Batteries and stacked cells

Abstract

A battery 1000 according to the present disclosure comprises a first electrode layer 10, a first solid electrolyte layer 20, and a second electrode layer 30 in this order. The first electrode layer 10 includes a first active material layer 12a, a second active material layer 12b that is positioned between the first active material layer 12a and the first solid electrolyte layer 20 and has the same polarity as the first active material layer 12a, and a second solid electrolyte layer 13 that is positioned between the first active material layer 12a and the second active material layer 12b. The second solid electrolyte layer 13 is directly connected to the first solid electrolyte layer 20. A layer-built battery according to the present disclosure comprises a plurality of batteries, the plurality of batteries being electrically connected in series or in parallel and layered.

Description

[Technical Field]

[0001] This disclosure relates to batteries and stacked batteries. [Background technology]

[0002] The battery capacity, voltage, and energy content can be improved by increasing the amount of active material in a battery, or by connecting multiple batteries in series or parallel. As technologies related to such battery structures or connections, for example, Patent Document 1 discloses an all-solid-state battery in which multiple positive and negative electrodes are alternately stacked via a solid electrolyte and connected in parallel. Patent Document 2 discloses an all-solid-state battery having a structure in which multiple composite material layers containing active material are stacked. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2018 / 181827 [Patent Document 2] Japanese Patent Publication No. 2020-4686 [Overview of the project] [Problems that the invention aims to solve]

[0004] The purpose of this disclosure is to provide a battery having a structure suitable for improving input / output characteristics. [Means for solving the problem]

[0005] The battery disclosed herein is a first electrode layer; First solid electrolyte layer, and second electrode layer, These are provided in this order, The first electrode layer is a first active material layer; A second active material layer located between the first active material layer and the first solid electrolyte layer, and having the same polarity as the first active material layer, and A second solid electrolyte layer positioned between the first active material layer and the second active material layer is included, and the second solid electrolyte layer is directly connected to the first solid electrolyte layer.

Advantages of the Invention

[0006] The present disclosure provides a battery having a structure suitable for improving input / output characteristics.

Brief Description of the Drawings

[0007] [Figure 1] FIG. 1 shows a schematic configuration of a battery 1000 according to the first embodiment. [Figure 2] FIG. 2 shows a schematic configuration of a battery 2000 according to the second embodiment. [Figure 3] FIG. 3 shows a schematic configuration of a battery 3000 according to the third embodiment. [Figure 4] FIG. 4 shows a schematic configuration of a battery 4000 according to the fourth embodiment. [Figure 5] FIG. 5 shows a schematic configuration of a laminated battery 5000 according to the fifth embodiment. [Figure 6] FIG. 6 shows a schematic configuration of a modified laminated battery 6000 according to the fifth embodiment.

Modes for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present disclosure will be specifically described with reference to the drawings.

[0009] Note that all of the embodiments described below show comprehensive or specific examples. Numerical values, shapes, materials, components, arrangement positions of components, connection forms, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0010] In this specification, terms indicating the relationship between elements such as parallel, terms indicating the shape of elements such as rectangular parallelepiped, and numerical ranges are not expressions representing only strict meanings, but are expressions meaning substantially equivalent ranges, for example, including differences of about several percent.

[0011] Each figure is not necessarily drawn precisely. In each figure, substantially the same configurations are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified.

[0012] In this specification and the drawings, the x-axis, y-axis, and z-axis indicate the three axes of a three-dimensional orthogonal coordinate system. In each embodiment, the z-axis direction is the thickness direction of the battery. Also, in this specification, unless otherwise specified, the "thickness direction" means the direction perpendicular to the surface on which each layer of the battery is laminated.

[0013] In this specification, unless otherwise specified, "plan view" means the case of viewing the battery along the lamination direction of each layer in the battery. In this specification, unless otherwise specified, "thickness" means the length in the lamination direction of the battery and each layer.

[0014] In this specification, unless otherwise specified, in the battery, "side surface" means the surface along the lamination direction, and "main surface" means the surface other than the side surface.

[0015] In this specification, "inner" and "outer" in "inner side" and "outer side" etc. mean that when the battery is viewed along the lamination direction in the battery, the center side of the battery is "inner" and the peripheral side of the battery is "outer".

[0016] In this specification, the terms "upper" and "lower" in the battery configuration do not refer to the upward (vertically upward) and downward (vertically downward) directions in absolute spatial perception, but rather to terms defined by the relative positional relationship based on the stacking order in the stacked configuration. Furthermore, the terms "upper" and "lower" apply not only when two components are placed in close proximity and touching each other, but also when two components are placed spaced apart and another component exists between them.

[0017] (First Embodiment) A battery according to the first embodiment will be described.

[0018] The battery according to the first embodiment comprises a first electrode layer, a first solid electrolyte layer, and a second electrode layer in this order. The first electrode layer includes a first active material layer, a second active material layer, and a second solid electrolyte layer. The second active material layer is located between the first active material layer and the first solid electrolyte layer. The first active material layer and the second active material layer have the same polarity. The second solid electrolyte layer is located between the first active material layer and the second active material layer. The second solid electrolyte layer is directly connected to the first solid electrolyte layer.

[0019] In the battery according to the first embodiment, the first electrode comprises a first active material layer and a second active material layer, and a second solid electrolyte layer is located between the first active material layer and the second active material layer. With this configuration, even when the capacity is increased by increasing the amount of active material in the battery according to the first embodiment, Li ions can easily be inserted into and removed from the active material contained in the first active material layer, which is located further away from the first solid electrolyte layer, via the second solid electrolyte layer. In other words, the active material contained in the first electrode can be efficiently utilized in the battery reaction. Therefore, with the above configuration, the battery according to the first embodiment can achieve excellent input / output characteristics even when, for example, it is made smaller and its capacity is increased.

[0020] Conventional solid-state batteries improve battery capacity and energy by increasing the amount of active material or by connecting multiple batteries in parallel or series. However, increasing the thickness of the active material layer makes it difficult for Li ions to enter and exit the active material layer, making high-rate charging and discharging difficult. Furthermore, miniaturization becomes difficult when multiple batteries are connected. Miniaturization becomes even more difficult when multiple batteries are connected in parallel using lead wires. In addition, the routing of lead wires is prone to short circuits and damage, raising reliability issues. Moreover, Li metal that accumulates near the surface of the active material layer can precipitate and cause short circuits. These problems tend to become more apparent as batteries are made smaller, have higher capacity, or have higher energy.

[0021] As described in the [Background Technology] section, Patent Document 1 discloses an all-solid-state battery in which multiple positive and negative electrodes are alternately stacked via a solid electrolyte and connected in parallel. This structure, in which the electrode layers and counter electrode layers are arranged to face each other alternately, is completely different from the battery disclosed in this disclosure, which stacks active material layers of the same polarity. In the all-solid-state battery disclosed in Patent Document 1, since the positive and negative electrodes are stacked alternately, that is, adjacent active material layers are active material layers of different polarities, expansion and contraction stresses occur between each layer of the positive and negative electrodes that face each other vertically, making it prone to structural defects.

[0022] In contrast, as in the battery according to the first embodiment described above, the battery of this disclosure has a first active material layer and a second active material layer, which are active material layers of the same polarity, stacked together, and a solid electrolyte located between the first and second active material layers. This configuration facilitates the insertion and removal of Li ions from both the first and second active material layers. Furthermore, with this configuration, even if the amount of active material in the first electrode is increased to increase capacity, for example, Li ions can be easily inserted and removed from the active material located far from the first solid electrolyte layer, i.e., the active material in the first active material layer. Therefore, the battery of this disclosure can suppress a decrease in high-rate charge and discharge characteristics even when increasing capacity by, for example, increasing the amount of active material in the first electrode. In other words, the battery of this disclosure can realize a battery with excellent input / output characteristics even when it is small and has increased capacity. In addition, since the adjacent first and second active material layers are active material layers of the same polarity and a soft solid electrolyte is present between them, structural defects are less likely to occur. Therefore, the battery of this disclosure also has excellent reliability.

[0023] Patent Document 2 discloses an all-solid-state battery having a structure in which multiple composite material layers containing active material are stacked. However, since this stacked structure is composed of composite material layers with different active material ratios layered on top of each other, if the composite material layers are made thicker to increase capacity, it is not easy to move Li located at deeper positions (i.e., further away from the solid electrolyte layer). In other words, the battery having the configuration disclosed in Patent Document 2 will have reduced input / output characteristics when, for example, the capacity is increased.

[0024] In contrast, the battery of this disclosure, as described above, has a configuration in which a first active material layer and a second active material layer, which are active material layers of the same polarity, are stacked, and a solid electrolyte is located between the first and second active material layers. With this configuration, insertion and deinsertion of Li ions to and from the active material at a deep position is good. Therefore, with such a configuration, it is possible to increase capacity while suppressing a decrease in input / output characteristics. Furthermore, with the above configuration, the battery of this disclosure enables high capacity in a single cell by connecting multiple active material layers at the electrodes. In other words, since it is not necessary to stack multiple single cells to increase capacity, it is possible to avoid the above-mentioned problems caused by the routing of lead wires. Therefore, with the battery of this disclosure, for example, even if the size is small and the capacity is increased, a highly reliable battery with excellent input / output characteristics can be realized.

[0025] As an example of a battery according to the first embodiment, battery 1000 will be described with reference to the drawings.

[0026] Figure 1 shows a schematic configuration of the battery 1000 according to the first embodiment. Figure 1(a) shows a cross-sectional view of the battery 1000 according to the first embodiment. Figure 1(b) shows a plan view of the battery 1000 viewed from below in the z-axis direction. Figure 1(a) shows a cross-section at the position indicated by line II in Figure 1(b).

[0027] As shown in Figure 1, the battery 1000 comprises a first electrode layer 10, a first solid electrolyte layer 20, and a second electrode layer 30 in that order. The first electrode layer 10 comprises a first current collector 11a, a first active material layer 12a, a second solid electrolyte layer 13, a second active material layer 12b, a second current collector 11b, and a third active material layer 12c in that order. The second electrode layer 30 comprises a current collector 31 and an active material layer 32. The first solid electrolyte layer 20 is located between the first electrode layer 10 and the second electrode layer 20. More specifically, the first solid electrolyte layer 20 is located between the third active material layer 12c of the first electrode layer 10 and the active material layer 32 of the second electrode layer 20. In the first electrode layer 10, a second solid electrolyte layer 13 is provided between the first active material layer 12a and the second active material layer 12b. In the battery 1000 shown in Figure 1, the first active material layer 12a, the second active material layer 12b, and the third active material layer 12c in the first electrode layer 10 are separated from each other and not in direct contact. The second current collector 11b is positioned between the second active material layer 12b and the third active material layer 12c and is in contact with both the second and third active material layers 12b and 12c. The first active material layer 12a, the second active material layer 12b, and the third active material layer 12c have the same polarity.

[0028] In the battery 1000 shown in Figure 1, the first active material layer 12a and the second active material layer 12b are separated from each other and do not directly contact each other, and the second solid electrolyte layer 13 is provided across the entire area between the first active material layer 12a and the second active material layer 12b. However, the configuration is not limited to this, and the first active material layer 12a and the second active material layer 12b may include portions that directly contact each other. In this case, the second solid electrolyte layer 13 is provided between the first active material layer 12a and the second active material layer 12b, in a region where the first active material layer 12a and the second active material layer 12b are separated from each other. To obtain better input / output characteristics, the region where the first active material layer 12a and the second active material layer 12b are separated may be, for example, 50% or more of the area of ​​the main surfaces where the first active material layer 12a and the second active material layer 12b face each other. Similarly, the second active material layer 12b and the third active material layer 12c may also include portions that are in direct contact with each other.

[0029] In the first electrode layer 10, for example, multiple active material layers are provided spaced apart from each other, so a thin, high-capacity first electrode layer 10 can be formed using, for example, a known lamination process. Furthermore, in the first electrode layer 10, the expansion and contraction of the active material layers due to charging and discharging can be dispersed and absorbed by each layer, thus suppressing structural defects such as delamination and cracks in the electrode layer. Therefore, the battery 1000 can have high capacity, excellent input / output characteristics, and even superior reliability.

[0030] The first current collector 11a and the second current collector 11b are electrically connected, for example, by a connecting electrode 40. That is, the connecting electrode 40 electrically connects, for example, the first active material layer 12a and the second active material layer 12b. For example, the first current collector 11a may be electrically connected in parallel with the second current collector 11b, as shown in Figure 1. That is, the first active material layer 12a may be electrically connected in parallel with the second active material layer 12b. A reaction layer 50, for example, is arranged between the first current collector 11a and the connecting electrode 40. By providing the connecting electrode 40, the capacities of each active material layer are combined without using lead terminals outside the battery, thus enabling the realization of a small, high-capacity, and highly reliable battery.

[0031] The connecting electrode 40 may be provided on the side of the battery 1000, as shown in Figure 1. This allows the first active material layer 12a and the second active material layer 12b to be connected using terminal electrodes formed on the side of the battery 1000. Therefore, with this configuration, a small, high-capacity, and highly reliable battery can be realized using the end-face coating method commonly applied to chip components. In addition, heat can be dissipated through the terminal electrodes formed on the surface, suppressing the deterioration of characteristics and reliability due to heat generation.

[0032] For example, one main surface of the first current collector 11a is in contact with the first active material layer 12a, while the opposite surface is exposed. By the first current collector 11a being in contact with the first active material layer 12a, current can be collected efficiently. Furthermore, the heat generated in the first active material layer 12a during operation can be released through the first current collector 11a, which is a high thermal conductor, thus improving reliability.

[0033] The second current collector 11b is smaller than, for example, the first current collector 11a. For example, as shown in Figure 1, the second current collector 11b does not need to be exposed to the side edge of the battery 1000 (i.e., the right side edge in Figure 1). The second current collector 11b, the second active material layer 12b, and the third active material layer 12c are arranged to recede inward from, for example, the side of the battery 1000 opposite to the side where the second current collector 11b and the connecting electrode 40 are joined. With such a configuration, the receded regions of the second current collector 11b, the second active material layer 12b, and the third active material layer 12c from the side of the battery 1000 can serve as pathways for, for example, the first active material layer 12a to exchange Li ions with the second electrode layer 20. For example, in the above-mentioned receded region, the second solid electrolyte layer 13 of the first electrode layer 10 can be directly connected to the first solid electrolyte layer 20. Furthermore, this configuration makes it possible to suppress delamination of layers from the side surface of the battery 1000. For example, a solid electrolyte can be provided in the recessed region, that is, the portion from the ends of the second active material layer 12b and the third active material layer 12c that have recessed inward to the side surface of the battery 1000. This allows for further suppression of delamination, which is prone to occurring due to the expansion and contraction of charging and discharging, due to the superior stress absorption properties of the solid electrolyte, which is softer than other constituent materials. The battery 1000 does not necessarily have a third active material layer 12c. In that case, the second active material layer 12b may be provided on the main surface of the second current collector 11b facing the first solid electrolyte layer 20 (i.e., the position where the third active material layer 12c is located in Figure 1).

[0034] The battery 1000 according to the first embodiment may have a region in plan view where the second current collector 11b is present and the second active material layer 12b is absent. That is, the second active material layer 12b may be located on the second current collector 11b and in a region in plan view that is inside the outer edge of the second current collector 11b. With such a configuration, current can be efficiently extracted from the second active material layer 12b.

[0035] In Figure 1, each layer constituting the first electrode layer 10, the first solid electrolyte layer 20, and each layer constituting the second electrode 30 (i.e., the current collector 31 and the active material layer 32) has a thin rectangular parallelepiped structure. That is, each layer is rectangular in plan view. The shape of each layer constituting the battery 1000 in plan view is not limited. Examples of shapes other than rectangles include circles, ellipses, or polygons.

[0036] The first electrode layer 10 may be a positive electrode layer. In this case, the first current collector 11a and the second current collector 11b are positive electrode current collectors, and the first active material layer 12a, the second active material layer 12b, and the third active material layer 12c are positive electrode active material layers.

[0037] When the first electrode layer 10 is the positive electrode layer, the second electrode layer 30 is the negative electrode layer. That is, the current collector 31 is the negative electrode current collector, and the active material layer 32 is the negative electrode active material layer.

[0038] In this specification, the first current collector 11a and the second current collector 11b in the first electrode layer 10, and the current collector 31 in the second electrode layer 30 may be simply referred to as "current collectors." Also, the first active material layer 12a, the second active material layer 12b, the third active material layer 12c, and the active material layer 32 may be simply referred to as "active material layers."

[0039] The current collector can be made of any conductive material. The material of the current collector is not particularly limited. Examples of current collector materials include stainless steel, nickel, aluminum, iron, titanium, copper, palladium, gold, platinum, or alloys of two or more of these. The current collector material may also include at least one selected from the group consisting of Al, Cu, and Ni. This configuration enables stable current collection during charging and discharging operations, while also suppressing resistance loss.

[0040] Examples of current collector shapes include foil, plate, or mesh. The material of the current collector may be appropriately selected considering that it does not melt or decompose under the manufacturing process, operating temperature, and operating pressure, as well as the battery operating potential and conductivity applied to the current collector. The material of the current collector may also be selected according to the required tensile strength and heat resistance. The current collector may be, for example, high-strength electrolytic copper foil or a clad material formed by laminating dissimilar metal foils.

[0041] A current collector located inside the battery, such as the second current collector 11b, may have at least one selected from the group consisting of holes and slits. The current collector's anchoring effect is improved by the entry of active material or solid electrolyte into the holes or slits. This effect suppresses delamination of layers due to expansion and contraction associated with charging and discharging. The holes and slits can also serve as pathways for the movement of Li ions. Furthermore, such holes and slits allow air that may be trapped between layers during lamination to be expelled, thereby suppressing delamination. Thus, a highly reliable battery can be realized.

[0042] The thickness of the current collector may be, for example, 10 μm or more and 100 μm or less. Even if the thickness of the current collector is less than 10 μm, it can be used within a range that satisfies the handling in the manufacturing process, characteristics such as current capacity, and reliability. The current collector, in particular the main surface of the second current collector 11b, is preferably roughened on both sides in order to improve bonding with the second active material layer 12b and the third active material layer 12c. This suppresses the occurrence of defects in the internal structure and improves reliability. For example, the maximum height Rz may be about the particle size of the active material (e.g., 1 to 10 μm). The sides of the battery 1000 may be processed to be a rough surface with irregularities in order to improve adhesion with the connecting electrode 40. For example, the connecting electrode 40 may be applied to a surface polished with #800 to #1000 grit sandpaper. The rough surface with irregularities may have a surface roughness such that the maximum height Rz is about 10 to 20 μm. This allows for the dispersion of surface energy, thereby reducing the influence of surface tension. When the material for the connecting electrode 40 is applied to the side of the battery 1000, wettability is improved, and the shape accuracy can be enhanced. Furthermore, the anchoring effect is improved, resulting in improved reliability of the connection between the connecting electrode 40 and the side of the battery 1000.

[0043] The positive electrode active material layer contains a positive electrode active material. The positive electrode active material is a substance in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted into or removed from its crystal structure at a higher potential than the negative electrode, and oxidation or reduction occurs as a result. The type of positive electrode active material can be appropriately selected depending on the type of battery, and known positive electrode active materials can be used.

[0044] The positive electrode active material may be a compound containing lithium and a transition metal element. More specifically, examples of such compounds are oxides containing lithium and a transition metal element or phosphoric acid compounds containing lithium and a transition metal element. An example of an oxide containing lithium and a transition metal element is LiNi x M 1-xLithium nickel composite oxides such as O2 (where M is at least one 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), layered oxides such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium manganate (LiMn2O4), or lithium manganates having a spinel structure (LiMn2O4, Li2MnO3, LiMnO2). An example of a phosphate compound containing lithium and a transition metal element is lithium iron phosphate (LiFePO4) having an olivine structure. Other examples of the positive electrode active material are sulfides such as sulfur (S) and lithium sulfide (Li2S). When the positive electrode active material is a sulfide, lithium niobate (LiNbO3) or the like may be coated or added to the positive electrode active material particles. As the positive electrode active material, only one of these materials may be used, or two or more of these materials may be combined and used.

[0045] The positive electrode active material layer may contain not only the positive electrode active material but also other additive materials. That is, the positive electrode active material layer may be a binder layer. Examples of the additive materials are solid electrolytes such as inorganic solid electrolytes and sulfide solid electrolytes, conductive aids such as acetylene black, or binders for binding such as polyethylene oxide and polyvinylidene fluoride. By mixing the positive electrode active material and the additive materials at a predetermined ratio, the lithium ion conductivity in the positive electrode active material layer can be improved, and the electron conductivity can also be improved. As the solid electrolyte, for example, the solid electrolyte exemplified as the material constituting the first solid electrolyte layer 20 described later can be used.

[0046] The thickness of the positive electrode active material layer may be, for example, 3 μm or more and 100 μm or less. That is, when the first electrode layer 10 is a positive electrode layer, the thicknesses of the first active material layer 12a, the second active material layer 12b, and the third active material layer 12c may each be 3 μm or more and 100 μm or less.

[0047] The negative electrode active material layer contains a negative electrode active material. The negative electrode active material is a substance in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted into or removed from its crystal structure at a lower potential than that of the positive electrode, and oxidation or reduction occurs as a result. 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.

[0048] Examples of negative electrode active materials include carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, and resin-fired carbon, or alloying materials combined with a solid electrolyte. Examples of alloying materials include LiAl, LiZn, Li3Bi, Li3Cd, Li3Sb, Li4Si, Li 4.4 Pb, Li 4.4 Sn, Li 0.17 C, and lithium alloys such as LiC6, lithium titanate (Li4Ti5O 12 Oxides of lithium and transition metal elements, such as zinc oxide (ZnO) and silicon oxide (SiO2). x These are metal oxides such as ). As the negative electrode active material, only one of these materials may be used, or two or more of these materials may be used in combination.

[0049] The negative electrode active material layer may contain not only the negative electrode active material but also other additive materials. That is, the negative electrode active material layer may be a mixture layer. Examples of additive materials include solid electrolytes such as inorganic solid electrolytes and sulfide solid electrolytes, conductive additives such as acetylene black, or binding binders such as polyethylene oxide and polyvinylidene fluoride. By mixing the negative electrode active material and additive materials in a predetermined ratio, the lithium ion conductivity within the negative electrode active material layer can be improved, as can the electronic conductivity. As the solid electrolyte, for example, a solid electrolyte exemplified as a material constituting the first solid electrolyte layer 20 described later may be used.

[0050] The thickness of the negative electrode active material layer may be, for example, 3 μm or more and 100 μm or less. That is, when the first electrode layer 10 is a negative electrode layer, the thicknesses of the first active material layer 12a, the second active material layer 12b, and the third active material layer 12c may each be 3 μm or more and 100 μm or less.

[0051] The first solid electrolyte layer 20 is disposed between the first electrode layer 10 and the second electrode layer 30. The first solid electrolyte layer 20 may be in contact with the first electrode layer 10 and the second electrode layer 30. For example, in the configuration shown in FIG. 1, the first solid electrolyte layer 20 may be in contact with the third active material layer 12c of the first electrode layer 10 and may also be in contact with the active material layer 32 of the second electrode layer 30.

[0052] The first solid electrolyte layer 20 contains a solid electrolyte. The first solid electrolyte layer 20 contains, for example, a solid electrolyte as a main component. Here, the main component refers to the component that is most contained in the first solid electrolyte layer 20 in terms of mass ratio. The solid electrolyte may be a known solid electrolyte for a battery that has no electronic conductivity but has ionic conductivity. For the solid electrolyte, for example, a solid electrolyte that conducts metal ions such as lithium ions and magnesium ions can be used. The solid electrolyte may be appropriately selected according to the conduction ion species. Examples of the solid electrolyte are sulfide-based solid electrolytes, oxide-based solid electrolytes, or halogen-based solid electrolytes.

[0053] Examples of sulfide-based solid electrolytes are Li2S-P2S5 systems, Li2S-SiS2 systems, Li2S-B2S3 systems, Li2S-GeS2 systems, Li2S-SiS2-LiI systems, Li2S-SiS2-Li3PO4 systems, Li2S-Ge2S2 systems, Li2S-GeS2-P2S5 systems, or Li2S-GeS2-ZnS systems.

[0054] Examples of oxide-based solid electrolytes are lithium-containing metal oxides such as Li2O-SiO2 and Li2O-SiO2-P2O5, Li x P y O 1-z N z such as lithium-containing metal nitrides, Li7La3Zr2O12 Alternatively, it may be a garnet-type solid electrolyte such as an elementally substituted version thereof, lithium phosphate (Li3PO4), or a lithium-containing transition metal oxide such as lithium titanium oxide.

[0055] Examples of halogen-based solid electrolytes include Li a Me b Y c This is a compound represented by Z6. Here, the equation a + mb + 3c = 6 and c > 0 are satisfied. Me is at least one element selected from the group consisting of metallic elements other than Li and Y and metalloid elements. Z is at least one element selected from the group consisting of F, Cl, Br, and I. The value of m represents the valence of Me.

[0056] "Metalloid elements" are B, Si, Ge, As, Sb, and Te. "Metallic elements" are all elements in groups 1 through 12 of the periodic table (except hydrogen), and all elements in groups 13 through 16 of the periodic table (except B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se).

[0057] To increase the ionic conductivity of halogen-based solid electrolytes, Me may be at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb.

[0058] Examples of halogenated solid electrolytes are Li3YCl6 or Li3YBr6.

[0059] As a solid electrolyte, only one of these materials may be used, or two or more of these materials may be used in combination.

[0060] The first solid electrolyte layer 20 may contain not only a solid electrolyte but also a binding binder such as polyethylene oxide and polyvinylidene fluoride.

[0061] The thickness of the first solid electrolyte layer 20 may be, for example, 5 μm or more and 150 μm or less.

[0062] The first solid electrolyte layer 20 may be composed of aggregates of solid electrolyte particles. The first solid electrolyte layer 20 may be composed of a sintered structure of solid electrolyte.

[0063] The material of the connecting electrode 40 only needs to have electronic conductivity. To alleviate stress on the battery 1000 caused by temperature changes or expansion or contraction of the battery element due to charging and discharging, a mixture with a soft resin material can be preferably used. Here, the battery element refers to the basic structure of the battery 1000, which consists of a first electrode layer, a first solid electrolyte layer, and a second electrode layer. The connecting electrode 40 may also contain a first metal material and a resin material. This allows the cushioning effect of the conductive material to absorb stress due to the difference in thermal expansion coefficient with respect to the surrounding area or shock, thereby increasing the reliability of the connection. In addition, the sealing effect of the resin component suppresses the intrusion of moisture and other substances into the battery, thereby suppressing the degradation of the properties of the easily degradable solid electrolyte. As a result, a highly reliable battery 1000 can be obtained.

[0064] The Young's modulus of the connecting electrode 40 may be lower than that of the current collector. This allows the stress on the connecting electrode 40 caused by temperature changes or expansion and contraction of the battery element due to charging and discharging to be mitigated by the buffering properties of the conductive material, including its resin. Because the connecting electrode 40 is deformable, it can follow the deformation of the cell caused by thermal shock or charge-discharge cycles, thereby suppressing delamination and damage. Furthermore, to alleviate stress on the battery 1000 and improve the reliability of the battery 1000, the Young's modulus of the connecting electrode 40 may be lower than that of the first solid electrolyte layer 20. To alleviate stress on the battery 1000 caused by expansion or contraction of the active material layer due to temperature changes and improve the reliability of the battery, the Young's modulus of the connecting electrode 40 may be smaller than that of the active material layer. The relative relationship of these Young's moduli can be determined, similar to Vickers hardness, from the displacement characteristics with respect to pressure when a rigid indenter (i.e., probe) is pressed in, and from the magnitude of the indentation. Furthermore, the connecting electrode 40 may be made of a material containing a solid electrolyte or the like in a conductive resin paste, from the viewpoint of being able to adjust the coefficient of thermal expansion and softness (e.g., Young's modulus).

[0065] The connecting electrode 40 may be made of a material containing conductive material particles or semiconductor material particles in a solid electrolyte. As described above, this allows for electrical connection while mitigating stress caused by the expansion or contraction of the current collector due to temperature changes, thereby enabling the realization of a high-capacity electrode with excellent high-rate characteristics.

[0066] The connecting electrode 40 may include a first metallic material and a solid electrolyte. This allows the coefficient of thermal expansion to be controlled to match the battery 1000, thereby suppressing structural defects caused by thermal shock during the thermal cycle with the battery components. As a result, a highly reliable battery can be realized.

[0067] As the conductive material used for the connecting electrode 40, for example, a thermosetting conductive paste can be used which contains high-melting-point, highly conductive metal particles (first metal material) including Ag, Cu, Ni, Zn, Al, Pd, Au, Pt or alloys thereof, low-melting-point metal particles (second metal material), 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 below the curing temperature of the conductive resin paste, and may be 300°C or lower. Examples of materials for the low-melting-point metal particles, i.e., the second metal material, include Sn, SnZn, SnAg, SnCu, SnAl, SnPb, In, InAg, InZn, InSn, Bi, BiAg, BiNi, BiSn, BiZn, or BiPb. By using a conductive paste containing such low-melting-point metal powder, solid-phase and liquid-phase reactions proceed at the contact area between the conductive paste and the current collector at a thermosetting temperature lower than the melting point of the low-melting-point metal particles. For example, sintering occurs even at a temperature less than half the melting point of the metal. This forms an alloy containing, for example, the metal contained in the conductive paste and the metal contained in the current collector. A diffusion layer, i.e., a reaction layer 50, containing the alloy is formed near the connection point between the current collector and the connecting electrode 40.

[0068] The connecting electrode 40 may include at least one selected from the group consisting of Sn, In, and Bi as a second metallic material, such as the low-melting-point metal particles mentioned above. This allows the connecting electrode 40 to be controlled to be soft. As a result, the connecting electrode 40 connects to the current collector by plastically engaging with the connection portion, increasing the contact area and reducing contact resistance. Furthermore, even if heat and stress act on the connection portion with the current collector, the connecting electrode 40 can undergo plastic deformation, thus suppressing the problem of the connecting electrode 40 fracturing and the connection being lost.

[0069] The reaction layer 50 is a diffusion layer containing an alloy at the connection point between the current collector and the connecting electrode 40. For example, if Ag or an Ag alloy is used as conductive particles for the connecting electrode 40 and Cu is used for the current collector, a highly conductive alloy containing AgCu is formed. Furthermore, by including a second metal material which is a low-melting-point metal, a reaction layer 50 of a low-melting-point alloy such as SnAg or SnCu can also be formed at around 200°C at the connection point between Ag (connecting electrode) and Cu (current collector), depending on the combination of the conductive particle material and the current collector material. In this way, the connecting electrode 40 and the current collector are integrally joined by the reaction layer 50 containing the alloy.

[0070] With the above configuration, the connecting electrode 40 and the current collector are seamlessly integrated via the reaction layer 50, resulting in a stronger connection than that of the anchoring effect. Therefore, problems such as disconnection of the components due to differences in thermal expansion caused by thermal cycling in each component of the battery 1000, or due to impact, are less likely to occur.

[0071] The shapes of the highly conductive metal particles as the first metallic material and the low-melting-point metal particles as the second metallic material are not limited. Examples of such shapes include spherical, flaky, or needle-shaped. The smaller the particle size of these metal particles, the lower the temperature at which sintering occurs, and the more readily alloying reactions and alloy diffusion proceed. Therefore, the particle size and shape of these metal particles can be appropriately adjusted to take into account the influence of thermal history on process design and battery characteristics.

[0072] The resin material used for the connecting electrode 40 may be a thermoplastic resin or a thermosetting resin.

[0073] Examples of thermoplastic resins include polyethylene resins, polypropylene resins, acrylic resins, polystyrene resins, vinyl chloride resins, silicone resins, polyamide resins, polyimide resins, fluorinated hydrocarbon resins, polyether resins, butadiene rubber, isoprene rubber, styrene-butadiene rubber (SBR), styrene-butadiene-styrene copolymer (SBS), styrene-ethylene-butadiene-styrene copolymer (SEBS), ethylene-propylene rubber, butyl rubber, chloroprene rubber, or acrylonitrile-butadiene rubber.

[0074] Examples of thermosetting resins are: (i) Amino resins such as urea resins, melamine resins, and guanamine resins, (ii) Epoxy resins such as bisphenol A type, bisphenol F type, phenol novolac type, and alicyclic type, (iii) Oxetane resins, (iv) Resol-type or novolac-type phenolic resin, or (v) Silicone-modified organic resins such as silicone epoxy and silicone polyester That is the case.

[0075] The connecting electrode 40 may be made of a material having pores or bubbles containing air or the like. This structure allows for control over a wide range of softness (e.g., Young's modulus), thereby further mitigating the stress on the battery 1000 caused by the expansion or contraction of the battery element due to temperature changes.

[0076] The connecting electrode 40 may contain a non-combustible material such as metal, ceramics, or a solid electrolyte. If the connecting electrode 40 contains a non-combustible material, it also has the effect of acting as a layer wall to suppress the spread of fire when the battery 1000 overheats abnormally.

[0077] From the viewpoint of the volumetric energy density of the battery, it is advantageous for the connecting electrode 40 to be thin. For example, the connecting electrode 40 may be thinner than the current collector. The thickness of the connecting electrode 40 may be, for example, 1 μm or more and 50 μm or less, or 2 μm or more and 40 μm or less. By having the thickness of the connecting electrode 40 within the above range, it is possible to suppress the decrease in volumetric energy density while easily mitigating the stress caused by the expansion or contraction of the current collector due to temperature changes, thereby stably bringing out the characteristics of the battery 1000.

[0078] With the above configuration, it is possible to realize a battery 1000 with excellent input / output characteristics.

[0079] In the first embodiment, a configuration in which the first electrode layer 10 comprises three active material layers was described. However, the number of active material layers provided in the first electrode layer 10 is not limited to this, and the first electrode layer 10 may comprise four or more active material layers. That is, the first electrode layer 10 further includes fourth to Nth active material layers (N is an integer of 4 or more) having the same polarity as the first to third active material layers. The Lth active material layer (L is an integer satisfying 4 ≤ L ≤ N) included in the fourth to Nth active material layers is located between the L-1st active material layer and the first solid electrolyte layer 20, and each of the fourth to Nth active material layers has a surface that is in contact with the solid electrolyte. The same applies to the following embodiments described later.

[0080] (Second Embodiment) The following describes a battery 2000 according to a second embodiment. Matters described in the above embodiments may be omitted.

[0081] Figure 2 shows a schematic configuration of the battery 2000 according to the second embodiment. Figure 2(a) shows a cross-sectional view of the battery 2000 according to the second embodiment. Figure 2(b) shows a plan view of the battery 2000 viewed from below in the z-axis direction. Figure 2(a) shows a cross-section at the position indicated by the line II-II in Figure 2(b).

[0082] As shown in Figure 2, the battery 2000 according to the second embodiment differs from the battery 1000 in that an insulating layer 60 is formed on the side surface of the battery 2000 where the connecting electrodes 40 are located.

[0083] The insulating layer 60 only needs to have electrical insulating properties. The insulating layer 60 prevents the connecting electrode 40 from coming into contact with the second electrode layer 30 due to the shedding of components from the active material layer 32 of the second electrode layer 30, thereby preventing a short circuit between the first electrode layer 10 and the second electrode layer 30. Other sides may also be covered with the insulating layer 60.

[0084] An example of a material for the insulating layer 60 is an insulating resin.

[0085] The thickness of the insulating layer 60 may be about the same as that of the connecting electrode 40. The thickness of the insulating layer 60 may be, for example, 1 μm or more and 50 μm or less, or 2 μm or more and 40 μm or less.

[0086] As the material for the insulating layer 60, for example, a liquid or powder-based thermosetting epoxy resin can be used. Such an applicable resin material can be applied to the side surface of the battery 2000 in liquid or powder form and then thermo-cured to fix the insulating layer 60 to the side surface of the battery 2000. As the material for the insulating layer 60, a material softer than the battery components (i.e., the current collector, active material, and solid electrolyte) is particularly suitable. For example, a general epoxy resin with an elastic modulus of 10 to 40 GPa may be used. As a result, the side surface of the battery 2000 covered with the insulating layer 60, together with the portion covered by the connecting electrodes 40, can absorb shocks. Therefore, the battery 2000 can be protected by the provision of the insulating layer 60.

[0087] Furthermore, even when thermal cycling occurs, the softness of the insulating material constituting the insulating layer 60 can absorb the stress caused by the difference in thermal expansion acting at the interface between the insulating layer 60 and the side surface of the battery 2000, and at the interface between the insulating layer 60 and the connecting electrode 40. This suppresses adverse effects on the solid structure of the battery 2000 (e.g., crack formation) or delamination.

[0088] The softness (e.g., Young's modulus) of the battery components and the insulating layer 60 can be evaluated using the method described above for the connecting electrode 40. Similar to Vickers hardness, the relative softness can be compared by applying a rigid indenter and comparing the magnitude of the resulting indentations. For example, when the indenter is pressed with the same force against each part of the battery cross-section, it is desirable that the material constituting the insulating layer 60 is indented the most than the other components.

[0089] The thermosetting conditions, including temperature and time, may be set within a range that does not adversely affect the battery characteristics. The thickness of the insulating layer 60 is, for example, sufficient for electrical insulation if it is 10 μm or more, while a thicker layer is better for shock absorption. There is no particular upper limit to the thickness, but it may be set to an appropriate thickness to avoid reducing the battery's energy density and volumetric capacity density.

[0090] This configuration makes it possible to obtain a battery 2000 with excellent input / output characteristics, as well as high performance and high reliability.

[0091] (Third embodiment) The following describes a battery 3000 according to a third embodiment. Matters described in the above embodiments may be omitted.

[0092] Figure 3 shows a schematic configuration of the battery 3000 according to the third embodiment. Figure 3(a) shows a cross-sectional view of the battery 3000 according to the third embodiment. Figure 3(b) shows a plan view of the battery 3000 viewed from below in the z-axis direction. Figure 3(a) shows a cross-section at the position indicated by line III-III in Figure 3(b).

[0093] As shown in Figure 3, the battery 3000 differs from the battery 1000 in that the connecting electrode 41 is formed by an inner via hole within the battery 3000. That is, in the battery 3000 according to the third embodiment, the connecting electrode 41 is located inside the first electrode layer 10.

[0094] By forming the connecting electrodes 41 in the inner via holes inside the battery, internal connection can be achieved using the via hole connection method commonly used in stacked devices and multilayer substrates. The connecting electrodes 41 can be incorporated at any location inside the battery, and by distributing the via hole positions in the upper and lower active material layers, the expansion and contraction stresses of the active material layers can be distributed and mitigated. Furthermore, since the upper and lower layers can be connected by multiple via electrodes, the reliability of both the electrical connection and the interlayer adhesion can be improved. Therefore, the battery 3000 according to the third embodiment can further enhance the reliability of the battery 3000 through the configuration of the connecting electrodes 41.

[0095] The connecting electrode 41 electrically connects the upper and lower current collectors (i.e., the first current collector 11a and the second current collector 11b) to each other via inner via holes. The inner via holes can be formed using common multilayer ceramic process techniques used in multilayer inductors or LTCCs (Low Temperature Co-fired Ceramics). For example, through-holes are created in the electrode layer by mechanical punching or laser processing, and then conductive material is filled in, for example, by printing using a metal mask. The holes may be, for example, circular (cylindrical) and may have a diameter of, for example, 100 to 500 μm. Another example of hole shape is rectangular.

[0096] The conductive material used to fill the via holes can be any conductive material with high electrical conductivity; for example, the same material as the connecting electrode 40 described in the first embodiment can be used.

[0097] In this way, by using via holes as connecting electrodes 41, they can be incorporated at any location inside the battery, and by forming multiple via hole positions on the upper and lower current collectors (i.e., the first current collector 11a and the second current collector 11b), the expansion and contraction stress of the electrode layer can be bound and restrained at various points. Furthermore, the reaction layer 51 diffuses and spreads outward beyond the diameter of the connecting electrode 41, resulting in a strong, integrated bond between the layers. Therefore, it is possible to suppress delamination due to expansion and contraction during battery operation and to improve connection reliability. Thus, in addition to excellent input characteristics, the battery 3000 has high performance and high reliability.

[0098] (Fourth Embodiment) The following describes a battery 4000 according to a fourth embodiment. Matters described in the above embodiments may be omitted.

[0099] Figure 4 shows a schematic configuration of the battery 4000 according to the fourth embodiment. Figure 4(a) shows a cross-sectional view of the battery 4000 according to the fourth embodiment. Figure 4(b) shows a plan view of the battery 4000 viewed from below in the z-axis direction. Figure 4(a) shows a cross-section at the position indicated by the line IV-IV in Figure 4(b).

[0100] As shown in Figure 4, battery 4000 differs from battery 1000 in that the second electrode layer 30 includes multiple active material layers. Specifically, the second electrode layer 30 comprises a first current collector 31a, a first active material layer 32a, a third solid electrolyte layer 33, a second active material layer 32b, a second current collector 31b, and a third active material layer 32c in this order. The third solid electrolyte layer 20 is positioned between the first active material layer 32a and the second active material layer 32b. In the second electrode layer 30, the third solid electrolyte layer 33 is provided between the first active material layer 32a and the second active material layer 32b. In the second electrode layer 30, the first active material layer 32a, the second active material layer 32b, and the third active material layer 32c are separated from each other and are not in direct contact. The second current collector 31b is positioned between the second active material layer 32b and the third active material layer 32c, and is in contact with both the second and third active material layers 32b and 32c. The first active material layer 32a, the second active material layer 32b, and the third active material layer 32c have the same polarity as each other.

[0101] In the battery 4000 shown in Figure 4, the first active material layer 32a and the second active material layer 32b are separated from each other and do not directly contact each other, and the third solid electrolyte layer 33 is provided across the entire area between the first active material layer 32a and the second active material layer 32b. However, the configuration is not limited to this, and the first active material layer 32a and the second active material layer 32b may include portions that directly contact each other. In this case, the third solid electrolyte layer 33 is provided between the first active material layer 32a and the second active material layer 32b, in a region where the first active material layer 32a and the second active material layer 32b are separated from each other. To obtain better input / output characteristics, the region where the first active material layer 32a and the second active material layer 32b are separated may be, for example, 50% or more of the area of ​​the main surfaces where the first active material layer 32a and the second active material layer 32b face each other. Similarly, the second active material layer 32b and the third active material layer 32c may also include portions that are in direct contact with each other.

[0102] With the above configuration, a thin second electrode layer 30 can be realized that facilitates the insertion and removal of Li ions, similar to the first electrode layer 10. Therefore, even with further miniaturization and increased capacity, a highly reliable battery 4000 with excellent input / output characteristics can be obtained.

[0103] The second electrode layer 30 may include a connecting electrode 42, just as the first electrode layer 10 includes a connecting electrode 40. The second electrode layer 30 may include a reaction layer 52, just as the first electrode layer 10 includes a reaction layer 50. The second electrode layer 30 may include an insulating layer 61, just as the first electrode layer 10 includes an insulating layer 60. The material of the connecting electrode 42 can be the same as that of the connecting electrode 40 described in the first embodiment. The material of the insulating layer 61 can be the same as that of the insulating layer 60 described in the second embodiment. The reaction layer 52 is the same as that of the reaction layer 50 described in the first embodiment.

[0104] With the above configuration, the input / output characteristics of the first electrode layer 10 and the second electrode layer 30 can be improved and the capacity can be increased.

[0105] (Fifth embodiment) The following describes a stacked battery 5000 according to a fifth embodiment. Matters described in the above embodiments may be omitted.

[0106] Figure 5 shows a schematic configuration of the stacked battery 5000 according to the fifth embodiment. Figure 5(a) shows a cross-sectional view of the stacked battery 5000 according to the fifth embodiment. Figure 5(b) shows a plan view of the stacked battery 5000 viewed from below in the z-axis direction. Figure 5(a) shows a cross-section at the position indicated by the VV line in Figure 5(b).

[0107] As shown in Figure 5, the stacked battery 5000 differs from the battery 2000 in that it consists of two stacked batteries 2000. In other words, the stacked battery 5000 has two single cells.

[0108] With the above configuration, it is possible to realize a high-performance and highly reliable battery even with increased capacity and energy.

[0109] The stacked battery 5000 is formed by stacking two batteries 2000, coating the connection surfaces of each with a conductive material, and then curing them to form a single unit. The conductive material used for connection only needs to be conductive. For example, the same conductive material as the connection electrode 40 described in the first embodiment can be used.

[0110] The individual cells included in the stacked battery 5000 may be arranged symmetrically. Figure 6 shows a schematic configuration of a modified stacked battery 6000 according to the fifth embodiment. Figure 6(a) shows a cross-sectional view of the modified stacked battery 6000 according to the fifth embodiment. Figure 6(b) shows a plan view of the stacked battery 6000 viewed from below in the z-axis direction. Figure 6(a) shows a cross-section at the position indicated by the line VI-VI in Figure 6(b).

[0111] Figures 5 and 6 show two single cells, but three or more single cells may be stacked. By arranging the single cells symmetrically as shown in Figure 6, or by minimizing the bias, stress resistance such as impact resistance is improved, thus enabling the construction of a highly reliable stacked battery.

[0112] This configuration, which connects multiple individual cells, makes it possible to create a high-performance and highly reliable battery with high voltage and energy capacity.

[0113] [Battery manufacturing method] The following describes an example of a method for manufacturing the battery according to this disclosure. As an example, a method for manufacturing battery 2000 according to the second embodiment will be described.

[0114] In the following explanation, the first electrode layer 10 is the positive electrode, and the second electrode layer 30 is the negative electrode.

[0115] First, pastes are prepared for printing and forming the positive electrode active material layer and the negative electrode active material layer. As the solid electrolyte raw material used in the mixture of the positive electrode active material layer and the negative electrode active material layer, for example, a glass powder of Li2S-P2S5 system sulfide with an average particle size of approximately 10 μm and mainly composed of triclinic crystals is prepared. This glass powder is, for example, 2 × 10 -3 From 3 x 10 -3 It has high ionic conductivity of approximately S / cm. As the positive electrode active material, for example, a layered Li·Ni·Co·Al composite oxide (e.g., LiNi) has an average particle size of about 5 μm. 0.8 Co 0.15 Al 0.05 A powder of O2 is used. A paste for the positive electrode active material layer is prepared by dispersing a mixture containing the above-mentioned positive electrode active material and the above-mentioned glass powder in an organic solvent or the like. As the negative electrode active material, for example, powder of natural graphite with an average particle size of about 10 μm is used. A paste for the negative electrode active material layer is prepared by dispersing a mixture containing the above-mentioned negative electrode active material and the above-mentioned glass powder in an organic solvent or the like.

[0116] Next, copper foil with a thickness of approximately 30 μm is prepared as the material to be used as the positive electrode current collector and the negative electrode current collector. The copper foil is, for example, roughened on both sides, with a maximum height Rz of approximately 3 to 7 μm. The following components (A) to (C) are prepared by screen printing.

[0117] (A) A component in which a paste for the negative electrode active material layer is printed on one side of the negative electrode current collector to a thickness of approximately 50 μm to 100 μm, and the paste for the negative electrode active material layer is dried at 80°C to 130°C. The paste for the negative electrode active material layer is dried to a thickness of 30 μm or more and 60 μm or less. (B) A component in which a paste for the positive electrode active material layer is printed on one side of the positive electrode current collector to a thickness of approximately 50 μm to 100 μm, and the paste for the positive electrode active material layer is dried at 80°C to 130°C. The paste for the positive electrode active material layer is dried to a thickness of 30 μm or more and 60 μm or less. (C) A component in which a paste for the positive electrode active material layer is printed on both sides of the positive electrode current collector to a thickness of approximately 50 μm to 100 μm, and the paste for the positive electrode active material layer is dried at 80°C to 130°C. The paste for the positive electrode active material layer is dried to a thickness of 30 μm or more and 60 μm or less.

[0118] This results in a negative electrode layer (i.e., component (A) above) in which a negative electrode active material layer is formed on one side of a copper foil that serves as a negative electrode current collector, a positive electrode layer (i.e., component (B) above) in which a positive electrode active material layer is formed on one side of a copper foil that serves as a positive electrode current collector, and a positive electrode laminate (i.e., component (C) above) in which positive electrode active material layers are formed on both sides of a copper foil that serves as a positive electrode current collector.

[0119] Next, a paste for the solid electrolyte layer is prepared by dispersing the mixture containing the aforementioned glass powder in an organic solvent or the like. The paste for the solid electrolyte layer is printed on the negative electrode active material layer of the negative electrode layer, the positive electrode active material layer of the positive electrode layer, and the positive electrode active material layers on both sides of the positive electrode laminate using a metal mask to a thickness of, for example, about 100 μm. After that, the negative electrode layer, positive electrode layer, and positive electrode laminate on which the solid electrolyte layer paste has been printed are dried at 80°C to 130°C.

[0120] Next, these components are stacked in the order of negative electrode layer, positive electrode laminate, and positive electrode layer. At this time, the positive electrode layer, positive electrode laminate, and negative electrode layer are stacked so that the solid electrolyte printed on the positive electrode active material layer of the positive electrode layer faces the solid electrolyte printed on one positive electrode active material layer of the positive electrode laminate, and furthermore, the solid electrolyte printed on the other positive electrode active material layer of the positive electrode laminate faces the solid electrolyte printed on the negative electrode active material layer of the negative electrode layer.

[0121] Next, the laminated body is pressed in a pressure mold. Specifically, between the laminate and the pressure mold plate, that is, between the upper surface of the negative electrode current collector of the laminate and the upper surface of the positive electrode current collector constituting the positive electrode layer, for example, a material with a thickness of 70 μm and an elastic modulus of 5 × 10⁻¹⁰ is applied. 6 An elastic sheet with a pressure of approximately Pa is inserted. In this configuration, pressure is applied to the laminate via the elastic sheet. Subsequently, the laminate is pressurized for 90 seconds while the pressurizing mold is heated to 50°C at a pressure of 300 MPa.

[0122] Next, a thermosetting conductive paste containing a metal with a low melting point (e.g., Sn) and conductive particles such as Ag particles with an average particle diameter of 0.5 μm is screen-printed to the side surface of the positive electrode layer to a thickness of approximately 30 μm. After this, the connecting electrode is formed by curing at, for example, 150°C to 200°C for 0.5 to 3 hours. Lamination may be performed as needed to achieve the desired thickness. During this curing process, a reaction layer is formed between the current collector and the connecting electrode, and the current collector and the connecting electrode become one unit. If a thin coating film is to be formed, finer particles or flaky particles may be used instead of conductive particles such as Ag particles. Furthermore, various low-melting-point metals may be included with the aim of forming an alloy with the current collector at the curing temperature.

[0123] Next, a thermosetting epoxy resin is screen-printed onto the side of the battery where no connecting electrodes are formed, to a thickness of approximately 30 μm (similar to that of the connecting electrodes). Then, it is cured at approximately 120 to 150°C for 1 to 3 hours, cooled to room temperature, and removed. In this way, the battery 2000 is obtained.

[0124] Note that the method and sequence of battery formation are not limited to the examples described above.

[0125] In the manufacturing method described above, an example was shown in which the paste for the positive electrode active material layer, the paste for the negative electrode active material layer, the paste for the solid electrolyte layer, and the conductive paste were applied by printing, but this is not the only method. Examples of printing methods include the doctor blade method, calendering method, spin coating method, dip coating method, inkjet method, offset method, die coating method, and spray method.

[0126] In the manufacturing method described above, a thermosetting conductive paste containing Ag particles was given as an example of the conductive paste, but it is not limited to this. As the conductive paste, a thermosetting conductive paste containing high-melting-point (e.g., 400°C or higher) highly conductive metal particles, low-melting-point metal particles, and resin may be used. The low-melting-point metal particles preferably have a melting point below the curing temperature of the conductive paste, for example, a melting point of 300°C or lower. Examples of materials for high-melting-point highly conductive metal particles include silver, copper, nickel, zinc, aluminum, palladium, gold, platinum, or alloys of these metals. Examples of materials for low-melting-point metal particles with a melting point of 300°C or less include tin, tin-zinc alloy, tin-silver alloy, tin-copper alloy, tin-aluminum alloy, tin-lead alloy, indium, indium-silver alloy, indium-zinc alloy, indium-tin alloy, bismuth, bismuth-silver alloy, bismuth-nickel alloy, bismuth-tin alloy, or bismuth-zinc alloy or bismuth-lead alloy. By using a conductive paste containing such low-melting-point metal particles, solid-phase and liquid-phase reactions proceed at the contact site between the metal particles in the conductive paste and the metal constituting the current collector, even at a thermosetting temperature lower than the melting point of high-conductivity metal particles with a high melting point. As a result, a diffusion region alloyed by solid-phase and liquid-phase reactions is formed around the contact site at the interface between the conductive paste and the surface of the current collector. An example of the alloy formed is a silver-copper alloy, a highly conductive alloy, when silver or a silver alloy is used for the conductive metal particles and copper is used for the current collector. Furthermore, by combining conductive metal particles with the current collector, silver-nickel alloys or silver-palladium alloys can also be formed. This configuration allows for a stronger bond between the connecting electrode and the current collector, for example, preventing the joint from separating due to thermal cycling or impact.

[0127] The shape of high-melting-point, highly conductive metal particles and low-melting-point metal particles is not limited. Examples of such shapes include spherical, flake-shaped, or needle-shaped. The particle size of high-melting-point, highly conductive metal particles and low-melting-point metal particles is not limited. For example, smaller particle sizes allow alloy reactions and diffusion to proceed at lower temperatures; therefore, particle size and shape are appropriately selected considering the impact of thermal history on process design and battery characteristics.

[0128] The resin used in thermosetting conductive pastes can function as a binding binder, and is selected based on the manufacturing process, considering factors such as printability and coatability. Examples of resins used in thermosetting conductive pastes include thermosetting resins. Examples of thermosetting resins include: (i) Amino resins such as urea resin, melamine resin, and guanamine resin, (ii) Epoxy resins such as bisphenol A type, bisphenol F type, phenol novolac type, and alicyclic type, (iii) Oxetane resin, (iv) resol-type or novolac-type phenolic resin, (v) Silicone-modified organic resins such as silicone epoxy and silicone polyester, The resin may use only one of these materials, or it may use a combination of two or more of these materials. [Industrial applicability]

[0129] The battery relating to this disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices or automobiles.

Claims

1. a first electrode layer; First solid electrolyte layer, and a second electrode layer; These are provided in this order, The first electrode layer is a first active material layer; A second active material layer located between the first active material layer and the first solid electrolyte layer, and having the same polarity as the first active material layer, A second solid electrolyte layer located between the first active material layer and the second active material layer. Includes, The second solid electrolyte layer is directly connected to the first solid electrolyte layer. In a plan view, the second active material layer is smaller than the first active material layer. battery.

2. The first active material layer is separated from the second active material layer. The battery according to claim 1.

3. The first electrode layer further includes a first current collector, The first current collector is in contact with the first active material layer. The battery according to claim 1 or 2.

4. The first current collector includes at least one selected from the group consisting of Al, Cu, and Ni. The battery according to claim 3.

5. The first electrode layer further includes a second current collector, The second current collector is in contact with the second active material layer. The battery according to any one of claims 1 to 4.

6. The first electrode layer further comprises a third active material layer, The third active material layer has the same polarity as the first and second active material layers. The battery according to claim 5, wherein the second current collector is disposed between the second active material layer and the third active material layer.

7. In a plan view, the region has the second current collector and the region lacks the second active material layer. The battery according to any one of claims 5 to 6.

8. The second current collector has at least one selected from the group consisting of holes and slits. The battery according to any one of claims 5 to 7.

9. The first active material layer is electrically connected in parallel with the second active material layer. The battery according to any one of claims 1 to 8.

10. Further equipped with connecting electrodes, The connecting electrode electrically connects the first active material layer and the second active material layer. The battery according to claim 9.

11. The connecting electrode is provided on the side of the battery. The battery according to claim 10.

12. The connecting electrode is located inside the first electrode layer. The battery according to claim 10.

13. The connecting electrode comprises a first metal material and a resin material. The battery according to any one of claims 10 to 12.

14. The connecting electrode comprises a first metallic material and a solid electrolyte. The battery according to any one of claims 10 to 12.

15. The connecting electrode further comprises a second metallic material, The second metal material has a lower melting point than the first metal material. The battery according to claim 13 or 14.

16. The second metallic material comprises at least one selected from the group consisting of Sn, In, and Bi. The battery according to claim 15.

17. The first electrode layer further includes a first current collector in contact with the first active material layer, The battery further comprises a reaction layer disposed between the first current collector and the connecting electrode, The reaction layer includes the second metal material, The battery according to claim 15 or 16.

18. The aforementioned second electrode layer comprises a plurality of active material layers. The battery according to any one of claims 1 to 17.

19. The first electrode layer further includes a first current collector in contact with the first active material layer and a second current collector in contact with the second active material layer. In a plan view, the second current collector is smaller than the first current collector. The battery according to claim 1.

20. A plurality of batteries according to any one of claims 1 to 19, The aforementioned multiple batteries are stacked, electrically connected in series or parallel. Stacked battery.

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