Battery and laminated battery

Abstract

A battery comprises a first electrode (10), a second electrode (20), and a solid electrolyte layer (30) positioned between the first electrode and the second electrode. The first electrode is provided with a first current collector (11) and a first active material layer (12) located between the first current collector and the solid electrolyte layer. The first current collector has at least one first slit (40, 440) that penetrates through the first current collector in the thickness direction and that is connected to an outer edge part of the first current collector.

Description

Technical Field

[0001] The present disclosure relates to a battery and a stacked battery.

Background Art

[0002] Patent Document 1 discloses a lithium-ion battery in which holes are provided in an inner region of a current collector plate. Further, Patent Document 2 discloses a storage battery using a metal porous body as a current collector.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a highly reliable battery and a stacked battery.

Means for Solving the Problems

[0005] A battery according to one aspect of the present disclosure includes a first electrode, a second electrode, and a solid electrolyte layer positioned between the first electrode and the second electrode. The first electrode includes a first current collector and a first active material layer positioned between the first current collector and the solid electrolyte layer. The first current collector has at least one first slit that penetrates the first current collector in a thickness direction and is connected to an outer edge portion of the first current collector.

Effects of the Invention

[0006] According to the present disclosure, a highly reliable battery and a stacked battery can be realized.

Brief Description of the Drawings

[0007]

Figure 1

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BEST MODE FOR CARRYING OUT THE INVENTION

[0008] (SUMMARY OF THE DISCLOSURE) A battery according to one aspect of the present disclosure includes a first electrode, a second electrode, and a solid electrolyte layer positioned between the first electrode and the second electrode. The first electrode includes a first current collector and a first active material layer positioned between the first current collector and the solid electrolyte layer. The first current collector has at least one first slit that penetrates the first current collector in the thickness direction and is connected to the outer edge of the first current collector.

[0009] With this configuration, delamination caused by the remaining air in the laminate constituting the battery is suppressed, and a battery that is dense and has few structural defects can be obtained. In particular, in a large-area battery or a thin-layer battery, air is likely to remain in the laminate. According to the battery according to this aspect, when the laminate is pressurized, the discharge of air from the central region to the outer edge of the laminate along the slit is promoted. As a result, structural defects are suppressed and the laminate becomes denser, so a highly reliable battery is realized.

[0010] Further, for example, the at least one first slit may be a plurality of first slits.

[0011] Thereby, the discharge of air from the inside of the laminate can be further promoted. That is, since air is more easily discharged, a battery that is dense and has few structural defects can be realized.

[0012] Further, for example, the planar shape of the first current collector may be rectangular or square. The plurality of first slits may be four first slits and may be connected to the center of each side in the plan view of the first current collector.

[0013] Thereby, the deviation of the air discharge distribution is reduced and homogenized in the plane. Also, the outer edge of the current collector to near the center can be connected by short slits. For this reason, the area of the slits in the current collector can be reduced, and the capacity of the battery can be increased.

[0014] Further, for example, the plurality of first slits may be provided point-symmetrically with respect to the center of the first current collector in a plan view.

[0015] As a result, the bias in the air discharge distribution is reduced and homogenized within the plane. For this reason, the occurrence of warping is suppressed, and a thin and large-sized battery can be realized.

[0016] Further, for example, the side wall of the at least one first slit may be inclined with respect to the thickness direction of the first current collector.

[0017] In this way, since the side wall of the slit is inclined, the contact area between the side wall and the active material layer or electrolyte component filled in the slit increases. As a result, an effect of strengthening the resistance to peeling of the current collector is obtained. For this reason, the bonding property between the current collector and the active material layer can be further strengthened while suppressing the structural defects of the battery.

[0018] Further, for example, the cross-sectional shape of the at least one first slit may be a trapezoidal shape in which the first side on the second electrode side is shorter than the second side facing the first side.

[0019] As a result, since the width of the slit is narrowed on the active material layer side of the current collector, even if the peeling stress of the current collector acts, the filling components such as the active material layer or electrolyte in the slit are caught and it becomes a structure that is difficult to come off. With such a structure, the bonding property of the current collector can be further strengthened while suppressing the structural defects.

[0020] Further, for example, the width of the at least one first slit may be wider at a portion closer to the outer edge of the first current collector than at a portion farther from the outer edge of the first current collector in a plan view.

[0021] As a result, the discharge of air from the inside of the laminate can be further promoted. That is, since air is more easily discharged, a battery that is dense and has few structural defects can be realized.

[0022] Further, for example, the at least one first slit may have a bent portion in a plan view.

[0023] Thereby, the anchor effect between the current collector and the active material layer is further enhanced. Therefore, a more reliable battery can be realized.

[0024] Further, for example, the width of the first slit may be 0.1 mm or more and 5 mm or less.

[0025] When the slit width is too large, the battery capacity decreases. By setting the width of the slit to be 0.1 mm or more and 5 mm or less, it is possible to achieve both an improvement in the reliability of the battery due to the air discharge effect and an increase in the battery capacity.

[0026] Further, for example, the first slit may extend from the outer edge portion in one direction toward the inside of the first current collector. The length of the first slit in the one direction may be 6% or more of the length of the first current collector in the one direction.

[0027] Thereby, it is possible to discharge the air that may remain in a portion relatively close to the outer edge portion, and a highly reliable battery can be realized.

[0028] Further, for example, the length of the first slit in the one direction may be less than 50% of the length of the first current collector in the one direction.

[0029] Thereby, it is possible to effectively discharge the air from the center of the laminate, and a highly reliable battery can be realized.

[0030] Further, for example, the area of the first active material layer in a plan view may be smaller than that of the first current collector. The first current collector may have a first region in contact with the first active material layer and a second region in contact with the solid electrolyte layer.

[0031] As a result, when the laminate is pressed, after air is discharged from the slit provided in the second region, the solid electrolyte can easily enter and fill the inside of the slit due to its softness. Therefore, a reliable and strong anchor effect can be obtained.

[0032] Further, for example, at least one of the first slits may be provided in the second region and may not be provided in the first region.

[0033] For example, by providing a soft solid electrolyte in the second region, the solid electrolyte can be deformed and easily filled into the slit when the laminate is pressed. As a result, a strong anchor effect can be obtained only in the second region. Therefore, without affecting the power generation element, it is possible to suppress defects and increase the density of a large-sized thin battery.

[0034] Further, for example, the first slit may be filled with a material contained in a layer of the first current collector that contacts the surface on the second electrode side. Further, for example, the layer may be the first active material layer or the solid electrolyte layer.

[0035] As a result, when the laminate is pressed, the slit bites into the layer in contact with the slit, such as the active material layer or the solid electrolyte layer. As a result, an anchor effect is obtained, so that the bonding interface strength between the current collector and the layer is improved, and a battery with high cycle characteristics and reliability can be realized.

[0036] Further, for example, the second electrode may include a second current collector and a second active material layer positioned between the second current collector and the solid electrolyte layer. The second current collector may have at least one second slit that penetrates the second current collector in the thickness direction and is connected to the outer edge of the second current collector.

[0037] As a result, it is possible to easily discharge air from both sides in the stacking direction of the laminate. Therefore, since air can be discharged more easily, a battery with a dense structure and few structural defects can be realized.

[0038] Further, for example, a stacked battery according to one aspect of the present disclosure includes a first battery and a second battery, each of which is a battery according to any one of claims 1 to 16. The first battery is laminated on a surface of the first current collector of the second battery, which is opposite to the first active material layer.

[0039] Thereby, a battery with a large capacity, or a high energy density, and high reliability can be realized.

[0040] Further, for example, the first current collector of the first battery and the first current collector of the second battery may be current collectors with different polarities from each other. The first battery and the second battery may be laminated such that the first current collectors of each other are in contact with each other. At least one of the at least one first slit of the first battery may not overlap with any of the at least one first slit of the second battery in a plan view.

[0041] Thereby, by arranging the slits of the current collectors to be connected so as not to overlap, for example, the joined and overlapped current collectors can be configured as a bipolar electrode. That is, the batteries can be connected in series. For example, by laminating large-sized and thin batteries, a high voltage can be supported, and a high-energy and large-capacity battery can be realized.

[0042] Further, for example, the first current collector of the first battery and the first current collector of the second battery may be current collectors with the same polarity from each other. The first battery and the second battery may be laminated such that the first current collectors of each other are in contact with each other. At least a part of at least one of the at least one first slit of the first battery may overlap with at least one of the at least one first slit of the second battery in a plan view.

[0043] As a result, the filling components in the slits of the active material layers or solid electrolytes of the upper and lower batteries are likely to be joined through the mutual slits. Thereby, a battery having an integrated structure and high reliability can be realized. For example, by configuring batteries connected in parallel, a high-reliability large-capacity battery can be realized.

[0044] As described above, in each aspect, since the peeling of the layers constituting the laminate and the structural defects caused by the remaining air are suppressed, a highly reliable battery can be realized.

[0045] Hereinafter, embodiments will be specifically described with reference to the drawings.

[0046] Note that each of the embodiments described below shows comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions of components, connection forms, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0047] Also, each figure is a schematic diagram and is not necessarily drawn precisely. Therefore, for example, the scales in each figure do not necessarily match. Also, in each figure, substantially the same configuration is denoted by the same reference numeral, and overlapping descriptions are omitted or simplified.

[0048] In the present specification and the drawings, the x-axis, y-axis, and z-axis indicate the three axes of a three-dimensional orthogonal coordinate system. In each embodiment, the z-axis direction is the thickness direction of the battery. In the present specification, the "thickness direction" means the direction perpendicular to the surface on which the layers are laminated.

[0049] In the present specification, "plan view" means the case of viewing the battery along the stacking direction of the battery, and "thickness" in the present specification is the length in the stacking direction of the battery and each layer.

[0050] In the present specification, "inner" and "outer" in "inner side" and "outer side" etc. refer to the inner and outer sides when the battery is viewed along the stacking direction of the battery.

[0051] In the present specification, the terms "upper" and "lower" in the battery configuration do not refer to the upward direction (vertically upward) and downward direction (vertically downward) in the absolute spatial recognition, but are used as terms defined by the relative positional relationship based on the stacking order in the stacked configuration. Further, the terms "above" and "below" are applicable not only when two components are arranged at intervals and another component exists between the two components, but also when the two components are arranged in close contact and the two components are in contact.

[0052] (Embodiment 1) [Overview of the battery] First, the battery according to Embodiment 1 will be described with reference to FIG. 1.

[0053] FIG. 1 is a cross-sectional view and a plan view showing the schematic configuration of the battery 1 according to the present embodiment. Specifically, FIG. 1(a) is a cross-sectional view of the battery 1. FIG. 1(b) is a plan view of the battery 1 viewed from the positive side of the z-axis. In FIG. 1(a), a cross-section at the position indicated by the line Ia-Ia in FIG. 1(b) is shown. In FIG. 1(b), in order to clearly show the shape of the slit 40, the slit 40 is hatched with oblique lines. This is the same for other plan views described later.

[0054] As shown in FIG. 1, the battery 1 includes a first electrode 10, a second electrode 20, and a solid electrolyte layer 30 positioned between the first electrode 10 and the second electrode 20. The battery 1 is an all-solid-state battery.

[0055] The first electrode 10 includes a first current collector 11 and a first active material layer 12. The first active material layer 12 is an example of a first electrode layer positioned between the first current collector 11 and the solid electrolyte layer 30. The first active material layer 12 is in contact with the surface of the first current collector 11 on the solid electrolyte layer 30 side.

[0056] The second electrode 20 is the counter electrode with respect to the first electrode 10. The second electrode 20 includes a second current collector 21 and a second active material layer 22. The second active material layer 22 is an example of a second electrode layer positioned between the second current collector 21 and the solid electrolyte layer 30. The second active material layer 22 is in contact with the surface of the second current collector 21 on the solid electrolyte layer 30 side.

[0057] The solid electrolyte layer 30 is an example of an electrolyte layer positioned between the first electrode 10 and the second electrode 20.

[0058] Hereinafter, the details of each layer constituting the battery 1 will be described.

[0059] In the battery 1 according to the present embodiment, the first electrode 10 is the positive electrode and the second electrode 20 is the negative electrode. That is, the first current collector 11 is the positive electrode current collector, and the first active material layer 12 contains the positive electrode active material. The second current collector 21 is the negative electrode current collector, and the second active material layer 22 contains the negative electrode active material.

[0060] Note that the first electrode 10 may be the negative electrode and the second electrode 20 may be the positive electrode. That is, the first current collector 11 may be the negative electrode current collector, and the first active material layer 12 may contain the negative electrode active material. The second current collector 21 may be the positive electrode current collector, and the second active material layer 22 may contain the positive electrode active material.

[0061] The first current collector 11, the first active material layer 12, the solid electrolyte layer 30, the second active material layer 22, and the second current collector 21 each have a rectangular shape in plan view. The plan view shapes of the first current collector 11, the first active material layer 12, the solid electrolyte layer 30, the second active material layer 22, and the second current collector 21 are not particularly limited, and may be square, or may be a shape other than a rectangle such as a circle, an ellipse, or a polygon.

[0062] In addition, in the present embodiment, the first current collector 11, the first active material layer 12, the solid electrolyte layer 30, the second active material layer 22, and the second current collector 21 are the same size as each other, and their respective outlines coincide in plan view, but it is not limited thereto. For example, the first active material layer 12 may be smaller than the second active material layer 22. The first active material layer 12 and the second active material layer 22 may be smaller than the solid electrolyte layer 30.

[0063] In this specification, when the first current collector 11 and the second current collector 21 are not particularly distinguished, they may be collectively referred to simply as the "current collector". The current collector may be formed of a conductive material and is not particularly limited.

[0064] The current collector is, for example, a foil-like body, a plate-like body, or a mesh-like body made of stainless steel, nickel (Ni), aluminum (Al), iron (Fe), titanium (Ti), copper (Cu), palladium (Pd), gold (Au), or platinum (Pt), or an alloy of two or more of these. The material of the current collector is appropriately selected in consideration of not melting and decomposing during the manufacturing process, the use temperature, and the use pressure, as well as the operating potential and conductivity of the battery applied to the current collector. In addition, the material of the current collector can also be selected according to the required tensile strength and heat resistance. The current collector may be, for example, a high-strength electrolytic copper foil or a clad material in which dissimilar metal foils are laminated.

[0065] The thickness of the current collector is, for example, in the range of 10 μm or more and 100 μm or less. Note that the surface of the current collector may be processed into a rough surface with irregularities from the viewpoint of enhancing the adhesion to the first active material layer 12 or the second active material layer 22. In addition, an adhesive component such as an organic binder may be applied to the surface of the current collector. Thereby, the bonding property at the interface between the current collector and other layers is strengthened, and the mechanical and thermal reliability of the battery 1, as well as the cycle characteristics and the like, can be improved.

[0066] As shown in FIGS. 1(a) and 1(b), at least one slit 40 is provided in the first current collector 11. The second current collector 21 is not provided with a slit. The specific structure of the slit 40 and the effects of providing the slit 40 will be described later.

[0067] The first active material layer 12 is located between the first current collector 11 and the solid electrolyte layer 30. Specifically, the first active material layer 12 is disposed in contact with the main surface of the first current collector 11 on the side of the solid electrolyte layer 30. In the present embodiment, the first active material layer 12 covers the entire main surface of the first current collector 11. The first active material layer 12 contains at least a positive electrode active material. That is, the first active material layer 12 is a layer mainly containing a positive electrode material such as a positive electrode active material.

[0068] The positive electrode active material is a substance in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted or removed in the crystal structure at a potential higher than that of the negative electrode, and oxidation or reduction is performed accordingly. The type of the positive electrode active material can be appropriately selected according to the type of the battery 1, and a known positive electrode active material can be used.

[0069] Compounds containing lithium and transition metal elements are used as the positive electrode active material. For example, oxides containing lithium and transition metal elements, and phosphate compounds containing lithium and transition metal elements are used. Examples of the oxides containing lithium and transition metal elements include, for example, LiNi x M 1-x O 2 (where M is at least one element among Co, Al, Mn, V, Cr, Mg, Ca, Ti, Zr, Nb, Mo, and W, and x satisfies 0 < x ≦ 1) and other lithium nickel composite oxides, lithium cobaltate (LiCoO 2 ), lithium nickelate (LiNiO 2 ), layered oxides such as lithium manganate (LiMn 2 O 4 ), or lithium manganate having a spinel structure (LiMn 2 O 4 , Li 2 MnO3 , LiMnO 2 ) etc. are used. As the phosphate compound containing lithium and transition metal elements, for example, lithium iron phosphate (LiFePO 4 ) etc. are used. Further, as the positive electrode active material, sulfides such as sulfur (S) and lithium sulfide (Li 2 S) etc. can also be used. In that case, lithium niobate (LiNbO 3 ) etc. can be used as the positive electrode active material particles by coating or adding. Note that only one of these materials may be used as the positive electrode active material, or two or more of these materials may be combined and used.

[0070] As described above, the first active material layer 12 which is the positive electrode active material layer only needs to contain at least the positive electrode active material. The first active material layer 12 may be a composite layer composed of a composite of the positive electrode active material and other additive materials. As other additive materials, for example, solid electrolytes such as inorganic solid electrolytes or sulfide solid electrolytes, conductive aids such as acetylene black, and binders for binding such as polyethylene oxide or polyvinylidene fluoride can be used. By mixing the positive electrode active material and other additive materials such as the solid electrolyte at a predetermined ratio in the first active material layer 12, the lithium ion conductivity in the first active material layer 12 can be improved, and the electron conductivity can also be improved.

[0071] The thickness of the first active material layer 12 is, for example, in the range of 5 μm or more and 300 μm or less, but is not limited thereto.

[0072] The second active material layer 22 is located between the second current collector 21 and the solid electrolyte layer 30. Specifically, the second active material layer 22 is disposed in contact with the main surface of the second current collector 21 on the solid electrolyte layer 30 side. In the present embodiment, the second active material layer 22 covers the entire main surface of the second current collector 21. The second active material layer 22 contains at least the negative electrode active material. That is, the second active material layer 22 is a layer mainly containing a negative electrode material such as the negative electrode active material.

[0073] The negative electrode active material is a substance in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted into or detached from the crystal structure at a potential lower than that of the positive electrode, and oxidation or reduction is performed accordingly. The type of the negative electrode active material can be appropriately selected according to the type of the battery 1, and known negative electrode active materials can be used.

[0074] As the negative electrode active material, for example, carbon materials such as natural graphite, artificial graphite, graphite carbon fiber or resin-fired carbon, and alloy-based materials compounded with a solid electrolyte can be used. Examples of the alloy-based materials include LiAl, LiZn, Li 3 Bi, Li 3 Cd, Li 3 Sb, Li 4 Si, Li 4.4 Pb, Li 4.4 Sn, Li 0.17 C or LiC 6 and other lithium alloys, lithium oxides with transition metal elements such as lithium titanate (Li 4 Ti 5 O 12 ), metal oxides such as zinc oxide (ZnO) or silicon oxide (SiO x ) can be used. Note that only one of these materials may be used as the negative electrode active material, or two or more of these materials may be combined and used.

[0075] As described above, the second active material layer 22, which is the negative electrode active material layer, only needs to contain at least the negative electrode active material. The second active material layer 22 may be a composite layer composed of a composite of the negative electrode active material and other additive materials. As the other additive materials, for example, solid electrolytes such as inorganic solid electrolytes or sulfide solid electrolytes, conductive aids such as acetylene black, and binders for binding such as polyethylene oxide or polyvinylidene fluoride can be used. By mixing the negative electrode active material and other additive materials such as a solid electrolyte at a predetermined ratio in the second active material layer 22, the lithium ion conductivity in the second active material layer 22 can be improved, and the electron conductivity can also be improved.

[0076] The thickness of the second active material layer 22 is, for example, in the range of 5 μm or more and 300 μm or less, but is not limited thereto.

[0077] The solid electrolyte layer 30 is disposed between the first active material layer 12 and the second active material layer 22 and is in contact with each of them. The solid electrolyte layer 30 contains at least a solid electrolyte. The solid electrolyte layer 30 contains, for example, a solid electrolyte as a main component.

[0078] The solid electrolyte may be any known solid electrolyte for a battery having ion conductivity. As the solid electrolyte, for example, a solid electrolyte that conducts metal ions such as lithium ions and magnesium ions can be used. The type of the solid electrolyte may be appropriately selected according to the type of conductive ions.

[0079] As the solid electrolyte, for example, an inorganic solid electrolyte such as a sulfide-based solid electrolyte or an oxide-based solid electrolyte can be used. As the sulfide-based solid electrolyte, for example, Li 2 S-P 2 S 5 system, Li 2 S-SiS 2 system, Li 2 S-B 2 S 3 system, Li 2 S-GeS 2 system, Li 2 S-SiS 2 -LiI system, Li 2 S-SiS 2 -Li 3 PO 4 system, Li 2 S-Ge 2 S 2 system, Li 2 S-GeS 2 -P 2 S 5 system, or Li 2 S-GeS 2 -ZnS system and other lithium-containing sulfides can be used. As the oxide-based solid electrolyte, for example, Li 2 O-SiO 2 or Li 2 O-SiO 2 -P 2 O5 Lithium-containing metal oxides such as x P y O 1-z N z Lithium-containing metal nitrides such as, lithium phosphate (Li 3 PO 4 ), and lithium-containing transition metal oxides such as lithium titanate oxide can be used. As the solid electrolyte, only one of these materials may be used, or two or more of these materials may be combined and used. In the present embodiment, the solid electrolyte layer 30 includes, as an example, a solid electrolyte having lithium ion conductivity.

[0080] In addition to the above solid electrolyte materials, the solid electrolyte layer 30 may include a binder for binding such as polyethylene oxide or polyvinylidene fluoride.

[0081] The thickness of the solid electrolyte layer 30 is, for example, in the range of 5 μm or more and 150 μm or less, but is not limited thereto.

[0082] Note that the solid electrolyte layer 30 may be configured as an aggregate of solid electrolyte particles. Further, the solid electrolyte layer 30 may be configured with a sintered structure of the solid electrolyte.

[0083] [Slit] Next, details of the slit 40 provided in the first current collector 11 will be described.

[0084] As shown in FIGS. 1(a) and 1(b), at least one slit 40 is provided in the first current collector 11. At least one slit 40 is an example of a first slit that penetrates the first current collector 11 in the thickness direction and is connected to the outer edge portion of the first current collector 11. The slit 40 extends from the outer edge portion of the first current collector 11 in one direction inside the first current collector 11. Specifically, the slit 40 is formed by cutting out the first current collector 11 from the outer edge portion to the inside. The outer edge portion is a part of the contour of the first current collector 11 in a plan view.

[0085] The slit 40 is filled with the material contained in the layer that contacts the surface of the first current collector 11 on the side of the second electrode 20. In other words, the slit 40 bites into the layer that contacts the surface on the side of the second electrode 20. In the present embodiment, since the layer that contacts the surface on the side of the second electrode 20 is the first active material layer 12, as shown in FIG. 1(a), a part of the first active material layer 12 is filled. A part of the first active material layer 12 completely fills the slit 40, for example. Alternatively, a part of the first active material layer 12 may be provided only in a part of the slit 40. That is, voids where a part of the first active material layer 12 does not exist may remain in the slit 40.

[0086] In the present embodiment, the first current collector 11 has a plurality of slits 40. Specifically, as shown in FIG. 1(b), the first current collector 11 has four slits 40a, 40b, 40c, and 40d. The four slits 40a, 40b, 40c, and 40d are connected to the center of each side of the first current collector 11 in a plan view. Specifically, the four slits 40a, 40b, 40c, and 40d are linearly formed from the midpoint of each of the four sides of the first current collector 11 toward the center of the first current collector 11.

[0087] The slits 40a and 40b are connected to the short sides of the first current collector 11. The slits 40a and 40b have an elongated shape extending in a direction orthogonal to the short side of the first current collector 11, that is, in a direction parallel to the long side (x-axis direction), from the center of the short side of the first current collector 11. The slit 40a and the slit 40b are provided on the same straight line extending in the x-axis direction. The slit 40a and the slit 40b have, for example, the same width w1 and the same length d1. Note that the width of the slit is the length in the short side direction of the slit. The length of the slit is the length in the long side direction of the slit.

[0088] Slits 40c and 40d are connected to the long sides of the first current collector 11. The slits 40c and 40d have an elongated shape extending in a direction orthogonal to the long side of the first current collector 11, that is, in a direction parallel to the short side (y-axis direction). The slit 40c and the slit 40d are provided on the same straight line extending in the y-axis direction. The slit 40c and the slit 40d have, for example, the same width w2 and the same length d2. The width w2 is, for example, equal to the width w1. Alternatively, the width w2 may be shorter or longer than the width w1. Also, the length d2 is, for example, shorter than the length d1. Alternatively, the length d2 may be equal to the length d1 or longer than the length d1.

[0089] In this specification, when the four slits 40a, 40b, 40c, and 40d are not particularly distinguished, they will be described as "slit 40".

[0090] The width, length, and height of the slit 40 are each set so that delamination does not occur in the laminate when the battery 1 is laminated. For example, assume that the battery 1 is rectangular with 150 mm × 100 mm and has a thickness of about 200 μm. In this case, as the first current collector 11, for example, a Cu current collector that is rectangular with 150 mm × 100 mm and has a thickness of about 15 μm can be used. At this time, the widths w1 and w2 of the slit 40 are, for example, about 100 μm. The slits 40a and 40b extend in a direction from the midpoint of the short side of the first current collector 11 toward the center of the first current collector 11. The length d1 of each of the slits 40a and 40b is, for example, about 33% of the length L1 of the long side of the first current collector 11, specifically 50 mm. The slits 40c and 40d extend in a direction from the midpoint of the long side of the first current collector 11 toward the center of the first current collector 11. The length d2 of each of the slits 40c and 40d is, for example, about 30% of the length L2 of the short side of the first current collector 11, specifically 30 mm. The slits 40a, 40b, 40c, and 40d are provided point-symmetrically with respect to the center of the first current collector 11.

[0091] In the case of a thin-layer laminate with a thickness of 100 μm, air may remain and cannot be discharged even in a region that is approximately 6% inside (with respect to the distance from the opposing side) relatively close to the outer edge. Therefore, for example, the lengths d1 of the slits 40a and 40b are set to be 6% or more of the length L1 of the long side of the first current collector 11. Also, the lengths d2 of the slits 40c and 40d are set to be 6% or more of the length L2 of the short side of the first current collector 11. Thereby, delamination of the laminate can be suppressed, and the occurrence of structural defects can be suppressed. Depending on the air retention position, by providing the slits 40 with a length of 6% or more for each side, a highly reliable battery 1 can be realized.

[0092] The lengths d1 of the slits 40a and 40b are, for example, less than 50% of the length L1 of the long side of the first current collector 11. That is, the slits 40a and 40b are not connected to each other. The lengths d2 of the slits 40c and 40d are, for example, less than 50% of the length L2 of the short side of the first current collector 11. That is, the slits 40c and 40d are not connected to each other. Since no slits 40 are provided near the center of the battery 1, a power generation region can be surely secured. Note that the slits 40 may reach the center of the first current collector 11 and divide the first current collector 11 with the slits 40. Such slits 40 may be provided as long as there are no problems in manufacturing and in the characteristics of the battery 1.

[0093] Also, the widths w1 and w2 of the slits 40 are, for example, 0.1 mm or more and 5 mm or less. The larger the widths w1 and w2 of the slits 40 are, the easier it is for air to be discharged, which is effective for suppressing delamination. Also, even when the slits 40 are sufficiently narrow as if the first current collector 11 was cut with a cutter blade or the like, an air discharge effect can be obtained as compared with the case without cutting.

[0094] The slit 40 is formed, for example, by notching a part of the first current collector 11 after laminating the first current collector 11, the first active material layer 12, the solid electrolyte layer 30, the second active material layer 22, and the second current collector 21 in this order. Alternatively, the first current collector 11 with the slit 40 formed in advance may be used for lamination. By applying pressure in the thickness direction to the laminate including the first current collector 11 provided with the slit 40, the air in the laminate is discharged.

[0095] FIG. 2 is a cross-sectional view showing a first example of the schematic configuration of the cross-section of the slit 40 provided in the first current collector 11 of the battery 1 according to the present embodiment. Specifically, FIG. 2 shows a cross-section orthogonal to the longitudinal direction of the slit 40. The same applies to FIGS. 3 to 5 described later.

[0096] As shown in FIG. 2, a part of the first active material layer 12 in contact with the first current collector 11 is filled in the slit 40. That is, the side walls 41 and 42 of the slit 40 are in contact with the first active material layer 12, respectively. Therefore, the step of the first current collector 11 due to the slit 40 is reduced by filling a part of the first active material layer 12. In the present embodiment, a state where the inside of the slit 40 is completely filled is schematically shown, but even if it is partially filled, an anchor effect can be obtained due to the effect of bonding a part of the first active material layer 12 to the side walls 41 and 42 of the slit 40. For this reason, compared with the state where the slit 40 is not filled, the effect of suppressing the peeling of the first current collector 11 is further improved.

[0097] In addition to the slit 40 provided from the outer edge portion of the first current collector 11, in order to further improve the anchor effect for preventing the peeling of the first current collector 11, an appropriate number of holes of an arbitrary shape may be provided in the first current collector 11 within a range that does not adversely affect the battery characteristics.

[0098] Hereinafter, the operation of the slit 40 formed in the first current collector 11 will be described in more detail.

[0099] By providing the first current collector 11 with the slit 40 connected to the outer edge portion, air can be more effectively discharged to the outside of the laminate during the compression process of the laminate than in the case where the slit 40 is not provided and in the case where holes or grooves not connected to the outer edge portion are provided. Further, the anchoring action at the joint portion with the first active material layer 12 filled inside the slit 40 can enhance the fixing property of the first current collector 11.

[0100] For example, in the case of holes or grooves not communicating with the outer edge portion, the main surface of the first current collector 11 is blocked by the press mold during compression. Therefore, these holes or grooves no longer function as air discharge paths. For this reason, as the laminate is made larger, thinner, or denser, the air that could not be discharged from the laminate remains, forming voids or delamination, making it difficult to obtain a defect-free high-density laminate. On the other hand, according to the battery 1 according to the present embodiment, since the slit 40 is connected to the outer edge portion of the first current collector 11, air is easily discharged. Therefore, a battery 1 that is dense, has few structural defects, and has high reliability can be realized.

[0101] Further, according to the battery 1 according to the present embodiment, since it has excellent air dischargeability, the effect that the pressure of the lamination and pressurization process can be increased and the pressure holding can be performed in a short time can also be obtained. Therefore, not only the high reliability and high performance of the battery 1 are improved, but also the productivity is improved. Therefore, the industrial utility value is extremely large.

[0102] Also, when laminated by heating, residual solvents and binder components may vaporize from the solid electrolyte layer 30, the first active material layer 12, and the second active material layer 22, which may cause structural defects. The slit 40 is also effective for discharging this vaporized gas.

[0103] Furthermore, since a part of the first active material layer 12 in contact with the first current collector 11 is filled in the slit 40, a stronger anchor effect can be generated by the joining of the side walls 41 and 42 of the slit 40 and the filling component. Such an improvement in the adhesiveness of the first current collector 11 is effective in improving the repetition of charge and discharge characteristics and the reliability against thermal cycling.

[0104] According to the above configuration, even if the current collecting surface is blocked by the pressing head during compression, the air discharge is effectively promoted by the slit 40 provided so as to be cut out from the outer edge portion of the first current collector 11. As a result, not only the suppression of structural defects such as delamination caused by air, but also the reduction of voids and the obtaining of a dense laminate are achieved. Due to this effect, the large-sized and thin battery 1 can be realized.

[0105] When comparing the configuration of the battery 1 according to the present embodiment with the configurations of the batteries described in Patent Document 1 and Patent Document 2, there are the following differences.

[0106] Patent Document 1 describes a lithium ion battery in which a plurality of holes are provided in the inner region of the current collector. However, no holes are provided in the outer peripheral region, and no holes communicating with the outer peripheral portion are provided. Therefore, when the batteries are stacked and pressed, the holes provided on the pressing surface are blocked, and there is a problem that air easily remains in the stack.

[0107] On the other hand, Patent Document 2 discloses a storage battery using a porous metal film as a current collector. Also in the storage battery disclosed in Patent Document 2, similar to Patent Document 1, no holes connected to the outer edge portion of the current collector are provided. In addition, the electrolyte of the storage battery according to Patent Document 2 uses a liquid, which is different from the configuration for suppressing defects in the solid structure in all-solid-state batteries.

[0108] In contrast, according to the battery 1 according to the present embodiment, the above-described problems are suppressed. Further, Patent Document 1 and Patent Document 2 do not disclose or suggest the battery 1 including the slit 40 connected to the outer edge portion of the first current collector 11 described in the present embodiment.

[0109] [Modification Example] Subsequently, a modification example of the cross-sectional shape of the slit 40 will be described with reference to FIGS. 3 to 5. First, Modification Example 1 will be described with reference to FIG. 3.

[0110] FIG. 3 is a cross-sectional view showing Modification Example 1 of the schematic configuration of the cross-section of the slit provided in the first current collector 11 of the battery 1 according to the present embodiment. The first current collector 11 may be provided with a slit 140 shown in FIG. 3.

[0111] The side walls 141 and 142 of the slit 140 are inclined with respect to the thickness direction of the first current collector 11. As shown in FIG. 3, the side walls 141 and 142 are parallel. That is, the distance between the side walls 141 and 142, that is, the width of the slit 140 is constant.

[0112] Thereby, due to the inclination of the side walls 141 and 142, the contact area with the components of the active material layer filled in the slit 140 can be increased. Thereby, the bonding property between the first current collector 11 and the first active material layer 12 can be further strengthened.

[0113] When a plurality of slits 140 are provided in the first current collector 11, the side walls of each of the plurality of slits 140 may be inclined at different angles from each other. The cross-sectional shape of the slit 140 and the state in which a part of the first active material layer 12 is filled can be confirmed, for example, simply by observing the cross-section obtained by cutting the first current collector 11 with a cutter or the cross-section created by means such as ion milling with a microscope.

[0114] Next, Modification 2 will be described with reference to FIG. 4. FIG. 4 is a cross-sectional view showing Modification 2 of the schematic configuration of the cross-section of the slit provided in the first current collector 11 of the battery 1 in the present embodiment. The first current collector 11 may be provided with a slit 240 shown in FIG. 4.

[0115] The side walls 241 and 242 of the slit 240 are inclined with respect to the thickness direction of the first current collector 11. The side walls 241 and 242 are separated from each other on the side of the first current collector 11 closer to the second electrode 20, and approach each other on the opposite side. That is, the cross-sectional shape of the slit 240 is a trapezoidal shape in which the first side on the side of the second electrode 20 is longer than the second side facing the first side. That is, the width of the slit 240 gradually narrows in the direction away from the second electrode 20 in the thickness direction of the first current collector 11.

[0116] Thereby, due to the inclination of the side walls 241 and 242, the contact area with the components of the active material layer filled in the slit 240 can be increased. Thereby, the bonding property between the first current collector 11 and the first active material layer 12 can be further strengthened.

[0117] Next, Modification 3 will be described with reference to FIG. 5. FIG. 5 is a cross-sectional view showing Modification 3 of the schematic configuration of the cross-section of the slit provided in the first current collector 11 of the battery 1 according to the present embodiment. The first current collector 11 may be provided with a slit 340 shown in FIG. 5.

[0118] The side walls 341 and 342 of the slit 340 are inclined with respect to the thickness direction of the first current collector 11. The side walls 341 and 342 approach each other on the side of the first current collector 11 closer to the second electrode 20, and are separated from each other on the opposite side. That is, the cross-sectional shape of the slit 340 is a trapezoidal shape in which the first side on the side of the second electrode 20 is shorter than the second side facing the first side. That is, the width of the slit 340 gradually widens in the direction away from the second electrode 20 in the thickness direction of the first current collector 11.

[0119] As a result, when the component of the first active material layer 12 is filled in the slit 340, even when a peeling stress acts on the first current collector 11, the filled component in the slit 340 is caught. For this reason, the peeling of the first current collector 11 is less likely to occur, and the suppression of structural defects and the bonding property of the first current collector 11 can be further enhanced.

[0120] Also, the plurality of slits 40, 140, 240, or 340 are provided point-symmetrically from the center of the first current collector 11. Thereby, a more uniform laminate can be obtained, and a warpage reduction effect can also be obtained.

[0121] (Embodiment 2) Hereinafter, Embodiment 2 will be described. In Embodiment 2, the main difference from Embodiment 1 is that slits are also provided in the second current collector. In the following description of Embodiment 2, the description will focus on the differences from Embodiment 1, and the description of the common points will be omitted or simplified.

[0122] FIG. 6 is a cross-sectional view and a plan view showing a schematic configuration of a battery 401 according to Embodiment 2. Specifically, FIG. 6(a) is a cross-sectional view of the battery 401. FIG. 6(b) is a plan view of the battery 401 as viewed from the positive side of the z-axis through the first electrode 10, the solid electrolyte layer 30, and the second active material layer 22. That is, FIG. 6(b) is a plan view showing the second current collector 421 as viewed from the positive side of the z-axis. FIG. 6(a) shows a cross-section at the position indicated by the line VIa-VIa in FIG. 6(b).

[0123] As shown in FIG. 6, the battery 401 according to the present embodiment includes a second electrode 420 instead of the second electrode 20 as compared with the battery 1 according to Embodiment 1. The second electrode 420 includes a second current collector 421 and a second active material layer 22. The second active material layer 22 includes differences such as different shapes, but is substantially the same as that in Embodiment 1, and thus the description thereof is omitted.

[0124] The second current collector 421 is provided with at least one slit 440. At least one slit 440 is an example of a second slit that penetrates the second current collector 421 in the thickness direction and is connected to the outer edge portion of the second current collector 421.

[0125] The slit 440 provided in the second current collector 421 is the same as the slit 40 provided in the first current collector 11. Specifically, the configurations applied to the slits 40, 140, 240, or 340 are also applicable to the slit 440. For example, the second current collector 421 has four slits 440 arranged point-symmetrically. The positions and shapes of the four slits 40 and the four slits 440 may be the same in a plan view. Note that at least one of the number, position, and shape of the slits may be different between the slit 40 provided in the first current collector 11 and the slit 440 provided in the second current collector 421. Thereby, the compression states of the first active material layer 12, the second active material layer 22, and the solid electrolyte layer 30 included in the laminate can be changed. For this reason, for the purpose of suppressing not only structural defects but also warping of the battery 401, the shapes and arrangements of the slits 40 and 440 may be appropriately set.

[0126] Also, the cross-sectional shape of the slit 440 may be the same as the cross-sectional shapes of the slits 40, 140, 240, or 340 shown in FIGS. 2 to 5. At this time, the inclination of the side walls may be different between the slits 40, 140, 240, or 340 provided in the first current collector 11 and the slit 440 provided in the second current collector 421. By providing a plurality of slits with different side wall inclinations, the durability against peeling stress in different directions can be enhanced.

[0127] As described above, in the battery 401 according to the present embodiment, the slits 40 and 440 provided in both of the two current collectors can make it easier to discharge air more. Further, by the action of the anchor effect of the members filled in each of the slits 40 and 440, the occurrence of structural defects and warping can be suppressed even in a thinner battery.

[0128] (Embodiment 3) Hereinafter, Embodiment 3 will be described. In Embodiment 3, compared with Embodiment 1, the planar shape of the slit provided in the first current collector is mainly different. In the following description of Embodiment 3, the description will focus on the differences from Embodiment 1, and the description of the common points will be omitted or simplified.

[0129] FIG. 7 is a cross-sectional view and a plan view showing a schematic configuration of a battery 501 according to Embodiment 3. Specifically, FIG. 7(a) is a cross-sectional view of the battery 501. FIG. 7(b) is a plan view of the battery 501 as viewed from the positive side of the z-axis. In FIG. 7(a), a cross-section at the position indicated by the VIIa-VIIa line in FIG. 7(b) is shown.

[0130] As shown in FIG. 7, the battery 501 according to the present embodiment is different from the battery 1 according to Embodiment 1 in that the first current collector 11 has a slit 540 instead of the slit 40. In a plan view, the slit 540 is wider at a portion closer to the outer edge than at a portion farther from the outer edge of the first current collector 11. That is, the slit 540 is wider on the outer edge side. Both the minimum value and the maximum value of the width of the slit 540 are in the range of 0.1 mm or more and 5 mm or less. The planar shape of the slit 540 is a trapezoid that is long in the height direction. That is, the degree of widening of the width of the slit 540 is constant regardless of the distance from the outer edge. Alternatively, the slit 540 may widen to a greater extent as it approaches the outer edge.

[0131] As described above, in the battery 501 according to the present embodiment, the width of the slit can be increased as it approaches the outer edge, so that the discharge of air can be further promoted.

[0132] Note that only one of the plurality of slits provided in the first current collector 11 is the slit 540, and the remaining slits may be the slits 40. Slits having the same shape as the slit 540 according to the present embodiment may be provided in the second current collector 21 as in the second embodiment. At this time, the opening degree of the width may be different between the slit 540 provided in the first current collector 11 and the slit provided in the second current collector 21.

[0133] (Embodiment 4) Hereinafter, Embodiment 4 will be described. In Embodiment 4, compared with Embodiment 1, the planar shape of the slit provided in the first current collector is mainly different. In the following description of Embodiment 4, the differences from Embodiment 1 will be mainly described, and the description of the common points will be omitted or simplified.

[0134] FIG. 8 is a cross-sectional view and a plan view showing a schematic configuration of a battery 601 according to Embodiment 4. Specifically, FIG. 8(a) is a cross-sectional view of the battery 601. FIG. 8(b) is a plan view of the battery 501 as viewed from the positive side of the z-axis. In FIG. 8(a), a cross-section at the position indicated by the line VIIIa-VIIIa in FIG. 8(b) is shown.

[0135] As shown in FIG. 8, the battery 601 according to the present embodiment is different from the battery 1 according to Embodiment 1 in that the first current collector 11 has a slit 640 instead of the slit 40. The slit 640 has a bent portion 641 in a plan view. The slit 640 extends from the outer edge portion of the first current collector 11 in the first direction, and extends in a second direction different from the first direction with the bent portion 641 as a boundary. That is, the slit 640 has a broken line shape bent in the middle. The angle formed by the first direction and the second direction is, for example, an obtuse angle greater than 90°, but is not limited thereto. The first direction and the second direction may be orthogonal to each other. The bent portion 641 is provided at a position closer to the end on the center side of the first current collector 11 than the end on the outer edge portion side of the first current collector 11 in the extending direction of the slit 640. Alternatively, the bent portion 641 may be located at the center of the slit 640 or on the outer edge portion side of the first current collector 11 with respect to the center.

[0136] As described above, according to the battery 601 according to the present embodiment, for example, when peeling occurs from the outer edge portion of the first current collector 11 to the first active material layer 12, the progress of the peeling toward the center can be suppressed by the engagement of the bent portion 641 at the bent portion 641. By having such a bent linear slit 640 in the first current collector 11, the occurrence and expansion of structural defects due to repeated charge and discharge and the stress of the thermal cycle can be suppressed. For this reason, a battery 601 that is difficult to deteriorate and has high reliability can be realized.

[0137] Note that the number of bent portions 641 included in one slit 640 may be plural. For example, by increasing the number of bent portions 641, the peeling suppression effect becomes even higher. An appropriate number of bent portions 641 may be provided in terms of ease of manufacturing processing and ease of production.

[0138] Further, the slit 640 may extend in a curved shape such as an arc shape or an elliptical arc shape. That is, the slit 640 may have a continuous bent portion 641 that bends smoothly. Also in this case, the effect of suppressing the peeling of the first current collector 11 can be obtained.

[0139] Further, only one of the plurality of slits provided in the first current collector 11 may be the slit 640, and the remaining slits may be the slit 40 or 540. A slit having the same shape as the slit 640 according to the present embodiment may be provided in the second current collector 21 as in the second embodiment. At this time, the number, position, and degree of bending of the bent portion 641 may be different between the slit 640 provided in the first current collector 11 and the slit provided in the second current collector 21.

[0140] (Embodiment 5) Hereinafter, Embodiment 5 will be described. In Embodiment 5, it is mainly different from Embodiment 1 in that each of the first active material layer and the second active material layer is provided only on a part of the main surface of the current collector. In the following description of Embodiment 5, the description will focus on the differences from Embodiment 1, and the description of the common points will be omitted or simplified.

[0141] FIG. 9 is a cross-sectional view and a plan view showing a schematic configuration of a battery 701 according to Embodiment 5. Specifically, FIG. 9(a) is a cross-sectional view of the battery 701. FIG. 9(b) is a plan view of the battery 701 as viewed from the positive side of the z-axis. In FIG. 9(a), a cross-section at the position indicated by the line IXa-IXa in FIG. 9(b) is shown.

[0142] As shown in FIG. 9, the battery 701 according to the present embodiment includes a first electrode 710, a second electrode 720, and a solid electrolyte layer 730. The first electrode 710 includes a first current collector 11 and a first active material layer 712. The second electrode 720 includes a second current collector 21 and a second active material layer 722. The first current collector 11 and the second current collector 21 are the same as those in Embodiment 1.

[0143] The area of each of the first active material layer 712 and the second active material layer 722 is different from that of the first active material layer 12 and the second active material layer 22 according to Embodiment 1 in a plan view. Specifically, the area of the first active material layer 712 is smaller than that of the first current collector 11 in a plan view. The area of the second active material layer 722 is smaller than that of the second current collector 21 in a plan view.

[0144] Therefore, as shown in FIG. 9(b), the first current collector 11 has a first region 711a in contact with the first active material layer 712 and a second region 711b not in contact with the first active material layer 712. In the present embodiment, the slit 40 is provided in the second region 711b of the first current collector 11 and is not provided in the first region 711a. That is, in a plan view, the slit 40 and the first active material layer 712 do not overlap, so the slit 40 is not filled with the material contained in the first active material layer 712. In other words, the slit 40 does not bite into the first active material layer 712.

[0145] The solid electrolyte layer 730 includes a first solid electrolyte layer 731 and a second solid electrolyte layer 732. The first solid electrolyte layer 731 is provided in contact with the first active material layer 712 and the second active material layer 722, respectively, between the first active material layer 712 and the second active material layer 722, in the same manner as the solid electrolyte layer 30 according to Embodiment 1. The first solid electrolyte layer 731 has the same size and the same shape as the first active material layer 712 and the second active material layer 722 in plan view.

[0146] The second solid electrolyte layer 732 is provided so as to surround the first active material layer 712, the first solid electrolyte layer 731, and the second active material layer 722. Specifically, in plan view, the second solid electrolyte layer 732 is provided in the second region 711b of the first current collector 11. The second solid electrolyte layer 732 overlaps the slit 40 in plan view. Specifically, a part of the second solid electrolyte layer 732 is filled in the slit 40.

[0147] The second solid electrolyte layer 732 contains the same solid electrolyte as the first solid electrolyte layer 731. Alternatively, the second solid electrolyte layer 732 may contain a solid electrolyte different from the solid electrolyte contained in the first solid electrolyte layer 731. For example, as the solid electrolyte contained in the second solid electrolyte layer 732, a material having a smaller Young's modulus and excellent deformability than the solid electrolyte contained in the first solid electrolyte layer 731 can be used. Thereby, a part of the second solid electrolyte layer 732 is easily filled in the slit 40.

[0148] For example, as the solid electrolyte contained in the second solid electrolyte layer 732, a sulfide-based or amorphous material, or a material having a small Young's modulus and excellent deformability can be used. For example, by using a material having a smaller Young's modulus than that of the first current collector 11, a part of the second solid electrolyte layer 732 is filled while being deformed into the slit 40 provided in the first current collector 11 during pressurization. Thereby, a strong anchor action effect strongly joined to the side walls 41 and 42 of the slit 40 can be obtained.

[0149] As described above, according to the battery 701 according to this embodiment, by filling a part of the second solid electrolyte layer 732 containing a highly deformable solid electrolyte into the slit 40, the anchor effect can act more strongly, and a strong bonding effect can be obtained between the first current collector 11 and the second solid electrolyte layer 732. Therefore, a more reliable battery 701 can be realized.

[0150] Note that, similar to Embodiment 2, the second current collector 21 may be provided with a slit 340. A part of the second solid electrolyte layer 732 may be filled in the slit 340 provided in the second current collector 21.

[0151] Also, the second solid electrolyte layer 732 does not necessarily surround the entire periphery of the first solid electrolyte layer 731. For example, the second solid electrolyte layer 732 may be provided along one side or two or more sides of the first solid electrolyte layer 731 in a plan view. Alternatively, the second solid electrolyte layer 732 may be provided only in a portion that overlaps the slit 40 provided in the first current collector 11 in a plan view.

[0152] (Embodiment 6) Hereinafter, Embodiment 6 will be described. In Embodiment 6, it is mainly different from Embodiment 1 in that a plurality of batteries are stacked. In the following description of Embodiment 6, the description will focus on the differences from Embodiment 1, and the description of the common points will be omitted or simplified.

[0153] FIG. 10 is a cross-sectional view and a plan view showing a schematic configuration of a stacked battery 800 according to Embodiment 6. Specifically, FIG. 10(a) is a cross-sectional view of the stacked battery 800. FIG. 10(b) is a plan view of the stacked battery 800 as viewed from the positive side of the z-axis, with the battery 801 on the positive side of the z-axis being seen through. That is, FIG. 10(b) is a plan view of the battery 802 on the negative side of the z-axis as viewed from the positive side of the z-axis. FIG. 10(a) shows a cross-section at the position indicated by the line Xa-Xa in FIG. 10(b).

[0154] As shown in FIG. 10, the laminated battery 800 includes two batteries 801 and 802. Specifically, the two batteries 801 and 802 are laminated in the thickness direction. The two batteries 801 and 802 are adhered by applying a conductive adhesive or the like.

[0155] In the present embodiment, the two batteries 801 and 802 are electrically connected in series. Specifically, one positive electrode and the other negative electrode of the two batteries 801 and 802 are directly connected. For example, the second current collector 421 of the battery 801 and the first current collector 11 of the battery 802 constitute a so-called bipolar electrode where one is the positive electrode and the other is the negative electrode. For example, in each of the batteries 801 and 802, the first current collector 11 is a positive electrode current collector, and the second current collector 421 is a negative electrode current collector.

[0156] Each of the batteries 801 and 802 has the same configuration as the battery 401 according to Embodiment 2. Specifically, in each of the batteries 801 and 802, a slit 40 is formed in the first current collector 11, and a slit 440 is formed in the second current collector 421. In FIG. 10(b), the slit 440 provided in the second current collector 421 of the battery 801 is represented by a broken line.

[0157] As shown in FIG. 10(b), the slit 40 and the slit 440 do not overlap in plan view. Specifically, the slit 40 provided in the first current collector 11 of the battery 802 is blocked by the second current collector 421 of the battery 801. For this reason, a part of the first active material layer 12 of the battery 802 filled in the slit 40 does not contact the second active material layer 22 of the battery 801. Similarly, the slit 440 provided in the second current collector 421 of the battery 801 is blocked by the first current collector 11 of the battery 802. For this reason, a part of the second active material layer 22 of the battery 801 filled in the slit 440 does not contact the first active material layer 12 of the battery 802. In this way, by preventing the slit 40 and the slit 440 from overlapping in plan view, contact between active materials with different polarities in each of the two laminated batteries 801 and 802 can be prevented.

[0158] As described above, since the current collectors of the plurality of batteries 801 and 802 are each provided with slits, air and structural defects can be reduced in the batteries 801 and 802 respectively, so that the inside of the laminate is made uniform and warpage is also reduced. For this reason, the batteries 801 and 802 can be stacked and connected in multiple layers.

[0159] Further, in the laminated battery 800 according to the present embodiment, since the slit 40 and the slit 440 do not overlap in plan view, the plurality of batteries 801 and 802 can be connected in series. In this way, a high-energy battery corresponding to a higher voltage can be realized, and a highly reliable laminated battery can be realized.

[0160] Note that the first current collector 11 of the battery 801 may not be provided with the slit 40. Further, the second current collector 421 of the battery 802 may not be provided with the slit 440.

[0161] Further, the second current collector 421 of the battery 801 may not be provided with the slit 440. Thereby, the slit 40 provided in the first current collector 11 of the battery 802 can be surely blocked by the second current collector 421. Similarly, the first current collector 11 of the battery 802 may not be provided with the slit 40. Thereby, the slit 440 provided in the second current collector 421 of the battery 801 can be surely blocked by the first current collector 11.

[0162] Further, the laminated battery 800 may include the battery 1, 401, 501, 601, or 701 instead of at least one of the batteries 801 and 802. Further, the number of laminated batteries in the laminated battery 800 is not limited to two, and may be three or more.

[0163] (Embodiment 7) Hereinafter, Embodiment 7 will be described. In Embodiment 7, it is mainly different from Embodiment 1 in that a plurality of batteries are laminated. In the following description of Embodiment 7, the differences from Embodiment 1 will be mainly described, and the description of the common points will be omitted or simplified.

[0164] FIG. 11 is a cross-sectional view and a plan view showing a schematic configuration of the stacked battery 900 according to Embodiment 7. Specifically, FIG. 11(a) is a cross-sectional view of the stacked battery 900. FIG. 11(b) is a plan view of the stacked battery 900 as viewed from the positive side of the z-axis through the battery 1 on the positive side of the z-axis. That is, FIG. 11(b) is a plan view of the battery 1 on the negative side of the z-axis as viewed from the positive side of the z-axis. In FIG. 11(a), a cross-section at the position indicated by the line XIa-XIa in FIG. 11(b) is shown.

[0165] As shown in FIG. 11, the stacked battery 900 includes two batteries 1. Specifically, the two batteries 1 are stacked in the thickness direction. The two batteries 1 are adhered by applying a conductive adhesive or the like.

[0166] In the present embodiment, the two batteries 1 are electrically connected in parallel. Specifically, the positive electrodes or the negative electrodes of the two batteries 1 are directly connected. For example, the first current collectors 11 of the two batteries 1 are connected to each other.

[0167] The first current collector 11 is provided with slits 40 in the same manner as in Embodiment 1. In the present embodiment, at least a part of the slits 40 of each of the two batteries 1 overlaps in a plan view. For example, as shown in FIG. 11(b), the four slits 40 provided in one of the first current collectors 11 of the two batteries 1 and the four slits 40 provided in the other first current collector 11 of the two batteries 1 completely coincide in a plan view.

[0168] Thereby, since the first active material layer 12 is shared and integrated through the slit 40, a strong bond can be obtained between the two batteries 1. Therefore, a highly reliable stacked battery 900 can be realized.

[0169] Note that the laminated battery 900 may include battery 401, 501, 601, 701, 801, or 802 instead of at least one of the two batteries 1. For example, when the laminated battery 900 includes two batteries 701, the second solid electrolyte layer 732 may include a powder that undergoes sintering in a compacting process, such as a sulfide-based solid electrolyte. Thereby, the batteries 701 can be easily integrated with each other via the slit 40. With such an effect, high bonding reliability can be obtained.

[0170] Also, the number of stacked batteries in the laminated battery 900 is not limited to two and may be three or more.

[0171] (Method for manufacturing a battery) Next, an example of a method for manufacturing the battery and the laminated battery according to each of the above embodiments will be described. Hereinafter, a method for manufacturing the laminated battery 800 according to Embodiment 6 shown in FIG. 10 described above will be described.

[0172] First, each paste used for printing and forming the first active material layer 12 (specifically, the positive electrode active material layer) and the second active material layer 22 (specifically, the negative electrode active material layer) is prepared. As a solid electrolyte raw material used in the formulation of each of the positive electrode active material layer and the negative electrode active material layer, for example, Li having an average particle diameter of about 10 μm and a triclinic crystal as a main component 2 S-P 2 S 5 -based sulfide glass powder is prepared. As this glass powder, for example, those having a high ionic conductivity of 2×10 -3 S / cm or more and 3×10 -3 S / cm or less can be used. As the positive electrode active material, for example, a layered Li·Ni·Co·Al composite oxide (LiNi 0.8 Co 0.15 Al 0.05 O 2) powder is used. A paste for a positive electrode active material layer is prepared by dispersing a mixture containing the above-described positive electrode active material and the above-described glass powder in an organic solvent or the like. Further, as the negative electrode active material, for example, a powder of natural graphite having an average particle diameter of about 10 μm is used. A paste for a negative electrode active material layer is similarly prepared by dispersing a mixture containing the above-described negative electrode active material and the above-described glass powder in an organic solvent or the like.

[0173] Next, as the material used for the first current collector 11 (specifically, the positive electrode current collector) and the second current collector 21 (specifically, the negative electrode current collector), for example, a copper foil having a thickness of about 15 μm is prepared. By the screen printing method, the paste for the positive electrode active material layer and the paste for the negative electrode active material layer are printed on one surface of each copper foil in a predetermined shape and with a thickness of about 50 μm or more and about 100 μm or less. The paste for the positive electrode active material layer and the paste for the negative electrode active material layer are dried in the range of 80 °C or more and 130 °C or less, thereby having a thickness of 30 μm or more and 60 μm or less. As a result, current collectors (copper foils) on which a positive electrode active material layer and a negative electrode active material layer are respectively formed, that is, a first electrode 10 (specifically, a positive electrode) and a second electrode 20 (specifically, a negative electrode) are obtained.

[0174] Next, a paste for a solid electrolyte layer is prepared by dispersing a mixture containing the above-described glass powder in an organic solvent or the like. Using a metal mask, the above-described paste for the solid electrolyte layer is printed on the surface of each of the active material layers of the positive electrode and the negative electrode, for example, with a thickness of about 100 μm. Thereafter, the positive electrode and the negative electrode on which the paste for the solid electrolyte layer is printed are dried in the range of 80 °C or more and 130 °C or less.

[0175] Next, at least one of the positive electrode and the negative electrode is each cut from the surface side of the current collector by a cutter blade by the thickness of the current collector into the shape of the slit 40. Then, by peeling off the cut portion of the current collector while leaving the active material layer, the slits 40 and 440 are formed. Note that slits may be formed in only one of the positive electrode and the negative electrode.

[0176] Next, a solid electrolyte printed on the positive electrode active material layer of the positive electrode and a solid electrolyte printed on the negative electrode active material layer of the negative electrode are laminated so as to face each other in contact with each other.

[0177] Next, an elastic body sheet having a modulus of elasticity of about 5×10 6 Pa is inserted between the pressure mold plates on the upper surface of the current collector. The thickness of the elastic body sheet is, for example, 70 μm. Then, while heating the pressure mold plates to 50°C at a pressure of 300 MPa, pressure is applied for 90 seconds. During this pressurization, a part of the active material layer enters the inside of the slit 40 and contacts the side walls 41 and 42 of the slit 40. For example, when the thickness of the current collector is about 15 μm, a part of the active material layer is filled in the slit 40 in the range of 10 μm or more and 15 μm or less.

[0178] Next, a thermosetting conductor paste containing silver particles is screen-printed on the surface of the current collector of the battery 801 manufactured as described above to a thickness of about 30 μm, and another battery 802 is placed at a predetermined position and crimped. At this time, the slit 40 is blocked by the other current collector when the two batteries 801 and 802 are joined together. This is repeated for the desired number of batteries for multi-layer formation. After this, for example, it is left standing while applying a pressure of about 1 kg / cm 2 and heat curing treatment is performed at a temperature of about 100°C or more and about 300°C or less for 60 minutes, and then cooled to room temperature.

[0179] Through the above steps, the laminated battery 800 is manufactured. Note that the manufacturing method and order of the battery 1 and the laminated battery 800 are not limited to the above examples.

[0180] In the above manufacturing method, an example of applying the positive electrode active material layer paste, the negative electrode active material layer paste, the solid electrolyte layer paste, and the conductor paste by printing is shown, but it is not limited thereto. As the printing method, for example, a doctor blade method, a calendar method, a spin coating method, a dip coating method, an inkjet method, an offset method, a die coating method, a spray method, etc. may be used. Note that the method of forming the slit 40 in the current collector may also be a technique such as laser cutting or punching using a mold.

[0181] In the above manufacturing method, a thermosetting conductive paste containing silver metal particles is shown as an example of the conductive paste, but it is not limited to this. Further, the resin used in the thermosetting conductive paste may be any resin that functions as a binder for binding, and furthermore, an appropriate one is selected according to the manufacturing process adopted, such as printability and coatability. The resin used in the thermosetting conductive paste includes, for example, a thermosetting resin. Examples of the thermosetting resin include (i) amino resins such as urea resin, melamine resin, and guanamine resin, (ii) epoxy resins such as bisphenol A type, bisphenol F type, phenol novolak type, and alicyclic type, (iii) oxetane resins, (iv) phenol resins such as resol type and novolak type, and (v) silicone-modified organic resins such as silicone epoxy and silicone polyester. Only one of these materials may be used for the resin, or two or more of these materials may be combined and used.

[0182] (Other embodiments) As described above, the battery and the laminated battery according to the present disclosure have been described based on the embodiments, but the present disclosure is not limited to these embodiments. As long as the gist of the present disclosure is not deviated from, various modifications conceived by those skilled in the art applied to the embodiments, and other forms constructed by combining some components in different embodiments are also included in the scope of the present disclosure.

[0183] For example, there may be only one first slit provided in the first current collector. Further, the first slit provided in the first current collector may extend from one end to the other end of the first current collector. That is, at least one first slit may be provided so as to divide the first current collector into a plurality. The plurality of first slits may extend radially from the center or near the center of the first current collector and connect to the outer edge portion of the first current collector. The same may apply to the second slit.

[0184] In addition, various changes, replacements, additions, omissions, etc. can be made to the above-described embodiments within the scope of the claims or their equivalents.

Industrial Applicability

[0185] The battery and the laminated battery according to the present disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices or automobiles.

Explanation of Reference Numerals

[0186] 1, 401, 501, 601, 701, 801, 802 Battery 10, 710 First Electrode 11 First Current Collector 12, 712 First Active Material Layer 20, 420, 720 Second Electrode 21, 421 Second Current Collector 22, 722 Second Active Material Layer 30, 730 Solid Electrolyte Layer 40, 40a, 40b, 40c, 40d, 140, 240, 340, 440, 540, 640 Slit 41, 42, 141, 142, 241, 242, 341, 342 Side Wall 641 Bend 711a First Region 711b Second Region 731 First Solid Electrolyte Layer 732 Second Solid Electrolyte Layer 800, 900 Laminated Battery

Claims

1. A first electrode, a second electrode, a solid electrolyte layer positioned between the first electrode and the second electrode, and comprising the first electrode being a first current collector, a first active material layer positioned between the first current collector and the solid electrolyte layer, and comprising the first current collector being having at least one first slit that penetrates the first current collector in the thickness direction and is connected to the outer edge of the first current collector, the first slit being filled with a material contained in the layer of the first current collector that contacts the surface on the second electrode side, a battery.

2. The at least one first slit is a plurality of first slits, the battery according to Claim 1.

3. The planar shape of the first current collector is rectangular or square, the plurality of first slits are four first slits and are connected to the center of each side of the first current collector in plan view, the battery according to Claim 2.

4. The plurality of first slits are provided symmetrically with respect to the center of the first current collector in plan view, the battery according to Claim 2 or 3.

5. The side wall of the at least one first slit is inclined with respect to the thickness direction of the first current collector, the battery according to any one of Claims 1 to 4.

6. The cross-sectional shape of the at least one first slit is a trapezoidal shape in which the first side on the second electrode side is shorter than the second side opposite to the first side, the battery according to Claim 5.

7. The width of the at least one first slit is wider in a portion closer to the outer edge than in a portion farther from the outer edge of the first current collector in plan view, the battery according to any one of Claims 1 to 6.

8. The at least one first slit has a bent portion in plan view, the battery according to any one of Claims 1 to 7.

9. The width of the first slit is 0.1 mm or more and 5 mm or less, the battery according to any one of Claims 1 to 8.

10. The first slit extends in one direction from the outer edge toward the inside of the first current collector, the length of the first slit in the one direction is 6% or more of the length of the first current collector in the one direction, the battery according to any one of Claims 1 to 9.

11. The length of the first slit in the one direction is less than 50% of the length of the first current collector in the one direction, the battery according to Claim 10.

12. The first active material layer has an area smaller than that of the first current collector in plan view. The first current collector has a first region in contact with the first active material layer and a second region in contact with the solid electrolyte layer. The battery according to any one of claims 1 to 11.

13. The at least one first slit is provided in the second region and not provided in the first region. The battery according to claim 12.

14. The layer is the first active material layer or the solid electrolyte layer. The battery according to any one of claims 1 to 13.

15. The second electrode includes a second current collector and a second active material layer positioned between the second current collector and the solid electrolyte layer. The second current collector has at least one second slit that penetrates the second current collector in the thickness direction and is connected to the outer edge of the second current collector. The battery according to any one of claims 1 to 14.

16. Comprising a first battery and a second battery, each being the battery according to any one of claims 1 to 15, wherein the first battery is laminated on a surface of the first current collector of the second battery opposite to the first active material layer. Laminated battery.

17. The first current collector of the first battery and the first current collector of the second battery are current collectors with different polarities from each other, the first battery and the second battery are laminated such that the first current collectors of each other are in contact, and the at least one first slit of the first battery does not overlap with any of the at least one first slits of the second battery in plan view. The laminated battery according to claim 16.

18. The first current collector of the first battery and the first current collector of the second battery are current collectors with the same polarity from each other, the first battery and the second battery are laminated such that the first current collectors of each other are in contact, and at least a part of the at least one first slit of the first battery overlaps with the at least one first slit of the second battery in plan view. The laminated battery according to claim 16.

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