JP2023128368A - Electrochemical cell and method for manufacturing the same - Google Patents

Abstract

To provide an electrochemical cell that can further improve electric capacity and a battery life and a method for manufacturing the same.SOLUTION: An electrochemical cell includes: a positive electrode layer 20 containing a positive electrode active material; a negative electrode layer 30 containing a negative electrode active material; and a solid electrolytic layer 10 containing a solid electrolytic material. The solid electrolytic layer 10 is located between the positive electrode layer 20 and the negative electrode layer 30. The solid electrolytic layer 10 is open to the positive electrode layer 20 side and has a positive electrode recess 11 into which the positive electrode layer 20 enters. The solid electrolytic layer 10 is open to the negative electrode layer 30 side and has a negative electrode recess 15 into which the negative electrode layer 30 enters. The positive electrode recess 11 and the negative electrode recess 15 are deviated in a surface direction of the solid electrolyte layer 10.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing an electrochemical cell and an electrochemical cell.

All-solid-state batteries (electrochemical cells) are known that use a solid electrolyte made of an inorganic material instead of the electrolyte of a lithium ion secondary battery or a gel electrolyte in which the electrolyte is held in a polymer.
In all-solid-state batteries, internal resistance inside the solid electrolyte increases due to contact resistance between inorganic materials.

To address these problems, for example, Patent Document 1 proposes an all-solid-state battery in which the internal resistance is reduced by forming irregularities on the surface of a solid electrolyte layer containing a solid electrolyte.

Japanese Patent Application Publication No. 2008-243735

As shown in FIG. 15, the electrode body 100 used in the all-solid-state battery (lithium ion secondary battery) of Patent Document 1 includes a positive electrode layer 120, a negative electrode layer 130, and a structure between the positive electrode layer 120 and the negative electrode layer 130. and a solid electrolyte layer 110 located thereon. A positive electrode recess 111 that opens toward the positive electrode layer 120 is formed in the solid electrolyte layer 110 . Thereby, in a cross-sectional view, positive electrode recesses 111 and positive electrode protrusions 112 are alternately formed on the positive electrode layer 120 side of the solid electrolyte layer 110. A negative electrode recess 115 opening toward the negative electrode layer 130 is formed in the solid electrolyte layer 110 . Thereby, in a cross-sectional view, negative electrode recesses 115 and negative electrode protrusions 116 are alternately formed on the negative electrode layer 130 side of the solid electrolyte layer 110.

In the invention of Patent Document 1, the distance D8 between the positive electrode recess 111 and the negative electrode recess 115 is different from the distance D9 between the positive electrode projection 112 and the negative electrode projection 116. That is, the distance between the positive electrode layer 120 and the negative electrode layer 130 is non-uniform. For this reason, the solid electrolyte layer 110 has low internal resistance and high internal resistance in some areas, resulting in a difference in current density and non-uniform battery reaction. As a result, the electrode utilization rate (electrical capacity) of the all-solid-state battery decreases, and the battery life decreases due to accelerated deterioration of specific parts.

Therefore, an object of the present invention is to provide an electrochemical cell and a method for manufacturing the electrochemical cell that can further increase the electric capacity and battery life.

In order to solve the above problems, the present invention has the following aspects.
The electrochemical cell according to the present invention includes a positive electrode layer containing a positive electrode active material, a negative electrode layer containing a negative electrode active material, and a solid electrolyte layer containing a solid electrolyte, and the solid electrolyte layer is different from the positive electrode layer. The solid electrolyte layer is located between the negative electrode layer and has a positive electrode recess that opens toward the positive electrode layer and into which the positive electrode layer enters, and the solid electrolyte layer opens toward the negative electrode layer and has a positive electrode recess into which the positive electrode layer enters. It has a negative electrode recess into which the negative electrode layer enters, and the positive electrode recess and the negative electrode recess are offset in the plane direction of the solid electrolyte layer.

According to this configuration, the internal resistance of the solid electrolyte layer can be made uniform, and the uniformity of the current density can be improved. Therefore, the electric capacity can be further increased and the battery life can be further increased.

Further, the solid electrolyte layer has at least two positive electrode recesses and two or more negative electrode recesses, and in plan view, the positive electrode recesses and the negative electrode recesses are alternately located in the surface direction of the solid electrolyte layer. You can leave it there.
According to this configuration, the uniformity of current density can be further improved.

Further, the depth of the positive electrode recess may be deeper than 1/2 of the thickness of the solid electrolyte layer, and the depth of the negative electrode recess may be deeper than 1/2 of the thickness of the solid electrolyte layer. .
According to this configuration, the electric capacity can be further increased.

Also, the difference between the thickness of the solid electrolyte layer and the depth of the positive electrode recess, the difference between the thickness of the solid electrolyte layer and the depth of the negative electrode recess, and the positive electrode in a cross-sectional view in the thickness direction of the solid electrolyte layer. The distance between the recess and the negative electrode recess may be equal to each other.
According to this configuration, the uniformity of current density can be further improved.

The method for manufacturing an electrochemical cell of the present invention includes a positive electrode layer containing a positive electrode active material, a negative electrode layer containing a negative electrode active material, and a solid electrolyte layer containing a solid electrolyte, wherein the solid electrolyte layer is connected to the positive electrode. A method for manufacturing an electrochemical cell located between the solid electrolyte layer and the negative electrode layer, the positive electrode recess being open to the positive electrode layer side of the solid electrolyte layer and into which the positive electrode layer enters, and the negative electrode of the solid electrolyte layer. A negative electrode recess that is open to the layer side and into which the negative electrode layer enters is positioned offset in the plane direction of the solid electrolyte layer.

According to this configuration, the internal resistance of the solid electrolyte layer can be made uniform, and the uniformity of the current density can be improved. Therefore, the electric capacity can be further increased and the battery life can be further increased.

Further, the solid electrolyte layer has at least two positive electrode recesses and two or more negative electrode recesses, and the positive electrode recesses and the negative electrode recesses are alternately located in the plane direction of the solid electrolyte layer in plan view. It's okay.
According to this configuration, the uniformity of current density can be further improved.

Further, the depth of the positive electrode recess may be deeper than 1/2 of the thickness of the solid electrolyte layer, and the depth of the negative electrode recess may be deeper than 1/2 of the thickness of the solid electrolyte layer. .
According to this configuration, the electric capacity can be further increased.

Also, the difference between the thickness of the solid electrolyte layer and the depth of the positive electrode recess, the difference between the thickness of the solid electrolyte layer and the depth of the negative electrode recess, and the positive electrode in a cross-sectional view in the thickness direction of the solid electrolyte layer. The distances between the recess and the negative electrode recess may be made equal to each other.
According to this configuration, the uniformity of current density can be further improved.

According to the electrochemical cell manufacturing method and electrochemical cell of the present invention, the electric capacity can be further increased and the battery life can be further increased.

FIG. 1 is a perspective view showing the appearance of an electrochemical cell according to an embodiment of the present invention. It is a sectional view showing an example of an electrode body housed in the same electrochemical cell. FIG. 3 is a plan view showing an example of the positional relationship between a positive electrode recess and a negative electrode recess. FIG. 3 is a plan view showing an example of the positional relationship between a positive electrode recess and a negative electrode recess. 3 is a cross-sectional view showing a method of manufacturing the electrode body of FIG. 2. FIG. 3 is a cross-sectional view showing a method of manufacturing the electrode body of FIG. 2. FIG. 3 is a cross-sectional view showing a method of manufacturing the electrode body of FIG. 2. FIG. 3 is a cross-sectional view showing a method of manufacturing the electrode body of FIG. 2. FIG. 3 is a cross-sectional view showing a method of manufacturing the electrode body of FIG. 2. FIG. 3 is a cross-sectional view showing a method of manufacturing the electrode body of FIG. 2. FIG. It is a sectional view showing other examples of the electrode body housed in the electrochemical cell concerning one embodiment of the present invention. FIG. 3 is a perspective view showing another example of an electrode body housed in an electrochemical cell according to an embodiment of the present invention. FIG. 3 is a perspective view showing another example of an electrode body housed in an electrochemical cell according to an embodiment of the present invention. FIG. 3 is a perspective view showing another example of an electrode body housed in an electrochemical cell according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of an electrode body used in a conventional all-solid-state battery.

Embodiments of an electrochemical cell according to the present invention will be described below with reference to the drawings. In the following embodiments, a coin-shaped all-solid-state battery (hereinafter also simply referred to as a "battery") will be cited as an example of an electrochemical cell, and the configuration of this battery will be described.
Note that in the drawings used in the following explanation, the scale of each member is appropriately changed and displayed in order to make each member a recognizable size.

≪Electrochemical cell≫
As shown in FIG. 1, the battery (electrochemical cell) 1 of this embodiment is a button-shaped battery that is circular in plan view. This battery 1 includes a container-shaped exterior body 2 and an electrode body housed inside the exterior body 2.

The exterior body 2 is formed of a laminate film. The laminate film has a metal foil, a fusion layer provided on the inner surface to cover the metal foil, and a protective layer provided on the outer surface to cover the metal foil.
The metal foil is made of a metal that blocks outside air and water vapor, such as aluminum or stainless steel.
The adhesive layer is formed of, for example, polyolefin such as polyethylene or polypropylene, or a copolymer containing two or more types of resin.
The protective layer is made of, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, or polyamide such as nylon.

The electrode body has a positive electrode layer containing a positive electrode active material, a negative electrode layer containing a negative electrode active material, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer. The solid electrolyte layer includes a solid electrolyte.
As shown in FIG. 2, the electrode body 3A of this embodiment includes a positive electrode layer 20, a negative electrode layer 30, and a solid electrolyte layer 10 located between the positive electrode layer 20 and the negative electrode layer 30.
The solid electrolyte layer 10 has a positive electrode recess 11 that opens toward the positive electrode layer 20 side. The positive electrode layer 20 is inserted into the positive electrode recess 11 .
The solid electrolyte layer 10 has a negative electrode recess 15 that opens toward the negative electrode layer 30 side. The negative electrode layer 30 is inserted into the negative electrode recess 15 .
The positive electrode recess 11 and the negative electrode recess 15 are positioned offset in the plane direction (X direction) of the solid electrolyte layer 10 .

The thickness T3A of the electrode body 3A is, for example, preferably 500 to 4000 μm, more preferably 800 to 3500 μm, even more preferably 1000 to 3000 μm. When the thickness T3A is equal to or greater than the above lower limit, the electric capacity of the battery 1 can be further increased. When the thickness T3A is less than or equal to the above upper limit value, the battery 1 can be made more compact.
The thickness T3A is determined, for example, by observing a cross section of the electrode body 3A in the thickness direction (Z direction) using a microscope or the like.

<Solid electrolyte layer>
Solid electrolyte layer 10 includes a solid electrolyte.
As the solid electrolyte, known ones used in all-solid-state batteries can be used. Examples of the solid electrolyte include oxide-based solid electrolytes.
Examples of the oxide solid electrolyte include Li _1.5 Al _0.5 Ge _1.5 P ₃ O ₁₂ (LAGP), Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ), Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ (LATP), Li ₁₀ GeP ₂ S ₁₂ (LGPS), Li _3.5 Ge _0.5 V _0.5 O ₄ (LGVO), LiTa ₂ PO ₈ (LTPO), La _0.57 Li _0.29 TiO ₃ (LLTO), Li _6.2 Ga _0.3 La _2.95 Rb _0.05 Zr ₂ O ₁₂ (LGLRZO), Li ₁₀ GeO ₂ P ₁₂ (LGPO), Li _{6. 25} La ₃ Zr ₂ Al _0.25 O ₁₂ and the like.
These solid electrolytes may be used alone or in combination of two or more.

The thickness T10 of the solid electrolyte layer 10 is, for example, preferably 300 to 3800 μm, more preferably 500 to 3300 μm, and even more preferably 800 to 2800 μm. When the thickness T10 is equal to or greater than the above lower limit, the strength of the battery 1 can be further increased. When the thickness T10 is less than or equal to the above upper limit value, the internal resistance of the battery 1 can be further reduced.
Thickness T10 is determined by the same method as thickness T3A.

The depth D11 of the positive electrode recess 11 is, for example, preferably 200 to 3,700 μm, more preferably 400 to 3,200 μm, and even more preferably 700 to 2,700 μm. When the depth D11 is equal to or greater than the above lower limit value, the internal resistance of the battery 1 can be further reduced. When the depth D11 is less than or equal to the above upper limit value, the strength of the solid electrolyte layer 10 can be further increased.
Depth D11 is determined by the same method as thickness T3A.

The width W11 of the positive electrode recess 11 is, for example, preferably 1 to 100 μm, more preferably 2 to 80 μm, and even more preferably 3 to 60 μm. When the width W11 is equal to or larger than the above lower limit, the positive electrode layer 20 easily enters the positive electrode recess 11. When the width W11 is less than or equal to the above upper limit value, the strength of the solid electrolyte layer 10 can be further increased.
The width W11 is determined by the same method as the thickness T3A.

A positive electrode protrusion 12 is formed between the two positive electrode recesses 11 .
The height H12 of the positive electrode protrusion 12 is the same as the depth D11 of the positive electrode recess 11.
The width W12 of the positive electrode convex portion 12 is, for example, preferably 1 to 300 μm, more preferably 2 to 240 μm, and even more preferably 3 to 180 μm. When the width W12 is equal to or greater than the above lower limit, the strength of the solid electrolyte layer 10 can be further increased. When the width W12 is less than or equal to the above upper limit value, the internal resistance of the battery 1 can be further reduced.
Width W12 is determined by the same method as thickness T3A.

The depth D15 of the negative electrode recess 15 is, for example, preferably 200 to 3,700 μm, more preferably 400 to 3,200 μm, and even more preferably 700 to 2,700 μm. When the depth D15 is equal to or greater than the above lower limit value, the internal resistance of the battery 1 can be further reduced. When the depth D15 is less than or equal to the above upper limit value, the strength of the solid electrolyte layer 10 can be further increased.
Depth D15 is determined by the same method as thickness T3A.

The width W15 of the negative electrode recess 15 is, for example, preferably 1 to 100 μm, more preferably 2 to 80 μm, and even more preferably 3 to 60 μm. When the width W15 is equal to or larger than the above lower limit value, the negative electrode layer 30 easily enters the negative electrode recess 15. When the width W15 is less than or equal to the above upper limit value, the strength of the solid electrolyte layer 10 can be further increased.
The width W15 is determined by the same method as the thickness T3A.

A negative electrode protrusion 16 is formed between the two negative electrode recesses 15 .
The height H16 of the negative electrode protrusion 16 is the same as the depth D15 of the negative electrode recess 15.
The width W16 of the negative electrode convex portion 16 is, for example, preferably 1 to 300 μm, more preferably 2 to 240 μm, and even more preferably 3 to 180 μm. When the width W16 is equal to or greater than the above lower limit, the strength of the solid electrolyte layer 10 can be further increased. When the width W16 is equal to or less than the above upper limit value, the internal resistance of the battery 1 can be further reduced.
Width W16 is determined by the same method as thickness T3A.

The difference between the thickness T10 of the solid electrolyte layer 10 and the depth D11 of the positive electrode recess 11 (the distance from the deepest part of the positive electrode recess 11 to the negative electrode layer 30) is defined as D1.
The difference between the thickness T10 of the solid electrolyte layer 10 and the depth D15 of the negative electrode recess 15 (the distance from the deepest part of the negative electrode recess 15 to the positive electrode layer 20) is defined as D2.
In a cross-sectional view of the solid electrolyte layer 10 in the thickness direction (Z direction), the distance between the positive electrode recess 11 and the negative electrode recess 15 in the surface direction (X direction) of the solid electrolyte layer 10 is defined as D3.
At this time, it is preferable that the distance D1, the distance D2, and the distance D3 are equal to each other. By making the distance D1, the distance D2, and the distance D3 equal to each other, the uniformity of the current density inside the solid electrolyte layer 10 can be further improved.
Here, "equal" means that the distance ratio (D1/D2, D1/D3, etc.) is within ±5%.

The solid electrolyte layer 10 has two or more positive electrode recesses 11 and two or more negative electrode recesses 15 . In the solid electrolyte layer 10 , the positive electrode recesses 11 and the negative electrode recesses 15 are preferably located alternately in the plane direction of the solid electrolyte layer 10 . Since the positive electrode recesses 11 and the negative electrode recesses 15 are alternately located, the uniformity of the current density inside the solid electrolyte layer 10 can be further improved.
Here, "the positive electrode recesses 11 and the negative electrode recesses 15 are alternately located in the plane direction of the solid electrolyte layer 10" means that, as shown in FIG. In addition to cases where positive electrode recesses 11 and negative electrode recesses 15 are alternately located, as shown in FIG. 4, positive electrode recesses 11 and negative electrode recesses 15 are alternately located only in the This shall include cases.
Note that the positive electrode recesses 11 and the negative electrode recesses 15 may be alternately located in any direction in plan view.

The depth D11 of the positive electrode recess 11 is preferably deeper than 1/2 of the thickness T10 of the solid electrolyte layer 10. When the depth D11 is deeper than 1/2 of the thickness T10, the deepest part of the positive electrode recess 11 is located inside the negative electrode protrusion 16. Therefore, the current density inside the solid electrolyte layer 10 can be further increased, and the electrical characteristics of the battery 1 can be further improved.
The upper limit of the depth D11 is not particularly limited, as long as it is smaller than the thickness T10.

The depth D15 of the negative electrode recess 15 is preferably deeper than 1/2 of the thickness T10 of the solid electrolyte layer 10. When the depth D15 is deeper than 1/2 of the thickness T10, the deepest part of the negative electrode recess 15 is located inside the positive electrode protrusion 12. Therefore, the current density inside the solid electrolyte layer 10 can be further increased, and the electrical characteristics of the battery 1 can be further improved.
The upper limit of the depth D15 is not particularly limited, as long as it is smaller than the thickness T10.

<Positive electrode layer>
The positive electrode layer 20 includes a positive electrode active material.
As the positive electrode active material, known materials used in all-solid-state batteries can be used. Examples of the positive electrode active material include a one-component cathode material, a binary cathode material, a ternary cathode material, and the like.
Examples of the one-component positive electrode material include LiMO ₂ (M represents a metal element such as Co, Ni, Mn, Al, Fe, etc.).
Examples of binary positive electrode materials include Li _1-x CoMnO ₄ (x is a number that satisfies 0<x<1), Li _x FePO ₄ (x is a number that satisfies 0<x≦1), Li _x V ₆ O ₁₃ (x is a number that satisfies 0<x≦1), Li _1-x Mn ₂ O ₄ (x is a number that satisfies 0<x<1), Li _1-x Ni _0.5 Mn _{1 .5} O ₄ (x is a number satisfying 0<x<1), and the like.
Examples of the ternary positive electrode material include LiNi _1/3 Mn _1/3 Co _1/3 O ₂ .
These positive electrode active materials may be used alone or in combination of two or more.

The thickness T20 of the positive electrode layer 20 is, for example, preferably 10 to 500 μm, more preferably 30 to 400 μm, and even more preferably 80 to 300 μm. When the thickness T20 is equal to or greater than the above lower limit, the electric capacity of the battery 1 can be further increased. When the thickness T20 is less than or equal to the above upper limit value, the internal resistance of the battery 1 can be further reduced.
Thickness T20 is determined by the same method as thickness T3A.

<Negative electrode layer>
Negative electrode layer 30 includes a negative electrode active material. As the negative electrode active material, known materials used in all-solid-state batteries can be used.
Examples of the negative electrode active material include metallic lithium, an alloy of metallic lithium and a metal other than lithium, and the like. Other negative electrode active materials include carbon materials such as carbon and graphite, silicon materials such as Si and SiO, and lithium transition metal composite oxides such as Li ₄ Ti ₅ O ₁₂ (LTO).
One type of negative electrode active material may be used alone, or two or more types may be used in combination.

The thickness T30 of the negative electrode layer 30 is, for example, preferably 10 to 500 μm, more preferably 30 to 400 μm, and even more preferably 80 to 300 μm. When the thickness T30 is equal to or greater than the above lower limit, the electric capacity of the battery 1 can be further increased. When the thickness T30 is less than or equal to the above upper limit value, the internal resistance of the battery 1 can be further reduced.
Thickness T30 is determined by the same method as thickness T3A.

≪Manufacturing method of electrochemical cell≫
The method for manufacturing an electrochemical cell of the present invention includes: a positive electrode recess that opens on the positive electrode layer side of the solid electrolyte layer and into which the positive electrode layer enters; and a negative electrode recess that opens on the negative electrode layer side of the solid electrolyte layer and into which the negative electrode layer enters; A step of shifting the solid electrolyte layer in a plane direction and positioning the solid electrolyte layer.
Below, the method for manufacturing an electrochemical cell of this embodiment will be described in detail with reference to the drawings.

As shown in FIG. 5, a solid electrolyte layer 10 is prepared.
To manufacture the solid electrolyte layer 10, solid electrolyte powder is compacted and fired in an electric furnace or the like to form the solid electrolyte layer 10.
Examples of the solid electrolyte powder include the solid electrolyte powder included in the solid electrolyte layer 10 described above.

The firing atmosphere is preferably an atmosphere containing oxygen in order to suppress oxygen vacancies, and if there is a concern about the influence of moisture, it is more preferable to select a dry atmosphere. In order to suppress distortion of the solid electrolyte sheet during firing, it is preferable to sandwich the solid electrolyte sheet between ceramic plates (made of Al ₂ O ₃ , MgO, etc.), graphite plates, or the like. In order to suppress reaction with the ceramic plate and volatilization of Li, a sheet made of the same material as the solid electrolyte or an oxide containing Li may be inserted between the ceramic plate and the ceramic plate.

Next, as shown in FIG. 6, a negative electrode recess 15 into which the negative electrode layer 30 enters is formed on one surface of the solid electrolyte layer 10. The method for forming the negative electrode recess 15 is not particularly limited, and examples thereof include a method using a laser, a method using photolithography, a method using a mold, and the like.
In the case of the method using a mold, the solid electrolyte layer 10 having the negative electrode recess 15 is obtained by filling a mold with the solid electrolyte powder described above, compacting it, and firing it.
Note that the negative electrode recess 15 may be formed in advance.

By forming the negative electrode recess 15, a portion where the negative electrode recess 15 is not formed remains as the negative electrode protrusion 16.

It is preferable that two or more negative electrode recesses 15 are formed. By forming two or more negative electrode recesses 15, the internal resistance of the battery 1 can be further reduced. The number of negative electrode recesses 15 to be formed is not particularly limited, but can be appropriately set in consideration of the ease of forming negative electrode recesses 15 by each of the above-mentioned forming methods and the viewpoint of maintaining the strength of solid electrolyte layer 10. .

The depth D15 of the negative electrode recess 15 is preferably formed deeper than 1/2 of the thickness T10 of the solid electrolyte layer 10. By forming the depth D15 of the negative electrode recess 15 to be deeper than 1/2 of the thickness T10 of the solid electrolyte layer 10, the current density inside the solid electrolyte layer 10 can be further increased, and the electrical characteristics of the battery 1 can be further improved. It will be done.

Next, as shown in FIG. 7, a negative electrode layer 30 is formed. The method of forming the negative electrode layer 30 is not particularly limited, and for example, a method of preparing a negative electrode slurry containing a negative electrode active material and dipping the solid electrolyte layer 10 into the negative electrode slurry, a method of applying the negative electrode slurry to the solid electrolyte layer 10 by screen printing, etc. Examples include a method of coating.

After forming the negative electrode layer 30, as shown in FIG. 8, the negative electrode layer 30 formed on the other surface of the solid electrolyte layer 10 (the surface on which the negative electrode recess 15 is not formed) is polished and removed.

Next, as shown in FIG. 7, a positive electrode recess 11 into which the positive electrode layer 20 enters is formed on the other surface of the solid electrolyte layer 10. The method for forming the positive electrode recess 11 is not particularly limited, and examples thereof include a method using a laser, a method using photolithography, and the like.
Note that the positive electrode recess 11 may be formed in advance.
By forming the positive electrode recess 11, a portion where the positive electrode recess 11 is not formed remains as the positive electrode protrusion 12.

The positive electrode recess 11 is shifted from the negative electrode recess 15 in the plane direction of the solid electrolyte layer 10 . By positioning the positive electrode recess 11 and the negative electrode recess 15 in a shifted manner in the plane direction of the solid electrolyte layer 10, the internal resistance of the solid electrolyte layer 10 can be made uniform, and the uniformity of the current density can be improved. Therefore, the electric capacity of the battery 1 can be further increased, and the battery life of the battery 1 can be further increased.
The position of the positive electrode recess 11 can be adjusted by adjusting the position of the irradiated laser, the shape of the photolithography mask, the shape of the mold, etc.

It is preferable that two or more positive electrode recesses 11 are formed. By forming two or more positive electrode recesses 11, the internal resistance of the battery 1 can be further reduced. The number of positive electrode recesses 11 to be formed is not particularly limited, but can be appropriately set in consideration of the ease of forming the positive electrode recesses 11 by each of the above-mentioned forming methods and the viewpoint of maintaining the strength of the solid electrolyte layer 10. .
The number of positive electrode recesses 11 to be formed is preferably the same as the number of negative electrode recesses 15 to be formed, since the uniformity of current density can be further improved.

The positive electrode recesses 11 are preferably located alternately with the negative electrode recesses 15 in the surface direction of the solid electrolyte layer 10 in plan view. By alternately locating the positive electrode recesses 11 and the negative electrode recesses 15, the uniformity of current density can be further improved.

The depth D11 of the positive electrode recess 11 is preferably formed deeper than 1/2 of the thickness T10 of the solid electrolyte layer 10. By forming the depth D11 of the positive electrode recess 11 to be deeper than 1/2 of the thickness T10 of the solid electrolyte layer 10, the current density inside the solid electrolyte layer 10 can be further increased, and the electrical characteristics of the battery 1 can be further improved. It will be done.

The difference between the thickness T10 of the solid electrolyte layer 10 and the depth D11 of the positive electrode recess 11 (the distance from the deepest part of the positive electrode recess 11 to the negative electrode layer 30) is defined as D1.
The difference between the thickness T10 of the solid electrolyte layer 10 and the depth D15 of the negative electrode recess 15 (the distance from the deepest part of the negative electrode recess 15 to the positive electrode layer 20) is defined as D2.
In a cross-sectional view of the solid electrolyte layer 10 in the thickness direction (Z direction), the distance between the positive electrode recess 11 and the negative electrode recess 15 in the surface direction (X direction) of the solid electrolyte layer 10 is defined as D3.
At this time, it is preferable to position the positive electrode recess 11 so that the distance D1, the distance D2, and the distance D3 are equal to each other. By positioning the positive electrode recess 11 so that the distance D1, the distance D2, and the distance D3 are equal to each other, the uniformity of the current density inside the solid electrolyte layer 10 can be further improved.
Here, "equal" means that the distance ratio (D1/D2, D1/D3, etc.) is within ±5%.

Next, as shown in FIG. 10, a positive electrode layer 20 is formed. The method of forming the positive electrode layer 20 is not particularly limited, and for example, a method of preparing a positive electrode slurry containing a positive electrode active material and dipping the solid electrolyte layer 10 on which the negative electrode layer 30 is formed in the positive electrode slurry, and forming the negative electrode layer 30. Examples include a method of applying a positive electrode slurry to the solid electrolyte layer 10 by screen printing or the like.

After forming the positive electrode layer 20, the positive electrode layer 20 formed on the other surface of the solid electrolyte layer 10 (the surface on which the negative electrode recess 15 is not formed) is polished and removed.
Through the above steps, an electrode body 3A as shown in FIG. 2 is obtained.

In the above description, the negative electrode layer 30 is formed on the solid electrolyte layer 10 and then the positive electrode layer 20 is formed, but the method for manufacturing an electrochemical cell of the present invention is not limited to the above-described embodiment.
For example, the negative electrode layer 30 may be formed after the positive electrode layer 20 is formed on the solid electrolyte layer 10.
When forming the positive electrode recess 11, a mold may be used to form the positive electrode recess 11.
In this case, a mold in which the negative electrode recess 15 and the positive electrode recess 11 are formed is used, and the mold is filled with solid electrolyte powder, compacted, and fired, thereby forming the negative electrode recess 15 and the positive electrode recess 11. A solid electrolyte layer 10 having the following properties is obtained. By sequentially forming a negative electrode layer 30 and a positive electrode layer 20 on this solid electrolyte layer 10, an electrode body 3A is obtained.
Note that the order in which the negative electrode layer 30 and the positive electrode layer 20 are formed is not particularly limited; the negative electrode layer 30 may be formed before the positive electrode layer 20 is formed, or the negative electrode layer 30 may be formed after the positive electrode layer 20 is formed. may be formed.

In the electrochemical cell of the present invention, since the positive electrode recess and the negative electrode recess are offset in the plane direction of the solid electrolyte layer, the internal resistance of the solid electrolyte layer can be made uniform, and the uniformity of current density can be improved. Therefore, the electric capacity can be further increased and the battery life can be further increased.
In the electrochemical cell manufacturing method of the present invention, the positive electrode recess and the negative electrode recess are positioned offset in the plane direction of the solid electrolyte layer, so that the internal resistance of the solid electrolyte layer can be made uniform and the uniformity of current density can be improved. It will be done. Therefore, the electric capacity can be further increased and the battery life can be further increased.

Although the electrochemical cell and the method for manufacturing the electrochemical cell of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit thereof.
For example, as shown in FIG. 11, the electrode body 3B may have a positive electrode recess 13 having a shallower depth D13 and a negative electrode recess 17 having a shallower depth D17 than the electrode body 3A.
Since the depth D13 of the positive electrode recess 13 is shallower than the depth D11, the difference between the thickness T10 of the solid electrolyte layer 10 and the depth D13 of the positive electrode recess 13 (from the deepest part of the positive electrode recess 13 to the negative electrode layer 30) is distance) D4 can be made larger than distance D1. Therefore, deterioration of specific parts can be suppressed and battery life can be further increased.
Since the depth D17 of the negative electrode recess 17 is shallower than the depth D15, the difference between the thickness T10 of the solid electrolyte layer 10 and the depth D17 of the negative electrode recess 17 (from the deepest part of the negative electrode recess 17 to the positive electrode layer 20) is distance) D5 can be made larger than distance D2. Therefore, deterioration of specific parts can be suppressed and battery life can be further increased.
In FIG. 11, distance D4 and distance D5 are equal. Therefore, the current density inside the solid electrolyte layer 10 can be made uniform.
Here, "equal" means that the distance ratio (D4/D5) is within ±5%.

The width W13 of the positive electrode recess 13 is the same as the width W11 of the positive electrode recess 11. The width W13 of the positive electrode recess 13 may be the same as or different from the width W11 of the positive electrode recess 11.
The height H14 of the positive electrode protrusion 14 is the same as the depth D13 of the positive electrode recess 13.
The width W14 of the positive electrode protrusion 14 is the same as the width W12 of the positive electrode protrusion 12. The width W14 of the positive electrode protrusion 14 may be the same as or different from the width W12 of the positive electrode protrusion 12.

The width W17 of the negative electrode recess 17 is the same as the width W15 of the negative electrode recess 15. The width W17 of the negative electrode recess 17 may be the same as or different from the width W15 of the negative electrode recess 15.
The height H18 of the negative electrode protrusion 18 is the same as the depth D17 of the negative electrode recess 17.
The width W18 of the negative electrode protrusion 18 is the same as the width W16 of the negative electrode protrusion 16. The width W18 of the negative electrode protrusion 18 may be the same as or different from the width W16 of the negative electrode protrusion 16.

As shown in FIG. 12, the electrode body 3C may have a linear positive electrode recess 11 and a linear negative electrode recess 15.

As shown in FIG. 13, the electrode body 3D may have a cylindrical positive electrode recess and a cylindrical negative electrode recess.

As shown in FIG. 14, the electrode body 3E may have a positive electrode recessed portion and a negative electrode recessed portion formed with a via.

For example, the shape of the solid electrolyte layer may not be circular in plan view but may be polygonal in plan view.
For example, instead of one electrode body, two or more electrode bodies may be stacked.

DESCRIPTION OF SYMBOLS 1... Electrochemical cell, 2... Exterior body, 3A, 3B, 3C, 3D, 3E... Electrode body, 10... Solid electrolyte layer, 11, 13... Positive electrode recessed part, 12, 14... Positive electrode convex part, 15, 17... Negative electrode Recessed portion, 16, 18... Negative electrode convex portion, 20... Positive electrode layer, 30... Negative electrode layer

Claims (8)

a positive electrode layer containing a positive electrode active material;
a negative electrode layer containing a negative electrode active material;
a solid electrolyte layer containing a solid electrolyte;
The solid electrolyte layer is located between the positive electrode layer and the negative electrode layer,
The solid electrolyte layer has a positive electrode recess that is open to the positive electrode layer side and into which the positive electrode layer enters,
The solid electrolyte layer has a negative electrode recess that is open to the negative electrode layer side and into which the negative electrode layer enters,
An electrochemical cell, wherein the positive electrode recess and the negative electrode recess are offset in a plane direction of the solid electrolyte layer. The solid electrolyte layer has two or more of the positive electrode recesses and two or more of the negative electrode recesses,
The electrochemical cell according to claim 1, wherein the positive electrode recesses and the negative electrode recesses are alternately located in a planar direction of the solid electrolyte layer. The depth of the positive electrode recess is deeper than 1/2 of the thickness of the solid electrolyte layer, and the depth of the negative electrode recess is deeper than 1/2 of the thickness of the solid electrolyte layer. 2. The electrochemical cell according to 2. a difference between the thickness of the solid electrolyte layer and the depth of the positive electrode recess;
a difference between the thickness of the solid electrolyte layer and the depth of the negative electrode recess;
The electrochemical cell according to claim 1, wherein distances between the positive electrode recess and the negative electrode recess in a cross-sectional view in the thickness direction of the solid electrolyte layer are equal to each other. a positive electrode layer containing a positive electrode active material;
a negative electrode layer containing a negative electrode active material;
a solid electrolyte layer containing a solid electrolyte;
A method for manufacturing an electrochemical cell, wherein the solid electrolyte layer is located between the positive electrode layer and the negative electrode layer,
a positive electrode recess that opens on the positive electrode layer side of the solid electrolyte layer and into which the positive electrode layer enters;
A method for manufacturing an electrochemical cell, wherein a negative electrode recess that opens on the negative electrode layer side of the solid electrolyte layer and into which the negative electrode layer enters is shifted in a planar direction of the solid electrolyte layer. The solid electrolyte layer has two or more positive electrode recesses and two or more negative electrode recesses,
6. The method for manufacturing an electrochemical cell according to claim 5, wherein the positive electrode recesses and the negative electrode recesses are alternately positioned in a planar direction of the solid electrolyte layer. The depth of the positive electrode recess is deeper than 1/2 of the thickness of the solid electrolyte layer, and the depth of the negative electrode recess is deeper than 1/2 of the thickness of the solid electrolyte layer. 6. The method for manufacturing an electrochemical cell according to 6. a difference between the thickness of the solid electrolyte layer and the depth of the positive electrode recess;
a difference between the thickness of the solid electrolyte layer and the depth of the negative electrode recess;
Manufacturing the electrochemical cell according to any one of claims 5 to 7, wherein distances between the positive electrode recess and the negative electrode recess in a cross-sectional view in the thickness direction of the solid electrolyte layer are made equal to each other. Method.

Images