JP7827490B2 - Method for manufacturing an electrochemical cell - Google Patents

Description

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

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

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

Japanese Patent Application Laid-Open 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 solid electrolyte layer 110 located between the positive electrode layer 120 and the negative electrode layer 130. The solid electrolyte layer 110 has positive electrode recesses 111 that open toward the positive electrode layer 120. As a result, 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. The solid electrolyte layer 110 has negative electrode recesses 115 that open toward the negative electrode layer 130. As a result, 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 protrusion 112 and the negative electrode protrusion 116. In other words, the distance between the positive electrode layer 120 and the negative electrode layer 130 is uneven. This creates areas of low and high internal resistance in the solid electrolyte layer 110, resulting in differences in current density and uneven battery reactions. This results in a decrease in the electrode utilization rate (electrical capacity) of the all-solid-state battery and a shortened battery life due to accelerated deterioration of specific areas.

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

In order to solve the above problems, the present invention has the following aspects.
A method for manufacturing an electrochemical cell according to the present invention includes a cathode layer including a cathode active material, an anode layer including an anode active material, and a solid electrolyte layer including a solid electrolyte , the solid electrolyte layer being located between the cathode layer and the anode layer, the solid electrolyte layer having a plurality of cathode recesses that open to the cathode layer side and into which a portion of the cathode layer fits, and the solid electrolyte layer having a plurality of anode recesses that open to the anode layer side and into which a portion of the anode layer fits, the cathode recesses and the anode recesses being offset in a surface direction of the solid electrolyte layer, the method comprising the steps of: forming anode recesses on one surface of the solid electrolyte layer; forming anode layer that covers one surface of the solid electrolyte layer and fills the anode recesses; then forming cathode recesses on the other surface of the solid electrolyte layer at a position offset from the anode recesses; and then forming cathode layer that covers the other surface of the solid electrolyte layer and fills the cathode recesses .

This configuration makes it possible to uniform the internal resistance of the solid electrolyte layer and improve the uniformity of current density. This in turn increases the electrical capacity and extends the battery life.

The solid electrolyte layer may have two or more positive electrode recesses and two or more negative electrode recesses, and the positive electrode recesses and the negative electrode recesses may be alternately positioned in a surface direction of the solid electrolyte layer in a plan view.
This configuration further improves the uniformity of the current density.

The depth of the positive electrode recess may be greater than half the thickness of the solid electrolyte layer, and the depth of the negative electrode recess may be greater than half the thickness of the solid electrolyte layer.
This configuration further increases the electrical capacity.

Furthermore, 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 distance between the positive electrode recess and the negative electrode recess in a cross-sectional view in the thickness direction of the solid electrolyte layer may be equal to each other.
This configuration further improves the uniformity of the current density.

According to the method for producing an electrochemical cell of the present invention, the electric capacity can be increased and the battery life can be extended.

1 is a perspective view showing the appearance of an electrochemical cell according to one embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of an electrode body housed in the electrochemical cell. FIG. 2 is a plan view showing an example of the positional relationship between a positive electrode recess and a negative electrode recess. FIG. 2 is a plan view showing an example of the positional relationship between a positive electrode recess and a negative electrode recess. 3A to 3C are cross-sectional views showing a method for manufacturing the electrode body of FIG. 2. 3A to 3C are cross-sectional views showing a method for manufacturing the electrode body of FIG. 2. 3A to 3C are cross-sectional views showing a method for manufacturing the electrode body of FIG. 2. 3A to 3C are cross-sectional views showing a method for manufacturing the electrode body of FIG. 2. 3A to 3C are cross-sectional views showing a method for manufacturing the electrode body of FIG. 2. 3A to 3C are cross-sectional views showing a method for manufacturing the electrode body of FIG. 2. FIG. 4 is a cross-sectional view showing another example of an electrode assembly housed in an electrochemical cell according to an embodiment of the present invention. FIG. 10 is a perspective view showing another example of an electrode assembly housed in an electrochemical cell according to an embodiment of the present invention. FIG. 10 is a perspective view showing another example of an electrode assembly housed in an electrochemical cell according to an embodiment of the present invention. FIG. 10 is a perspective view showing another example of an electrode assembly housed in an electrochemical cell according to an embodiment of the present invention. FIG. 1 is a cross-sectional view showing an example of an electrode body used in a conventional all-solid-state battery.

Hereinafter, embodiments of an electrochemical cell according to the present invention will be described with reference to the drawings. In the following embodiments, a coin-type all-solid-state battery (hereinafter simply referred to as a "battery") will be taken as an example of an electrochemical cell, and the configuration of this battery will be described.
In the drawings used in the following description, the scale of each component is appropriately changed to make it recognizable.

Electrochemical Cell
1, the battery (electrochemical cell) 1 of this embodiment is a button-type battery that is circular in plan view. The battery 1 includes a container-shaped exterior body 2 and an electrode assembly housed inside the exterior body 2.

The exterior body 2 is formed of a laminate film. The laminate film has a metal foil, a bonding 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 fusion layer is formed from, for example, a polyolefin such as polyethylene or polypropylene, or a copolymer containing two or more types of resin.
The protective layer is formed from, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, or polyamide such as nylon.

The electrode assembly 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 contains a solid electrolyte.
As shown in FIG. 2, the electrode body 3A of this embodiment has 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 to the positive electrode layer 20 side. The positive electrode layer 20 fits into the positive electrode recess 11.
The solid electrolyte layer 10 has an anode recess 15 that opens to the anode layer 30 side. The anode recess 15 is filled with the anode layer 30.
The positive electrode recess 11 and the negative electrode recess 15 are positioned so as to be shifted 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, and even more preferably 1000 to 3000 μm. When the thickness T3A is equal to or greater than the above lower limit, the electrical capacity of the battery 1 can be increased. When the thickness T3A is equal to or less than the above upper limit, the battery 1 can be made more compact.
The thickness T3A can be determined, for example, by observing a cross section of the electrode body 3A cut in the thickness direction (Z direction) using a microscope or the like.

<Solid electrolyte layer>
The solid electrolyte layer 10 includes a solid electrolyte.
As the solid electrolyte, a known solid electrolyte used in all-solid-state batteries can be used, and examples of the solid electrolyte include oxide-based solid electrolytes.
Examples of oxide-based solid electrolytes 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), and 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} ), _{Li10GeO2P12 (} LGPO), _{Li6.25La3Zr2Al0.25O12 ,} 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 equal to or less than the above upper limit, the internal resistance of the battery 1 can be further reduced.
The thickness T10 is determined in the same manner as the thickness T3A.

The depth D11 of the positive electrode recess 11 is, for example, preferably 200 to 3700 μm, more preferably 400 to 3200 μm, and even more preferably 700 to 2700 μm. When the depth D11 is equal to or greater than the above lower limit, the internal resistance of the battery 1 can be further reduced. When the depth D11 is equal to or less than the above upper limit, the strength of the solid electrolyte layer 10 can be further increased.
The depth D11 is determined in the same manner as the 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 greater than the above lower limit, the positive electrode layer 20 easily enters the positive electrode recess 11. When the width W11 is equal to or less than the above upper limit, the strength of the solid electrolyte layer 10 can be further increased.
The width W11 is determined in the same manner 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 convex portion 12 is the same as the depth D11 of the positive electrode concave portion 11.
The width W12 of the positive electrode protrusion 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 equal to or less than the above upper limit, the internal resistance of the battery 1 can be further reduced.
The width W12 is determined in the same manner as the thickness T3A.

The depth D15 of the negative electrode recess 15 is, for example, preferably 200 to 3700 μm, more preferably 400 to 3200 μm, and even more preferably 700 to 2700 μm. When the depth D15 is equal to or greater than the above lower limit, the internal resistance of the battery 1 can be further reduced. When the depth D15 is equal to or less than the above upper limit, the strength of the solid electrolyte layer 10 can be further increased.
The depth D15 is determined in the same manner as the 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 greater than the above lower limit, the negative electrode layer 30 easily enters the negative electrode recess 15. When the width W15 is equal to or less than the above upper limit, the strength of the solid electrolyte layer 10 can be further increased.
The width W15 is determined in the same manner 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 protrusion 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, the internal resistance of the battery 1 can be further reduced.
The width W16 is determined in the same manner as the 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.
In this case, it is preferable that the distance D1, the distance D2, and the distance D3 are equal to one another. By making the distance D1, the distance D2, and the distance D3 equal to one another, the uniformity of the current density inside the solid electrolyte layer 10 can be further improved.
Here, "equal" means that the ratio of the distances (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 positioned alternately in the surface direction of the solid electrolyte layer 10. By positioning the positive electrode recesses 11 and the negative electrode recesses 15 alternately, the uniformity of the current density inside the solid electrolyte layer 10 can be further improved.
Here, "positive electrode recesses 11 and negative electrode recesses 15 are alternately positioned in the surface direction of solid electrolyte layer 10" includes not only a case where positive electrode recesses 11 and negative electrode recesses 15 are alternately positioned in both the X direction and the Y direction in plan view as shown in FIG. 3 , but also a case where positive electrode recesses 11 and negative electrode recesses 15 are alternately positioned only in the X direction in plan view as shown in FIG. 4 .
The positive electrode recesses 11 and the negative electrode recesses 15 may be alternately positioned in any direction in a plan view.

The depth D11 of the positive electrode recess 11 is preferably greater than half the thickness T10 of the solid electrolyte layer 10. When the depth D11 is greater than half the thickness T10, the deepest part of the positive electrode recess 11 is located inside the negative electrode protrusion 16. This further increases the current density inside the solid electrolyte layer 10, thereby further improving the electrical characteristics of the battery 1.
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 greater than half the thickness T10 of the solid electrolyte layer 10. When the depth D15 is greater than half the thickness T10, the deepest part of the negative electrode recess 15 is located inside the positive electrode projection 12. This further increases the current density inside the solid electrolyte layer 10, thereby further improving the electrical characteristics of the battery 1.
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 contains a positive electrode active material.
The positive electrode active material may be any known material used in all-solid-state batteries, such as a single-component positive electrode material, a binary positive electrode material, or a ternary positive electrode material.
An example of a single-component positive electrode material is LiMO ₂ (M represents a metal element such as Co, Ni, Mn, Al, or Fe).
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), and Li _1-x Ni _0.5 Mn _1.5 O ₄ (x is a number that satisfies 0<x<1).
An example of a ternary positive electrode material is 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 electrical capacity of the battery 1 can be further increased. When the thickness T20 is equal to or less than the above upper limit, the internal resistance of the battery 1 can be further reduced.
The thickness T20 is determined in the same manner as the thickness T3A.

<Negative electrode layer>
The negative electrode layer 30 includes a negative electrode active material. As the negative electrode active material, a known material used in all-solid-state batteries can be used.
Examples of the negative electrode active material include metallic lithium, alloys of metallic lithium and metals other than lithium, etc. Other examples of the negative electrode active material 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).
The negative electrode active material may be used alone or in combination of two or more kinds.

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 electrical capacity of the battery 1 can be further increased. When the thickness T30 is equal to or less than the above upper limit, the internal resistance of the battery 1 can be further reduced.
The thickness T30 is determined in the same manner as the thickness T3A.

<Electrochemical cell manufacturing method>
The method for manufacturing an electrochemical cell of the present invention includes a step of positioning a positive electrode recess that opens on the positive electrode layer side of the solid electrolyte layer and into which the positive electrode layer is fitted, 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 is fitted, so as to be offset in the plane direction of the solid electrolyte layer.
The method for manufacturing an electrochemical cell according to this embodiment will be described in detail below with reference to the drawings.

As shown in FIG. 5, a solid electrolyte layer 10 is prepared.
To manufacture the solid electrolyte layer 10, a powder of the solid electrolyte is compacted and then fired in an electric furnace or the like to form the solid electrolyte layer 10.
The solid electrolyte powder may be the solid electrolyte powder contained in the solid electrolyte layer 10 described above.

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

6, an anode recess 15 into which the anode layer 30 fits is formed on one surface of the solid electrolyte layer 10. The method for forming the anode recess 15 is not particularly limited, and examples thereof include a method using a laser, a method using photolithography, and a method using a mold.
In the method using a mold, the solid electrolyte powder described above is filled into a mold, compacted, and fired to obtain the solid electrolyte layer 10 having the negative electrode recess 15 .
The negative electrode recess 15 may be formed in advance.

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

It is preferable to form two or more negative electrode recesses 15. Forming two or more negative electrode recesses 15 can further reduce the internal resistance of the battery 1. The number of negative electrode recesses 15 to be formed is not particularly limited, but can be set appropriately taking into consideration the ease of forming the negative electrode recesses 15 using each of the formation methods described above and the need to maintain the strength of the solid electrolyte layer 10.

The depth D15 of the negative electrode recess 15 is preferably greater than half the thickness T10 of the solid electrolyte layer 10. By making the depth D15 of the negative electrode recess 15 greater than half the thickness T10 of the solid electrolyte layer 10, the current density inside the solid electrolyte layer 10 can be increased, thereby further improving the electrical characteristics of the battery 1.

Next, as shown in FIG. 7, the negative electrode layer 30 is formed. The method for forming the negative electrode layer 30 is not particularly limited, and examples include a method in which a negative electrode slurry containing a negative electrode active material is prepared and the solid electrolyte layer 10 is dipped into the negative electrode slurry, or a method in which the negative electrode slurry is applied to the solid electrolyte layer 10 by screen printing or the like.

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

7, a positive electrode recess 11 into which the positive electrode layer 20 is inserted 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 and a method using photolithography.
The positive electrode recess 11 may be formed in advance.
By forming the positive electrode recess 11 , the portion where the positive electrode recess 11 is not formed remains as the positive electrode protrusion 12 .

The positive electrode recess 11 is positioned with a deviation 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 with a deviation from 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. This allows the electric capacity of the battery 1 to be further increased, and the battery life of the battery 1 to be further improved.
The position of the positive electrode recess 11 can be adjusted by the position of the irradiated laser, the shape of the photolithography mask, the shape of the mold, and the like.

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

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

The depth D11 of the positive electrode recess 11 is preferably greater than half the thickness T10 of the solid electrolyte layer 10. By making the depth D11 of the positive electrode recess 11 greater than half the thickness T10 of the solid electrolyte layer 10, the current density inside the solid electrolyte layer 10 can be increased, thereby further improving the electrical characteristics of the battery 1.

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.
In this case, 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 one another. By positioning the positive electrode recess 11 so that the distance D1, the distance D2, and the distance D3 are equal to one another, the uniformity of the current density inside the solid electrolyte layer 10 can be further improved.
Here, "equal" means that the ratio of the distances (D1/D2, D1/D3, etc.) is within ±5%.

Next, as shown in FIG. 10, the positive electrode layer 20 is formed. The method for forming the positive electrode layer 20 is not particularly limited, and examples include a method in which a positive electrode slurry containing a positive electrode active material is prepared and the solid electrolyte layer 10 on which the negative electrode layer 30 has been formed is dipped into the positive electrode slurry, or a method in which the positive electrode slurry is applied to the solid electrolyte layer 10 on which the negative electrode layer 30 has been formed by screen printing or the like.

After the positive electrode layer 20 is formed, 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 positive electrode layer 20 may be formed on the solid electrolyte layer 10 and then the negative electrode layer 30 may be formed.
When forming the positive electrode recess 11, the positive electrode recess 11 may be formed using a mold.
In this case, a mold in which the anode recesses 15 and the cathode recesses 11 are formed is used, and the mold is filled with solid electrolyte powder, followed by powder compaction and firing, thereby obtaining the solid electrolyte layer 10 having the anode recesses 15 and the cathode recesses 11. The anode layer 30 and the cathode layer 20 are sequentially formed on the solid electrolyte layer 10, thereby obtaining the electrode body 3A.
The order in which the negative electrode layer 30 and the positive electrode layer 20 are formed is not particularly limited, and the negative electrode layer 30 may be formed before the positive electrode layer 20, or the positive electrode layer 20 may be formed before the negative electrode layer 30.

In the electrochemical cell of the present invention, the positive electrode recesses and the negative electrode recesses are offset in the plane direction of the solid electrolyte layer, which makes it possible to uniform the internal resistance of the solid electrolyte layer and improve the uniformity of the current density, thereby further increasing the electric capacity and the battery life.
In the method for producing an electrochemical cell of the present invention, the positive electrode recesses and the negative electrode recesses are positioned so as to be offset in the planar direction of the solid electrolyte layer, thereby making it possible to uniform the internal resistance of the solid electrolyte layer and improve the uniformity of the current density, thereby further increasing the electric capacity and the battery life.

The electrochemical cell and the method for manufacturing an electrochemical cell according to the present invention have been described above, but the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the invention.
For example, as shown in FIG. 11, the electrode body 3B may have a shallower depth D13 of the positive electrode recess 13 and a shallower depth D17 of the negative electrode recess 17 than the electrode body 3A.
Because the depth D13 of the positive electrode recess 13 is shallower than the depth D11, the difference D4 between the thickness T10 of the solid electrolyte layer 10 and the depth D13 of the positive electrode recess 13 (the distance from the deepest part of the positive electrode recess 13 to the negative electrode layer 30) can be made larger than the distance D1. This makes it possible to suppress deterioration of specific portions and further extend the battery life.
Because the depth D17 of the negative electrode recess 17 is shallower than the depth D15, the difference D5 between the thickness T10 of the solid electrolyte layer 10 and the depth D17 of the negative electrode recess 17 (the distance from the deepest part of the negative electrode recess 17 to the positive electrode layer 20) can be made larger than the distance D2. This makes it possible to suppress deterioration of a specific portion and further extend the battery life.
11, the distance D4 is equal to the distance D5, which allows the current density inside the solid electrolyte layer 10 to be uniform.
Here, "equal" means that the ratio of the distances (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 convex portion 14 is the same as the depth D13 of the positive electrode concave portion 13.
The width W14 of the positive electrode convex portion 14 is the same as the width W12 of the positive electrode convex portion 12. The width W14 of the positive electrode convex portion 14 may be the same as or different from the width W12 of the positive electrode convex portion 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 convex portion 18 is the same as the depth D17 of the negative electrode concave portion 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, an electrode body 3E may have a positive electrode recess with a via formed therein and a negative electrode recess with a via formed therein.

For example, the shape of the solid electrolyte layer may be polygonal in plan view instead of circular in plan view.
For example, the electrode body may be a stack of two or more electrodes instead of one.

1... electrochemical cell, 2... outer casing, 3A, 3B, 3C, 3D, 3E... electrode assembly, 10... solid electrolyte layer, 11, 13... positive electrode recess, 12, 14... positive electrode protrusion, 15, 17... negative electrode recess, 16, 18... negative electrode protrusion, 20... positive electrode layer, 30... negative electrode layer

Claims (4)

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 plurality of positive electrode recesses that are open to the positive electrode layer side and into which a portion of the positive electrode layer is inserted;
the solid electrolyte layer has a plurality of negative electrode recesses that are open to the negative electrode layer side and into which a portion of the negative electrode layer is inserted;
a method for manufacturing an electrochemical cell, wherein the positive electrode recess and the negative electrode recess are misaligned in a plane direction of the solid electrolyte layer,
After forming an anode recess on one surface of a solid electrolyte layer, an anode layer is formed to cover the one surface of the solid electrolyte layer and fill the anode recess, and then
a positive electrode recess formed on the other surface of the solid electrolyte layer at a position offset from the negative electrode recess, and then a positive electrode layer formed to cover the other surface of the solid electrolyte layer and fill the positive electrode recess. In a plan view, the positive electrode recess and the negative electrode recess are arranged in a surface direction of the solid electrolyte layer,
The method for manufacturing an electrochemical cell according to claim 1 , wherein the electrodes are alternately positioned. 3. The method for manufacturing an electrochemical cell according to claim 1 , wherein the depth of the positive electrode recess is greater than half the thickness of the solid electrolyte layer, and the depth of the negative electrode recess is greater than half the thickness of the solid electrolyte layer. 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;
4. The method for manufacturing an 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 made equal to each other.