolyte layer was manufactured by applying and drying the paste for the solid electrolyte layer on the PET film according to the doctor blade method.

The obtained laminated structure was cut so that the positive electrode current collector layer is exposed from one end surface and the negative electrode current collector layer is exposed from the single surface on the side opposite to that end surface. Next, the cut laminated structure was baked at 800° C. for 1 hour to obtain the laminated body320. The size of the obtained laminated body320was 5.5 mm in length×4.0 mm in width×1.0 mm in thickness.

Conductive Cu paste for the outer electrode was applied to the entire surfaces of the first side surface321and the second side surface322of the laminated body320obtained by the baking step, the range of 1 mm from the end portion of the upper surface325on the side of the first side surface321, the range of 1 mm from the end portion thereof on the side of the second side surface322, the range of 1 mm from the end portion of the lower surface326on the side of the first side surface321, and the range of 1 mm from the end portion thereof on the side of the second side surface322according to the screen printing method and was burned at 500° C. in a reducing atmosphere. Additionally, conductive Cu paste for the outer electrode was not applied to the third side surface323and the fourth side surface324of the laminated body320. In this way, the laminated all-solid-state secondary battery311according to the first embodiment in which the upper surface sub-electrodes361band371band the lower surface sub-electrodes361cand371cwere provided and the outer positive electrode361and the outer negative electrode371had a U-shaped cross-section was manufactured.

The laminated all-solid-state secondary battery312according to the second embodiment in which the outer positive electrode362and the outer negative electrode372had an L-shaped cross-section was manufactured similarly to Example 1 except that conductive Cu paste for the outer electrode was not applied to the upper surface325of the laminated body320.

The laminated all-solid-state secondary battery313according to the third embodiment in which the outer positive electrode363and the outer negative electrode373had a U-shaped cross-section were manufactured similarly to Example 1 except that the application range of conductive Cu paste for the outer electrode of the upper surface325of the laminated body320was in the range of 0.4 mm from the end portion on the side of the first side surface321and the range of 0.4 mm from the end portion on the side of the second side surface322and the application range of conductive Cu paste for the outer electrode of the lower surface326of the laminated body320was in the range of 0.4 mm from the end portion on the side of the first side surface321and the range of 0.4 mm from the end portion on the side of the second side surface322.

The laminated all-solid-state secondary battery314according to the fourth embodiment in which the outer positive electrode364and the outer negative electrode374had an L-shaped cross-section was manufactured similarly to Example 1 except that conductive Cu paste for the outer electrode was not applied to the upper surface325of the laminated body320and the application range of conductive Cu paste for the outer electrode of the lower surface326of the laminated body320was in the range of 0.4 mm from the end portion on the side of the first side surface321and the range of 0.4 mm from the end portion on the side of the second side surface322.

The laminated all-solid-state secondary battery315according to the fifth embodiment in which the outer positive electrode365and the outer negative electrode375had an I-shaped cross-section was manufactured similarly to Example 1 except that conductive Cu paste for the outer electrode was not applied to the upper surface325and the lower surface326of the laminated body320.

Comparative Example 1

The conventional laminated all-solid-state secondary battery310shown inFIGS. 11 and 12were manufactured similarly to Example 1 except that conductive Cu paste for the outer electrode was applied to the range of 1 mm from the end portion on the side of the first side surface321in the third side surface323and the fourth side surface of the laminated body320and the range of 1 mm from the end portion on the side of the second side surface322by the dip coating method and was dried to form the side surface sub-electrodes360aand370aon the third side surface323and the fourth side surface of the laminated body320.

The first charge and discharge capacity, the pulse discharge cycle characteristics, the charge and discharge cycle characteristics, and the mounted shear strength for the laminated all-solid-state secondary batteries manufactured by Examples 1 to 5 and Comparative Example 1 were measured by the following method. The results are shown in Table 1 below together with the structures of the positive and outer negative electrodes and the number of electrode surfaces.

<First Charge and Discharge Capacity>

The first charge and discharge capacity was measured in an environment of 25° C. In the charge capacity, a constant current of 0.1 C was applied until the cell voltage reached 1.6 V and the capacity when held for 3 hours was measured. The discharge capacity was measured by charging and then discharging at a constant current of 0.2 C until the cell voltage reached 0 V. Table 1 shows one discharge capacity (the first discharge capacity). Additionally, the discharge capacity is a relative value when the discharge capacity of the laminated all-solid-state secondary battery manufactured by Comparative Example 1 is 100.

In the pulse discharge cycle characteristics, the number of pulse discharge cycles was measured by charging at the same charging condition as that of the first charge and discharge capacity in an environment of 25° C., discharging for 1 second with a large current of 20 C, and repeating the pause for 59 seconds until the cell voltage reached 1.2V.

<Charge and Discharge Cycle Characteristics>

The measurement of the first charge and discharge capacity was defined as one cycle and the charge and discharge capacity retention rate after repeating this up to 1000 cycles was evaluated as the charge and discharge cycle characteristics. The charge and discharge cycle characteristics in this embodiment were calculated by the following formula.

Charge and discharge capacity retention rate [%] after 1000 cycles=(discharge capacity after 1000 cycles÷first discharge capacity)×100

The laminated all-solid-state secondary battery manufactured in Examples and Comparative Examples was mounted on a land electrode on a glass epoxy substrate and reflow-soldered to mount the cell on the glass epoxy substrate. The mounted laminated all-solid-state secondary battery was subjected to stress from the side by operating a load cell at a speed of 0.15 mm/s from the side surface of the laminated all-solid-state secondary battery using a shear strength tester so that the laminated all-solid-state secondary battery was peeled off from the glass epoxy substrate and the stress applied when the laminated all-solid-state secondary battery was peeled off from the glass epoxy substrate was measured as the mounted shear strength.

In the laminated all-solid-state secondary batteries of Examples 1 to 5 in which the side end portions (the side surface sub-electrodes361ato365a) of the outer positive electrodes361to365were located at the positions not facing the side end portion of the negative electrode340and the side end portions (the side surface sub-electrodes371ato375a) of the outer negative electrodes371to375were located at the positions not facing the side end portion of the positive electrode330, all of the first charge and discharge capacity, the pulse discharge cycle characteristics, and the charge and discharge cycle characteristics were improved as compared with the laminated all-solid-state secondary battery of Comparative Example 1.

Particularly, in the laminated all-solid-state secondary batteries of Examples 3 to 5 in which the upper end portions and the lower end portions of the outer positive electrodes363to365were located at the positions not facing the negative electrode340and the upper end portions and the lower end portions of the outer negative electrodes373to375were located at the positions not facing the positive electrode330, all of the first charge and discharge capacity, the pulse discharge cycle characteristics, and the charge and discharge cycle characteristics were improved. However, in the laminated all-solid-state secondary battery of Example 5 without the upper surface sub-electrode and the lower surface sub-electrode, the mounted shear strength was lowered.

(Preparing of Paste for Solid Electrolyte Layer)

As the solid electrolyte powder, Li1.3Al0.3Ti1.7(PO4)3powder was used. Li1.3Al0.3Ti1.7(PO4)3powder was prepared by the following method.

First, wet mixing was performed with a ball mill using Li2CO3powder, Al2O3powder, TiO2powder, and NH4H2PO4powder as starting materials and then dehydration drying was performed to obtain a powder mixture. Next, the obtained powder mixture was calcined in the air to obtain a calcined powder. The obtained calcined powder was subjected to wet-grinding with a ball mill to obtain Li1.3Al0.3T1.7(PO4)3powder.

100 parts of ethanol and 200 parts of toluene were added to 100 parts of the above Li1.3Al0.3T1.7(PO4)3powder as solvents and were wet-mixed with a ball mill. Then, 16 parts of the system binder and 4.8 parts of benzyl butyl phthalate were further added and wet-mixed to prepare paste for a solid electrolyte layer.

(Preparing of Paste for Positive Electrode Active Material Layer and Paste for Negative Electrode Active Material Layer)

Li3V2(PO4)3powder was used as the positive electrode active material powder and the negative electrode active material powder.

Li3V2(PO4)3powder was prepared by the following method.

First, Li2CO3powder, V2O5powder, and NH4H2PO4were used as starting materials, were wet-mixed with a ball mill, and then were dehydrated and dried to obtain a powder mixture. Then, the obtained powder mixture was calcined at 850° C. to obtain a calcined powder. The obtained calcined powder was subjected to wet-grinding with a ball mill to obtain Li3V2(PO4)3powder.

parts of a binder and 65 parts of dihydroterpineol as a solvent were added to 100 parts of the Li3V2(PO4)3powder and were kneaded and dispersed to prepare the paste for the positive electrode active material layer and the paste for the negative electrode active material layer.

(Preparing of Paste for Positive Electrode Current Collector Layer and Paste for Negative Electrode Current Collector Layer)

As the materials of the positive electrode current collector layer and the negative electrode current collector layer, 10 parts of a binder and 50 parts of dihydroterpineol as a solvent were added to 100 parts of Cu powder and were kneaded and dispersed to prepare the paste for the positive electrode current collector layer and the paste for the negative electrode current collector layer.

(Preparing of Conductive Material Paste for Outer Electrode)

20 parts of dihydroterpineol was added as a solvent to 100 parts of Cu powder and was kneaded and dispersed to prepare a conductive material paste for an outer electrode.

Using these pastes, a laminated all-solid-state secondary battery was manufactured as follows.

(Manufacturing of Positive Electrode Unit)

The green sheet for the solid electrolyte layer was formed by applying and drying the paste for the solid electrolyte layer on the PET film as the base material by the doctor blade method. Next, the paste for the positive electrode active material layer, the paste for the positive electrode current collector layer, and the paste for the positive electrode active material layer were printed on the green sheet for the solid electrolyte layer in this order according to the screen printing method to form the green sheet for the positive electrode in which the positive electrode active material layer, the positive electrode current collector layer, and the positive electrode active material layer were laminated in this order. Next, the paste for the solid electrolyte layer was printed in a margin other than the positive electrode according to the screen printing method to form and dry the solid electrolyte layer substantially having the same plane height as that of the positive electrode. Then, the obtained laminated body was peeled off from the PET film to manufacture the positive electrode unit.

(Manufacturing of Negative Electrode Unit)

The negative electrode unit was manufactured similarly to the manufacturing of the positive electrode unit except that the paste for the negative electrode active material layer and the paste for the negative electrode current collector layer were used instead of the paste for the positive electrode current collector layer and the paste for the positive electrode active material layer.

The plurality of positive electrode units and the plurality of negative electrode units were alternately laminated. Next, the green sheet for the solid electrolyte layer was laminated on both major surfaces of the obtained laminated body as a plurality of layers to obtain a unit laminated body. The obtained unit laminated body was subjected to thermo-compression bonding by mold pressing.

Additionally, the green sheet for the solid electrolyte layer was manufactured by applying and drying the paste for the solid electrolyte layer on the PET film according to the doctor blade method.

Next, as shown inFIG. 17, the first groove161and the second groove162were formed from the upper surface side of the obtained unit laminated body120by a fine laser processing machine.

Next, as shown inFIG. 18, the first groove161and the second groove162were filled with conductive material paste for the outer electrode according to a screen printing method and were dried. In this way, the first groove161and the second groove162were filled with the conductive material. In addition, when the grooves were not sufficiently filled with the conductive material paste for the outer electrode by one screen printing, screen printing was performed a plurality of times.

Next, as shown inFIG. 19, the conductive material paste for the outer electrode was printed on the surface of the upper surface of the unit laminated body120according to the screen printing method and was dried to form the sub-electrode164.

Next, as shown inFIG. 20, the notch165penetrating the unit laminated body120was formed in the first groove161and the second groove162filled with the conductive material163by a fine laser processing machine to obtain a unit laminated body piece (unbaked laminated all-solid-state secondary battery).

Then, the obtained unit laminated body piece was heated to 750° C. at a heating rate of 200° C./hour in a nitrogen atmosphere, was baked for 2 hours at that temperature, and then was cooled to a room temperature. The size of the laminated all-solid-state secondary battery11obtained after baking was 5.50 mm×4.00 mm×1.02 mm.

The laminated all-solid-state secondary battery12according to the seventh embodiment was manufactured similarly to Example 6 except that a groove was provided around the first groove161and the second groove162filled with the conductive material163of the unit laminated body120by a fine laser processing machine before the sub-electrode forming step and a sub-electrode was formed in the groove in the sub-electrode forming step. Additionally, the size of the laminated all-solid-state secondary battery12obtained after baking was 5.50 mm×4.00 mm×1.00 mm. In the laminated all-solid-state secondary battery12obtained in Example 7, since the sub-electrode was formed in the groove, the height was lowered by 0.02 mm compared to the laminated all-solid-state secondary battery11obtained by Example 6.

The laminated all-solid-state secondary battery13according to the eighth embodiment was manufactured similarly to Example 6 except that the sub-electrode was not formed. Additionally, the size of the laminated all-solid-state secondary battery13obtained after baking was 5.50 mm×4.00 mm×1.00 mm. Since the laminated all-solid-state secondary battery13obtained in Example 8 was not provided with the sub-electrode, the height was lowered by 0.02 mm compared to the laminated all-solid-state secondary battery11obtained by Example 6.

The laminated all-solid-state secondary battery14according to the ninth embodiment was manufactured similarly to Example 6 except that the solid electrolyte layer was not formed on the upper surface225after manufacturing the unit laminated body220as shown inFIG. 24in the unit laminated body manufacturing step and the solid electrolyte layer250cwas formed on the surface of the upper surface of the unit laminated body220as shown inFIG. 27(the solid electrolyte layer forming step) without performing the sub-electrode forming step after the conductive material filling step. Additionally, the size of the laminated all-solid-state secondary battery14obtained after baking was 5.50 mm×4.00 mm×1.00 mm.

Comparative Example 2

The unit laminated body obtained by the unit laminated body manufacturing step of Example 6 was cut and the obtained unit laminated body piece was baked to obtain the laminated sintered body20shown inFIGS. 29 and 30. The size of the laminated sintered body20was 5.50 mm×4.00 mm×1.00 mm.

The first side surface21of the laminated sintered body20was immersed into the conductive material paste for the outer electrode used in Example 6 to a depth facing the negative electrode40so that the conductive material paste for the outer electrode was applied to the first side surface21. Next, the second side surface22of the laminated sintered body20was immersed into the conductive material paste for the outer electrode to a depth facing the positive electrode30so that the conductive material paste for the outer electrode was applied to the second side surface22. The applied conductive material paste for the outer electrode was dried to manufacture the conventional laminated all-solid-state secondary battery10shown inFIGS. 29 and 30. Additionally, the size of the obtained laminated all-solid-state secondary battery10was 5.54 mm×4.04 mm×1.04 mm. In the laminated all-solid-state secondary battery10obtained by Comparative Example 1, since the outer electrode was formed on the outer surface of the laminated sintered body20, the volume was larger than those of the laminated all-solid-state secondary batteries11to14obtained by Examples 6 to 9 depending on the thickness of the outer electrode.

In the laminated all-solid-state secondary batteries manufactured by Examples 6 to 9 and Comparative Example 2, the charge and discharge capacity, the volumetric energy density, and the cycle characteristics were measured by the following method. The results are shown in Table 2 below together with the cross-sectional shapes of the positive and outer negative electrodes.

The first charge and discharge capacity was measured in an environment of 25° C. In the charge capacity, a constant current of 0.1 C was applied until the cell voltage reached 1.6 V and the capacity when held for 3 hours was measured. The discharge capacity was measured by charging and then discharging at a constant current of 0.2 C until the cell voltage reached 0 V. The discharge capacity is a relative value when the discharge capacity of the laminated all-solid-state secondary battery manufactured by Comparative Example 2 is 100.

The volumetric energy density was calculated by the following formula.

Volumetric energy density (mWh/L)=first discharge capacity (μAh)×average discharge voltage (V)÷volume (mm3) of laminated all-solid-state secondary battery

Table 2 shows relative values in a state in which the discharge capacity of the laminated all-solid-state secondary battery manufactured in Comparative Example 2 is 100.

<Charge and Discharge Cycle Characteristics>

The measurement of the charge and discharge capacity was defined as one cycle and the charge and discharge capacity retention rate after repeating this up to 1000 cycles was evaluated as the charge and discharge cycle characteristics. The charge and discharge cycle characteristics in this embodiment were calculated by the following formula.

Charge and discharge capacity retention rate [%] after 1000 cycles=(discharge capacity (μAh) after 1000 cycles÷first discharge capacity (μAh))×100

In the laminated all-solid-state secondary batteries of Examples 6 to 9 in which the upper end portions of the outer positive electrode61and the outer negative electrode71were on the inside (the lower side) of the upper end portion of the laminated sintered body20in the laminating direction, the charge and discharge capacity, the volumetric energy density, and the cycle characteristics were improved compared to the laminated all-solid-state secondary battery of Comparative Example 1.

Particularly, in the laminated all-solid-state secondary battery of Example 7 in which the lower surface sub-electrode62aand the lower surface sub-electrode72awere embedded in the lower surface26of the laminated sintered body20, the volumetric energy density was improved. This is because the lower surface sub-electrode62aand the lower surface sub-electrode72awere embedded in the lower surface26of the laminated sintered body20so that the volume of the laminated all-solid-state secondary battery was smaller than that of Example 6.

INDUSTRIAL APPLICABILITY

According to the present invention, it is possible to provide a laminated all-solid-state secondary battery having excellent charge and discharge capacity, pulse discharge cycle characteristics, and cycle characteristics.

REFERENCE SIGNS LIST