Battery

Abstract

To provide a battery having high reliability.SOLUTION: A plurality of cells electrically connected in parallel, each of the plurality of cells including a positive electrode layer, a negative electrode layer, a first current collector in contact with one of the positive electrode layer and the negative electrode layer, a second current collector in contact with the other of the positive electrode layer and the negative electrode layer, an electrolyte layer disposed between the positive electrode layer and the negative electrode layer, and a terminal electrically connected to at least one of the first current collector and the second current collector, in a plan view, an end portion of the first current collector in a first direction not facing the terminal and an end portion of the second current collector in the first direction do not overlap each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] The capacity can be increased by electrically connecting batteries in parallel. As a technology related to such parallel connection, for example, Patent Document 1 discloses a thin-film solid-state secondary battery having an electrode lead-out portion at one end of a current collector body. Patent Document 2 discloses an all-solid-state battery in which a terminal current collector is attached to an end face of a laminate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-103129 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-120717 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need in the art for batteries that have high reliability. [Means for solving the problem]

[0005] The present disclosure provides: A plurality of cells electrically connected in parallel, Each of the plurality of cells a positive electrode layer; a negative electrode layer; a current collector in contact with the positive electrode layer or the negative electrode layer; an electrolyte layer disposed between the positive electrode layer and the negative electrode layer; and a side surface of the current collector includes an exposed portion exposed from the electrolyte layer and a shielded portion shielded by the electrolyte layer; The area of ​​the shielding portion is larger than the area of ​​the exposed portion. Provide the battery. [Effects of the Invention]

[0006] According to the present disclosure, a highly reliable battery can be realized. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view and a top view schematically showing the configuration of a battery according to Embodiment 1. FIG. [Figure 2] FIG. 2 is a top view of the negative electrode current collector. [Figure 3] FIG. 3 is a cross-sectional view and a top view schematically showing the configuration of the battery according to the second embodiment. [Figure 4] FIG. 4 is a cross-sectional view and a top view schematically showing the configuration of a battery according to the third embodiment. [Figure 5] FIG. 5 is a cross-sectional view and a top view schematically showing the configuration of a battery according to the fourth embodiment. [Figure 6] FIG. 6 is a cross-sectional view and a top view schematically showing the structure of a battery according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Summary of one aspect of the present disclosure) The battery according to the first aspect of the present disclosure comprises: A plurality of cells electrically connected in parallel, Each of the plurality of cells a positive electrode layer; a negative electrode layer; a current collector in contact with the positive electrode layer or the negative electrode layer; an electrolyte layer disposed between the positive electrode layer and the negative electrode layer; and a side surface of the current collector includes an exposed portion exposed from the electrolyte layer and a shielded portion shielded by the electrolyte layer; The area of ​​the shielded portion is larger than the area of ​​the exposed portion.

[0009] According to the first aspect, a highly reliable battery can be realized.

[0010] In a second aspect of the present disclosure, for example, the battery according to the first aspect may further include a terminal electrically connected to the current collector, and the exposed portion may be in contact with the terminal. This structure can improve the bonding strength between the current collector and the electrolyte layer.

[0011] In a third aspect of the present disclosure, for example, in the battery according to the first or second aspect, the electrolyte layer may be a solid electrolyte layer containing a solid electrolyte. With such a structure, a highly reliable battery can be realized.

[0012] In a fourth aspect of the present disclosure, for example, in the battery according to the first to third aspects, the electrolyte layers of the adjacent cells may be joined together around the periphery of the shielding portion. With this structure, the battery can have a large capacity.

[0013] In a fifth aspect of the present disclosure, for example, in the batteries according to the first to fourth aspects, the current collector may have a protruding portion, and the exposed portion may be included in the protruding portion. This structure allows efficient connection to the electrode terminal.

[0014] In a sixth aspect of the present disclosure, for example, in the battery according to the fifth aspect, the current collector may have a remaining portion other than the protruding portion, and the width of the protruding portion may be narrower than the width of the remaining portion. With this structure, it is possible to reduce the areas where peeling is likely to occur between the current collector and the electrolyte layer.

[0015] In a seventh aspect of the present disclosure, for example, in the battery according to the fifth or sixth aspect, the current collector may have a remaining portion other than the protruding portion, and the thickness of the protruding portion may be smaller than the thickness of the remaining portion. This structure reduces the areas where peeling is likely to occur between the current collector and the electrolyte layer.

[0016] In an eighth aspect of the present disclosure, for example, in the batteries according to the first to seventh aspects, the current collector may have through holes. Such a structure can improve the bonding strength between the current collector and the electrolyte layer.

[0017] In a ninth aspect of the present disclosure, for example, in the battery according to the eighth aspect, the electrolyte layer may be present inside the through-hole. With this structure, the bonding strength between the current collector and the electrolyte layer can be improved.

[0018] In a tenth aspect of the present disclosure, for example, the battery according to any one of the first to ninth aspects may further include a bonding layer, which may be located at the interface between the current collector and the electrolyte layer and may contain at least one element contained in the current collector and at least one element contained in the electrolyte layer. Such a structure can improve the bonding strength between the current collector and the electrolyte layer.

[0019] In an eleventh aspect of the present disclosure, for example, in the battery according to the tenth aspect, the bonding layer may be present at the interface between the shielding portion and the electrolyte layer. This structure can improve the bonding strength between the current collector and the electrolyte layer.

[0020] In a twelfth aspect of the present disclosure, for example, the battery according to any one of the first to eleventh aspects may further include a dummy current collector surrounding the shielding portion of the current collector. This structure can further reduce pressure variations during pressure bonding.

[0021] In a thirteenth aspect of the present disclosure, for example, in the battery according to the twelfth aspect, the dummy current collector may contain the same material as the current collector. With this structure, pressure variation can be further reduced during pressure bonding.

[0022] In a fourteenth aspect of the present disclosure, for example, in the battery according to the twelfth aspect, the dummy current collector may contain an insulating material. With this structure, pressure variations can be further reduced.

[0023] In a fifteenth aspect of the present disclosure, for example, in the batteries according to the twelfth to fourteenth aspects, the dummy current collector may be electrically isolated from the current collector. With this structure, a highly reliable battery can be realized.

[0024] In a sixteenth aspect of the present disclosure, for example, in the battery according to the fifteenth aspect, the dummy current collector may be spaced apart from the current collector. With this configuration, a highly reliable battery can be realized.

[0025] In a seventeenth aspect of the present disclosure, for example, in the batteries according to the twelfth to sixteenth aspects, the dummy current collector may be exposed from the electrolyte layer. This structure can further reduce pressure variations during pressure bonding.

[0026] In an eighteenth aspect of the present disclosure, for example, in the batteries according to the twelfth to seventeenth aspects, each of the plurality of cells may have a flat plate shape, the battery may be configured by stacking the plurality of cells, and the dummy current collector may be located at the same height as the current collector in the stacking direction of the plurality of cells. This structure can reduce areas where peeling is likely to occur between the current collector and the electrolyte layer.

[0027] In a nineteenth aspect of the present disclosure, for example, in the batteries according to the twelfth to seventeenth aspects, each of the plurality of cells may have a flat plate shape, the battery may be configured by stacking the plurality of cells, and the dummy current collector may be located at a different height from the current collector in the stacking direction of the plurality of cells. This structure can reduce areas where peeling is likely to occur between the current collector and the electrolyte layer.

[0028] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0029] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concepts are described as optional components.

[0030] In addition, the drawings are not necessarily strict illustrations, and the same reference numerals are used to designate substantially the same components in the drawings, and redundant explanations are omitted or simplified.

[0031] (Embodiment 1) [Overview of stacked battery] First, the battery according to this embodiment will be described.

[0032] FIG. 1 is a schematic diagram illustrating the configuration of a stacked battery 100 according to the first embodiment. In this embodiment, the battery 100 is a stacked battery. Therefore, in this specification, the "battery 100" may be referred to as the "stacked battery 100." FIG. 1(a) is a cross-sectional view of the battery 100 according to this embodiment. FIG. 1(b) is a top view of the battery 100.

[0033] As shown in FIG. 1(a), the battery 100 includes multiple cells 30, a positive terminal 16, and a negative terminal 17. In this specification, a "cell" may be referred to as a "solid-state battery cell." The multiple cells 30 are electrically connected in parallel. As shown in FIG. 1(b), each of the multiple cells 30 has, for example, a rectangular shape in a plan view. Each of the multiple cells 30 has two pairs of end faces facing each other. Each of the multiple cells 30 has, for example, a flat plate shape. The battery 100 is configured by stacking the multiple cells 30. In this embodiment, the first direction x is the direction from one end of a pair of end faces of a specific cell 30 to the other end. The second direction y is the direction from one end of another pair of end faces of the specific cell 30 to the other end, and is perpendicular to the first direction x. The third direction z is the stacking direction of the multiple cells 30, and is perpendicular to both the first direction x and the second direction y.

[0034] The number of the plurality of cells 30 is not particularly limited, and may be 20 to 100, 2 to 100, or 2 to 100. In this embodiment, the battery 100 includes a plurality of cells 30a and 30b. The plurality of cells 30a and 30b are stacked in this order.

[0035] The positive electrode terminal 16 and the negative electrode terminal 17 are each electrically connected to the plurality of cells 30. The positive electrode terminal 16 and the negative electrode terminal 17 are each shaped like a plate, for example. The positive electrode terminal 16 and the negative electrode terminal 17 face each other. The positive electrode terminal 16 and the negative electrode terminal 17 are aligned in the first direction x. The plurality of cells 30 are located between the positive electrode terminal 16 and the negative electrode terminal 17. In this specification, the positive electrode terminal 16 and the negative electrode terminal 17 may be simply referred to as "terminals."

[0036] Each of the multiple cells 30 has a positive electrode current collector 11, a positive electrode layer 12, a negative electrode current collector 13, a negative electrode layer 14, and an electrolyte layer 15. The positive electrode current collector 11, the positive electrode layer 12, the electrolyte layer 15, the negative electrode layer 14, and the negative electrode current collector 13 are arranged in this order in the third direction z or in the direction opposite to the third direction z. In this specification, the positive electrode current collector 11 and the negative electrode current collector 13 may be simply referred to as "current collectors."

[0037] The positive electrode current collector 11 has, for example, a plate shape. The positive electrode current collector 11 is electrically connected to each of the positive electrode layer 12 and the positive electrode terminal 16. The positive electrode current collector 11 may be in direct contact with each of the positive electrode layer 12 and the positive electrode terminal 16. For example, the main surface of the positive electrode current collector 11 may be in direct contact with the positive electrode layer 12. The "main surface" refers to the surface of the positive electrode current collector 11 having the largest area. An end (end face) of the positive electrode current collector 11 may be in direct contact with the positive electrode terminal 16. The positive electrode current collector 11 and the negative electrode terminal 17 are electrically separated from each other via a gap. The shortest distance between the positive electrode current collector 11 and the negative electrode terminal 17 is not particularly limited and may be 20 μm to 100 μm, 1 μm to 100 μm, or 1 μm to 10 μm. In this specification, the vicinity of the end face of the cell 30 may be referred to as the "end region" of the cell 30. The positive electrode current collector 11 and the negative electrode terminal 17 are electrically separated from each other, for example, in the end region of the cell 30 via a gap.

[0038] The positive electrode layer 12 has, for example, a rectangular shape in a plan view. The positive electrode layer 12 is disposed on the positive electrode current collector 11. The positive electrode layer 12, for example, partially covers the main surface of the positive electrode current collector 11. The positive electrode layer 12 may cover a region including the center of gravity of the main surface of the positive electrode current collector 11. The positive electrode layer 12 is not formed, for example, in an end region of the cell 30.

[0039] The negative electrode current collector 13 has, for example, a plate shape. The negative electrode current collector 13 is electrically connected to each of the negative electrode layer 14 and the negative electrode terminal 17. The negative electrode current collector 13 may be in direct contact with each of the negative electrode layer 14 and the negative electrode terminal 17. For example, a main surface of the negative electrode current collector 13 may be in direct contact with the negative electrode layer 14. An end (end face) of the negative electrode current collector 13 may be in direct contact with the negative electrode terminal 17. The negative electrode current collector 13 and the positive electrode terminal 16 are electrically separated from each other via a gap. The shortest distance between the negative electrode current collector 13 and the positive electrode terminal 16 is not particularly limited and may be 20 μm or more and 100 μm or less, 1 μm or more and 100 μm or less, or 1 μm or more and 10 μm or less. The negative electrode current collector 13 and the positive electrode terminal 16 are electrically separated from each other via a gap, for example, in the end region of the cell 30. In this embodiment, the exposed portion 13a of the negative electrode current collector 13 contacts the negative electrode terminal 17. In other words, the negative electrode current collector 13 has the exposed portion 13a as a contact surface with the negative electrode terminal 17. The side surface of the negative electrode current collector 13 is composed of the exposed portion 13a and the shielded portion 13b. The "side surface" refers to a surface other than the main surface of the negative electrode current collector 13. The "main surface" refers to the surface of the negative electrode current collector 13 that has the largest area. The negative electrode current collector 13 has no portion exposed to the outside other than the exposed portion 13a.

[0040] The position of the negative electrode current collector 13 is, for example, shifted in the first direction x from the position of the positive electrode current collector 11. In a plan view, the gap between the negative electrode current collector 13 and the positive electrode terminal 16 does not overlap, for example, the gap between the positive electrode current collector 11 and the negative electrode terminal 17.

[0041] The negative electrode layer 14 has, for example, a rectangular shape in a plan view. The negative electrode layer 14 is disposed on the negative electrode current collector 13. The negative electrode layer 14, for example, partially covers the main surface of the negative electrode current collector 13. The negative electrode layer 14 may cover a region including the center of gravity of the main surface of the negative electrode current collector 13. The negative electrode layer 14 is not formed, for example, in an end region of the cell 30.

[0042] The electrolyte layer 15 is located between the positive electrode current collector 11 and the negative electrode current collector 13. In other words, the electrolyte layer 15 is located between the positive electrode layer 12 and the negative electrode layer 14. The electrolyte layer 15 is in contact with both the positive electrode terminal 16 and the negative electrode terminal 17. The electrolyte layer 15 may be in contact with both the positive electrode layer 12 and the negative electrode layer 14.

[0043] FIG. 2 is a top view of the negative electrode current collector 13. As shown in FIG.

[0044] As shown in FIGS. 1 and 2, the side surface of the negative electrode current collector 13 has an exposed portion 13a and a shielded portion 13b. The exposed portion 13a is a portion exposed from the electrolyte layer 15. The shielded portion 13b is a portion shielded from the outside by the electrolyte layer 15. In other words, the shielded portion 13b is a non-exposed portion that is not exposed from the electrolyte layer 15. In this embodiment, the area of ​​the shielded portion 13b is larger than the area of ​​the exposed portion 13a. This configuration makes it possible to provide a large-capacity stacked battery 100 that is characterized by its small size, excellent impact resistance, high energy density, and high reliability.

[0045] The ratio (S2 / S1) of the area S2 of the shielding portion 13b to the area S1 of the exposed portion 13a is not particularly limited and is appropriately determined depending on the size, material, etc. of the battery 100. The ratio (S2 / S1) is, for example, in the range of 2 or more and 50 or less.

[0046] In this embodiment, the negative electrode current collector 13 has a protruding portion 13p and a remaining portion 13r. The protruding portion 13p is a tab-shaped portion. The remaining portion 13r is a portion other than the protruding portion 13p. The area (area in a plan view) of the protruding portion 13p is smaller than the area (area in a plan view) of the remaining portion 13r. In this embodiment, both the protruding portion 13p and the remaining portion 13r have a rectangular shape. However, the shapes of the protruding portion 13p and the remaining portion 13r are not particularly limited. The exposed portion 13a is located on a side surface of the protruding portion 13p. The exposed portion 13a is not in contact with the electrolyte layer 15. The exposed portion 13a is electrically connected to the negative electrode terminal 17. In this embodiment, the entire exposed portion 13a is included in the protruding portion 13p. However, only a portion of the exposed portion 13a may be included in the protruding portion 13p. The shielding portion 13b is located on a side surface of the remaining portion 13r and a side surface of the protruding portion 13p. However, the shielding portion 13b does not include the exposed portion 13a of the side surface of the protruding portion 13p. The shielding portion 13b is in contact with the electrolyte layer 15. The main surface of the remaining portion 13r may be in direct contact with the negative electrode layer 14 and the electrolyte layer 15. The main surface of the protruding portion 13p may be in direct contact with the electrolyte layer 15. With this configuration, most of the negative electrode current collector 13 can be embedded in the electrolyte layer 15. The negative electrode current collector 13 can be connected to the negative electrode terminal 17 while reducing the area of ​​the portion that can become the starting point for peeling between the layers.

[0047] In the negative electrode current collector 13, the protruding portion 13p is a portion that extends in the first direction x from the remaining portion 13r. The length of the protruding portion 13p of the negative electrode current collector 13 in the second direction y is shorter than the length of the remaining portion 13r in the second direction y. In other words, the width of the protruding portion 13p is narrower than the width of the remaining portion 13r. This configuration reduces the area of ​​the exposed portion 13a. Furthermore, the interface between the exposed portion 13a and the electrolyte layer 15 is reduced. As a result, the area where peeling is likely to occur between the negative electrode current collector 13 and the electrolyte layer 15 can be reduced, thereby achieving a highly reliable battery 100.

[0048] In this embodiment, the width direction of the battery 100 is parallel to the second direction y and perpendicular to both the first direction x and the third direction z. The stacking direction of the multiple cells 30 is parallel to the third direction z. The width of the protruding portion 13p and the width of the remaining portion 13r are dimensions in the width direction of each portion when the battery 100 is viewed from above.

[0049] The shielding portion 13b of the negative electrode current collector 13 is firmly sandwiched between the electrolyte layers 15, which have high adhesive strength. The electrolyte layers 15 of adjacent cells 30 are bonded to each other around the shielding portion 13b. In this embodiment, by connecting multiple cells 30 in parallel using a common negative electrode current collector 13, the negative electrode current collector 13 and the electrolyte layer 15 can be firmly bonded to each other. As a result, the areas where peeling is likely to occur between the negative electrode current collector 13 and the electrolyte layer 15 can be reduced. This configuration makes it possible to provide a large-capacity stacked battery 100 that is characterized by its small size, excellent impact resistance, high energy density, and high reliability.

[0050] As described above, the battery 100 includes a plurality of cells 30a and 30b. The cell 30a includes a positive electrode current collector 11a, a positive electrode layer 12a, a negative electrode current collector 13, a negative electrode layer 14a, and an electrolyte layer 15a. The cell 30b includes a positive electrode current collector 11b, a positive electrode layer 12b, a negative electrode current collector 13, a negative electrode layer 14b, and an electrolyte layer 15b. The negative electrode current collector 13 is shared by the cells 30a and 30b. The positive electrode current collectors 11a and 11b and the negative electrode current collector 13 are alternately arranged in the third direction z. In the gap between the negative electrode current collector 13 and the positive electrode terminal 16, the electrolyte layer 15a may be in contact with the electrolyte layer 15b.

[0051] [Stacked battery configuration] Each component of the battery 100 will be described in more detail below.

[0052] First, each component of a stacked battery 100 according to one embodiment of the present invention will be described.

[0053] The positive electrode layer 12 functions as a positive electrode active material layer containing a positive electrode active material. The positive electrode layer 12 may contain the positive electrode active material as a main component. The main component means the component most contained in the positive electrode layer 12 by weight ratio. The positive electrode active material is a substance in which metal ions such as lithium (Li) ions and magnesium (Mg) ions are inserted or detached in its 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, and known positive electrode active materials can be used. Examples of the positive electrode active material include compounds containing lithium and transition metal elements. Examples of such compounds include oxides containing lithium and transition metal elements, and phosphate compounds containing lithium and transition metal elements. Examples of the oxide containing lithium and transition metal elements include, for example, LiNi x M 1-x O2 (M is at least one element selected from the group consisting of Co, Al, Mn, V, Cr, Mg, Ca, Ti, Zr, Nb, Mo, and W, and x satisfies 0 < x ≤ 1), such as lithium nickel composite oxides, layered oxides such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium manganate (LiMn2O4), and lithium manganate having a spinel structure (LiMn2O4, Li2MnO3, LiMO2) are used. Examples of the phosphate compound containing lithium and transition metal elements include lithium iron phosphate (LiFePO4) having an olivine structure. Sulfides such as sulfur (S) and lithium sulfide (Li2S) can also be used as the positive electrode active material. A material obtained by coating or adding lithium niobate (LiNbO3) or the like to particles containing a sulfide can also be used as the positive electrode active material. The positive electrode active material may be used alone or in combination of two or more kinds.

[0054] As described above, the positive electrode layer 12 is not particularly limited as long as it contains a positive electrode active material. The positive electrode layer 12 may be a mixture layer composed of a mixture of a positive electrode active material and other additive materials. Examples of other additive materials that can be used include solid electrolytes such as inorganic solid electrolytes, conductive additives such as acetylene black, and binders such as polyethylene oxide and polyvinylidene fluoride. By mixing the positive electrode active material and other additive materials in a predetermined ratio in the positive electrode layer 12, it is possible to improve the lithium ion conductivity and electronic conductivity within the positive electrode layer 12.

[0055] The thickness of the positive electrode layer 12 is, for example, not less than 5 μm and not more than 300 μm.

[0056] The negative electrode layer 14 functions as a negative electrode active material layer containing a negative electrode material such as a negative electrode active material. The negative electrode layer 14 may contain the negative electrode material as a main component. The negative electrode active material is a material in which metal ions such as lithium (Li) ions and magnesium (Mg) ions are inserted or extracted into or from its crystal structure at a potential lower than that of the positive electrode, and oxidation or reduction occurs accordingly. The type of negative electrode active material can be appropriately selected depending on the type of battery, and known negative electrode active materials can be used. Examples of negative electrode active materials that can be used include carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, and resin-baked carbon, and alloy-based materials to be mixed with a solid electrolyte. Examples of alloy-based materials include LiAl, LiZn, Li3Bi, Li3Cd, Li3Sb, Li4Si, and Li 4.4 Pb, Li 4.4 Sn, Li 0.17 C, lithium alloys such as LiC6, lithium titanate (Li4Ti5O 12 ), oxides of lithium and transition metal elements, zinc oxide (ZnO), silicon oxide (SiO x The negative electrode active material may be used alone or in combination of two or more.

[0057] As described above, the anode layer 14 is not particularly limited as long as it contains an anode active material. The anode layer 14 may be a mixture layer composed of a mixture of an anode active material and other additive materials. Examples of other additive materials that can be used include solid electrolytes such as inorganic solid electrolytes, conductive additives such as acetylene black, and binders such as polyethylene oxide and polyvinylidene fluoride. By mixing the anode active material and other additive materials in a predetermined ratio in the anode layer 14, it is possible to improve the lithium ion conductivity and electronic conductivity within the anode layer 14.

[0058] The thickness of the negative electrode layer 14 is, for example, not less than 5 μm and not more than 300 μm.

[0059] The electrolyte layer 15 may be a solid electrolyte layer containing a solid electrolyte. The solid electrolyte is not particularly limited as long as it has ionic conductivity, and known battery electrolytes can be used. Examples of the solid electrolyte include electrolytes that conduct metal ions such as Li ions and Mg ions. The solid electrolyte can be selected appropriately depending on the type of conductive ions. Examples of the solid electrolyte include inorganic solid electrolytes such as sulfide-based solid electrolytes and oxide-based solid electrolytes. Examples of the sulfide-based solid electrolyte include lithium-containing sulfides such as Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, Li2S-SiS2-LiI, Li2S-SiS2-Li3PO4, Li2S-Ge2S2, Li2S-GeS2-P2S5, and Li2S-GeS2-ZnS. Oxide-based solid electrolytes include lithium-containing metal oxides such as Li2O-SiO2 and Li2O-SiO2-P2O5, and Li x P y O 1-z N z Lithium-containing metal nitrides such as lithium phosphate (LiPO), lithium-containing transition metal oxides such as lithium titanium oxide, etc. Only one of these materials may be used as the solid electrolyte, or two or more of these materials may be used in combination.

[0060] The electrolyte layer 15 may contain, in addition to the above solid electrolyte, a binder such as polyethylene oxide or polyvinylidene fluoride.

[0061] The thickness of the electrolyte layer 15 is, for example, not less than 5 μm and not more than 150 μm.

[0062] The solid electrolyte may have a particle shape. The solid electrolyte may be a sintered body.

[0063] Next, the positive electrode terminal 16 and the negative electrode terminal 17 will be described. These terminals 16 and 17 are made of, for example, a low-resistance conductor. For example, the terminals 16 and 17 are made of a cured conductive resin containing conductive metal particles such as Ag. The terminals 16 and 17 may be made of a conductive metal plate, such as a stainless steel plate, coated with a conductive adhesive. The conductive adhesive allows the stack of multiple cells 30 to be sandwiched between two metal plates. The conductive adhesive is not particularly limited as long as it can maintain conductivity and bonding within the operating temperature range of the battery stack 100 and during the manufacturing process of the battery stack 100. The configuration, thickness, and material of the conductive adhesive are not particularly limited as long as the conductive adhesive does not affect the life characteristics and battery characteristics of the battery stack 100 and maintains its durability when a current is passed through the conductive adhesive at the maximum rate required in the operating environment of the battery stack 100. The terminals 16 and 17 may be plated with, for example, Ni-Sn.

[0064] The positive electrode current collector 11 and the negative electrode current collector 13 are not particularly limited as long as they are made of a conductive material. Examples of materials for the current collectors 11 and 13 include stainless steel, nickel, aluminum, iron, titanium, copper, palladium, gold, and platinum. These materials for the current collectors 11 and 13 may be used alone or as an alloy of two or more of them. The current collectors 11 and 13 may be in the form of a foil, a plate, a mesh, or the like. The material for the current collectors 11 and 13 is not particularly limited as long as it does not melt or decompose due to the manufacturing process of the battery 100, the operating temperature of the battery 100, or the pressure within the battery 100. The material can be appropriately selected taking into account the operating potential of the battery 100 applied to the current collectors 11 and 13 and the conductivity of the current collectors 11 and 13. Furthermore, the material for the current collectors 11 and 13 can also be selected depending on the tensile strength and heat resistance required for the current collectors 11 and 13. Examples of materials for the current collectors 11 and 13 include copper, aluminum, and alloys containing these as main components. The current collectors 11 and 13 may be made of high-strength electrolytic copper foil or a clad material made by laminating foils of different metals. The thickness of the current collectors 11 and 13 is, for example, 10 μm or more and 100 μm or less.

[0065] The configurations of the stacked battery 100 described above may be combined with each other as appropriate.

[0066] The configuration of the battery 100 of this embodiment differs from the configurations of the batteries described in Patent Documents 1 and 2 in the following points.

[0067] Patent Document 1 discloses a thin-film solid-state secondary battery having an electrode lead-out portion at one end of a main body of a current collector. The battery described in Patent Document 1 has an electrode lead-out portion that is formed so as to extend to the outside of a negative electrode active material layer and be exposed to the atmosphere.

[0068] Patent Document 2 discloses an all-solid-state battery in which a terminal current collector is attached to an end face of a laminate including parallel current collectors. However, in the all-solid-state battery of Patent Document 2, there is no gap between the terminal current collector and the parallel current collector.

[0069] In the battery configurations described in Patent Documents 1 and 2, the arrangement of the electrodes for extracting current from the current collector and the configuration of the current collector differ from the configuration of battery 100 of this embodiment, and therefore the following problems may occur.

[0070] In the battery configuration of Patent Document 1, the electrode lead portion of the current collector layer is formed so as to be exposed to the atmosphere. Therefore, peeling is likely to occur at the interface between the exposed current collector layer and the solid electrolyte layer. If the battery of Patent Document 1 is subjected to an impact, the mechanical connection strength of the battery may be compromised. Furthermore, if a thermal shock occurs, stress is generated due to the difference in thermal expansion coefficients between the current collector layer and the solid electrolyte layer. As a result, peeling is likely to occur at the interface between the current collector layer and the solid electrolyte layer. The battery's durability against thermal cycles also tends to be insufficient. Furthermore, in Patent Document 1, foreign matter may adhere to the exposed portion of the current collector layer. This may result in a short circuit.

[0071] In contrast to Patent Documents 1 and 2, in the battery 100 of this embodiment, multiple cells 30 are electrically connected in parallel and integrated. In the battery 100, the positive electrode current collector 11 and the negative electrode terminal 17 are electrically separated from each other via a gap, and the negative electrode current collector 13 and the positive electrode terminal 16 are electrically separated from each other via a gap. Furthermore, in the battery 100 of this embodiment, for example, the negative electrode current collector 13 is embedded in the electrolyte layer 15, and the exposed portion 13a of the negative electrode current collector 13 is connected to the negative electrode terminal 17. Therefore, the battery 100 of this embodiment is less likely to suffer from the above-mentioned problems. Patent Documents 1 and 2 do not disclose the above-mentioned configuration of the battery 100 of this embodiment.

[0072] [Battery manufacturing method] Next, an example of a method for manufacturing the battery 100 according to this embodiment will be described. The battery 100 according to this embodiment can be manufactured by, for example, a sheet manufacturing method.

[0073] In this specification, the process of producing the cell 30 may be referred to as a "sheet production process." In the sheet production process, for example, a laminate is produced in which precursors of each component of the cell 30 included in the battery 100 according to this embodiment are stacked. In the laminate, for example, a precursor of the positive electrode current collector 11, a sheet of the positive electrode layer 12, a sheet of the electrolyte layer 15, a sheet of the negative electrode layer 14, and a precursor of the negative electrode current collector 13 are stacked in this order. A predetermined number of laminates are produced in accordance with the number of cells 30 to be connected in parallel. The order in which the components included in the laminate are formed is not particularly limited.

[0074] First, the sheet manufacturing process will be described. The sheet manufacturing process includes a step of manufacturing sheets that are precursors of the components of the cell 30 and stacking the sheets.

[0075] The sheet of the positive electrode layer 12 can be produced, for example, by the following method. First, a positive electrode active material, a solid electrolyte as a mixture, a conductive additive, a binder, and a solvent are mixed to obtain a slurry for producing the sheet of the positive electrode layer 12. In this specification, the slurry for producing the sheet of the positive electrode layer 12 is sometimes referred to as a "positive electrode active material slurry." Next, the positive electrode active material slurry is applied onto a precursor of the positive electrode current collector 11 using a printing method or the like. The resulting coating film is dried to form a sheet of the positive electrode layer 12.

[0076] As the precursor of the positive electrode current collector 11, for example, a copper foil having a thickness of about 30 μm can be used. As the positive electrode active material, for example, a Li·Ni·Co·Al composite oxide (LiNi 0.8 Co 0.15 Al 0.05 As the solid electrolyte mixture, for example, a glass powder of Li2S-P2S5-based sulfide having an average particle size of about 10 μm and containing triclinic crystals as the main component can be used. The solid electrolyte can be, for example, a 2×10 -3 S / cm or more 3×10 -3 It has high ionic conductivity of less than S / cm.

[0077] The positive electrode active material slurry can be applied, for example, by screen printing, onto one surface of copper foil, which is a precursor of the positive electrode current collector 11. The resulting coating film has, for example, a predetermined shape and a thickness of approximately 50 μm to 100 μm. The coating film is then dried to obtain a sheet of the positive electrode layer 12. The coating film may be dried at a temperature of 80°C to 130°C. The thickness of the sheet of the positive electrode layer 12 is, for example, 30 μm to 60 μm.

[0078] The sheet of the negative electrode layer 14 can be produced, for example, by the following method. First, a negative electrode active material, a solid electrolyte, a conductive additive, a binder, and a solvent are mixed to obtain a slurry for producing the sheet of the negative electrode layer 14. In this specification, the slurry for producing the sheet of the negative electrode layer 14 may be referred to as a "negative electrode active material slurry." The negative electrode active material slurry is applied onto a precursor of the negative electrode current collector 13 using a printing method or the like. The resulting coating film is dried to form a sheet of the negative electrode layer 14.

[0079] For example, a copper foil having a thickness of about 30 μm can be used as the precursor of the negative electrode current collector 13. For example, a natural graphite powder having an average particle size of about 10 μm can be used as the negative electrode active material. For example, the solid electrolyte exemplified in the method for producing the sheet of the positive electrode layer 12 can be used.

[0080] The negative electrode active material slurry can be applied, for example, by screen printing, onto one surface of copper foil, which is a precursor of the negative electrode current collector 13. The resulting coating film has, for example, a predetermined shape and a thickness of approximately 50 μm to 100 μm. The coating film is then dried to obtain a sheet of the negative electrode layer 14. The coating film may be dried at a temperature of 80°C to 130°C. The thickness of the sheet of the negative electrode layer 14 is, for example, 30 μm to 60 μm.

[0081] The electrolyte layer 15 sheet is disposed between the positive electrode layer 12 sheet and the negative electrode layer 14 sheet. The electrolyte layer 15 sheet can be fabricated, for example, by the following method. First, a solid electrolyte, a conductive additive, a binder, and a solvent are mixed to obtain a slurry for fabricating the electrolyte layer 15 sheet. In this specification, the slurry for fabricating the electrolyte layer 15 sheet may be referred to as a "solid electrolyte slurry." The solid electrolyte slurry is applied onto the positive electrode layer 12 sheet. Similarly, the solid electrolyte slurry is applied onto the negative electrode layer 14 sheet. The solid electrolyte slurry is applied, for example, by a printing method using a metal mask. The resulting coated film has a thickness of, for example, about 100 μm. Next, the coated film is dried. The coated film may be dried at a temperature of 80°C or higher and 130°C or lower. As a result, the electrolyte layer 15 sheets are formed on the positive electrode layer 12 sheet and the negative electrode layer 14 sheet.

[0082] The method for producing the sheet of the electrolyte layer 15 is not limited to the above-mentioned method. The sheet of the electrolyte layer 15 may also be produced by the following method. First, a solid electrolyte slurry is applied to a substrate using a printing method or the like. The substrate is not particularly limited as long as a sheet of the electrolyte layer 15 can be formed thereon, and examples thereof include Teflon (registered trademark), polyethylene terephthalate (PET), and the like. The shape of the substrate is, for example, a film or foil. Next, the coated film formed on the substrate is dried to obtain a sheet of the electrolyte layer 15. The sheet of the electrolyte layer 15 can be peeled off from the substrate and used.

[0083] The solvents used in the positive electrode active material slurry, negative electrode active material slurry, and solid electrolyte slurry are not particularly limited as long as they can dissolve the binder and do not adversely affect battery characteristics. Examples of solvents that can be used include alcohols such as ethanol, isopropanol, n-butanol, and benzyl alcohol, organic solvents such as toluene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethylene glycol ethyl ether, isophorone, butyl lactate, dioctyl phthalate, dioctyl adipate, N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP), and water. These solvents may be used alone or in combination of two or more.

[0084] In this embodiment, the screen printing method is exemplified as a method for applying the positive electrode active material slurry, the negative electrode active material slurry, and the solid electrolyte slurry, but the application method is not limited to this. As the application method, 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 also be used.

[0085] The positive electrode active material slurry, the negative electrode active material slurry, and the solid electrolyte slurry may contain, in addition to the above-mentioned positive electrode active material, negative electrode active material, solid electrolyte, conductive additive, binder, and solvent, auxiliary agents such as plasticizers as needed. The method for mixing the slurries is not particularly limited. Additives such as thickeners, plasticizers, antifoaming agents, leveling agents, and adhesion promoters may be added to the slurries as needed.

[0086] Next, the sheet of electrolyte layer 15 formed on the sheet of positive electrode layer 12 is superimposed on the sheet of electrolyte layer 15 formed on the sheet of negative electrode layer 14. This results in a laminate in which the precursor of positive electrode current collector 11, positive electrode layer 12, electrolyte layer 15, negative electrode layer 14, and negative electrode current collector 13 are laminated in this order.

[0087] Next, the precursor of the positive electrode current collector 11 is cut to obtain the positive electrode current collector 11. Specifically, the precursor of the positive electrode current collector 11 is cut so that when the negative electrode terminal 17 is placed, the positive electrode current collector 11 and the negative electrode terminal 17 are electrically separated from each other via a gap. The cut surface of the positive electrode current collector 11 extends, for example, straight in the second direction y. Cutting of the precursor of the positive electrode current collector 11 can be performed, for example, using a laser. The positive electrode current collector 11 can be formed by cutting the precursor of the positive electrode current collector 11. The shortest distance between the positive electrode current collector 11 and the negative electrode terminal 17 is, for example, 10 μm. The positive electrode current collector 11 and the negative electrode terminal 17 are electrically separated from each other by the gap between them. In other words, the gap between the positive electrode current collector 11 and the negative electrode terminal 17 provides electrical insulation.

[0088] Next, the precursor of the negative electrode current collector 13 is cut to obtain the negative electrode current collector 13. Specifically, the precursor of the negative electrode current collector 13 is cut so that when the positive electrode terminal 16 is placed, the negative electrode current collector 13 and the positive electrode terminal 16 are electrically separated from each other via a gap. The cut surface of the negative electrode current collector 13 extends, for example, straight in the second direction y. Cutting of the precursor of the negative electrode current collector 13 can be performed, for example, using a laser. The negative electrode current collector 13 can be formed by cutting the precursor of the negative electrode current collector 13. The shortest distance between the negative electrode current collector 13 and the positive electrode terminal 16 is, for example, 10 μm. The negative electrode current collector 13 and the positive electrode terminal 16 are electrically separated from each other by the gap between them. In other words, the gap between the negative electrode current collector 13 and the positive electrode terminal 16 is electrically insulating.

[0089] The order in which the precursor of the positive electrode current collector 11 and the precursor of the negative electrode current collector 13 are cut is not particularly limited. The precursor of the positive electrode current collector 11 may be cut after the precursor of the negative electrode current collector 13, or the precursor of the negative electrode current collector 13 may be cut after the precursor of the positive electrode current collector 11 is cut. The cutting of the precursor of the positive electrode current collector 11 and the cutting of the precursor of the negative electrode current collector 13 may be performed before the sheet of the electrolyte layer 15 formed on the sheet of the positive electrode layer 12 and the sheet of the electrolyte layer 15 formed on the sheet of the negative electrode layer 14 are superimposed. The cutting of the precursor of the positive electrode current collector 11 and the cutting of the precursor of the negative electrode current collector 13 may be performed using a means such as dicing. The precursor of the positive electrode current collector 11 may be cut and a portion of the precursor removed to provide an insulating portion. The precursor of the negative electrode current collector 13 may be cut and a portion of the precursor removed to provide an insulating portion.

[0090] As described above, the precursor of the positive electrode current collector 11 is cut, and further, the precursor of the negative electrode current collector 13 is cut, thereby obtaining the cell 30.

[0091] Next, a predetermined number of cells 30 are prepared. A conductive adhesive, for example, is applied to each of the main surfaces of the positive electrode current collector 11 exposed to the outside of the cell 30 and the negative electrode current collector 13 exposed to the outside of the cell 30. A screen printing method, for example, can be used to apply the conductive adhesive. In this specification, the main surfaces of the positive electrode current collector 11 and the negative electrode current collector 13 coated with the adhesive material are sometimes referred to as "adhesive surfaces." Next, the adhesive surface of the positive electrode current collector 11 of one cell 30 is bonded to the adhesive surface of the positive electrode current collector 11 of another cell 30, or the adhesive surface of the negative electrode current collector 13 of one cell 30 is bonded to the adhesive surface of the negative electrode current collector 13 of another cell 30. This allows multiple cells 30 to be stacked. The adhesive surfaces can be bonded to each other, for example, by pressure bonding. The temperature during bonding is, for example, 50°C or higher and 100°C or lower. When bonding the bonding surfaces together, the pressure applied to the cells 30 is, for example, 300 MPa or more and 400 MPa or less. The time for applying pressure to the cells 30 is, for example, 90 seconds or more and 120 seconds or less. For bonding, a low-resistance conductive tape can be used instead of a conductive adhesive. A paste-like silver powder or copper powder can also be used instead of a conductive adhesive. By pressurizing and bonding the bonding surface of one cell 30 coated with paste-like silver powder or copper powder to the bonding surface of another cell 30, the current collectors can be mechanically bonded to each other by an anchor effect via the metal particles. The method for stacking multiple cells 30 is not particularly limited as long as the method can provide adhesion and conductivity.

[0092] Next, each of the multiple cells 30 is electrically connected to the positive electrode terminal 16 and the negative electrode terminal 17. The multiple cells 30 can be electrically connected to the terminals 16 and 17, for example, by the following method. First, a conductive resin paste is applied to the surface of the stack of the multiple cells 30 where the terminals 16 and 17 are to be disposed. The terminals 16 and 17 are formed by hardening the conductive resin paste. This results in the battery 100 according to this embodiment. The temperature for hardening the conductive resin paste is, for example, about 100°C or higher and 300°C or lower. The time for hardening the conductive resin paste is, for example, 60 minutes.

[0093] The conductive resin paste may be a thermosetting conductive paste containing high-melting-point, highly conductive metal particles, such as Ag, Cu, Ni, Zn, Al, Pd, Au, Pt, or an alloy thereof, low-melting-point metal particles, and a resin. The melting point of the highly conductive metal particles is, for example, 400°C or higher. The melting point of the low-melting-point metal particles may be 300°C or lower, or lower than the curing temperature of the conductive resin paste. Examples of materials for the low-melting-point metal particles include Sn, SnZn, SnAg, SnCu, SnAl, SnPb, In, InAg, InZn, InSn, Bi, BiAg, BiNi, BiSn, BiZn, and BiPb. By using a conductive paste containing such low-melting-point metal powder, solid-phase and liquid-phase reactions proceed at the contact point between the conductive paste and the current collector at a thermosetting temperature lower than the melting point of the low-melting-point metal particles. As a result, for example, an alloy containing the metal contained in the conductive paste and the metal contained in the current collector is formed. A diffusion layer containing the alloy is formed near the connection between the current collector and the terminal. When Ag or an Ag alloy is used as the conductive particles and Cu is used for the current collector, a highly conductive alloy containing AgCu is formed. Furthermore, AgNi, AgPd, etc. can be formed by combining the material of the conductive particles with the material of the current collector. In this way, the terminal and the current collector are integrally joined by the diffusion layer containing the alloy. With this configuration, the terminal and the current collector are connected more firmly than by the anchor effect. Therefore, problems such as disconnection of the components due to differences in thermal expansion of the components of the battery 100 due to thermal cycles or impacts are less likely to occur.

[0094] The shapes of the highly conductive metal particles and the low-melting-point metal particles are not particularly limited and may be spherical, scaly, needle-like, or the like. The smaller the particle size of these metal particles, the lower the temperature at which the alloying reaction and alloy diffusion proceed. Therefore, the particle size and shape of these metal particles can be appropriately adjusted taking into account the process design and the effect of thermal history on battery characteristics.

[0095] The resin used in the thermosetting conductive paste is not particularly limited as long as it functions as a binder, and an appropriate resin can be selected depending on the manufacturing process to be adopted, such as suitability for printing methods and coatability. Resins used in the thermosetting conductive paste include, for example, thermosetting resins. Examples of thermosetting resins include amino resins such as urea resin, melamine resin, and guanamine resin; epoxy resins such as bisphenol A, bisphenol F, phenol novolac, and alicyclic; phenolic resins such as oxetane resin, resol, and novolac; and silicone-modified organic resins such as silicone epoxy and silicone polyester. These resins may be used alone or in combination of two or more.

[0096] In this embodiment, the battery 100 may further include a bonding layer to improve the bonding strength between the current collector and the electrolyte layer 15. The bonding layer is located at the interface between the positive electrode current collector 11 and the electrolyte layer 15. The bonding layer is also located at the interface between the contact portion of the side surface of the negative electrode current collector 13 and the electrolyte layer 15. Examples of materials for the bonding layer include components constituting the current collector. Examples of components constituting the current collector include copper, aluminum, and alloys containing these as main components. Examples of other bonding layer materials include oxides, sulfides, and halides. The bonding layer may further include other components constituting the current collector and / or components constituting the electrolyte layer 15. This allows the current collector to be firmly bonded to the electrolyte layer 15 inside the stacked battery 100. With this configuration, the bonding strength at the interface between the current collector and the electrolyte layer 15 can be improved by chemical bonding, thereby realizing an integrated stacked battery 100 with higher bonding strength.

[0097] The bonding layer can be produced by stacking multiple cells 30 as described above and bonding them together under pressure. For example, when bonding the bonding surfaces of multiple cells 30 together under pressure, copper contained in the current collector and sulfide contained in the electrolyte layer 15 diffuse at the interface between the current collector and the electrolyte layer 15, forming a copper sulfide layer. The bonding layer may contain substances other than copper sulfide. The temperature at which the bonding layer is formed is, for example, 100°C. The time for forming the bonding layer is, for example, 5 minutes. The thickness of the bonding layer formed in this manner is approximately 1 μm. However, the thickness of the bonding layer is not particularly limited and may be, for example, 0.1 μm or more and 10 μm or less.

[0098] The presence of the bonding layer produced as described above can be confirmed by observing the cross section of the battery 100 using a normal optical microscope, a laser microscope, or a scanning electron microscope (SEM). The composition of the bonding layer can be evaluated by composition analysis using, for example, a bonding layer electron probe microanalyzer (EPMA).

[0099] The manufacturing method of this embodiment shows an example in which the battery 100 is produced by a powder pressing process. However, it is also possible to produce a laminate of sintered bodies using a firing process, and then to produce the terminals 16 and 17 by applying a conductive resin paste to the laminate and baking it.

[0100] In the battery 100, multiple cells 30 are connected in parallel, sharing a negative electrode current collector 13. Positive electrode current collectors 11 are located on the top and bottom surfaces of the cells. However, the battery may also have multiple cells 30 connected in parallel, sharing a positive electrode current collector 11. In this case, negative electrode current collectors 13 are located on the top and bottom surfaces of the cells. Furthermore, most of the positive electrode current collector 11 is embedded in the electrolyte layer 15, and the positive electrode current collector 11 may have an exposed portion for contacting a positive electrode terminal 16.

[0101] (Embodiment 2) FIG. 3 is a schematic diagram illustrating the configuration of a battery 200 according to the second embodiment. FIG. 3(a) is a cross-sectional view of the battery 200 according to the present embodiment. FIG. 3(b) is a top view of the battery 200. Elements common to the battery 100 according to the first embodiment and the battery 200 according to the present embodiment are denoted by the same reference numerals, and their description may be omitted. That is, the following descriptions of the respective embodiments may be mutually applied unless technically inconsistent. Furthermore, the respective embodiments may be combined with each other unless technically inconsistent.

[0102] 3, in the negative electrode current collector 13, the thickness of the protruding portion 13p is smaller than the thickness of the remaining portion 13r. This allows the area of ​​the exposed portion 13a to be further reduced. Therefore, the interface between the exposed portion 13a and the electrolyte layer 15 can be reduced without affecting the electrical characteristics of the battery 200. As a result, the area where peeling is likely to occur between the negative electrode current collector 13 and the electrolyte layer 15 can be reduced, thereby realizing a highly reliable battery 200.

[0103] Because the thickness of the protruding portion 13p is smaller than the thickness of the remaining portion 13r, variations in pressure during pressure bonding are reduced. Furthermore, because the area of ​​the exposed portion 13a in contact with the negative electrode terminal 17 is small, even if stress due to tension occurs in the negative electrode terminal 17, it is less likely to affect the negative electrode current collector 13. This further improves the bonding strength between the negative electrode current collector 13 and the electrolyte layer 15. Furthermore, because multiple cells 30 connected in parallel can be firmly integrated into a compact unit, a battery 200 with large capacity, high energy density, and high reliability can be realized.

[0104] The ratio (D2 / D1) of the thickness D2 of the protruding portion 13p to the thickness D1 of the remaining portion 13r is not particularly limited and is determined appropriately depending on the size, material, etc. of the battery 200. The ratio (D2 / D1) is, for example, in the range of 3 to 10.

[0105] The thickness of the protruding portion 13p and the thickness of the remaining portion 13r can be determined by averaging values ​​measured at any number of points (for example, five points). For the measurement, for example, a micrometer is used. In this embodiment, the thickness is the dimension in a direction parallel to the third direction z.

[0106] (Embodiment 3) FIG. 4 is a schematic diagram illustrating the configuration of a battery 300 according to the third embodiment. FIG. 4(a) is a cross-sectional view of the battery 300 according to the present embodiment. FIG. 4(b) is a top view of the battery 300. As shown in FIG. 4, in the stacked battery 300, the negative electrode current collector 13 further has lock holes 21. In this specification, the lock holes 21 may be referred to as "through holes." Except for the above, the structure of the battery 300 is the same as the structure of the battery 100 according to the first embodiment.

[0107] The lock holes 21 are, for example, through-holes that penetrate the negative electrode current collector 13 in the stacking direction of the multiple cells 30. The lock holes 21 are formed in the portion where the negative electrode current collector 13 and the electrolyte layer 15 contact each other. The lock holes 21 are not formed in the portion where the negative electrode current collector 13 and the negative electrode layer 14 contact each other. The lock holes 21 may be formed in the remaining portion 13r of the negative electrode current collector 13 or in the protruding portion 13p. The electrolyte layer 15 is present inside the lock holes 21. In other words, the inside of the lock holes 21 is filled with the electrolyte that constitutes the electrolyte layer 15. This configuration improves the bonding strength between the negative electrode current collector 13 and the electrolyte layer 15 due to the anchor effect. Furthermore, since the multiple cells 30 connected in parallel can be firmly integrated into a small size, a battery 300 with high capacity, high energy density, and high reliability can be realized.

[0108] The shape, size, and number of the lock holes 21 are not particularly limited as long as they can improve the bonding strength between the negative electrode current collector 13 and the electrolyte layer 15. The shape of the lock holes 21 is, for example, cylindrical. The size of the lock holes 21 is not particularly limited, and may be 200 μm or more and 500 μm or less in diameter, 30 μm or more and 500 μm or less in diameter, or 30 μm or more and 100 μm or less in diameter. The number of lock holes 21 formed in the negative electrode current collector 13 is not particularly limited.

[0109] The method for forming the lock holes 21 in the negative electrode current collector 13 is not particularly limited. For example, after preparing a precursor for the negative electrode current collector 13 as described above, the lock holes 21 can be formed by cutting the precursor for the negative electrode current collector 13. Specifically, the lock holes 21 can be formed in the precursor for the negative electrode current collector 13 by cutting a portion of the negative electrode current collector 13 so as to penetrate the precursor in the stacking direction. The lock holes 21 extend, for example, straight in the stacking direction of the multiple cells 30. The precursor for the negative electrode current collector 13 can be cut, for example, with a laser. The lock holes 21 can be formed in the negative electrode current collector 13 by cutting the precursor for the negative electrode current collector 13. Another example of forming the lock holes 21 in the negative electrode current collector 13 is punching. In this case, the lock holes 21 can be formed by punching a metal sheet in the negative electrode current collector 13. The intervals between each of the multiple lock holes 21 are, for example, 50 μm. With this configuration, the bonding strength between the negative electrode current collector 13 and the electrolyte layer 15 can be improved.

[0110] (Embodiment 4) FIG. 5 is a schematic diagram illustrating the configuration of a battery 400 according to the fourth embodiment. FIG. 5(a) is a cross-sectional view of the battery 400 according to the present embodiment. FIG. 5(b) is a top view of the battery 400. As shown in FIG. 5, in the battery 400, each of the multiple cells further includes a dummy current collector 31. Except for the above, the structure of the battery 400 is the same as the structure of the battery 100 according to the first embodiment.

[0111] In this embodiment, the dummy current collector 31 is located around the battery 400. Furthermore, the dummy current collector 31 is located around the shielding portion 13b of the negative electrode current collector 13. This configuration reduces pressure variations during pressure bonding, thereby achieving a highly reliable battery 400. This also makes it easier to achieve a uniform density within the laminate.

[0112] The dummy current collector 31 is electrically isolated from the negative electrode current collector 13. That is, the negative electrode current collector 13 is electrically insulated from the dummy current collector 31. The dummy current collector 31 is separated from the negative electrode current collector 13 by a gap. With this configuration, the dummy current collector 31 can function as a reinforcing material. Therefore, a highly reliable battery 400 can be realized.

[0113] A portion of the dummy current collector 31 may be embedded in the electrolyte layer 15. The dummy current collector 31 may be exposed from the electrolyte layer 15. In other words, the dummy current collector 31 may have a portion exposed from the electrolyte layer 15. The exposed portion of the dummy current collector 31 may be in contact with the positive electrode terminal 16. The dummy current collector 31 is not in contact with, for example, the negative electrode terminal 17. The dummy current collector 31 is, for example, U-shaped in a plan view.

[0114] The dummy current collector 31 is located at the same height as the negative electrode current collector 13 in the stacking direction of the multiple cells 30. Therefore, stress caused by bending of the current collector, which is generated around the negative electrode current collector 13 during pressure bonding, can be reduced. This makes it easier to achieve uniform density inside the stack. As a result, structural defects in the battery 400 are reduced. Furthermore, areas where peeling is likely to occur between the negative electrode current collector 13 and the electrolyte layer 15 can be reduced, resulting in a highly reliable battery 400. Furthermore, by forming the dummy current collector 31, a battery 400 can be easily manufactured in which stress caused by bending of the current collector can be reduced.

[0115] The dummy current collector 31 can be produced, for example, by the following method. First, a precursor of the negative electrode current collector 13 is produced as described above. Next, the precursor of the negative electrode current collector 13 is cut to obtain the dummy current collector 31. Specifically, the precursor of the negative electrode current collector 13 is cut so that the negative electrode current collector 13 and the dummy current collector 31 are electrically separated from each other via a gap. The cut surface of the negative electrode current collector 13 extends straight in the first direction x and the second direction y, for example. Cutting the precursor of the negative electrode current collector 13 can be performed, for example, using a laser. By cutting the precursor of the negative electrode current collector 13, the negative electrode current collector 13 and the dummy current collector 31 can be formed. The gap between the negative electrode current collector 13 and the dummy current collector 31 is, for example, 30 μm. Cutting the precursor of the negative electrode current collector 13 may be performed using a means such as dicing. The dummy current collector 31 may be formed by cutting the precursor of the negative electrode current collector 13 and removing a portion of the precursor.

[0116] The dummy current collector 31 does not function as a current collector, to be precise. Therefore, the material used for the dummy current collector 31 is not particularly limited. For example, the dummy current collector 31 may contain the same material as the positive electrode current collector 11 or the negative electrode current collector 13, or may contain an insulating material. The dummy current collector 31 may be made of the same material as the positive electrode current collector 11 or the negative electrode current collector 13, or may be made of an insulating material. Note that, by having the same hardness as the positive electrode current collector 11 or the negative electrode current collector 13, pressure variations during pressure bonding are further reduced. This allows for the realization of a highly reliable battery 400. In this regard, the dummy current collector 31 may be made of the same material as the current collectors 11 and / or 13.

[0117] The dummy current collector 31 may further have a lock hole. The lock hole is, for example, a through-hole that penetrates the dummy current collector 31 in the stacking direction of the multiple cells 30. The electrolyte layer 15 is present inside the lock hole. In other words, the lock hole is filled with the electrolyte that constitutes the electrolyte layer 15. With this configuration, the anchor effect can improve the bonding strength between the dummy current collector 31 and the electrolyte layer 15. Furthermore, since the multiple cells 30 connected in parallel can be firmly integrated into a compact unit, a battery 400 with large capacity, high energy density, and high reliability can be realized.

[0118] The shape, size, and number of the lock holes are not particularly limited as long as they can improve the bonding strength between dummy current collector 31 and electrolyte layer 15. The shape of the lock holes is, for example, cylindrical. The size of the lock holes is not particularly limited, and may be 200 μm or more and 500 μm or less in diameter, 30 μm or more and 500 μm or less in diameter, or 30 μm or more and 100 μm or less in diameter. The number of lock holes formed in dummy current collector 31 is not particularly limited.

[0119] There is no particular limitation on the method for forming lock holes in dummy current collector 31. They can be formed by the same method as that for forming lock holes 21. The intervals between the multiple lock holes are, for example, 50 μm. With this configuration, the bonding strength between dummy current collector 31 and electrolyte layer 15 can be improved.

[0120] In this embodiment, a bonding layer may be further formed to improve the bonding strength between the dummy current collector 31 and the electrolyte layer 15. The bonding layer is located at the interface between the dummy current collector 31 and the electrolyte layer 15. The material of the bonding layer may contain the components constituting the dummy current collector 31 and / or the components constituting the electrolyte layer 15. With this configuration, the bonding strength at the interface between the dummy current collector 31 and the electrolyte layer 15 can be improved by chemical bonding, thereby realizing an integrated stacked battery 400 with higher bonding strength.

[0121] (Embodiment 5) FIG. 6 is a schematic diagram illustrating the configuration of a battery 500 according to the fifth embodiment. FIG. 6(a) is a cross-sectional view of the battery 500 according to the present embodiment. FIG. 6(b) is a top view of the battery 500. As shown in FIG. 6, in the battery 500, each of the multiple cells further includes a dummy current collector 41. Except for the above, the structure of the battery 500 is the same as the structure of the battery 100 according to the first embodiment.

[0122] In this embodiment, the dummy current collector 41 is located around the periphery of the battery 500. However, the dummy current collector 41 differs from the battery 400 in that it is located on a different plane from the negative electrode current collector 13. That is, the dummy current collector 41 is located at a different height from the negative electrode current collector 13 in the stacking direction of the multiple cells 30. The dummy current collector 41 is electrically isolated from the positive electrode current collector 11, the positive electrode layer 12, and the negative electrode layer 14. A portion of the dummy current collector 41 may be embedded in the electrolyte layer 15. The dummy current collector 41 may be exposed from the electrolyte layer 15. In other words, the dummy current collector 41 may have a portion exposed from the electrolyte layer 15. The exposed portion of the dummy current collector 41 may be in contact with the positive electrode terminal 16. The dummy current collector 41 is not in contact with, for example, the negative electrode terminal 17. The dummy current collector 41 has, for example, a U-shape in plan view. With this configuration, even if a thermal shock occurs, stress caused by the difference in thermal expansion coefficient between the current collector and the electrolyte layer 15 can be reduced. Therefore, peeling between the negative electrode current collector 13 and the electrolyte layer 15 is unlikely to occur. As a result, a battery 500 with high reliability against thermal cycles can be realized.

[0123] The dummy current collector 41 can be produced, for example, by the following method. First, a precursor of the dummy current collector 41 is formed on a sheet of the electrolyte layer 15. Next, the precursor of the dummy current collector 41 is cut to obtain the dummy current collector 41. Specifically, the precursor of the dummy current collector 41 is cut so that the dummy current collector 41 is positioned around the cell. The cut surface of the precursor of the dummy current collector 41 extends straight in the first direction x and the second direction y, for example. The precursor of the dummy current collector 41 can be cut using, for example, a laser. The dummy current collector 41 can be formed by cutting the precursor of the dummy current collector 41. The precursor of the dummy current collector 41 may be cut using a means such as dicing.

[0124] To be precise, the dummy current collector 41 does not function as a current collector. Therefore, the material used for the dummy current collector 41 is not particularly limited. For example, the same material as that of the dummy current collector 31 may be used. Note that the dummy current collector 41 has a hardness similar to that of the positive electrode current collector 11 or the negative electrode current collector 13, and thus can reduce stress caused by the difference in thermal expansion coefficient between the current collector and the electrolyte layer 15 even when a thermal shock occurs. Therefore, delamination between the negative electrode current collector 13 and the electrolyte layer 15 is unlikely to occur. As a result, a battery 500 with high reliability against thermal cycles can be realized.

[0125] Like the dummy current collector 31, the dummy current collector 41 may further have lock holes. The lock holes are, for example, through-holes that penetrate the dummy current collector 41 in the stacking direction of the multiple cells 30. The electrolyte layer 15 is present inside the lock holes. In other words, the lock holes are filled with the electrolyte that constitutes the electrolyte layer 15. With this configuration, the anchor effect can improve the bonding strength between the dummy current collector 41 and the electrolyte layer 15. Furthermore, since the multiple cells 30 connected in parallel can be firmly integrated into a small size, a battery 500 with large capacity, high energy density, and high reliability can be realized.

[0126] While the battery and stacked battery according to the present disclosure have been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications conceivable by those skilled in the art to the embodiments and other forms constructed by combining some of the components of the embodiments are also included within the scope of the present disclosure. [Industrial Applicability]

[0127] The battery according to the present disclosure can be used as a secondary battery such as an all-solid-state battery used in various electronic devices, automobiles, etc. Explanation of symbols

[0128] 11 Positive electrode current collector 12 Positive electrode layer 13 Negative electrode current collector 13a Exposed part 13b Shield part 13p protruding part 13r remaining part 14 negative electrode layer 15 Electrolyte layer 16 Positive terminal 17 Negative terminal 21 Rock Hall 30 cells 31,41 Dummy current collector 100,200,300,400,500 batteries

Claims

1. A plurality of cells electrically connected in parallel, Each of the plurality of cells a positive electrode layer; a negative electrode layer; a current collector in contact with the positive electrode layer or the negative electrode layer; an electrolyte layer disposed between the positive electrode layer and the negative electrode layer; and a side surface of the current collector includes an exposed portion exposed from the electrolyte layer and a shielded portion shielded by the electrolyte layer; The area of ​​the shielding portion is larger than the area of ​​the exposed portion. battery.

2. a terminal electrically connected to the current collector; The exposed portion is in contact with the terminal. The battery of claim 1 .

3. The electrolyte layer is a solid electrolyte layer containing a solid electrolyte. The battery according to claim 1 or 2.

4. The electrolyte layers of the adjacent cells are joined together around the shielding portion. The battery according to any one of claims 1 to 3.

5. The current collector has a protruding portion, The exposed portion is included in the protruding portion. The battery of any one of claims 1 to 4.

6. the current collector has a remaining portion other than the protruding portion, The width of the protruding portion is narrower than the width of the remaining portion. The battery of claim 5.

7. the current collector has a remaining portion other than the protruding portion, The thickness of the protruding portion is smaller than the thickness of the remaining portion. The battery according to claim 5 or 6.

8. The current collector has through holes. The battery of any one of claims 1 to 7.

9. The electrolyte layer is present inside the through-hole. The battery of claim 8.

10. Further comprising a bonding layer; the bonding layer is located at the interface between the current collector and the electrolyte layer, and contains at least one element among the elements contained in the current collector and at least one element among the elements contained in the electrolyte layer; 10. The battery of claim 1.

11. the bonding layer is present at the interface between the shielding portion and the electrolyte layer; The battery of claim 10.

12. Further comprising a dummy current collector present around the shielding portion of the current collector.

12. The battery of claim 1.

13. The dummy current collector contains the same material as the current collector. The battery of claim 12.

14. The dummy current collector includes an insulating material. The battery of claim 12.

15. The dummy current collector is electrically isolated from the current collector.

15. The battery of any one of claims 12 to 14.

16. The dummy current collector is spaced apart from the current collector.

16. The battery of claim 15.

17. the dummy current collector is exposed from the electrolyte layer.

17. The battery of any one of claims 12 to 16.

18. Each of the plurality of cells has a flat plate shape, the battery is configured by stacking the plurality of cells, The dummy current collector is located at the same height as the current collector in the stacking direction of the plurality of cells.

18. The battery of any one of claims 12 to 17.

19. Each of the plurality of cells has a flat plate shape, the battery is configured by stacking the plurality of cells, the dummy current collector is located at a different height from the current collector in the stacking direction of the plurality of cells.

18. The battery of any one of claims 12 to 17.

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