Battery

Abstract

The battery disclosed herein comprises a plurality of units electrically connected in parallel, wherein the plurality of units respectively comprise: a positive electrode layer; a negative electrode layer; a current collector in contact with the positive electrode layer or the negative electrode layer; and an electrolyte layer arranged between the positive electrode layer and the negative electrode layer, wherein the side surface of the current collector comprises an exposed portion exposed from the electrolyte layer and a shielded portion shielded by the electrolyte layer, and the area of ​​the shielded portion is larger than the area of ​​the exposed portion.

Description

Technical Field

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

[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 secondary battery having an electrode extraction portion at one end of a collector body. Patent Document 2 discloses a fully solid battery having a terminal collector mounted on the end face of a stack.

[0003] Prior Art Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2007-103129

[0005] Patent Document 2: Japanese Patent Application Publication No. 2013-120717 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the prior art, there is a demand for batteries with high reliability.

[0008] Means for solving problems

[0009] The present disclosure provides a battery having a plurality of cells electrically connected in parallel,

[0010] The plurality of units respectively include:

[0011] positive electrode layer;

[0012] Negative electrode layer;

[0013] a current collector in contact with the positive electrode layer or the negative electrode layer; and

[0014] an electrolyte layer disposed between the positive electrode layer and the negative electrode layer,

[0015] The side surface of the current collector includes an exposed portion exposed from the electrolyte layer and a shielded portion shielded by the electrolyte layer.

[0016] The area of ​​the shielding portion is larger than the area of ​​the exposed portion.

[0017] Effects of the Invention

[0018] According to the present disclosure, a battery having high reliability can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view and a plan view for schematically explaining the structure of the battery according to the first embodiment.

[0020] Figure 2 It is a top view of the negative electrode current collector.

[0021] Figure 3 It is a cross-sectional view and a plan view for schematically illustrating the structure of the battery according to the second embodiment.

[0022] Figure 4 It is a cross-sectional view and a plan view for schematically illustrating the structure of a battery according to the third embodiment.

[0023] Figure 5 It is a cross-sectional view and a plan view for schematically illustrating the structure of a battery according to the fourth embodiment.

[0024] Figure 6 It is a cross-sectional view and a plan view for schematically illustrating the structure of a battery according to the fifth embodiment. DETAILED DESCRIPTION

[0025] (Summary of a technical solution involved in the present disclosure)

[0026] The battery according to the first technical solution of the present disclosure,

[0027] having a plurality of units electrically connected in parallel,

[0028] The plurality of units respectively include:

[0029] positive electrode layer;

[0030] Negative electrode layer;

[0031] a current collector in contact with the positive electrode layer or the negative electrode layer; and

[0032] an electrolyte layer disposed between the positive electrode layer and the negative electrode layer,

[0033] The side surface of the current collector includes an exposed portion exposed from the electrolyte layer and a shielded portion shielded by the electrolyte layer.

[0034] The area of ​​the shielding portion is larger than the area of ​​the exposed portion.

[0035] According to the first invention, a battery with high reliability can be realized.

[0036] In the second technical solution of the present disclosure, for example, the battery according to the first technical solution may further include a terminal electrically connected to the current collector, and the exposed portion may be in contact with the terminal. With such a structure, the bonding strength between the current collector and the electrolyte layer can be improved.

[0037] 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 battery with high reliability can be realized.

[0038] In a fourth aspect of the present disclosure, for example, in the battery according to the first to third aspects, the electrolyte layers of adjacent cells may be joined to each other around the shielding portion. With such a structure, the battery capacity can be increased.

[0039] In a fifth aspect of the present disclosure, for example, in the battery according to the first to fourth aspects, the current collector may have a protrusion, and the exposed portion may be included in the protrusion. With such a structure, the electrode terminal can be efficiently connected.

[0040] In the sixth technical solution of the present disclosure, for example, based on the battery involved in the fifth technical solution, the current collector may have a residual portion other than the protrusion, and the width of the protrusion may be smaller than the width of the residual portion. According to such a structure, the portion between the current collector and the electrolyte layer that is prone to peeling can be reduced.

[0041] In the seventh technical solution of the present disclosure, for example, based on the battery involved in the fifth or sixth technical solution, the collector may have a residual portion other than the protruding portion, and the thickness of the protruding portion may be smaller than the thickness of the residual portion. According to such a structure, the portion between the collector and the electrolyte layer that is prone to peeling can be reduced.

[0042] In an eighth aspect of the present disclosure, for example, in the battery according to the first to seventh aspects, the current collector may have a through hole. With such a structure, the bonding strength between the current collector and the electrolyte layer can be increased.

[0043] 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 such a structure, the bonding strength between the current collector and the electrolyte layer can be increased.

[0044] In the tenth technical solution of the present disclosure, for example, on the basis of the battery involved in the first to ninth technical solutions, a bonding layer may be further provided, and the bonding layer may be located at the interface between the current collector and the electrolyte layer, and may contain 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. According to such a structure, the bonding strength between the current collector and the electrolyte layer can be improved.

[0045] In the 11th technical solution of the present disclosure, for example, in the battery according to the 10th technical solution, the bonding layer may be present at the interface between the shielding portion and the electrolyte layer. With such a structure, the bonding strength between the current collector and the electrolyte layer can be improved.

[0046] In a twelfth aspect of the present disclosure, for example, in addition to the battery according to the first to eleventh aspects, a dummy current collector may be further provided around the shielding portion of the current collector. With such a structure, it is possible to further reduce the fluctuation of the pressure during the crimping.

[0047] In a thirteenth aspect of the present disclosure, for example, in the battery according to the twelfth aspect, the dummy current collector may be made of the same material as the current collector. With such a structure, it is possible to further reduce the variation in pressure during compression.

[0048] In a fourteenth aspect of the present disclosure, for example, in the battery according to the twelfth aspect, the dummy current collector may include an insulating material. With such a structure, it is possible to further reduce the variation in pressure.

[0049] In a fifteenth aspect of the present disclosure, for example, in the battery according to any one of the twelfth to fourteenth aspects, the dummy current collector can be electrically separated from the current collector. With such a structure, a highly reliable battery can be realized.

[0050] In a sixteenth aspect of the present disclosure, for example, in the battery according to the fifteenth aspect, the dummy current collector can be separated from the current collector. With such a structure, a battery with high reliability can be realized.

[0051] In a seventeenth aspect of the present disclosure, for example, in the battery according to any one of the twelfth to sixteenth aspects, the dummy current collector may be exposed from the electrolyte layer. With such a structure, it is possible to further reduce fluctuations in pressure during compression bonding.

[0052] In the 18th technical solution of the present disclosure, for example, based on the battery involved in the 12th to 17th technical solutions, the plurality of units can each have a flat plate shape, the battery can be formed by stacking the plurality of units, and the dummy current collector can be located at the same height as the current collector in the stacking direction of the plurality of units. According to such a structure, the portion between the current collector and the electrolyte layer that is prone to peeling can be reduced.

[0053] In the 19th technical solution of the present disclosure, for example, based on the battery involved in the 12th to 17th technical solutions, the plurality of units may each have a flat plate shape, the battery may be formed by stacking the plurality of units, and the dummy current collector may be located at a different height from the current collector in the stacking direction of the plurality of units. According to such a structure, the portion between the current collector and the electrolyte layer that is prone to peeling can be reduced.

[0054] Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0055] Furthermore, the embodiments described below all represent general or specific examples. The numerical values, shapes, materials, components, configuration positions and connection methods of the components shown in the following embodiments are only examples, and their main purpose does not limit the present disclosure. In addition, the components in the following embodiments that are not recorded in the independent claims representing the highest concept are described as arbitrary components.

[0056] In addition, each figure does not necessarily illustrate strictly. In each figure, the same code|symbol is attached|subjected to the substantially same structure, and the repeated description is abbreviate|omitted or simplified.

[0057] (Implementation Method 1)

[0058] [Overview of laminated battery]

[0059] First, the battery according to this embodiment will be described.

[0060] Figure 1 This is a schematic diagram for explaining the structure of a laminated battery 100 according to Embodiment 1. In this embodiment, the battery 100 is a laminated battery. Therefore, in this specification, the "battery 100" may be referred to as a "laminated battery 100". Figure 1 (a) is a cross-sectional view of a battery 100 according to this embodiment. Figure 1 (b) is a top view of the battery 100 .

[0061] like Figure 1 As shown in (a), the battery 100 includes a plurality of cells 30, a positive electrode terminal 16, and a negative electrode terminal 17. In this specification, a "cell" may be referred to as a "solid battery cell". The plurality of cells 30 are electrically connected in parallel. Figure 1As shown in (b), each of the plurality of units 30 has, for example, a rectangular shape when viewed from above. Each of the plurality of units 30 has two sets of a pair of end faces that are opposite to each other. Each of the plurality of units 30 has, for example, a flat plate shape. The battery 100 is constructed by stacking a plurality of units 30. In the present embodiment, the first direction x is a direction from one of a pair of end faces of a specific unit 30 toward the other. The second direction y is a direction from one of the other pair of end faces of the specific unit 30 toward the other, and is a direction orthogonal to the first direction x. The third direction z is a stacking direction of the plurality of units 30, and is a direction orthogonal to the first direction x and the second direction y, respectively.

[0062] The number of the plurality of cells 30 is not particularly limited, and may be 20 or more and 100 or less, 2 or more and 10 or less. 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.

[0063] The positive terminal 16 and the negative terminal 17 are electrically connected to the plurality of cells 30, respectively. The shape of each of the positive terminal 16 and the negative terminal 17 is, for example, a plate shape. The positive terminal 16 and the negative terminal 17 are opposite to each other. The positive terminal 16 and the negative terminal 17 are arranged in the first direction x. The plurality of cells 30 are located between the positive terminal 16 and the negative terminal 17. In this specification, the positive terminal 16 and the negative terminal 17 are sometimes referred to as "terminals".

[0064] The plurality of cells 30 respectively include a positive electrode collector 11, a positive electrode layer 12, a negative electrode collector 13, a negative electrode layer 14, and an electrolyte layer 15. The positive electrode collector 11, the positive electrode layer 12, the electrolyte layer 15, the negative electrode layer 14, and the negative electrode 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 collector 11 and the negative electrode collector 13 are sometimes referred to as simply "collectors".

[0065] The positive electrode collector 11 has, for example, a plate-like shape. The positive electrode collector 11 is electrically connected to the positive electrode layer 12 and the positive terminal 16, respectively. The positive electrode collector 11 may be in direct contact with the positive electrode layer 12 and the positive terminal 16, respectively. For example, the main surface of the positive electrode collector 11 may be in direct contact with the positive electrode layer 12. "Main surface" refers to the surface with the largest area of ​​the positive electrode collector 11. The end (end surface) of the positive electrode collector 11 may be in direct contact with the positive terminal 16. The positive electrode collector 11 and the negative terminal 17 are electrically separated from each other by a gap. There is no particular limitation on the shortest distance between the positive electrode collector 11 and the negative terminal 17, and it may be greater than 20 μm and less than 100 μm, greater than 1 μm and less than 100 μm, or greater than 1 μm and less than 10 μm. In this specification, the vicinity of the end surface of the unit 30 is sometimes referred to as the "end region" of the unit 30. The positive electrode current collector 11 and the negative electrode terminal 17 are electrically separated from each other via a gap, for example, in an end region of the cell 30 .

[0066] The positive electrode layer 12 has a rectangular shape in a plan view, for example. The positive electrode layer 12 is disposed on the positive electrode collector 11. The positive electrode layer 12 partially covers the main surface of the positive electrode collector 11, for example. The positive electrode layer 12 may cover the area including the center of gravity of the main surface of the positive electrode collector 11. The positive electrode layer 12 is not formed in the end area of ​​the cell 30, for example.

[0067] The negative electrode collector 13 has, for example, a plate-like shape. The negative electrode collector 13 is electrically connected to the negative electrode layer 14 and the negative electrode terminal 17, respectively. The negative electrode collector 13 may be in direct contact with the negative electrode layer 14 and the negative electrode terminal 17, respectively. For example, the main surface of the negative electrode collector 13 may be in direct contact with the negative electrode layer 14. The end (end face) of the negative electrode collector 13 may be in direct contact with the negative electrode terminal 17. The negative electrode collector 13 and the positive electrode terminal 16 are electrically separated from each other via a gap. There is no particular limitation on the shortest distance between the negative electrode collector 13 and the positive electrode terminal 16, which may be 20 μm or more and 100 μm or more, 1 μm or more and 10 μm or less. The negative electrode 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 unit 30. In the present embodiment, the exposed portion 13a of the negative electrode collector 13 is in contact with the negative electrode terminal 17. In other words, the negative electrode current collector 13 has an 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. "Side surface" refers to a surface other than the main surface of the negative electrode current collector 13. "Main surface" refers to the surface of the negative electrode current collector 13 with the largest area. The negative electrode current collector 13 may not have any part exposed to the outside except the exposed portion 13a.

[0068] The position of the negative electrode collector 13 is offset from the position of the positive electrode collector 11 in the first direction x. In a plan view, the gap between the negative electrode collector 13 and the positive electrode terminal 16 does not overlap the gap between the positive electrode collector 11 and the negative electrode terminal 17 .

[0069] The negative electrode layer 14 has a rectangular shape in a plan view, for example. The negative electrode layer 14 is disposed on the negative electrode collector 13. The negative electrode layer 14 partially covers the main surface of the negative electrode collector 13, for example. The negative electrode layer 14 may cover the area including the center of gravity of the main surface of the negative electrode collector 13. The negative electrode layer 14 is not formed in the end area of ​​the cell 30, for example.

[0070] The electrolyte layer 15 is located between the positive electrode collector 11 and the negative electrode 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 may be in contact with the positive electrode terminal 16 and the negative electrode terminal 17, respectively. The electrolyte layer 15 may be in contact with the positive electrode layer 12 and the negative electrode layer 14, respectively.

[0071] Figure 2 It is a plan view of the negative electrode current collector 13 .

[0072] like Figure 1 and Figure 2 As shown, the side of the negative electrode 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. According to such a structure, a large-capacity stacked battery 100 with the characteristics of being small, excellent in impact resistance, high in energy density, and high in reliability can be provided.

[0073] The ratio (S2 / S1) of the area S2 of the shielded portion 13b to the area S1 of the exposed portion 13a is appropriately determined according to the size and material of the battery 100 and is not particularly limited. The ratio (S2 / S1) is, for example, in the range of 2 or more and 50 or less.

[0074] In the present embodiment, the negative electrode current collector 13 has a protrusion 13p and a residual portion 13r. The protrusion 13p is a tab-shaped portion. The residual portion 13r is a portion other than the protrusion 13p. The area of ​​the protrusion 13p (area when viewed from above) is smaller than the area of ​​the residual portion 13r (area when viewed from above). In the present embodiment, both the protrusion 13p and the residual portion 13r have a rectangular shape. However, there is no particular limitation on the shapes of the protrusion 13p and the residual portion 13r. The exposed portion 13a is located on the side of the protrusion 13p. The exposed portion 13a is not in contact with the electrolyte layer 15. The exposed portion 13a is electrically connected to the negative terminal 17. In the present embodiment, the exposed portion 13a is entirely included in the protrusion 13p. However, only a portion of the exposed portion 13a may be included in the protrusion 13p. The shielded portion 13b is located on the side of the residual portion 13r and the side of the protrusion 13p. However, the shielded portion 13b does not include the exposed portion 13a on the side of the protruding portion 13p. The shielded portion 13b is in contact with the electrolyte layer 15. The main surface of the remaining portion 13r can be in direct contact with the negative electrode layer 14 and the electrolyte layer 15. The main surface of the protruding portion 13p can be in direct contact with the electrolyte layer 15. According to such a structure, most of the negative electrode collector 13 is buried in the electrolyte layer 15. The area of ​​the portion that becomes the starting point of interlayer peeling can be reduced, and the negative electrode collector 13 can be connected to the negative terminal 17.

[0075] In the negative electrode current collector 13, the protrusion 13p is a portion extending from the residual portion 13r along the first direction x. The length of the protrusion 13p of the negative electrode current collector 13 in the second direction y is smaller than the length of the residual portion 13r in the second direction y. In other words, the width of the protrusion 13p is smaller than the width of the residual portion 13r. According to such a structure, the area of ​​the exposed portion 13a can be reduced. Furthermore, the interface between the exposed portion 13a and the electrolyte layer 15 is reduced. As a result, the portion where peeling easily occurs between the negative electrode current collector 13 and the electrolyte layer 15 can be reduced, so that a battery 100 with high reliability can be realized.

[0076] In this embodiment, the width direction of the battery 100 is a direction parallel to the second direction y, and is a direction perpendicular to both the first direction x and the third direction z. The stacking direction of the plurality of 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 related to the width direction of each portion when the battery 100 is viewed from above.

[0077] The shielding portion 13b of the negative electrode current collector 13 is firmly held by the electrolyte layer 15 having a high bonding strength. The electrolyte layers 15 of adjacent units 30 are bonded to each other around the shielding portion 13b. In the present embodiment, by connecting a plurality of units 30 in parallel in a manner of sharing the negative electrode current collector 13, the negative electrode current collector 13 and the electrolyte layer 15 can be firmly bonded. As a result, the portion where peeling easily occurs between the negative electrode current collector 13 and the electrolyte layer 15 can be reduced. According to such a structure, a large-capacity stacked battery 100 having the characteristics of being small, excellent in impact resistance, high in energy density, and high in reliability can be provided.

[0078] As described above, the battery 100 includes a plurality of cells 30a and 30b. The cell 30a includes a positive electrode collector 11a, a positive electrode layer 12a, a negative electrode collector 13, a negative electrode layer 14a, and an electrolyte layer 15a. The cell 30b includes a positive electrode collector 11b, a positive electrode layer 12b, a negative electrode collector 13, a negative electrode layer 14b, and an electrolyte layer 15b. The negative electrode collector 13 is shared by the cells 30a and 30b. The plurality of positive electrode collectors 11a and 11b and the negative electrode collector 13 are alternately arranged in the third direction z. In the gap between the negative electrode collector 13 and the positive electrode terminal 16, the electrolyte layer 15a may be in contact with the electrolyte layer 15b.

[0079] [Structure of laminated battery]

[0080] Hereinafter, each structure of the battery 100 will be described in more detail.

[0081] First, the respective structures of the laminated battery 100 according to one embodiment of the present invention will be described.

[0082] 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 a positive electrode active material as a main component. The main component refers to a component that is contained in the largest amount by weight in the positive electrode layer 12. The positive electrode active material refers to a substance that undergoes oxidation or reduction accompanied by the insertion or removal of metal ions such as lithium (Li) ions and magnesium (Mg) ions in its crystal structure at a higher potential than that of the negative electrode. The type of positive electrode active material may be appropriately selected according to the type of battery, and known positive electrode active materials may be used. Examples of the positive electrode active material include compounds containing lithium and transition metal elements. Examples of the compound 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 LiNi x M 1-xLithium nickel composite oxides such as lithium niobate (LiCoO2), lithium nickelate (LiNiO2), lithium manganate (LiMn2O4), and layered oxides such as lithium cobaltate (LiCoO2), lithium nickelate (LiNiO2), and lithium manganate (LiMn2O4), and lithium manganate (LiMn2O4, Li2MnO3, and LiMnO2) having a spinel structure. As a phosphate compound containing lithium and a transition metal element, lithium iron phosphate (LiFePO4) having an olivine structure can be used. Sulfides such as sulfur (S) and lithium sulfide (Li2S) can also be used as the positive electrode active material. A substance formed by coating or adding lithium niobate (LiNbO3) and the like to particles containing sulfides can also be used as the positive electrode active material. The positive electrode active material can be used alone or in combination of two or more.

[0083] 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 can be a mixture layer composed of a mixture of a positive electrode active material and other additives. As other additives, solid electrolytes such as inorganic solid electrolytes, conductive additives such as acetylene black, adhesives such as polyethylene oxide and polyvinylidene fluoride, etc. can be used. In the positive electrode layer 12, by mixing the positive electrode active material with other additives in a predetermined ratio, the lithium ion conductivity in the positive electrode layer 12 can be improved, and the electronic conductivity can also be improved.

[0084] The thickness of the positive electrode layer 12 is, for example, not less than 5 μm and not more than 300 μm.

[0085] The negative electrode layer 14 functions as a negative electrode active material layer containing negative electrode materials such as negative electrode active materials. The negative electrode layer 14 may contain negative electrode materials as a main component. Negative electrode active materials refer to substances that undergo oxidation or reduction in their crystal structure in which metal ions such as lithium (Li) ions and magnesium (Mg) ions are inserted or released at a lower potential than the positive electrode. The type of negative electrode active material may be appropriately selected according to the type of battery, and known negative electrode active materials may be used. As the negative electrode active material, carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, and resin sintered carbon, and alloy materials to be mixed with a solid electrolyte may be used. As alloy materials, LiAl, LiZn, Li3Bi, Li3Cd, Li3Sb, Li4Si, Li 4.4 Pb、Li 4.4 Sn、Li 0.17 C, LiC6 and other lithium alloys, lithium titanate (Li4Ti5O 12 ) and other lithium and transition metal oxides, zinc oxide (ZnO), silicon oxide (SiO x ) and other metal oxides. The negative electrode active material may be used alone or in combination of two or more.

[0086] As described above, the negative electrode layer 14 is not particularly limited as long as it contains a negative electrode active material. The negative electrode layer 14 may be a mixture layer composed of a mixture of a negative electrode active material and other additives. As other additives, solid electrolytes such as inorganic solid electrolytes, conductive additives such as acetylene black, binders such as polyoxyethylene and polyvinylidene fluoride, etc. may be used. In the negative electrode layer 14, by mixing the negative electrode active material and other additives in a predetermined ratio, the lithium ion conductivity in the negative electrode layer 14 can be improved, and the electronic conductivity can also be improved.

[0087] The thickness of the negative electrode layer 14 is, for example, not less than 5 μm and not more than 300 μm.

[0088] The electrolyte layer 15 can be a solid electrolyte layer containing a solid electrolyte. The solid electrolyte is not particularly limited as long as it has ionic conductivity, and a known battery electrolyte can be used. As a solid electrolyte, for example, an electrolyte that conducts metal ions such as Li ions and Mg ions can be used. The solid electrolyte can be appropriately selected according to the type of conductive ions. As a solid electrolyte, for example, an inorganic solid electrolyte such as a sulfide-based solid electrolyte and an oxide-based solid electrolyte can be used. As a sulfide-based solid electrolyte, for example, 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 can be used. As an oxide-based solid electrolyte, lithium-containing metal oxides such as Li2O-SiO2, Li2O-SiO2-P2O5, Li2S-SiS2-Li3PO4, Li2S-Ge2S2, Li2S-GeS2-P2S5, and Li2S-GeS2-ZnS can be used. x P y O 1-z N z Lithium-containing metal nitrides such as lithium phosphate (Li3PO4) and lithium titanium oxide and other lithium-containing transition metal oxides, etc. As the solid electrolyte, only one of these materials may be used, or two or more of these materials may be used in combination.

[0089] The electrolyte layer 15 may contain a binder such as polyoxyethylene or polyvinylidene fluoride in addition to the above-mentioned solid electrolyte.

[0090] The thickness of the electrolyte layer 15 is, for example, 5 μm or more and 150 μm or less.

[0091] The solid electrolyte may have a particle shape. The solid electrolyte may be a sintered body.

[0092] Next, the positive terminal 16 and the negative terminal 17 are described. These terminals 16 and 17 are composed of, for example, a conductor with low resistance. As the terminals 16 and 17, for example, a material obtained by curing a conductive resin containing conductive metal particles such as Ag is used. The terminals 16 and 17 can be made by applying a conductive adhesive to a conductive metal plate such as a SUS plate. Through the conductive adhesive, a stack of multiple units 30 can be clamped by two metal plates. The conductive adhesive is not particularly limited as long as it can maintain conductivity and bonding properties within the operating temperature range of the stacked battery 100 and during the manufacturing process of the stacked battery 100. The composition, 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 stacked battery 100 when the conductive adhesive is energized at the required maximum rate under the operating environment of the stacked battery 100, and the durability of the conductive adhesive can be maintained. The terminals 16 and 17 can be plated with Ni-Sn or the like.

[0093] The positive electrode current collector 11 and the negative electrode current collector 13 are not particularly limited as long as they are made of conductive materials. Examples of the materials of the current collectors 11 and 13 include stainless steel, nickel, aluminum, iron, titanium, copper, palladium, gold, and platinum. These materials of the current collectors 11 and 13 can be used alone or as an alloy composed of two or more. The current collectors 11 and 13 can be a foil, a plate, a mesh, etc. There are no particular limitations on the materials of the current collectors 11 and 13 as long as the current collectors 11 and 13 do not melt or decompose due to the manufacturing process of the battery 100, the operating temperature of the battery 100, and the pressure inside the battery 100. The materials can be appropriately selected in consideration of the working potential of the battery 100 applied to the current collectors 11 and 13 and the conductivity of the current collectors 11 and 13. In addition, the materials of the current collectors 11 and 13 can also be selected based on the tensile strength and heat resistance required of the current collectors 11 and 13. Examples of materials for the current collectors 11 and 13 include copper, aluminum, and alloys containing them as main components. The current collectors 11 and 13 may be electrolytic copper foil having high strength or a clad material formed by laminating different types of metal foils. The thickness of the current collectors 11 and 13 is, for example, not less than 10 μm and not more than 100 μm.

[0094] The above-mentioned structures of the laminated battery 100 can be combined with each other as appropriate.

[0095] The configuration of the battery 100 of the present embodiment is different from the configurations of the batteries described in Patent Documents 1 and 2 in the following points.

[0096] Patent Document 1 discloses a thin film solid secondary battery having an electrode lead-out portion at one end of a current collector main body. The battery described in Patent Document 1 has an electrode lead-out portion formed to extend outside the negative electrode active material layer and to be exposed to the atmosphere.

[0097] Patent Document 2 discloses a solid-state battery in which a terminal current collector is attached to the end surface of a stacked body including parallel current collectors. However, in the solid-state battery of Patent Document 2, there is no gap between the terminal current collector and the parallel current collector.

[0098] The battery structures described in Patent Documents 1 and 2 are different from the battery 100 of the present embodiment in the arrangement of electrodes for extracting current from the current collector and the structure of the current collector, and thus the following problems occur.

[0099] In the battery structure of Patent Document 1, the electrode extraction portion of the collector layer is formed in a manner exposed to the atmosphere. Therefore, peeling is likely to occur at the interface between the exposed collector layer and the solid electrolyte layer. When an impact is applied to the battery of Patent Document 1, there may sometimes be problems with the mechanical connection strength of the battery. In addition, in the event of a thermal shock, stress is generated due to the different thermal expansion coefficients of the collector layer and the solid electrolyte layer. As a result, peeling is likely to occur at the interface between the collector layer and the solid electrolyte layer. The durability of the battery with respect to hot and cold cycles is also likely to be insufficient. In addition, in Patent Document 1, foreign matter may sometimes adhere to the exposed portion of the collector layer. This may cause a short circuit.

[0100] Compared with Patent Documents 1 and 2, in the battery 100 of the present embodiment, a plurality of cells 30 are electrically connected in parallel and integrated. In the battery 100, the positive electrode collector 11 and the negative electrode terminal 17 are electrically separated from each other via a gap, and the negative electrode collector 13 and the positive electrode terminal 16 are electrically separated from each other via a gap. In addition, in the battery 100 of the present embodiment, for example, the negative electrode collector 13 is buried in the electrolyte layer 15, and the exposed portion 13a of the negative electrode collector 13 is connected to the negative electrode terminal 17. Therefore, the above-mentioned problem does not occur in the battery 100 of the present embodiment. Patent Documents 1 and 2 do not disclose the above-mentioned structure in the battery 100 of the present embodiment.

[0101] [Battery manufacturing method]

[0102] Next, an example of a method for manufacturing the battery 100 according to the present embodiment will be described. The battery 100 according to the present embodiment can be manufactured by, for example, a sheet manufacturing method.

[0103] In this specification, the process of manufacturing the unit 30 is sometimes referred to as a "sheet manufacturing process". In the sheet manufacturing process, for example, a stacked body is manufactured by stacking precursors of the components of the unit 30 included in the battery 100 according to the present embodiment. In the stacked body, for example, a precursor of the positive electrode 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 collector 13 are stacked in this order. A predetermined number of stacked bodies are manufactured according to the number of units 30 to be connected in parallel. There is no particular limitation on the order in which the components included in the stacked body are formed.

[0104] First, the sheet material production step will be described. The sheet material production step includes the steps of producing sheets as precursors of the respective components of the unit 30 and stacking the sheets.

[0105] The sheet of the positive electrode layer 12 can be made, for example, by the following method. First, a positive electrode active material, a solid electrolyte as a mixture, a conductive aid, a binder, and a solvent are mixed to obtain a slurry for making a sheet of the positive electrode layer 12. In this specification, the slurry for making a sheet of the positive electrode layer 12 is sometimes referred to as "positive electrode active material slurry". Next, the positive electrode active material slurry is applied to the precursor of the positive electrode collector 11 by a printing method or the like. The obtained coating is dried to form a sheet of the positive electrode layer 12.

[0106] 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 a solid electrolyte used as a mixture, for example, a glass powder containing Li2S-P2S5-based sulfide with an average particle size of about 10 μm and containing triclinic crystals as the main component can be used. The solid electrolyte has, for example, 2×10 -3 S / cm or more and 3×10 -3 High ionic conductivity of less than S / cm.

[0107] The positive electrode active material slurry can be applied to one side surface of the copper foil as the precursor of the positive electrode current collector 11 by screen printing, for example. The obtained coating film has a predetermined shape, and a thickness of about 50 μm or more and 100 μm or less. Next, the coating film is dried to obtain a sheet of the positive electrode layer 12. The drying of the coating film can be performed at a temperature of 80° C. or more and 130° C. or less. The thickness of the sheet of the positive electrode layer 12 is, for example, 30 μm or more and 60 μm or less.

[0108] The sheet of the negative electrode layer 14 can be made, for example, by the following method. First, a negative electrode active material, a solid electrolyte, a conductive aid, a binder, and a solvent are mixed to obtain a slurry for making a sheet of the negative electrode layer 14. In this specification, the slurry for making a sheet of the negative electrode layer 14 is sometimes referred to as "negative electrode active material slurry". The negative electrode active material slurry is applied to the precursor of the negative electrode collector 13 by printing or the like. The obtained coating is dried to form a sheet of the negative electrode layer 14.

[0109] As a precursor of the negative electrode current collector 13, for example, a copper foil having a thickness of about 30 μm can be used. As the negative electrode active material, for example, natural graphite powder having an average particle size of about 10 μm can be used. As the solid electrolyte, for example, the materials exemplified in the method for producing the sheet of the positive electrode layer 12 can be used.

[0110] The negative electrode active material slurry can be applied to one side surface of the copper foil as the precursor of the negative electrode current collector 13 by screen printing, for example. The obtained coating film has a predetermined shape, and a thickness of about 50 μm or more and 100 μm or less. Next, the coating film is dried to obtain a sheet of the negative electrode layer 14. The drying of the coating film can be performed at a temperature of 80° C. or more and 130° C. or less. The thickness of the sheet of the negative electrode layer 14 is, for example, 30 μm or more and 60 μm or less.

[0111] The sheet of the electrolyte layer 15 is arranged between the sheet of the positive electrode layer 12 and the sheet of the negative electrode layer 14. The sheet of the electrolyte layer 15 can be made, for example, by the following method. First, a solid electrolyte, a conductive aid, a binder and a solvent are mixed to obtain a slurry for making a sheet of the electrolyte layer 15. In this specification, the slurry for making a sheet of the electrolyte layer 15 is sometimes referred to as "solid electrolyte slurry". The solid electrolyte slurry is applied to the sheet of the positive electrode layer 12. Similarly, the solid electrolyte slurry is applied to the sheet of the negative electrode layer 14. The application of the solid electrolyte slurry is carried out, for example, by a printing method using a metal mask. The obtained coating has a thickness of, for example, about 100 μm. Next, the coating is dried. The drying of the coating can be carried out at a temperature of 80° C. or more and 130° C. or less. Thus, sheets of the electrolyte layer 15 are formed on the sheet of the positive electrode layer 12 and on the sheet of the negative electrode layer 14, respectively.

[0112] The method for preparing the sheet of the electrolyte layer 15 is not limited to the above method. The sheet of the electrolyte layer 15 can also be prepared by the following method. First, a solid electrolyte slurry is applied to a substrate by a printing method or the like. As a substrate, there is no particular limitation as long as a sheet of the electrolyte layer 15 can be formed thereon, and examples thereof include Teflon (registered trademark), polyethylene terephthalate (PET), etc. The shape of the substrate is, for example, a film or foil. Next, the coating 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 for use.

[0113] The solvent used for the positive electrode active material slurry, the negative electrode active material slurry and the solid electrolyte slurry is not particularly limited as long as it can dissolve the binder and does not adversely affect the battery characteristics. As a solvent, for example, alcohols such as ethanol, isopropanol, n-butanol, benzyl alcohol, 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), N-methyl-2-pyrrolidone (NMP) and other organic solvents and water can be used. These solvents can be used alone or in combination of two or more.

[0114] In the present embodiment, as a method for coating the positive electrode active material slurry, the negative electrode active material slurry and the solid electrolyte slurry, a screen printing method is exemplified, but the coating method is not limited thereto. As the coating method, a blade coating method, a calendering method, a spin coating method, a dip coating method, an inkjet method, an offset printing method, a die coating method, a spray coating method, etc. can be used.

[0115] In the positive electrode active material slurry, the negative electrode active material slurry and the solid electrolyte slurry, 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 can be mixed as needed. There is no particular limitation on the mixing method of the slurry. Additives such as thickeners, plasticizers, defoamers, leveling agents, and adhesion-imparting agents can be added to the slurry as needed.

[0116] Next, the sheet of electrolyte layer 15 formed on the sheet of positive electrode layer 12 is overlapped with the sheet of electrolyte layer 15 formed on the sheet of negative electrode layer 14. Thus, a laminated body is obtained in which the precursor of the positive electrode collector 11, the positive electrode layer 12, the electrolyte layer 15, the negative electrode layer 14 and the precursor of the negative electrode collector 13 are stacked in this order.

[0117] Next, the precursor of the positive electrode collector 11 is cut to obtain the positive electrode collector 11. In detail, when the negative terminal 17 is configured, the precursor of the positive electrode collector 11 is cut in such a manner that the positive electrode collector 11 and the negative terminal 17 are electrically separated from each other with a gap therebetween. The cut surface of the positive electrode collector 11 extends straight in the second direction y, for example. The cutting of the precursor of the positive electrode collector 11 can be performed, for example, by a laser. By cutting the precursor of the positive electrode collector 11, the positive electrode collector 11 can be formed. The shortest distance between the positive electrode collector 11 and the negative terminal 17 is, for example, 10 μm. The positive electrode collector 11 and the negative terminal 17 are electrically separated from each other by the gap between the positive electrode collector 11 and the negative terminal 17. That is, the gap between the positive electrode collector 11 and the negative terminal 17 is electrically insulated.

[0118] Next, the precursor of the negative electrode collector 13 is cut to obtain the negative electrode collector 13. In detail, when the positive terminal 16 is configured, the precursor of the negative electrode collector 13 is cut in such a manner that the negative electrode collector 13 and the positive terminal 16 are electrically separated from each other with a gap therebetween. The cut surface of the negative electrode collector 13 extends straight in the second direction y, for example. The cutting of the precursor of the negative electrode collector 13 can be performed, for example, by a laser. By cutting the precursor of the negative electrode collector 13, the negative electrode collector 13 can be formed. The shortest distance between the negative electrode collector 13 and the positive terminal 16 is, for example, 10 μm. The negative electrode collector 13 and the positive terminal 16 are electrically separated from each other by the gap between the negative electrode collector 13 and the positive terminal 16. That is, the gap between the negative electrode collector 13 and the positive terminal 16 is electrically insulated.

[0119] There is no particular limitation on the order of cutting the precursor of the positive electrode collector 11 and the precursor of the negative electrode collector 13. The precursor of the negative electrode collector 13 may be cut after the precursor of the positive electrode collector 11 is cut, or the precursor of the positive electrode collector 11 may be cut after the precursor of the negative electrode collector 13 is cut. The cutting of the precursor of the positive electrode collector 11 and the cutting of the precursor of the negative electrode 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 overlapped. The cutting of the precursor of the positive electrode collector 11 and the cutting of the precursor of the negative electrode collector 13 may be performed by dicing or the like. The precursor of the positive electrode collector 11 may be cut, and an insulating portion may be provided by removing a portion of the precursor. The precursor of the negative electrode collector 13 may be cut, and an insulating portion may be provided by removing a portion of the precursor.

[0120] As described above, the precursor of the positive electrode current collector 11 is cut, and the precursor of the negative electrode current collector 13 is cut, thereby obtaining the cell 30 .

[0121] Next, a predetermined number of units 30 are prepared. On the main surface of the positive electrode collector 11 exposed to the outside of the unit 30 and the main surface of the negative electrode collector 13 exposed to the outside of the unit 30, for example, a conductive adhesive is applied respectively. As a method for applying the conductive adhesive, for example, a screen printing method can be cited. In this specification, the main surface of the positive electrode collector 11 and the negative electrode collector 13 coated with the adhesive material is sometimes referred to as a "bonding surface". Next, the bonding surface of the positive electrode collector 11 of the unit 30 is bonded to the bonding surface of the positive electrode collector 11 of another unit 30, or the bonding surface of the negative electrode collector 13 of the unit 30 is bonded to the bonding surface of the negative electrode collector 13 of another unit 30. In this way, a plurality of units 30 can be stacked. The bonding surfaces can be bonded to each other, for example, by pressure bonding. The temperature when the bonding surfaces are bonded to each other is, for example, not less than 50°C and not more than 100°C. When bonding the bonding surfaces to each other, the pressure applied to the unit 30 is, for example, greater than 300 MPa and less than 400 MPa. The time for applying pressure to the unit 30 is, for example, greater than 90 seconds and less than 120 seconds. For bonding, a low-resistance conductive tape may be used instead of a conductive adhesive. Paste of silver powder or copper powder may also be used instead of a conductive adhesive. If the bonding surface of a unit 30 coated with a paste of silver powder or copper powder is pressed against the bonding surface of another unit 30, the collectors can be mechanically bonded to each other through the anchoring effect via the metal particles. The method of stacking a plurality of units 30 is not particularly limited as long as it is a method that can obtain bonding and conductivity.

[0122] Next, the plurality of cells 30 are electrically connected to the positive terminal 16 and the negative terminal 17, respectively. For example, the following method can be used to electrically connect the plurality of cells 30 to the terminals 16 and 17, respectively. First, in the stack of the plurality of cells 30, a conductive resin paste is applied to the surface where the terminals 16 and 17 are to be arranged. The conductive resin paste is cured to form the terminals 16 and 17. Thus, the battery 100 according to the present embodiment is obtained. The temperature when the conductive resin paste is cured is, for example, about 100° C. or more and 300° C. or less. The time for curing the conductive resin paste is, for example, 60 minutes.

[0123] As a conductive resin paste, for example, a thermosetting conductive paste containing high-conductive metal particles with a high melting point, metal particles with a low melting point, and a resin can be used, wherein the high-conductive metal particles with a high melting point contain Ag, Cu, Ni, Zn, Al, Pd, Au, Pt or their alloys. The melting point of the high-conductive metal particles is, for example, above 400°C. The melting point of the low-melting metal particles can be below the curing temperature of the conductive resin paste, and can be below 300°C. As materials of low-melting metal particles, for example, Sn, SnZn, SnAg, SnCu, SnAl, SnPb, In, InAg, InZn, InSn, Bi, BiAg, BiNi, BiSn, BiZn and BiPb can be cited. By using a conductive paste containing such a low-melting metal powder, a solid-phase and liquid-phase reaction is carried out at the contact portion between the conductive paste and the collector at a thermosetting temperature lower than the melting point of the low-melting metal particles. Thus, for example, an alloy containing the metal contained in the conductive paste and the metal contained in the collector is formed. A diffusion layer containing the alloy is formed near the connection between the collector and the terminal. When Ag or an Ag alloy is used as the conductive particles and Cu is used for the collector, a highly conductive alloy containing AgCu is formed. In addition, AgNi, AgPd, etc. are also formed by the combination of the material of the conductive particles and the material of the collector. In this way, the terminal and the collector are integrally joined through the diffusion layer containing the alloy. According to the above structure, the terminal and the collector are more firmly connected compared to the anchoring effect. Therefore, it is difficult to cause problems such as differences in thermal expansion caused by thermal cycles of the components of the battery 100, or disconnection of the components due to impact.

[0124] There is no particular limitation on the shape of the highly conductive metal particles and the low melting point metal particles, and they may be spherical, flaky, needle-shaped, etc. As the particle size of these metal particles is smaller, the alloying reaction and the diffusion of the alloy are carried out at a lower temperature. Therefore, the particle size and shape of these metal particles can be appropriately adjusted in consideration of the process design and the influence of the thermal history on the battery characteristics.

[0125] The resin used in the thermosetting conductive paste is not particularly limited as long as it can function as an adhesive, and an appropriate material can be selected based on the adaptability to the printing method, the coating property, and the manufacturing process to be adopted. The resin used in the thermosetting conductive paste includes, for example, a thermosetting resin. As a thermosetting resin, for example, urea resin, melamine resin, guanamine resin and other amino resins, bisphenol A type, bisphenol F type, novolac type, alicyclic epoxy resins, oxetane resin, resol type, novolac type phenolic resins, silicone epoxy, silicone polyester and other silicone modified organic resins can be cited. These resins can be used alone or in combination of two or more.

[0126] In this embodiment, in order to improve the bonding strength between the current collector and the electrolyte layer 15, the battery 100 may also be formed with a bonding layer. The bonding layer is located at the interface between the positive electrode current collector 11 and the electrolyte layer 15. In addition, the bonding layer is located at the interface between the contact portion of the side of the negative electrode current collector 13 and the electrolyte layer 15. As materials for the bonding layer, components constituting the current collector can be cited. As components constituting the current collector, copper, aluminum and alloys containing them as main components can be cited. In addition, as materials for other bonding layers, oxides, sulfides, and halides can be cited. The bonding layer may also contain other components constituting the current collector and / or components constituting the electrolyte layer 15. As a result, the current collector and the electrolyte layer 15 are firmly bonded inside the stacked battery 100. According to such a structure, the bonding strength is improved by chemical bonding at the interface between the current collector and the electrolyte layer 15, so that a stacked battery 100 integrated with a higher bonding strength can be achieved.

[0127] The bonding layer can be made by stacking a plurality of units 30 as described above and pressing them together. For example, when the bonding surfaces of a plurality of units 30 are pressed together, the copper contained in the collector and the sulfide contained in the electrolyte layer 15 diffuse at the interface between the collector and the electrolyte layer 15 to form a copper sulfide layer. The bonding layer may contain substances other than copper sulfide. The temperature when forming the bonding layer is, for example, 100°C. The time for forming the bonding layer is, for example, 5 minutes. The thickness of the bonding layer thus formed is about 1 μm. However, there is no particular limitation on the thickness of the bonding layer, and for example, it can be greater than 0.1 μm and less than 10 μm.

[0128] The presence of the thus produced bonding layer can be confirmed by observing the cross section of the battery 100 using a conventional optical microscope, laser microscope or scanning electron microscope (SEM). The composition of the bonding layer can be evaluated by, for example, analyzing the bonding layer using an electron beam microanalyzer (EPMA).

[0129] In the manufacturing method of this embodiment, an example of manufacturing the battery 100 by a powder pressing process is shown. However, the terminals 16 and 17 may be manufactured by manufacturing a stack of sintered bodies by a firing process, applying a conductive resin paste to the stack, and firing the stack.

[0130] The battery 100 connects a plurality of cells 30 in parallel in a manner of sharing a negative electrode current collector 13. The positive electrode current collector 11 is located on the upper surface and the lower surface of the cell. The battery may also connect a plurality of cells 30 in parallel in a manner of sharing a positive electrode current collector 11. In this case, the negative electrode current collector 13 is located on the upper surface and the lower surface of the cell. In addition, most of the positive electrode current collector 11 is buried in the electrolyte layer 15, and the positive electrode current collector 11 may have an exposed portion for contacting the positive terminal 16.

[0131] (Implementation Method 2)

[0132] Figure 3 This is a schematic diagram for explaining the structure of a battery 200 according to the second embodiment. Figure 3 (a) is a cross-sectional view of a battery 200 according to this embodiment. Figure 3 (b) is a top view of the battery 200. The same reference numerals are attached to the common elements in the battery 100 of the first embodiment and the battery 200 of the present embodiment, and their descriptions are omitted. That is, the descriptions related to the following embodiments are applicable to each other as long as they are not technically contradictory. In addition, the embodiments can be combined with each other as long as they are not technically contradictory.

[0133] like Figure 3 As shown, in the negative electrode current collector 13, the thickness of the protruding portion 13p is smaller than the thickness of the residual portion 13r. As a result, the area of ​​the exposed portion 13a can 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 portion between the negative electrode current collector 13 and the electrolyte layer 15 where peeling easily occurs can be reduced, so that a battery 200 with high reliability can be realized.

[0134] The thickness of the protruding portion 13p is smaller than the thickness of the residual portion 13r, so the uneven variation of the pressure during crimping is reduced. In addition, since the area of ​​the exposed portion 13a in contact with the negative terminal 17 is small, even if the negative terminal 17 generates stress caused by tension, it is difficult to affect the negative electrode collector 13. Therefore, the bonding strength between the negative electrode collector 13 and the electrolyte layer 15 can be further improved. In addition, since the plurality of cells 30 connected in parallel can be firmly integrated in a small size, a battery 200 with a large capacity, high energy density and high reliability can be realized.

[0135] The ratio (D2 / D1) of the thickness D2 of the protruding portion 13p to the thickness D1 of the remaining portion 13r is appropriately determined according to the size and material of the battery 200 and is not particularly limited. The ratio (D2 / D1) is, for example, in the range of 3 or more and 10 or less.

[0136] The thickness of the protrusion 13p and the thickness of the remaining portion 13r can be determined by the average value measured at any plurality of points (eg, 5 points). The measurement is performed using, for example, a micrometer. In the present embodiment, the thickness is a dimension in a direction parallel to the third direction z.

[0137] (Implementation 3)

[0138] Figure 4 This is a schematic diagram for explaining the structure of a battery 300 according to the third embodiment. Figure 4(a) is a cross-sectional view of a battery 300 according to this embodiment. Figure 4 (b) is a top view of the battery 300. Figure 4 As shown, in the laminated battery 300, the negative electrode current collector 13 further has a locking hole 21. In this specification, the locking hole 21 may be referred to as a "through hole." Except for this, the structure of the battery 300 is the same as that of the battery 100 of the first embodiment.

[0139] The keyhole 21 is, for example, a through hole that penetrates the negative electrode collector 13 in the stacking direction of the plurality of units 30. The keyhole 21 is formed in the portion where the negative electrode collector 13 contacts the electrolyte layer 15. The keyhole 21 is not formed in the portion where the negative electrode collector 13 contacts the negative electrode layer 14. The keyhole 21 may be formed in the residual portion 13r of the negative electrode collector 13 or in the protruding portion 13p. The electrolyte layer 15 exists inside the keyhole 21. That is, the inside of the keyhole 21 is filled with the electrolyte constituting the electrolyte layer 15. According to such a structure, the bonding strength between the negative electrode collector 13 and the electrolyte layer 15 is improved by the anchoring effect. In addition, since the plurality of units 30 connected in parallel can be firmly integrated in a small size, a battery 300 with a large capacity, high energy density and high reliability can be realized.

[0140] There is no particular limitation on the shape, size, and number of the keyholes 21 as long as the bonding strength between the negative electrode current collector 13 and the electrolyte layer 15 can be improved. The shape of the keyhole 21 is, for example, cylindrical. There is no particular limitation on the size of the keyhole 21, and the diameter may be greater than 200 μm and less than 500 μm, the diameter may be greater than 30 μm and less than 500 μm, or the diameter may be greater than 30 μm and less than 100 μm. There is no particular limitation on the number of keyholes 21 formed in the negative electrode current collector 13.

[0141] There is no particular limitation on the method for forming the keyhole 21 in the negative electrode collector 13. For example, after the precursor of the negative electrode collector 13 is prepared as described above, the keyhole 21 can be formed by cutting the precursor of the negative electrode collector 13. In detail, the keyhole 21 can be formed in the precursor of the negative electrode collector 13 by cutting a portion of the negative electrode collector 13 in a manner that penetrates relative to the stacking direction. The keyhole 21 extends straight in the stacking direction of the plurality of units 30, for example. The cutting of the precursor of the negative electrode collector 13 can be performed, for example, by laser. By cutting the precursor of the negative electrode collector 13, the keyhole 21 can be formed in the negative electrode collector 13. As another example of forming the keyhole 21 in the negative electrode collector 13, punching can be cited. In this case, the keyhole 21 can be formed by punching the negative electrode collector 13 to open a plurality of small holes in the metal sheet. The interval between each of the plurality of keyholes 21 is, for example, 50 μm. According to such a structure, the bonding strength between the negative electrode current collector 13 and the electrolyte layer 15 can be improved.

[0142] (Implementation 4)

[0143] Figure 5 This is a schematic diagram for explaining the structure of a battery 400 according to the fourth embodiment. Figure 5 (a) is a cross-sectional view of a battery 400 according to this embodiment. Figure 5 (b) is a top view of the battery 400. Figure 5 As shown, in the battery 400, each of the plurality of cells further includes a dummy current collector 31. Except for this, the structure of the battery 400 is the same as that of the battery 100 of the first embodiment.

[0144] In this embodiment, the dummy current collector 31 is located around the battery 400. In addition, the dummy current collector 31 exists around the shielding portion 13b of the negative electrode current collector 13. According to such a structure, it is possible to reduce the uneven variation of the pressure during the crimping. Therefore, it is possible to realize a battery 400 with high reliability. As a result, the density inside the stack is easily uniform.

[0145] The dummy current collector 31 is electrically separated 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 via a gap. According to such a structure, the dummy current collector 31 functions as a reinforcing material. Therefore, a battery 400 with high reliability can be realized.

[0146] A portion of the dummy current collector 31 may be buried 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 dummy current collector 31 may be in contact with the positive electrode terminal 16 at the exposed portion. The dummy current collector 31, for example, does not contact the negative electrode terminal 17. The dummy current collector 31 is, for example, U-shaped in a plan view.

[0147] The dummy current collector 31 is located at the same height as the negative electrode current collector 13 in the stacking direction of the plurality of cells 30. Therefore, during crimping, the stress caused by the bending of the current collector, which is concentrated around the negative electrode current collector 13, can be reduced. As a result, the density inside the stack is easily uniform. As a result, the structural defects of the battery 400 are reduced. In addition, since the portion where the negative electrode current collector 13 and the electrolyte layer 15 are easily peeled off can be reduced, a battery 400 with high reliability can be realized. In addition, by forming the dummy current collector 31, a battery 400 that can reduce the stress caused by the bending of the current collector can be easily manufactured.

[0148] The dummy current collector 31 can be made, for example, by the following method. First, a precursor of the negative electrode current collector 13 is made as described above. Then, the precursor of the negative electrode current collector 13 is cut to obtain the dummy current collector 31. In detail, the precursor of the negative electrode current collector 13 is cut in such a way that the negative electrode current collector 13 and the dummy current collector 31 are electrically separated from each other with a gap therebetween. The cut surface of the negative electrode current collector 13 extends straight in the first direction x and the second direction y, for example. The cutting of 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. The cutting of the precursor of the negative electrode current collector 13 can be performed by means such as dicing. The precursor of the negative electrode current collector 13 can be cut, and the dummy current collector 31 can be formed by removing a portion of the precursor.

[0149] To be precise, the dummy current collector 31 does not function as a current collector. Therefore, there is no particular limitation on the material used for the dummy current collector 31. For example, it may include the same material as the positive current collector 11 or the negative current collector 13, or may include an insulating material. It may be made of the same material as the positive current collector 11 or the negative current collector 13, or may be made of an insulating material. Furthermore, the dummy current collector 31 can further reduce the uneven variation of pressure during crimping by having the same degree of hardness as the positive current collector 11 or the negative current collector 13. Therefore, a battery 400 with high reliability can be achieved. From this point of view, the dummy current collector 31 can be made of the same material as the collector 11 and / or 13.

[0150] The dummy current collector 31 may further have a keyhole. The keyhole is, for example, a through hole that penetrates the dummy current collector 31 in the stacking direction of the plurality of units 30. An electrolyte layer 15 is present inside the keyhole. In other words, the inside of the keyhole is filled with an electrolyte constituting the electrolyte layer 15. According to such a structure, the bonding strength between the dummy current collector 31 and the electrolyte layer 15 can be improved by the anchoring effect. In addition, the plurality of units 30 connected in parallel can be firmly integrated in a small size, so that a battery 400 with a large capacity, high energy density and high reliability can be realized.

[0151] There is no particular limitation on the shape, size and number of the keyholes as long as the bonding strength between the dummy current collector 31 and the electrolyte layer 15 can be improved. The shape of the keyhole is, for example, cylindrical. There is no particular limitation on the size of the keyhole, and the diameter may be greater than 200 μm and less than 500 μm, the diameter may be greater than 30 μm and less than 500 μm, or the diameter may be greater than 30 μm and less than 100 μm. There is no particular limitation on the number of keyholes formed in the dummy current collector 31.

[0152] There is no particular limitation on the method of forming the keyholes in the dummy current collector 31. The keyholes 21 can be formed by the same method. The interval between the plurality of keyholes is, for example, 50 μm. With such a structure, the bonding strength between the dummy current collector 31 and the electrolyte layer 15 can be increased.

[0153] In this embodiment, in order to improve the bonding strength between the dummy current collector 31 and the electrolyte layer 15, a bonding layer may be further formed. 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 include components constituting the dummy current collector 31 and / or components constituting the electrolyte layer 15. According to such a structure, the bonding strength can be improved by chemical bonding at the interface between the dummy current collector 31 and the electrolyte layer 15, so that a stacked battery 400 integrated by a higher bonding strength can be realized.

[0154] (Implementation 5)

[0155] Figure 6 This is a schematic diagram for explaining the structure of a battery 500 according to the fifth embodiment. Figure 6 (a) is a cross-sectional view of a battery 500 according to this embodiment. Figure 6 (b) is a top view of the battery 500. Figure 6 As shown, in battery 500, each of the plurality of cells further includes dummy current collectors 41. Except for this, the structure of battery 500 is the same as that of battery 100 of the first embodiment.

[0156] In the present embodiment, the dummy current collector 41 is located around the battery 500. However, it is different from the battery 400 in that the dummy current collector 41 is arranged on a plane different from the negative electrode collector 13. That is, the dummy current collector 41 is located at a height different from the negative electrode collector 13 in the stacking direction of the plurality of units 30. The dummy current collector 41 is electrically separated from the positive electrode collector 11, the positive electrode layer 12, and the negative electrode layer 14. A portion of the dummy current collector 41 may be buried 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 dummy current collector 41 may be in contact with the positive terminal 16 at the exposed portion. The dummy current collector 41, for example, does not contact the negative terminal 17. The dummy current collector 41 is, for example, U-shaped when viewed from above. According to such a structure, even if a thermal shock occurs, the stress caused by the difference in thermal expansion coefficient between the current collector and the electrolyte layer 15 can be reduced. Therefore, it is difficult for the negative electrode current collector 13 and the electrolyte layer 15 to peel off. As a result, the battery 500 with high reliability against thermal cycles can be realized.

[0157] The dummy current collector 41 can be made, 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. Then, the precursor of the dummy current collector 41 is cut to obtain the dummy current collector 41. In detail, the precursor of the dummy current collector 41 is cut in such a way that the dummy current collector 41 is located around the unit. 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 cutting of the precursor of the dummy current collector 41 can be performed, for example, using a laser. By cutting the precursor of the dummy current collector 41, the dummy current collector 41 can be formed. The cutting of the precursor of the dummy current collector 41 can be performed by means such as dicing.

[0158] To be precise, the dummy current collector 41 does not function as a current collector. Therefore, there is no particular limitation on the material used for the dummy current collector 41. For example, the same material as the dummy current collector 31 can be used. Furthermore, the dummy current collector 41 has the same degree of hardness as the positive electrode current collector 11 or the negative electrode current collector 13, so that even if a thermal shock occurs, the stress caused by the different thermal expansion coefficients of the current collector and the electrolyte layer 15 can be reduced. Therefore, it is difficult for the negative electrode current collector 13 and the electrolyte layer 15 to peel off between the layers. As a result, a battery 500 with high reliability for thermal cycles can be achieved.

[0159] The dummy current collector 41 may also have a keyhole like the dummy current collector 31. The keyhole is, for example, a through hole that penetrates the dummy current collector 41 in the stacking direction of the plurality of units 30. The electrolyte layer 15 is present inside the keyhole. That is, the inside of the keyhole is filled with an electrolyte constituting the electrolyte layer 15. According to such a structure, the bonding strength between the dummy current collector 41 and the electrolyte layer 15 can be improved by the anchoring effect. In addition, since the plurality of units 30 connected in parallel can be firmly integrated in a small size, a battery 500 with a large capacity, high energy density and high reliability can be realized.

[0160] The battery and stacked battery involved in the present disclosure are described above based on the embodiments, but the present disclosure is not limited to these embodiments. As long as it does not deviate from the main purpose of the present disclosure, various modifications that can be thought of by those skilled in the art are applied to the embodiments to obtain the scheme, and other schemes constructed by combining some of the constituent elements in the embodiments are all included in the scope of the present disclosure.

[0161] Industrial Availability

[0162] 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, and the like.

[0163] Description of Reference Numerals

[0164] 11. Positive electrode collector

[0165] 12. Positive electrode layer

[0166] 13. Negative electrode collector

[0167] 13a Exposed part

[0168] 13b Shielded part

[0169] 13p protrusion

[0170] 13r Remaining part

[0171] 14 Negative electrode layer

[0172] 15 Electrolyte layer

[0173] 16 Positive terminal

[0174] 17 Negative terminal

[0175] 21 Keyhole

[0176] 30 units

[0177] 31, 41 Dummy current collector

[0178] 100, 200, 300, 400, 500 batteries

Claims

1. A battery comprising a plurality of cells electrically connected in parallel, The plurality of units respectively have: positive electrode layer; Negative electrode layer; a current collector in contact with the positive electrode layer or the negative electrode layer; and an electrolyte layer disposed between the positive electrode layer and the negative electrode layer, The 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, The current collector has a protrusion, The exposed portion is included in the protruding portion.

2. The battery according to claim 1, further comprising a terminal electrically connected to the current collector, The exposed portion is in contact with the terminal.

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

4. The battery according to claim 1 or 2, The electrolyte layers of adjacent cells are joined to each other around the shielding portion.

5. The battery according to claim 1 or 2, The current collector has a residual portion other than the protruding portion, The width of the protruding portion is smaller than the width of the residual portion.

6. The battery according to claim 1 or 2, The current collector has a residual portion other than the protruding portion, The thickness of the protruding portion is smaller than the thickness of the residual portion.

7. The battery according to claim 1, The current collector has through holes.

8. The battery according to claim 7, The electrolyte layer exists inside the through hole.

9. The battery according to claim 1, It also has 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 according to claim 9, The bonding layer exists at the interface between the shielding portion and the electrolyte layer.

11. The battery according to claim 1, A dummy current collector is further provided around the shielded portion of the current collector.

12. The battery according to claim 11, The dummy current collector includes the same material as the current collector.

13. The battery according to claim 11, The dummy current collector includes an insulating material.

14. The battery according to any one of claims 11 to 13, The dummy current collector is electrically separated from the current collector.

15. The battery according to claim 14, The dummy current collector is separated from the current collector.

16. The battery according to any one of claims 11 to 13, The dummy current collector is exposed from the electrolyte layer.

17. The battery according to any one of claims 11 to 13, The plurality of units each have a flat plate shape, The battery is formed 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 according to any one of claims 11 to 13, The plurality of units each have a flat plate shape, The battery is formed by stacking the plurality of cells. The dummy current collector is located at a height different from that of the current collector in a stacking direction of the plurality of cells.

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