Battery and battery manufacturing method

Abstract

This battery (1) comprises a unit cell (60) having: an electrode current collector (10); a first layer (20); a second layer (30); a third layer (40); and a counter electrode current collector (50). The first layer (20) includes an electrode active material layer (21) and a first insulating layer (22) that is electrically insulating and disposed at an end section of the first layer (20) in a first direction. The second layer (30) includes a solid electrolyte layer (31). The third layer (40) includes a counter electrode active material layer (41). A first region (71) that is not covered by the first layer (20) is provided at an end section of a main surface (11) of the electrode current collector (10) in the first direction. A second region (72) that is not covered by the second layer (30) in a plan view is provided at an end section of the first layer (20) in the first direction. A third region (73) that is not covered by the third layer (40) in a plan view is provided at an end section of the second layer (30) in the first direction.

Description

Battery and method for manufacturing the battery

[0001] The present disclosure relates to batteries and methods for manufacturing batteries.

[0002] Patent Document 1 describes a battery in which an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, and a counter electrode current collector are stacked.

[0003] Patent Document 2 describes a battery in which an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, and a counter electrode current collector are stacked. In the battery described in Patent Document 2, non-facing portions are provided at the ends of the electrode active material layer and the solid electrolyte layer.

[0004] Patent Document 3 describes a battery in which an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, and a counter electrode current collector are stacked. In the battery described in Patent Document 3, a step is provided between the electrode active material layer and the counter electrode active material layer, and an insulating layer is disposed on the counter electrode current collector.

[0005] JP 2019-140079 A JP 2020-129519 A JP 2022-104137 A

[0006] An object of the present disclosure is to provide a battery suitable for achieving both high resistance to short circuits and highly efficient productivity.

[0007] A battery according to one aspect of the present disclosure includes a unit cell having an electrode current collector, a first layer disposed on a main surface of the electrode current collector, a second layer disposed on the opposite side of the first layer from the electrode current collector, a third layer disposed on the opposite side of the second layer from the first layer, and a counter electrode current collector disposed on the opposite side of the third layer from the second layer, wherein the first layer is aligned with an electrode active material layer along a first direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector and is disposed at an end of the first layer in the first direction. and a first insulating layer having electronic insulation properties, the second layer including an electrolyte layer, and the third layer including a counter electrode active material layer, wherein an end portion of the main surface of the electrode current collector in the first direction is provided with a first region that is not covered with the first layer, the end portion of the first layer in the first direction is provided with a second region that is not covered with the second layer in a plan view with respect to the main surface of the electrode current collector, and the end portion of the second layer in the first direction is provided with a third region that is not covered with the third layer in the plan view.

[0008] A method for manufacturing a battery according to one aspect of the present disclosure includes: preparing an electrode current collector; laminating the first layer on a main surface of the electrode current collector so that a first region not covered by the first layer is provided at an end of the main surface of the electrode current collector in a first direction, which is a direction from the center toward the outer edge of the main surface of the electrode current collector; laminating the second layer on a side of the first layer opposite the electrode current collector so that a second region not covered by the second layer is provided at the end of the first layer in the first direction, in a plan view with respect to the main surface of the electrode current collector; and laminating a counter electrode current collector on the third layer on the side opposite to the second layer so as to provide a third region that is not covered by the third layer at an end of the second layer in the first direction, the third region being located at the end of the second layer in the first direction, the first layer including an electrode active material layer and a first insulating layer having electronic insulation that is aligned with the electrode active material layer along the first direction and is disposed at the end of the first layer in the first direction, the second layer including an electrolyte layer, and the third layer including a counter electrode active material layer.

[0009] According to the present disclosure, it is possible to provide a battery that is suitable for achieving both high resistance to short circuits and highly efficient productivity.

[0010] FIG. 1 is a top view of a battery according to embodiment 1. FIG. 2 is a cross-sectional view of the battery according to embodiment 1. FIG. 3 is a cross-sectional view showing another example of the structure of an end portion of a unit cell according to embodiment 1. FIG. 4 is a cross-sectional view of another battery according to embodiment 1. FIG. 5 is a top view of a battery according to modified example 1 of embodiment 1. FIG. 6 is a cross-sectional view of a battery according to modified example 1 of embodiment 1. FIG. 7 is a cross-sectional view of a battery according to modified example 2 of embodiment 1. FIG. 8 is a cross-sectional view of a battery according to modified example 3 of embodiment 1. FIG. 9 is a cross-sectional view of another battery according to modified example 3 of embodiment 1. FIG. 10 is a cross-sectional view of a battery according to modified example 4 of embodiment 1. FIG. 11 is a cross-sectional view of a battery according to modified example 5 of embodiment 1. FIG. 12 is a cross-sectional view of another battery according to modified example 5 of embodiment 1. FIG. 13 is a cross-sectional view of a battery according to modified example 6 of embodiment 1. FIG. 14 is a flowchart showing a method for manufacturing a battery according to modified example 5 of embodiment 1. FIG. 15 is a top view showing an example of a laminated electrode plate. FIG. 16 is a cross-sectional view of a battery according to embodiment 2. FIG. 17 is a flowchart showing a method for manufacturing a battery according to embodiment 2.

[0011] (Findings that Form the Basis of the Present Disclosure) As described above, batteries have been proposed that have a structure in which an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, and a counter electrode current collector are stacked. Generally, the electrode current collector and electrode active material layer, and the counter electrode current collector and counter electrode active material layer, have electronic conductivity, and therefore contact between these electrodes of opposite polarity results in conduction, i.e., a short circuit. Therefore, high resistance to short circuits is important for long-term use of batteries. Furthermore, an electrical connection structure such as a terminal may be formed at the end of a battery. While an electrical connection structure can be easily formed by providing a region at the end of the electrode current collector that is not covered by the electrode active material layer, this region is prone to short circuits due to contact between the electrode current collector and the counter electrode active material layer and counter electrode current collector.

[0012] Patent Document 1 mentions stability during a short circuit, but does not mention resistance to a short circuit.

[0013] Patent Document 2 suggests that providing non-facing portions on the electrode active material layer can improve resistance to short circuits. However, the entire surface of the electrode current collector is covered with a layer, which is expected to make it difficult to form terminals for the purpose of electrical conduction between batteries, for example.

[0014] Patent Document 3 suggests that resistance to short circuits can be improved by providing a non-facing portion on a laminate in which an electrode active material layer and a solid electrolyte layer are stacked with their outer edges aligned, and by providing an insulating layer on a counter electrode current collector. However, stacking the electrode active material layer and the solid electrolyte layer with their outer edges aligned requires a stacking technique with high positional accuracy, and it is expected that highly efficient production will be difficult, as this will increase the takt time.

[0015] The present inventors have investigated a battery having a structure in which an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, and a counter electrode current collector are stacked. As a result, they have found that in order to efficiently stack each layer while improving resistance to short circuits, it is effective to provide an area in at least some layers that is not covered by the adjacent layer. Furthermore, they have found that in order to improve resistance to short circuits, it is effective to provide an insulating layer on the end of at least some layers. From the above findings, they have conceived the configuration according to the present disclosure.

[0016] (Summary of the Present Disclosure) As an overview of the present disclosure, examples of a battery and a method for manufacturing a battery according to the present disclosure will be described below.

[0017] A battery according to a first aspect of the present disclosure includes a unit cell having an electrode current collector, a first layer disposed on a main surface of the electrode current collector, a second layer disposed on the opposite side of the first layer from the electrode current collector, a third layer disposed on the opposite side of the second layer from the first layer, and a counter electrode current collector disposed on the opposite side of the third layer from the second layer, wherein the first layer is aligned with an electrode active material layer along a first direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector and is disposed at an end of the first layer in the first direction. and a first insulating layer having electronic insulation properties, the second layer including an electrolyte layer, and the third layer including a counter electrode active material layer, wherein an end portion of the main surface of the electrode current collector in the first direction is provided with a first region that is not covered with the first layer, the end portion of the first layer in the first direction is provided with a second region that is not covered with the second layer in a plan view with respect to the main surface of the electrode current collector, and the end portion of the second layer in the first direction is provided with a third region that is not covered with the third layer in the plan view.

[0018] As a result, at the end of the unit cell in the first direction, where the first region is provided and it is easy to form an electrical connection structure on the electrode current collector, the first insulating layer is disposed at the end of the first layer, thereby suppressing contact of an electrode of opposite polarity with the electrode active material layer and improving the battery's resistance to short circuits. Furthermore, at the end of the unit cell in the first direction, the second region and the third region are provided, so the end of the second layer is supported by the first layer, and the end of the third layer is supported by the second layer. As a result, collapse of the second layer and the third layer can be suppressed at the end of the unit cell in the first direction, where terminals can be easily formed. Furthermore, because the second region and the third region are provided, even if the positional accuracy during formation of the second layer and the third layer is not high, it is possible to prevent the outer edges of the second layer and the third layer from protruding from the first layer and the second layer, respectively, at the end of the unit cell in the first direction, thereby avoiding a structure that is prone to collapse, and thus facilitating increased productivity. As described above, according to this aspect, a battery suitable for achieving both high resistance to short circuits and highly efficient productivity can be realized.

[0019] Furthermore, for example, a battery according to a second aspect of the present disclosure may be the battery according to the first aspect, wherein the unit cell includes two of each of the first layer, the second layer, the third layer, and the counter electrode current collector, the two first layers being disposed on both main surfaces of the electrode current collector, the two second layers being disposed on the opposite side of each of the two first layers from the electrode current collector, the two third layers being disposed on the opposite side of each of the two second layers from the first layer, and the two counter electrode current collectors being disposed on the opposite side of each of the two third layers from the second layer, and the first region being provided at an end in the first direction of each of the two main surfaces of the electrode current collector, the second region being provided at an end in the first direction of each of the two first layers, and the third region being provided at an end in the first direction of each of the two second layers.

[0020] This allows the above-described structure, which is highly resistant to short circuits and can be produced efficiently, to be realized on both main surfaces of the electrode current collector. Furthermore, when the unit cells are densified by pressing or the like, the stress applied to both sides of the electrode current collector in the stacking direction is less likely to differ, and warping of the unit cells can be suppressed.

[0021] Furthermore, for example, a battery according to a third aspect of the present disclosure may be the battery according to the first aspect, wherein a fourth region that is not covered by the counter electrode current collector in the plan view is provided at an end of the third layer in the first direction.

[0022] This prevents the counter electrode current collector from coming into contact with the outer edge of the third layer in the first direction when the counter electrode current collectors are stacked, thereby preventing the end of the third layer from collapsing. Also, the distance between the counter electrode current collector and the electrode current collector is increased, preventing contact between the counter electrode current collector and the electrode current collector.

[0023] and the first region is provided at an end in the first direction of each of the two first layers, the second region is provided at an end in the first direction of each of the two first layers, the third region is provided at an end in the first direction of each of the two second layers, and the fourth region is provided at an end in the first direction of each of the two third layers.

[0024] This allows the above-described structure, which is highly resistant to short circuits and can be produced efficiently, to be realized on both main surfaces of the electrode current collector. Furthermore, when the unit cells are densified by pressing or the like, the stress applied to both sides of the electrode current collector in the stacking direction is less likely to differ, and warping of the unit cells can be suppressed.

[0025] Furthermore, for example, a battery according to a fifth aspect of the present disclosure may be a battery according to any one of the first to fourth aspects, wherein the second layer further includes a second insulating layer having electronic insulation properties that is aligned with the electrolyte layer along the first direction and is disposed at an end of the second layer in the first direction.

[0026] This allows the second insulating layer to prevent the electrolyte layer from collapsing.

[0027] Furthermore, for example, a battery according to a sixth aspect of the present disclosure may be the battery according to any one of the first to fourth aspects, in which the third region is a part of the electrolyte layer.

[0028] This ensures electronic insulation at the end of the second layer, and since there is no need to form a separate insulating layer to ensure such electronic insulation, the second layer can be formed in one step, allowing batteries to be manufactured at low cost and with high efficiency.

[0029] Furthermore, for example, a battery according to a seventh aspect of the present disclosure may be the battery according to any one of the first to sixth aspects, wherein the third layer further includes a third insulating layer having electronic insulation properties that is aligned with the counter electrode active material layer along the first direction and that is disposed at an end of the third layer in the first direction.

[0030] This allows the third insulating layer to prevent contact of the counter electrode active material layer with an electrode of opposite polarity, improving the battery's resistance to short circuits and preventing the counter electrode active material layer from collapsing.

[0031] Furthermore, for example, a battery according to an eighth aspect of the present disclosure may be a battery according to any one of the first to seventh aspects, wherein at an end of the unit cell in a second direction from the center toward the outer edge of the main surface of the electrode current collector and different from the first direction, the side surfaces of the electrode current collector, the first layer, the second layer, and the third layer may be flush with each other.

[0032] As a result, a first region or the like is provided at the end of the unit cell in the first direction, while at the end of the unit cell in the second direction different from the first direction, there are no steps on the side surfaces of the first layer, second layer, and third layer stacked on the electrode current collector, and no space that does not function as a battery is formed due to the steps, thereby improving the actual volumetric energy density of the battery.

[0033] Furthermore, for example, a battery according to a ninth aspect of the present disclosure may be the battery according to any one of the first to seventh aspects, wherein at an end of the unit cell in a second direction that is from the center toward the outer edge of the main surface of the electrode current collector and that is different from the first direction, side surfaces of the electrode current collector, the first layer, the second layer, the third layer, and the counter electrode current collector may be flush with each other.

[0034] As a result, a first region or the like is provided at the end of the unit cell in the first direction, while at the end of the unit cell in the second direction different from the first direction, there are no steps on the side surfaces of each layer, and no spaces that do not function as a battery are formed due to the steps, thereby improving the actual volumetric energy density of the battery.

[0035] Furthermore, for example, a battery according to a tenth aspect of the present disclosure is the battery according to any one of the first to ninth aspects, wherein at least one selected from the group consisting of the electrode active material layer, the first insulating layer, and the electrolyte layer may contain a sulfide solid electrolyte.

[0036] As a result, a sulfide solid electrolyte having excellent ionic conductivity, formability, and insulating properties is contained in at least one of the electrode active material layer, the first insulating layer, and the electrolyte layer, which makes it possible to achieve high resistance to short circuits, highly efficient productivity, and higher output of the battery.

[0037] Furthermore, for example, a battery according to an eleventh aspect of the present disclosure is the battery according to any one of the first to tenth aspects, wherein at least one selected from the group consisting of the electrode active material layer, the first insulating layer, and the electrolyte layer may contain a styrene-based elastomer.

[0038] As a result, a styrene-based elastomer with excellent flexibility and elasticity is contained in at least one of the electrode active material layer, the first insulating layer, and the electrolyte layer, making the layer containing the styrene-based elastomer less likely to collapse, and further improving the battery's high resistance to short circuits.

[0039] Furthermore, for example, a battery according to a twelfth aspect of the present disclosure is the battery according to any one of the first to eleventh aspects, wherein a part of an end portion of the counter electrode current collector in the first direction may protrude in the first direction beyond the third layer in the planar view.

[0040] This makes it possible to form an electrical connection structure such as a terminal on the counter electrode current collector at the end of the battery in the first direction, making the structure less complicated than when the electrical connection structure is formed on the main surface of the counter electrode current collector.

[0041] Furthermore, for example, a battery according to a thirteenth aspect of the present disclosure may be a battery according to any one of the first to twelfth aspects, including a plurality of the unit cells, and the plurality of unit cells may be stacked.

[0042] As a result, since the above unit cells are stacked, a stacked battery suitable for achieving both high resistance to short circuits and highly efficient productivity of the battery can be realized.

[0043] A method for manufacturing a battery according to a fourteenth aspect of the present disclosure includes preparing an electrode current collector, and laminating the first layer on a main surface of the electrode current collector so that a first region not covered by the first layer is provided at an end of the main surface of the electrode current collector in a first direction that is a direction from the center toward an outer edge of the main surface of the electrode current collector, and laminating the second layer on a side of the first layer opposite the electrode current collector so that a second region not covered by the second layer is provided at the end of the first layer in the first direction, in a plan view with respect to the main surface of the electrode current collector; laminating the third layer on a side of the second layer opposite to the first layer so that a third region that is not covered by the third layer in the plan view is provided at an end of the second layer in the first direction, the third region being not covered by the third layer; and laminating a counter electrode current collector on the side of the third layer opposite to the second layer, the side of the third layer opposite to the second layer, wherein the first layer includes an electrode active material layer and a first insulating layer that is aligned with the electrode active material layer along the first direction and has electronic insulation and is disposed at the end of the first layer in the first direction, the second layer includes an electrolyte layer, and the third layer includes a counter electrode active material layer.

[0044] Furthermore, for example, a manufacturing method for a battery according to a fifteenth aspect of the present disclosure may be the manufacturing method for a battery according to the fourteenth aspect, wherein, in stacking the counter electrode current collector, the counter electrode current collector is stacked on the third layer such that a fourth region that is not covered by the counter electrode current collector in the plan view is provided at an end of the third layer in the first direction.

[0045] As a result, it is possible to manufacture a battery that is suitable for achieving both high resistance to short circuits and highly efficient productivity.

[0046] Furthermore, for example, a method for manufacturing a battery according to a sixteenth aspect of the present disclosure may be a method for manufacturing a battery according to the fourteenth or fifteenth aspect, further comprising cutting the electrode current collector, the first layer, the second layer, and the third layer all at once along a direction intersecting a main surface of the electrode current collector, to form a cut surface at an end of a laminate in which the electrode current collector, the first layer, the second layer, and the third layer are stacked, in a direction from the center toward the outer edge of the main surface of the electrode current collector and in a second direction different from the first direction.

[0047] This eliminates the need to stack the electrode current collector, first layer, second layer, and third layer in the shapes after cutting, making it easier to manufacture the battery. Also, the battery capacity can be adjusted by the position at which the laminate is cut, improving capacity precision.

[0048] Furthermore, for example, a manufacturing method for a battery according to a seventeenth aspect of the present disclosure may be the manufacturing method for a battery according to the fourteenth or fifteenth aspect, further including cutting the electrode current collector, the first layer, the second layer, the third layer, and the counter electrode current collector collectively along a direction intersecting a main surface of the electrode current collector, to form a cut surface at an end of a stack in which the electrode current collector, the first layer, the second layer, the third layer, and the counter electrode current collector are stacked, in a direction from the center toward the outer edge of the main surface of the electrode current collector and in a second direction different from the first direction.

[0049] This eliminates the need to stack the electrode current collector, the first layer, the second layer, the third layer, and the counter electrode current collector in the shapes after cutting, making it possible to easily manufacture a battery. Furthermore, the battery capacity can be adjusted by the position at which the laminate is cut, thereby improving capacity precision.

[0050] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0051] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not described in the independent claims are described as optional components.

[0052] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0053] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel or perpendicular, terms indicating the shape of elements, such as rectangular or circular, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0054] In this specification and the drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional Cartesian coordinate system. The x-axis and y-axis are directions parallel to the main surface of the electrode current collector, and the z-axis is a direction perpendicular to the main surface of the electrode current collector. When the shape of the battery in a plan view is rectangular, the x-axis and y-axis are directions parallel to a first side of the rectangle and a second side perpendicular to the first side, respectively. The z-axis is the stacking direction of the multiple unit cells included in the battery. In this specification, the "stacking direction" coincides with the direction normal to the main surfaces of the current collector and the active material layer. In this specification, the term "plan view" refers to a view perpendicular to the main surface of the electrode current collector, unless otherwise specified.

[0055] Furthermore, in this specification, unless otherwise specified, "protruding" means protruding outward from the center of the unit cell in a cross-sectional view perpendicular to the main surface of the electrode current collector. "Element A protrudes from element B" means that the tip of element A protrudes more than the tip of element B in the protruding direction, i.e., the tip of element A is farther from the center of the unit cell than the tip of element B. The "protruding direction" is considered to be a direction parallel to the main surface of the electrode current collector. Furthermore, "protruding portion of element A" means a part of element A that protrudes more than the tip of element B in the protruding direction. Furthermore, element B may be a part other than the protruding portion of element A. The element is, for example, an active material layer, a solid electrolyte layer, an insulating layer, a current collector, etc.

[0056] Furthermore, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing between components of the same type.

[0057] First Embodiment [1. Configuration] First, the configuration of a battery according to a first embodiment will be described with reference to FIGS. 1 and 2. FIG.

[0058] Fig. 1 is a top view of a battery 1 according to this embodiment. Fig. 2 is a cross-sectional view of the battery 1 according to this embodiment. Fig. 1 shows the planar shape of the battery 1 when viewed from the positive side of the z-axis. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1.

[0059] 1 and 2 , the battery 1 according to the present embodiment includes a unit cell 60 having an electrode current collector 10, a first layer 20 including an electrode active material layer 21 and a first insulating layer 22, a second layer 30 including a solid electrolyte layer 31, a third layer 40 including a counter electrode active material layer 41, and a counter electrode current collector 50. In the unit cell 60, the electrode current collector 10, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 50 are stacked in this order along the z-axis. As shown in FIG. 2 , the battery 1 is formed from one unit cell 60. The battery 1 is, for example, an all-solid-state battery.

[0060] As shown in Figures 1 and 2, the unit cell 60 has side faces 61 and 62 facing away from each other and side faces 63 and 64 facing away from each other. Side face 61 is the side face of the unit cell 60 facing in the direction moving toward the positive side of the x-axis. Side face 62 is the side face of the unit cell 60 facing in the direction moving toward the negative side of the x-axis. Side face 63 is the side face of the unit cell 60 facing in the direction moving toward the positive side of the y-axis. Side face 64 is the side face of the unit cell 60 facing in the direction moving toward the negative side of the y-axis.

[0061] Hereinafter, the direction along the x-axis toward the positive side will be referred to as the "positive x-axis direction." Hereinafter, the direction along the x-axis toward the negative side will be referred to as the "negative x-axis direction." Hereinafter, the direction along the y-axis toward the positive side will be referred to as the "positive y-axis direction." Hereinafter, the direction along the y-axis toward the negative side will be referred to as the "negative y-axis direction." The positive x-axis direction and the negative x-axis direction are perpendicular to the positive y-axis direction and the negative y-axis direction. The positive x-axis direction and the negative x-axis direction are opposite directions, and the positive y-axis direction and the negative y-axis direction are opposite directions. In this specification, the positive x-axis direction is an example of a first direction, which is a direction from the center toward the outer edge of the main surface 11 of the electrode current collector 10. The negative x-axis direction is a direction from the center toward the outer edge of the main surface 11 of the electrode current collector 10 and is an example of a second direction different from the first direction. The positive y-axis direction or the negative y-axis direction may be the second direction.

[0062] 1 , the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided at the end of the unit cell 60 on the side surface 61 side, but these regions may be provided at the end of the unit cell 60 on the side surface 62 side, the side surface 63 side, or the side surface 64 side. The first region 71, the second region 72, the third region 73, and the fourth region 74 will be described in detail later.

[0063] The planar shape of the battery 1 and the unit cell 60 is rectangular as shown in FIG. 1 . That is, the general shape of the battery 1 and the unit cell 60 is a flattened rectangular parallelepiped. Here, "flat" means that the thickness is shorter than each side or the maximum width of the main surface. Each side or the maximum width of the main surface of the battery 1 and the unit cell 60 is, for example, 10 mm or more and 500 mm or less. The planar shape of the battery 1 and the unit cell 60 may be a polygon, such as a square, hexagon, or octagon, or may be a circle or an ellipse. Note that in the drawings related to this specification, the thickness of each layer is exaggerated to make the layer structure of the unit cell easier to understand. Also, in the drawings related to this specification, the lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 in the positive x-axis direction are exaggerated to make the structure of the unit cell easier to understand.

[0064] The side surfaces 62, 63, and 64 of the unit cell 60 are composed of the side surfaces of the electrode current collector 10, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 50, and at least a portion of each may be a flat plane. When at least a portion of the side surfaces 62, 63, and 64 are flat, at least the side surfaces of the electrode current collector 10, the first layer 20, the second layer 30, and the third layer 40 are flush with one another and lie on the same flat plane. In other words, at the ends of the unit cell 60 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, the side surfaces of the electrode current collector 10, the first layer 20, the second layer 30, and the third layer 40 are flush with one another. Furthermore, at the ends of the unit cell 60 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, the side surfaces of the electrode current collector 10, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 50 may be flush with each other. This means that at the ends of the unit cell 60 where the first region 71, the second region 72, the third region 73, and the fourth region 74 are not provided, there are no steps on the side surfaces of the layers, and no spaces that do not function as a battery due to the steps are formed, thereby improving the volumetric energy density of the battery 1. Furthermore, since the side surfaces of the layers can be flush with each other by cutting the layers together, for example, the battery 1 can be manufactured more easily.

[0065] Furthermore, at the ends in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, the side surface of the first layer 20 includes the side surface of the electrode active material layer 21, the side surface of the second layer 30 includes the side surface of the solid electrolyte layer 31, and the side surface of the third layer 40 includes the side surface of the counter electrode active material layer 41. Therefore, at the ends in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, the side surfaces of the electrode current collector 10, the electrode active material layer 21, the solid electrolyte layer 31, the counter electrode active material layer 41, and the counter electrode current collector 50 are flush with each other.

[0066] The side surfaces 62, 63, and 64 are, for example, cut surfaces. Specifically, the side surfaces 62, 63, and 64 are surfaces formed by cutting with a blade such as a cutter, and are surfaces having, for example, cut marks such as fine grooves. By being cut surfaces, the side surfaces of each layer of the unit cell 60 can be easily made flush. The cut marks may be smoothed by polishing, etc. The shape of the cut surfaces is not limited.

[0067] As shown in FIG. 1, when the unit cell 60 has a rectangular shape in plan view, the side surfaces 61, 62, 63, and 64 each form one side of the rectangle of the unit cell 60 in plan view.

[0068] The unit cell 60 has one each of the electrode current collector 10, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 50. In a plan view, the electrode current collector 10, the electrode active material layer 21, the solid electrolyte layer 31, the counter electrode active material layer 41, and the counter electrode current collector 50 overlap each other.

[0069] One main surface 11 of the electrode current collector 10 is in contact with the electrode active material layer 21 and the first insulating layer 22 of the first layer 20. The thickness of the electrode current collector 10 is, for example, 5 μm or more and 100 μm or less. In this specification, the thickness of the current collector and each layer is the length in the stacking direction, and is the average value of the overall thickness unless otherwise specified.

[0070] Known materials can be used as the material of the electrode current collector 10. For example, a foil, plate, or mesh-like body made of copper, aluminum, nickel, iron, stainless steel, platinum, gold, or an alloy of two or more of these materials can be used for the electrode current collector 10. In addition to the foil, plate, or mesh-like body, the electrode current collector 10 may also include a connection layer that is a layer containing a conductive material and is provided in a portion that contacts the first layer 20.

[0071] The counter electrode current collector 50 is disposed on the side of the third layer 40 opposite to the second layer 30 side. The counter electrode current collector 50 is in contact with the upper surface of the third layer 40. The counter electrode current collector 50 faces the electrode current collector 10 via the first layer 20, the second layer 30, and the third layer 40. The thickness of the counter electrode current collector 50 is, for example, 5 μm or more and 100 μm or less.

[0072] Known materials can be used as the material of the counter electrode current collector 50. For example, a foil, plate, or mesh-like body made of copper, aluminum, nickel, iron, stainless steel, platinum, gold, or an alloy of two or more of these materials can be used for the counter electrode current collector 50. Note that, in addition to the foil, plate, or mesh-like body, the counter electrode current collector 50 may also include a connection layer that is a layer containing a conductive material and is provided in a portion that contacts the third layer 40.

[0073] The first layer 20 includes an electrode active material layer 21 and a first insulating layer 22 that is aligned with the electrode active material layer 21 along the positive x-axis direction and is disposed at the end of the first layer 20 in the positive x-axis direction. The first layer 20 is disposed on one main surface 11 of the electrode current collector 10. The electrode active material layer 21 and the first insulating layer 22 each have a thickness of, for example, 5 μm or more and 300 μm or less. The thickness of the electrode active material layer 21 and the thickness of the first insulating layer 22 are, for example, substantially the same. "Substantially the same" means, for example, that the difference between the thicknesses of two comparison objects is 5% or less. The thickness of the first insulating layer 22 may be thinner than the thickness of the electrode active material layer 21.

[0074] The electrode active material layer 21 is disposed on one main surface 11 of the electrode current collector 10. The surface of the electrode active material layer 21 opposite the electrode current collector 10 side is in contact with the solid electrolyte layer 31. The surface of the electrode active material layer 21 opposite the electrode current collector 10 side is completely covered by the solid electrolyte layer 31. The electrode active material layer 21 and the counter electrode active material layer 41 face each other with the solid electrolyte layer 31 interposed therebetween. In a plan view, the area of ​​the electrode active material layer 21 is larger than the area of ​​the counter electrode active material layer 41. The outer edge of the electrode active material layer 21 in the positive x-axis direction is located outside the outer edge of the counter electrode active material layer 41 in the positive x-axis direction. The materials used for the electrode active material layer 21 will be described later.

[0075] The first insulating layer 22 has electronic insulation properties. The first insulating layer 22 may further have ionic insulation properties. The first insulating layer 22 is in contact with the main surface 11 and the end face of the electrode active material layer 21 in the positive x-axis direction. The first insulating layer 22 suppresses contact of an electrode of opposite polarity with the electrode active material layer 21, thereby improving the short-circuit resistance of the battery 1.

[0076] The first insulating layer 22 extends on the main surface 11 in the direction in which the end face of the electrode active material layer 21 in the positive x-axis direction extends (the y-axis direction). The first insulating layer 22 includes a portion that does not overlap with the electrode active material layer 21 in a plan view. The surface of the first insulating layer 22 opposite the electrode current collector 10 contacts the solid electrolyte layer 31. The first insulating layer 22 is provided along the entire end face of the electrode active material layer 21 in the positive x-axis direction, but may be provided on only a portion of the end face of the electrode active material layer 21 in the positive x-axis direction. The material used for the first insulating layer 22 will be described later.

[0077] The second layer 30 is entirely composed of a solid electrolyte layer 31. The second layer 30 is disposed on the side of the first layer 20 opposite to the electrode current collector 10 side. The thickness of the solid electrolyte layer 31 is, for example, not less than 5 μm and not more than 150 μm.

[0078] The solid electrolyte layer 31 is disposed on the side of the electrode active material layer 21 opposite to the electrode current collector 10 side. The solid electrolyte layer 31 is located between the electrode active material layer 21 and the counter electrode active material layer 41, and is in contact with the electrode active material layer 21 and the counter electrode active material layer 41. The solid electrolyte layer 31 covers a part of the surface of the first insulating layer 22 opposite to the electrode current collector 10 side. The material used for the solid electrolyte layer 31 will be described later.

[0079] The third layer 40 is entirely composed of a counter electrode active material layer 41. The third layer 40 is disposed on the side of the second layer 30 opposite to the first layer 20. The counter electrode active material layer 41 has a thickness of, for example, 5 μm or more and 300 μm or less.

[0080] The counter electrode active material layer 41 is disposed on the side of the solid electrolyte layer 31 opposite to the electrode active material layer 21. The counter electrode active material layer 41 is stacked on the solid electrolyte layer 31 and faces the electrode active material layer 21. The material used for the counter electrode active material layer 41 will be described later.

[0081] Here, the materials used for the solid electrolyte layer 31, the electrode active material layer 21, the counter electrode active material layer 41, and the first insulating layer 22 will be described.

[0082] The solid electrolyte layer 31 is an example of an electrolyte layer containing an electrolyte material. The solid electrolyte layer 31 contains at least a solid electrolyte as an electrolyte material, and may contain a binder material as necessary. The solid electrolyte layer 31 may contain a solid electrolyte having lithium ion conductivity. The electrolyte material contained in the solid electrolyte layer 31 is entirely solid electrolyte, except for unavoidable impurities, for example. Note that the electrolyte material used in the solid electrolyte layer 31 may further contain a nonaqueous electrolyte solution, a gel electrolyte solution, or an ionic liquid, as long as it contains a solid electrolyte as a main component. The following describes a case where the electrolyte material contained in the solid electrolyte layer 31 is entirely solid electrolyte.

[0083] As the solid electrolyte, known materials such as lithium ion conductors, sodium ion conductors, magnesium ion conductors, etc. can be used. As the solid electrolyte, for example, a solid electrolyte material such as a sulfide solid electrolyte, a halide solid electrolyte, an oxide solid electrolyte, a polymer solid electrolyte, or a complex hydride solid electrolyte can be used.

[0084] As the sulfide solid electrolyte, in the case of a material that can conduct lithium ions, for example, Li ２ S-P ２ S ５ , Li ２ S-SiS ２ , Li ２ S-B ２ S ３ , Li ２ S-GeS ２ , Li ３．２５ Ge ０．２５ P ０．７５ S ４ , Li １０ GeP ２ S １２ These include LiX, Li ２ O, M.O. ｑ , Li ｐ MO ｑ The element X in "LiX" is at least one selected from the group consisting of F, Cl, Br and I. ｑ " and "Li ｐ MO ｑ " The element M is at least one selected from the group consisting of P, Si, Ge, B, Al, Ga, In, Fe, and Zn. ｑ " and "Li ｐ MO ｑ In the above formula, p and q are each independently a natural number.

[0085] Examples of sulfide solid electrolytes include Li ２ S-P ２ S ５ Li-based glass ceramics may also be used. ２ S-P ２ S ５ LiX, Li ２ O, M.O. ｑ , Li ｐ MO ｑ or the like may be added, or two or more selected from LiCl, LiBr, and LiI may be added. Li ２ S-P ２ S ５Since Li-based glass ceramics are relatively soft materials, ２ S-P ２ S ５ According to the battery 1 containing the glass ceramics, a highly durable battery can be manufactured.

[0086] Examples of oxide solid electrolytes include LiTi ２ (P.O. ４ ) ３ and NASICON-type solid electrolytes, such as (LaLi)TiO, which are typified by their element substitution products. ３ Perovskite-type solid electrolyte based on Li １４ ZnGe ４ O １６ , Li ４ SiO ４ , LiGeO ４ and LISICON-type solid electrolytes, such as those substituted with Li ７ La ３ Zr ２ O １２ and garnet-type solid electrolytes, such as those substituted with Li ３ P.O. ４ and its N-substituted derivatives, LiBO ２ , Li ３ BO ３ Based on Li-B-O compounds such as Li ２ SO ４ , Li ２ CO ３ Glasses containing added metals, glass ceramics, etc. can be used.

[0087] Examples of the halide solid electrolyte include Li ３ Y(Cl, Br, I) ６ , Li ２．７ Y １．１ (Cl, Br, I) ６ , Li ２ Mg(F, Cl, Br, I) ４ , Li ２ Fe (F, Cl, Br, I) ４ , Li(Al,Ga,In)(F,Cl,Br,I) ４ , Li ３ (Al, Ga, In) (F, Cl, Br, I) ６ , Li３ (Ca, Y, Gd) (Cl, Br, I) ６ , Li ２．７ (Ti,Al)F ６ , Li ２．５ (Ti,Al)F ６ , Li(Ta,Nb)O(F,Cl) ４ In the present disclosure, when an element in a formula is expressed as "(Al, Ga, In)", this notation indicates at least one element selected from the group of elements in the parentheses. That is, "(Al, Ga, In)" is synonymous with "at least one selected from the group consisting of Al, Ga, and In". The same applies to other elements.

[0088] As the polymer solid electrolyte, for example, a compound of a polymer compound and a lithium salt can be used. The polymer compound may have an ethylene oxide structure. A polymer compound having an ethylene oxide structure can contain a large amount of lithium salt. Therefore, the ionic conductivity can be further improved. As the lithium salt, LiPF ６ , LiBF ４ , LiSbF ６ , LiAsF ６ , LiSO ３ CF ３ , LiN(SO ２ F) ２ , LiN(SO ２ CF ３ ) ２ , LiN(SO ２ C ２ F ５ ) ２ , LiN(SO ２ CF ３ ) (SO ２ C ４ F ９ ), LiC(SO ２ CF ３ ) ３ The lithium salts may be used alone or in combination of two or more.

[0089] Examples of complex hydride solid electrolytes include LiBH ４ - LiI, LiBH ４ -P ２ S５ etc. can be used.

[0090] As the binder material, for example, elastomers such as styrene-based elastomers are used, and organic compounds such as polyvinylidene fluoride, polytetrafluoroethylene, acrylic resin, or cellulose resin may also be used.

[0091] A styrene-based elastomer refers to an elastomer containing repeating units derived from styrene. The repeating units refer to molecular structures derived from monomers and are sometimes called constituent units. Styrene-based elastomers are suitable as binder materials due to their excellent flexibility and elasticity. The content of repeating units derived from styrene in the styrene-based elastomer is not particularly limited, and is, for example, 5% by mass or more and 70% by mass or less.

[0092] The styrene-based elastomer may be a block copolymer containing a first block composed of repeating units derived from styrene and a second block composed of repeating units derived from a conjugated diene. Examples of conjugated dienes include butadiene and isoprene. The repeating units derived from the conjugated diene may be hydrogenated. That is, the repeating units derived from the conjugated diene may or may not have an unsaturated bond such as a carbon-carbon double bond. The block copolymer may have a triblock arrangement composed of two first blocks and one second block. The block copolymer may be an ABA triblock copolymer. In this triblock copolymer, the A block corresponds to the first block and the B block corresponds to the second block. The first block functions, for example, as a hard segment. The second block functions, for example, as a soft segment.

[0093] Examples of styrene-based elastomers include styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene block copolymer (SEEPS), styrene-butadiene rubber (SBR), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and hydrogenated styrene-butadiene rubber (HSBR). The styrene-based elastomer may include SBR or SEBS. A mixture containing two or more selected from these may be used as the binder material. Styrene-based elastomers are suitable as binder materials due to their excellent flexibility and elasticity.

[0094] The styrene-based elastomer may be a styrene-based triblock copolymer. Examples of styrene-based triblock copolymers include styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene block copolymer (SEEPS), styrene-butadiene-styrene block copolymer (SBS), and styrene-isoprene-styrene block copolymer (SIS). These styrene-based triblock copolymers are sometimes called styrene-based thermoplastic elastomers. These styrene-based triblock copolymers tend to be flexible and have high strength.

[0095] The styrene-based elastomer may contain a modifying group, which means a functional group that chemically modifies all repeating units contained in the polymer chain, some repeating units contained in the polymer chain, or the terminal portion of the polymer chain.

[0096] The binder material may include a binder material other than a styrene-based elastomer. Alternatively, the binder material may be a styrene-based elastomer. In other words, the binder material may include only a styrene-based elastomer.

[0097] In this embodiment, one of the electrode active material layer 21 and the counter electrode active material layer 41 is a positive electrode active material layer, and the other is a negative electrode active material layer.

[0098] The positive electrode active material layer contains at least a positive electrode active material, and may contain at least one of an electrolyte material such as a solid electrolyte, a conductive additive, and a binder material, as necessary.

[0099] As the positive electrode active material, known materials capable of occluding and releasing (inserting and desorbing, or dissolving and depositing) lithium ions, sodium ions, magnesium ions, etc. can be used. As the positive electrode active material, materials capable of extracting and inserting lithium ions include transition metal oxides, transition metal fluorides, polyanion materials, fluorinated polyanion materials, transition metal sulfides, transition metal oxysulfides, transition metal oxynitrides, sulfur, and lithium-containing compounds thereof. Examples of lithium-containing transition metal oxides include Li(NiCoAl)O ２ , Li(NiCoMn)O ２ , LiCoO ２ Li(NiCoAl)O ２ means that Ni, Co, and Al are contained in any ratio. Li(NiCoMn)O ２ means that Ni, Co and Mn are contained in any ratio.

[0100] The solid electrolyte may be any of the solid electrolyte materials exemplified above. The conductive material used in the conductive additive may be, for example, acetylene black, carbon black, graphite, carbon fiber, vapor-grown carbon, or conductive carbon such as carbon nanotubes. The binder may be any of the binder materials exemplified above.

[0101] The negative electrode active material layer contains at least a negative electrode active material, and may contain at least one of an electrolyte material such as a solid electrolyte, a conductive additive, and a binder material, as necessary.

[0102] The negative electrode active material may be a known material capable of occluding and releasing (inserting and desorbing, or dissolving and precipitating) lithium ions, sodium ions, magnesium ions, etc. As the negative electrode active material, in the case of a material capable of extracting and inserting lithium ions, for example, a carbon material such as natural graphite, artificial graphite, graphite carbon fiber, or resin-baked carbon, metallic lithium, a lithium alloy, silicon (Si), tin (Sn), a silicon compound, a tin compound, or an oxide of lithium and a transition metal element may be used.

[0103] The solid electrolyte may be any of the solid electrolyte materials exemplified above. The conductive additive may be any of the conductive materials exemplified above. The binder material may be any of the binder materials exemplified above.

[0104] The first insulating layer 22 contains one or more insulating materials having electronic insulating properties.

[0105] The insulating material is a material that exhibits electronic insulation, i.e., a material with low electronic conductivity. Examples of insulating materials include metal oxides such as silicon oxide, titanium oxide, and aluminum oxide, minerals such as mica and marble, heat-dissipating fillers such as boron nitride, aluminum nitride, and beryllium oxide, and resin particles such as latex particles and acrylic particles. Resin materials such as silicone resin, epoxy resin, acrylic resin, and polyimide resin may also be used as insulating materials.

[0106] The first insulating layer 22 may contain a solid electrolyte as an insulating material. The above-mentioned solid electrolyte materials can be used as the solid electrolyte.

[0107] The first insulating layer 22 may contain a binder material as an insulating material. Examples of the binder material include the binder materials exemplified above. The binder material contained in the first insulating layer 22 may be the same as the binder material used in the electrode active material layer 21, or may be a different binder material.

[0108] The insulating material contained in the first insulating layer 22 may also contain an active material exhibiting insulating properties. Examples of the active material exhibiting insulating properties include lithium iron phosphate, titanium oxide, lithium titanate, niobium titanium oxide, lithium vanadium oxide, and silicon.

[0109] The shape of the insulating material contained in the first insulating layer 22 is not particularly limited. The insulating material may be needle-shaped, spherical, oval-spherical, or the like. The insulating material may be particulate. Alternatively, the first insulating layer 22 may be formed by curing a liquid resin material such as a thermosetting resin or an ultraviolet-curable resin. In this case, a liquid resin material in which particulate insulating material is dispersed may be used.

[0110] The first insulating layer 22 may contain the same material as the solid electrolyte layer 31. The first insulating layer 22 may also be made of the same material as the solid electrolyte layer 31.

[0111] At least one selected from the group consisting of the electrode active material layer 21, the first insulating layer 22, and the solid electrolyte layer 31 may contain a sulfide solid electrolyte. Furthermore, the counter electrode active material layer 41 may contain a sulfide solid electrolyte. The sulfide solid electrolyte has excellent ionic conductivity, formability, and insulating properties, and therefore can provide the battery 1 with high resistance to short circuits, highly efficient productivity, and high output power.

[0112] At least one selected from the group consisting of the electrode active material layer 21, the first insulating layer 22, and the solid electrolyte layer 31 may contain a styrene-based elastomer. The counter electrode active material layer 41 may also contain a styrene-based elastomer. Styrene-based elastomers have excellent flexibility and elasticity, making layers containing the styrene-based elastomer less likely to collapse, thereby further improving the short-circuit resistance of the battery 1.

[0113] Next, the end structure of the unit cell 60 will be described.

[0114] As shown in FIGS. 1 and 2 , in the unit cell 60, a first region 71, a second region 72, a third region 73, and a fourth region 74 that are not covered by the upper layer are provided at the end in the positive x-axis direction (the end along the side surface 61 in the example shown in FIG. 1 ).

[0115] Specifically, a first region 71 that is not covered by the first layer 20 is provided at an end of the main surface 11 of the electrode current collector 10 in the positive x-axis direction. The first region 71 is not in contact with the first layer 20, the second layer 30, the third layer 40, or the counter electrode current collector 50. In the first region 71, the main surface 11 of the electrode current collector 10 is exposed. The provision of the first region 71 makes it possible to easily form an electrical connection structure, such as a terminal, on the electrode current collector 10. Furthermore, when connecting multiple unit cells 60, the first regions 71 in the electrode current collector 10 can be joined together by welding or the like, thereby reducing the resistance of the connection structure.

[0116] Furthermore, a second region 72 that is not covered by the second layer 30 in plan view is provided at the end of the first layer 20 in the positive x-axis direction. The second region 72 is not in contact with the second layer 30, the third layer 40, or the counter electrode current collector 50. The second region 72 is part of the first insulating layer 22 of the first layer 20, and in the example shown in FIGS. 1 and 2 , does not include the electrode active material layer 21. The first insulating layer 22 is exposed in the second region 72. By providing the second region 72, the outer edge of the second layer 30 is positioned more inward than the outer edge of the first layer 20 in the positive x-axis direction. This means that the end of the second layer 30 is supported by the first layer 20, preventing the second layer 30 from collapsing. Furthermore, at the end of the unit cell 60 in the positive x-axis direction where the first region 71 is provided, if the outer edge of the second layer 30 protrudes from the first layer 20, the possibility of collapse is particularly high. However, by providing the second region 72, it is possible to prevent the outer edge of the second layer 30 from protruding from the first layer 20 even if the positional accuracy during formation of the second layer 30 is not high. Therefore, it is possible to manufacture the battery 1 with high efficiency while reducing the risk of the second layer 30 collapsing.

[0117] Furthermore, a third region 73 that is not covered by the third layer 40 in plan view is provided at the end of the second layer 30 in the positive x-axis direction. The third region 73 is not in contact with the third layer 40 or the counter electrode current collector 50. The third region 73 is farther from the electrode current collector 10 than the second region 72. The second layer 30, including its end in the positive x-axis direction, is entirely formed of the solid electrolyte layer 31, and the third region 73 is a part of the solid electrolyte layer 31. The solid electrolyte layer 31 is exposed in the third region 73. By providing the third region 73, the outer edge of the third layer 40 is positioned more inward than the outer edge of the second layer 30 in the positive x-axis direction. This means that the end of the third layer 40 is supported by the second layer 30, preventing the end of the third layer 40 from collapsing. Furthermore, at the end of the unit cell 60 in the positive x-axis direction where the first region 71 is provided, if the outer edge of the third layer 40 protrudes from the second layer 30, the possibility of collapse is particularly high. However, by providing the third region 73, it is possible to prevent the outer edge of the third layer 40 from protruding from the second layer 30 even if the positional accuracy during formation of the third layer 40 is not high. Therefore, it is possible to manufacture the battery 1 with high efficiency while reducing the risk of the third layer 40 collapsing.

[0118] Furthermore, the provision of the third region 73 increases the distance between the counter electrode current collector 50 and the counter electrode active material layer 41 and the electrode current collector 10, thereby making it possible to suppress contact between the counter electrode current collector 50 and the counter electrode active material layer 41 and the electrode current collector 10. Furthermore, because the third region 73 is part of the solid electrolyte layer 31, electronic insulation can be ensured at the end of the second layer 30, and there is no need to form a separate insulating layer to ensure such electronic insulation. Therefore, the second layer 30 can be formed in one step, and the battery 1 can be manufactured at low cost and with high efficiency.

[0119] Furthermore, a fourth region 74 that is not covered by the counter electrode current collector 50 in plan view is provided at the end of the third layer 40 in the positive x-axis direction. The fourth region 74 is farther from the electrode current collector 10 than the third region 73. The third layer 40, including its end in the positive x-axis direction, is entirely composed of the counter electrode active material layer 41, and the fourth region 74 is a part of the counter electrode active material layer 41. The counter electrode active material layer 41 is exposed in the fourth region 74. The provision of the fourth region 74 prevents the counter electrode current collector 50 from contacting the outer edge of the third layer 40 in the positive x-axis direction during stacking of the counter electrode current collectors 50, thereby preventing the end of the third layer 40 from collapsing. Furthermore, the distance between the counter electrode current collector 50 and the electrode current collector 10 is increased, thereby preventing contact between the counter electrode current collector 50 and the electrode current collector 10.

[0120] On the other hand, conventional batteries do not have a structure in which the first region 71 to the fourth region 74 are provided. For example, in the battery disclosed in Patent Document 3, a region corresponding to the first region 71 is provided in the electrode current collector, and a region corresponding to the third region 73 is provided in the solid electrolyte layer, but regions corresponding to the second region 72 and the fourth region 74 are not provided, so the solid electrolyte layer and the counter electrode active material layer are prone to collapse. Furthermore, in order to prevent collapse, it is necessary to improve the positional accuracy of each layer, which makes it difficult to improve the manufacturing efficiency of the battery.

[0121] 1 , the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided along the side surface 61 in a plan view. The first region 71, the second region 72, the third region 73, and the fourth region 74 are elongated in a plan view, and in the example shown in FIG. 1 , the direction perpendicular to the x-axis positive direction (the y-axis direction) is the longitudinal direction. Furthermore, the fourth region 74, the third region 73, the second region 72, and the first region 71 are arranged in this order along the x-axis positive direction in a plan view.

[0122] Although not shown, the unit cell 60 may have insulating tape or insulating resin covering at least a portion of the first region 71, the second region 72, the third region 73, and the fourth region 74. This makes it possible to prevent the portions of the first layer 20, the second layer 30, and the third layer 40 that are covered with the insulating tape or insulating resin from collapsing.

[0123] The length of the first region 71 is, for example, 1 mm or more and 20 mm or less, which allows the energy density of the battery 1 to be increased while ensuring an area in which an electrical connection structure such as a terminal can be easily formed on the electrode current collector 10.

[0124] The length of each of the second region 72, the third region 73, and the fourth region 74 is, for example, 0.1 mm or more and 5 mm or less, which can enhance the effect of providing the second region 72, the third region 73, and the fourth region 74 described above and can increase the energy density of the battery 1. The length of each of the second region 72, the third region 73, and the fourth region 74 may be 0.5 mm or more and 2 mm or less.

[0125] The lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 may be the same, or at least one of them may be different. The length of the third region 73 may be longer than the lengths of the second region 72 and the fourth region 74. The length of the first region 71 may be longer than the lengths of the second region 72, the third region 73, and the fourth region 74.

[0126] Here, the lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 are lengths in the positive x-axis direction in plan view. The length of the first region 71 is also the distance between the outer edge of the electrode current collector 10 and the outer edge of the first layer 20 in the positive x-axis direction in plan view. The length of the second region 72 is also the distance between the outer edge of the first layer 20 and the outer edge of the second layer 30 in the positive x-axis direction in plan view. The length of the third region 73 is also the distance between the outer edge of the second layer 30 and the outer edge of the third layer 40 in the positive x-axis direction in plan view. The length of the fourth region 74 is also the distance between the outer edge of the third layer 40 and the outer edge of the counter electrode current collector 50 in the positive x-axis direction in plan view.

[0127] In the present embodiment, the electrode active material layer 21 may be a negative electrode active material layer, and the counter electrode active material layer 41 may be a positive electrode active material layer. In the present embodiment, the electrode active material layer 21 is larger than the counter electrode active material layer 41, so that metal ions are more easily taken up into the electrode active material layer 21, which is a negative electrode active material layer, and thus precipitation of metal derived from the metal ions is suppressed, making it less likely for an internal short circuit to occur, and further improving the resistance of the battery 1 to short circuits.

[0128] The above-described configuration of the battery 1 makes it possible to achieve both high resistance to short circuits and highly efficient productivity of the battery 1.

[0129] 1 and 2, the electrode current collector 10, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 50 form a stepped structure at the end of the unit cell 60 in the positive x-axis direction, but this is not limiting. Fig. 3 is a cross-sectional view showing another example of the structure of the end of the unit cell 60.

[0130] In the example shown in FIG. 3 , the first layer 20 has, in the second region 72, an inclined surface 25 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction. The entire second region 72 is, for example, a region where the inclined surface 25 is formed. Furthermore, the second layer 30 has, in the third region 73, an inclined surface 35 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction. The entire third region 73 is, for example, a region where the inclined surface 35 is formed. Furthermore, the third layer 40 has, in the fourth region 74, an inclined surface 45 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction. The entire fourth region 74 is, for example, a region where the inclined surface 45 is formed. In the example shown in FIG. 3 , the inclined surface 25 and the inclined surface 35 are connected, and the inclined surface 35 and the inclined surface 45 are connected. In other words, the inclined surfaces 25, 35, and 45 form a single continuous inclined surface.

[0131] The formation of the inclined surfaces 25, 35 and 45 makes it difficult for corners to form in the first layer 20 of the second region 72, the second layer 30 of the third region 73 and the third layer 40 of the fourth region 74, and the material of these layers is less likely to fall off, making it less likely for short circuits to occur.

[0132] These inclined surface shapes can be formed, for example, by performing a high-pressure press process such as a roll press on a portion including the end of a laminate in which the first layer 20, the second layer 30, and the third layer 40 are stacked on the electrode current collector 10 so that the end becomes stepped.

[0133] The angle that each of the inclined surfaces 25, 35, and 45 forms with respect to the main surface 11 is, for example, less than 45 degrees. This makes it even more difficult for the layer material to fall off. The angle that each of the inclined surfaces 25, 35, and 45 forms with respect to the main surface 11 may be 30 degrees or less, or may be 10 degrees or less. Furthermore, the angle that each of the inclined surfaces 25, 35, and 45 forms with respect to the main surface 11 is, for example, 1 degree or more.

[0134] In the example shown in FIG. 3 , the first layer 20 has a recess 26 in the third region 73 where the second layer 30 is recessed. The second layer 30 also has a recess 36 in the fourth region 74 where the third layer 40 is recessed. This increases the bonding strength of the layers stacked above and below at the end in the positive x-axis direction, making it less likely for the materials of these layers to fall off and suppressing delamination. This reduces the likelihood of short circuits due to contact between electrodes of opposite polarity. This recessed shape can be formed, for example, by performing a high-pressure press, such as a roll press, on a portion of the stack including the end of the electrode current collector 10, in which the first layer 20, the second layer 30, and the third layer 40 are stacked on the electrode current collector 10 so that the end is stepped.

[0135] The depth of each of the recesses 26 and 36 is, for example, not less than 1 μm and not more than 10 μm.

[0136] 3 , the surface of the first layer 20 facing the second layer 30 below the inclined surface 45 (i.e., the position overlapping with the inclined surface 45 in a plan view) has a portion that inclines so as to move away from the electrode current collector 10 in the positive x-axis direction. Therefore, at the outer edge of the third layer 40 in the positive x-axis direction in a plan view, the thickness of the first layer 20 (electrode active material layer 21 in the example shown in FIG. 3 ) is greater than the thickness of the first layer 20 inside this position.

[0137] The structure of the ends of the first layer 20, the second layer 30, and the third layer 40 in the positive x-axis direction shown in FIG. 3 may also be included in the batteries according to the embodiments and modifications described below.

[0138] 1 and 2, the fourth region 74 is provided in the third layer 40, but this is not limiting. The fourth region 74 does not have to be provided in the third layer 40. Fig. 4 is a cross-sectional view of another battery 1a according to the present embodiment.

[0139] 4, the battery 1a includes a unit cell 60a and is formed from one unit cell 60a. The unit cell 60a differs from the unit cell 60 in that the fourth region 74 is not provided in the third layer 40.

[0140] In the unit cell 60a, the counter electrode current collector 50 completely covers the third layer 40 in plan view, and the end of the third layer 40 in the positive x-axis direction is not provided with the fourth region 74 as described above. This reduces the contact resistance between the counter electrode active material layer 41 constituting the third layer 40 and the counter electrode current collector 50, enabling the battery 1a to have a high output. In the example shown in Fig. 4 , the counter electrode current collector 50 protrudes in the positive x-axis direction beyond the outer edge of the third layer 40 in plan view, but the outer edges of the third layer 40 and the counter electrode current collector 50 in the positive x-axis direction may be aligned.

[0141] The structure in which the fourth region 74 is not provided in the third layer 40 as shown in FIG. 4 may be included in a battery having the third layer 40 among the batteries according to the embodiments and modifications described below.

[0142] [2. Modifications] The following describes batteries according to modifications of the present embodiment. In the following description of the modifications, differences from the first embodiment and each modification will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0143] [2-1. Modification 1] First, a battery according to Modification 1 of Embodiment 1 will be described. Fig. 5 is a top view of battery 101 according to this modification. Fig. 6 is a cross-sectional view of battery 101 according to this modification. Fig. 5 shows the shape of battery 101 in plan view when viewed from the positive side of the z-axis. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5.

[0144] 5 and 6 , the battery 101 includes a unit cell 160 and is formed from one unit cell 160. The unit cell 160 differs from the unit cell 60 according to the first embodiment in that the unit cell 160 has an electrode current collector 110 and a counter electrode current collector 150 instead of the electrode current collector 10 and the counter electrode current collector 50.

[0145] The electrode current collector 110 has a protrusion 111, which is a portion of the end of the electrode current collector 110 in the x-axis positive direction that protrudes further in the x-axis positive direction than other portions. The electrode current collector 110 has a shape in which a rectangular tab-shaped protrusion 111 is added to the electrode current collector 10 having a rectangular shape in a plan view as described above. The protrusion 111 functions, for example, as a lead for electrical connection. Another lead material may be joined to the protrusion 111. In the example shown in FIGS. 5 and 6 , the first region 71 is provided only in the portion of the main surface 11 of the electrode current collector 110 where the protrusion 111 is located. However, the first region 71 may also be provided inside the protrusion 111 on the electrode current collector 110. Furthermore, in a plan view, a portion of the protrusion 111 may be covered by the first insulating layer 22 of the first layer 20. 5 and 6 , in a plan view, the position of the outer edge of the electrode current collector 110 in the x-axis positive direction other than the protrusion 111 coincides with the position of the outer edge of the first layer 20 in the x-axis positive direction. Note that the first insulating layer 22 of the first layer 20 may cover the end face of the electrode current collector 110 in the x-axis positive direction. Furthermore, the electrode current collector 110 may not have the protrusion 111. In other words, an electrode current collector 10 provided with a first region 71 may be used instead of the electrode current collector 110.

[0146] The counter electrode current collector 150 has a protrusion 151, which is a portion of an end of the counter electrode current collector 150 in the x-axis positive direction that protrudes further in the x-axis positive direction than other portions. The counter electrode current collector 150 has a shape in which a rectangular tab-shaped protrusion 151 is added to the counter electrode current collector 50, which has a rectangular shape in a plan view. The protrusion 151 protrudes further in the x-axis positive direction than the third layer 40 in a plan view. The protrusion 151 functions as, for example, a lead for making an electrical connection. Another lead material may be joined to the protrusion 151.

[0147] The protrusion 151 faces the electrode current collector 110 via the first insulating layer 22. The protrusion 151 and the protrusion 111 are arranged at positions where they do not overlap in a plan view. The first insulating layer 22 does not have to be formed at a position where they do not overlap with the protrusion 151 in a plan view.

[0148] Thus, in the battery 101, the protrusion 151, which is part of the end of the counter electrode current collector 150 in the positive x-axis direction, protrudes further in the positive x-axis direction than the third layer 40 in a plan view. This makes it possible to form an electrical connection structure, such as a terminal, on the counter electrode current collector 150 at the end of the battery 101, making the structure less complicated than if the electrical connection structure were formed on the main surface of the counter electrode current collector 150. Furthermore, even if the counter electrode current collector 150 has the protrusion 151, the first insulating layer 22 is disposed at the end of the first layer 20 in the positive x-axis direction, thereby suppressing short circuits due to contact between the protrusion 151 and the electrode active material layer 21 and the electrode current collector 110.

[0149] [2-2. Modification 2] Next, a description will be given of a battery according to Modification 2 of Embodiment 1. Fig. 7 is a cross-sectional view of a battery 201 according to this modification.

[0150] 7 , the battery 201 includes a unit cell 260 and is formed from one unit cell 260. The unit cell 260 differs from the unit cell 160 according to the first modification of the first embodiment in that the unit cell 260 has a second layer 230 instead of the second layer 30.

[0151] The second layer 230 includes a solid electrolyte layer 31 and a second insulating layer 32 that is aligned with the solid electrolyte layer 31 along the positive x-axis direction and is disposed at the end of the second layer 230 in the positive x-axis direction. The thickness of the second insulating layer 32 is, for example, 5 μm or more and 150 μm or less. The thickness of the solid electrolyte layer 31 and the thickness of the second insulating layer 32 are, for example, substantially the same. The thickness of the second insulating layer 32 may be thinner than the thickness of the solid electrolyte layer 31.

[0152] The second insulating layer 32 has electronic insulation properties. The second insulating layer 32 may further have ionic insulation properties. The second insulating layer 32 is in contact with the surface of the first layer 20 facing the second layer 230 and the end face of the solid electrolyte layer 31 in the positive x-axis direction. By disposing the second insulating layer 32 at the end of the second layer 230, collapse of the solid electrolyte layer 31 can be suppressed. Furthermore, if the second insulating layer 32 has ionic insulation properties, the second insulating layer 32 suppresses ion conduction to the solid electrolyte layer 31 due to contact between the solid electrolyte layer 31 and electrolytes of other batteries, etc., and can suppress unexpected ion movement in the battery 201.

[0153] The second insulating layer 32 extends on the first layer 20 in the direction in which the end face of the solid electrolyte layer 31 in the positive x-axis direction extends (the y-axis direction). The second insulating layer 32 includes a portion that does not overlap with the solid electrolyte layer 31 in a plan view. The second insulating layer 32 is provided along the entire end of the solid electrolyte layer 31 in the positive x-axis direction, but may be provided on only a portion of the end of the solid electrolyte layer 31 in the positive x-axis direction. For example, the second insulating layer 32 does not have to be formed in a position that does not overlap the protrusion 151 in a plan view.

[0154] The second insulating layer 32 contains one or more insulating materials having electronic insulating properties. Examples of the insulating materials that can be used include the materials exemplified above as insulating materials that can be used for the first insulating layer 22. The second insulating layer 32 may contain a sulfide solid electrolyte. The second insulating layer 32 may also contain a styrene-based elastomer.

[0155] The second insulating layer 32 may contain the same material as the first insulating layer 22. The second insulating layer 32 may also be made of the same material as the first insulating layer 22.

[0156] In the unit cell 260, at the end of the second layer 230 in the positive x-axis direction, a portion of the solid electrolyte layer 31 and the second insulating layer 32 are not covered by the third layer 40 in a plan view. Therefore, the third region 73 is formed by a portion of the solid electrolyte layer 31 and a portion of the second insulating layer 32. In the third region 73, the solid electrolyte layer 31 and the second insulating layer 32 are exposed. In a plan view, the third layer 40 may completely cover the solid electrolyte layer 31, and the third region 73 may be formed by only a portion of the second insulating layer 32.

[0157] The second layer 230 may be used in place of the second layer 30 in the batteries according to the embodiments and modifications exemplified above or described below.

[0158] [2-3. Modification 3] Next, a description will be given of a battery according to Modification 3 of Embodiment 1. Fig. 8 is a cross-sectional view of a battery 301 according to this modification.

[0159] 8 , the battery 301 includes a unit cell 360 and is formed from one unit cell 360. The unit cell 360 differs from the unit cell 160 according to the first modification of the first embodiment in that the unit cell 360 has a third layer 340 instead of the third layer 40.

[0160] The third layer 340 includes a counter electrode active material layer 41 and a third insulating layer 42 that is aligned with the counter electrode active material layer 41 along the positive x-axis direction and is disposed at an end of the third layer 340 in the positive x-axis direction. The thickness of the third insulating layer 42 is, for example, 5 μm or more and 300 μm or less. The thickness of the counter electrode active material layer 41 and the thickness of the third insulating layer 42 are, for example, substantially the same. The thickness of the third insulating layer 42 may be thinner than the thickness of the counter electrode active material layer 41.

[0161] The third insulating layer 42 has electronic insulation properties. The third insulating layer 42 may further have ionic insulation properties. The third insulating layer 42 is in contact with the surface of the second layer 30 facing the third layer 340 and the end face of the counter electrode active material layer 41 in the positive x-axis direction. By disposing the third insulating layer 42 at the end of the third layer 340, contact of an electrode of opposite polarity with the counter electrode active material layer 41 can be suppressed, thereby improving the short-circuit resistance of the battery 301. Furthermore, collapse of the counter electrode active material layer 41 can be suppressed.

[0162] The third insulating layer 42 extends on the second layer 30 in the direction in which the end face of the counter electrode active material layer 41 in the x-axis positive direction extends (the y-axis direction). The third insulating layer 42 includes a portion that does not overlap with the counter electrode active material layer 41 in a planar view. The third insulating layer 42 is provided along the entire end of the counter electrode active material layer 41 in the x-axis positive direction, but may be provided on a portion of the end of the counter electrode active material layer 41 in the x-axis positive direction. For example, the third insulating layer 42 does not have to be formed in a position that does not overlap with the protrusion 151 in a planar view.

[0163] The third insulating layer 42 contains one or more insulating materials having electronic insulation properties. Examples of the insulating materials that can be used include the materials exemplified above as insulating materials that can be used for the first insulating layer 22. The third insulating layer 42 may contain a sulfide solid electrolyte. The third insulating layer 42 may also contain a styrene-based elastomer.

[0164] The third insulating layer 42 may contain the same material as the first insulating layer 22. The third insulating layer 42 may also be made of the same material as the first insulating layer 22.

[0165] In the unit cell 360, at the end of the third layer 340 in the positive x-axis direction, a portion of the third insulating layer 42 is not covered by the counter electrode current collector 150 in a plan view. Therefore, the fourth region 74 is a portion of the third insulating layer 42. This allows the outer edge of the counter electrode current collector 150 in the positive x-axis direction to be supported by the third insulating layer 42, thereby preventing the counter electrode active material layer 41 from collapsing. Furthermore, the counter electrode current collector 150 completely covers the counter electrode active material layer 41 in a plan view. This reduces the contact resistance between the counter electrode active material layer 41 and the counter electrode current collector 150, enabling the battery 301 to have a high output. The counter electrode current collector 150 does not need to cover the third insulating layer 42 in a plan view.

[0166] 8, the fourth region 74 is provided in the third layer 340, but this is not limiting. The fourth region 74 does not have to be provided in the third layer 340. Fig. 9 is a cross-sectional view of another battery 301a according to this modification.

[0167] 9, the battery 301a includes a unit cell 360a and is formed from one unit cell 360a. The unit cell 360a differs from the unit cell 360 in that the fourth region 74 is not provided in the third layer 340.

[0168] In unit cell 360a, counter electrode current collector 150 completely covers third layer 340 in plan view, and fourth region 74 as described above is not provided at the end in the positive x-axis direction of third layer 340. In the example shown in Fig. 9 , counter electrode current collector 150 as a whole protrudes in the positive x-axis direction beyond the outer edge of third layer 340 in plan view, but the outer edge of third layer 340 and the outer edge of counter electrode current collector 150 in the positive x-axis direction other than protruding portion 151 may be aligned.

[0169] The third layer 340 having the fourth region 74 or the third layer 340 not having the fourth region 74 may be used in place of the third layer 40 in the batteries according to the embodiments and variants exemplified above or described below.

[0170] 2-4. Modification 4 Next, a description will be given of a battery according to Modification 4 of Embodiment 1. Fig. 10 is a cross-sectional view of a battery 401 according to this modification.

[0171] 10 , the battery 401 includes a unit cell 460 and is formed from one unit cell 460. The unit cell 460 differs from the unit cell 160 according to the first modification of the first embodiment in that the unit cell 460 has a first layer 420 instead of the first layer 20.

[0172] The first layer 420 includes an electrode active material layer 421 and a first insulating layer 422 that are different in size from the electrode active material layer 21 and the first insulating layer 22 of the first layer 20. In a plan view, the area of ​​the electrode active material layer 421 is smaller than the area of ​​the counter electrode active material layer 41. In a plan view, the outer edge of the electrode active material layer 421 in the positive x-axis direction is located more inward than the outer edge of the counter electrode active material layer 41 in the positive x-axis direction. Therefore, the length of the first insulating layer 422 in the positive x-axis direction is increased, and the first insulating layer 422 can enhance the effect of suppressing contact of an electrode of opposite polarity with the electrode active material layer 421.

[0173] In this modification, the electrode active material layer 421 may be a positive electrode active material layer, and the counter electrode active material layer 41 may be a negative electrode active material layer. In this modification, the counter electrode active material layer 41 is larger than the electrode active material layer 421, so that metal ions are more easily taken up into the counter electrode active material layer 41, which is a negative electrode active material layer, and therefore precipitation of metal derived from the metal ions is suppressed, making it less likely for an internal short circuit to occur, and thus enabling the battery 401 to further improve its resistance to short circuits.

[0174] The first layer 420 may be used in place of the first layer 20 in the batteries according to the embodiments and modifications exemplified above or described below.

[0175] 2-5. Modification 5 Next, a description will be given of a battery according to Modification 5 of Embodiment 1. Fig. 11 is a cross-sectional view of a battery 501 according to this modification.

[0176] 11 , the battery 501 includes a unit cell 560 and is formed from one unit cell 560. The unit cell 560 differs from the unit cell 160 according to the first modification of the first embodiment in that the unit cell 560 has two of each of the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150.

[0177] 11 , two first layers 20 are disposed on both main surfaces 11 and 12 of an electrode current collector 110. Two second layers 30 are disposed on the side of each of the two first layers 20 opposite the electrode current collector 110. Two third layers 40 are disposed on the side of each of the two second layers 30 opposite the first layer 20. Two counter electrode current collectors 150 are disposed on the side of each of the two third layers 40 opposite the second layer 30.

[0178] 11 , a first region 71 that is not covered by either of the two first layers 20 is provided at the end in the positive x-axis direction of each of the main surfaces 11 and 12 of the electrode current collector 110. A second region 72 that is not covered by either of the two second layers 30 is provided at the end in the positive x-axis direction of each of the two first layers 20. A third region 73 that is not covered by either of the two third layers 40 is provided at the end in the positive x-axis direction of each of the two second layers 30. A fourth region 74 that is not covered by either of the two counter electrode current collectors 150 is provided at the end in the positive x-axis direction of each of the two third layers 40.

[0179] In this way, in the unit cell 560, a structure similar to the stacked structure of the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150 formed on the main surface 11 of the electrode current collector 110 of the unit cell 160 is also formed upside down on the main surface 12 facing away from the main surface 11 of the electrode current collector 110. Therefore, the unit cell 560 has a stacked structure that is symmetrical with respect to the electrode current collector 110.

[0180] This makes it possible to suppress a difference in the stress applied to both sides of the electrode current collector 110 in the stacking direction when the unit cell 560 is densified by pressing or the like, thereby suppressing warping of the unit cell 560. Furthermore, even if stress is generated due to expansion and contraction of the electrode active material layer 21 and the counter electrode active material layer 41 during use of the battery 501, it is possible to suppress a difference in the stress generated on both sides of the electrode current collector 110 in the stacking direction, thereby suppressing warping of the unit cell 560. Furthermore, since it is possible to extract currents of two electrode active material layers 21 from one electrode current collector 110, it is possible to increase the volumetric energy density.

[0181] In the unit cell 560 according to this modification, the laminate structure formed on the main surface 11 of the unit cell 160 is also formed on the main surface 12. However, instead of the unit cell 160, the laminate structure formed on the main surface 11 of a unit cell according to any of the above-described embodiments and modifications other than the unit cell 160 may also be formed on the main surface 12 of the unit cell.

[0182] An example of a battery in which the laminate structure formed on the main surface 11 of a unit cell other than unit cell 560 is also formed on main surface 12 will be described with reference to FIG. 12 . FIG. 12 is a cross-sectional view of another battery 501a according to this modification. As shown in FIG. 12 , battery 501a includes a unit cell 560a, and is formed from one unit cell 560a. In unit cell 560a, a structure similar to the laminate structure of first layer 20, second layer 30, third layer 340, and counter electrode current collector 150 formed on main surface 11 of electrode current collector 110 of unit cell 360 is also formed on main surface 12 facing back to main surface 11 of electrode current collector 110. This provides the same effects as those of battery 501 described above.

[0183] [2-6. Modification 6] Next, a battery according to Modification 6 of Embodiment 1 will be described. Fig. 13 is a cross-sectional view of a battery 601 according to this modification. In Fig. 13, the outline of the insulating member 80 at a position where the protrusion 111 is not formed is indicated by a dashed line.

[0184] 13 , the battery 601 includes a unit cell 660, and is formed from one unit cell 660. The unit cell 660 differs from the unit cell 560 according to the fifth modification of the first embodiment in that the unit cell 660 further includes an insulating member 80.

[0185] The insulating member 80 covers the end face of the electrode current collector 110 in the positive x-axis direction, except for the portion where the protrusion 111 is formed. The insulating member 80 also covers the end face of the first layer 20 in the positive x-axis direction. For example, the insulating member 80 is provided on both the positive y-axis direction and the negative y-axis direction of the protrusion 111. This further suppresses short circuits due to contact between the protrusion 151 and the electrode current collector 110. In the example shown in FIG. 13 , the insulating member 80 covers the entire second region 72 and a portion of the third region 73 on the second region 72 side. The insulating member 80 does not cover a portion of the third region 73. A gap is provided between the third layer 40 and the insulating member 80. As long as the insulating member 80 covers the portion of the end face of the electrode current collector 110 in the positive x-axis direction that overlaps with the protrusion 151 in a plan view, it is not necessary for the insulating member 80 to cover other portions. The insulating member 80 may cover a part of the first region 71. The insulating member 80 may cover the entire third region 73. The insulating member 80 may cover at least a part of the fourth region 74.

[0186] The insulating member 80 has electronic insulation and ionic insulation properties. For example, insulating tape or insulating resin is used as the insulating member 80. Examples of resins used for the insulating tape and insulating resin include silicone resin, epoxy resin, acrylic resin, and polyimide resin. The resin may be a thermosetting resin or an ultraviolet-curing resin.

[0187] [3. Manufacturing Method] Next, a method for manufacturing a battery according to the present embodiment and each of the modifications of the present embodiment will be described. The following mainly describes a method for manufacturing a battery 501 according to the fifth modification of the first embodiment, but other batteries can also be manufactured by appropriately applying the manufacturing method described below. Figure 14 is a flowchart showing a method for manufacturing a battery 501 according to the fifth modification of the first embodiment. Note that the manufacturing method for the battery 501 described below is an example, and the manufacturing method for the battery 501 is not limited to the following example.

[0188] First, in the manufacturing method of the battery 501, an electrode current collector 10 without a protrusion 111 is prepared (step S11). Next, a first layer 20 is laminated on both main surfaces 11 and 12 of the electrode current collector 10 (step S12). At this time, the first layer 20 is laminated on the main surfaces 11 and 12 so that a first region 71 not covered by the first layer 20 is provided at the end of each of the main surfaces 11 and 12 in the positive x-axis direction. This prevents the first layer 20 from protruding from the main surface 11 even if the formation position of the first layer 20 is slightly shifted. Therefore, the first layer 20 can be formed with high efficiency without excessively increasing the positional accuracy of the first layer 20. Note that when manufacturing a battery in which the first layer 20 is not laminated on the main surface 12 side of the battery 1, the first layer 20 is laminated only on the main surface 11.

[0189] Next, the second layer 30 is laminated on the first layer 20 on the side opposite to the electrode current collector 10 (step S13). At this time, the second layer 30 is laminated on the first layer 20 so that a second region 72 that is not covered by the second layer 30 is provided at the end of the first layer 20 in the positive x-axis direction. As a result, even if the formation position of the second layer 30 is slightly shifted, it will not protrude from the first layer 20, and therefore the second layer 30 can be formed with high efficiency without excessively increasing the positional accuracy of the second layer 30.

[0190] Next, the third layer 40 is laminated on the second layer 30 on the side opposite to the first layer 20 (step S14). At this time, the third layer 40 is laminated on the second layer 30 so that a third region 73 that is not covered by the third layer 40 is provided at the end of the second layer 30 in the positive x-axis direction. As a result, even if the formation position of the third layer 40 is slightly shifted, it will not protrude from the second layer 30, and therefore the third layer 40 can be formed with high efficiency without excessively increasing the positional accuracy of the third layer 40.

[0191] When laminating the first layer 20, the second layer 30, and the third layer 40, a high-pressure press treatment (step S15) is performed as necessary after each of steps S12 to S14. This results in a laminated electrode plate in which the first layer 20, the second layer 30, and the third layer 40 are laminated in this order from the main surface 11 and 12 side on both main surfaces 11 and 12 of the electrode current collector 10.

[0192] The first layer 20, the second layer 30, and the third layer 40 are each formed in this order by, for example, a wet coating method. By using the wet coating method, the first layer 20, the second layer 30, and the third layer 40 can be easily laminated on the electrode current collector 10. As the wet coating method, a coating method such as a die coating method, a doctor blade method, a roll coater method, a screen printing method, or an inkjet method can be used, but the wet coating method is not limited to these methods.

[0193] When the wet coating method is used, a coating process is performed in which a slurry is obtained by appropriately mixing the materials for forming the electrode active material layer 21, the first insulating layer 22, the solid electrolyte layer 31, and the counter electrode active material layer 41 with a solvent. As the material for the first insulating layer 22, a liquid resin material may be prepared instead of the slurry.

[0194] The solvent used in the paint-making step may be a known solvent used in producing a known all-solid-state battery (for example, a lithium-ion all-solid-state battery).

[0195] The slurries for each layer obtained in the coating process are applied to both main surfaces 11 and 12 of the electrode current collector 10 in the order of the first layer 20, the second layer 30, and the third layer 40. In this case, the next layer may be applied after the previous layer has been applied, or the next layer may be applied while the previous layer is being applied. In other words, steps S12, S13, and S14 may be performed simultaneously. Furthermore, when applying the first layer 20, which includes two types of layers, the electrode active material layer 21 and the first insulating layer 22 are applied simultaneously, for example, by using a die capable of discharging two types of slurries. The application direction in this case is perpendicular to the direction in which the electrode active material layer 21 and the first insulating layer 22 are arranged. The electrode active material layer 21 and the first insulating layer 22 may also be applied sequentially. Similarly to the first layer 20, the second layer 230 and the third layer 340 each including two types of layers can be formed in the same manner as the first layer 20.

[0196] The slurry for each layer is applied sequentially, and after all layers have been applied, a high-pressure press treatment (step S15) is performed to promote the filling of the material for each layer. The high-pressure press treatment may be performed after each layer is applied. For example, the high-pressure press treatment may be performed after each layer is applied in the first layer 20, the second layer 30, and the third layer 40, or may be performed separately after each of the first and second layers, or may be performed all at once after all three layers have been applied. When the high-pressure press treatment is performed two or more times, the pressure of the final high-pressure press treatment may be the highest. For example, a roll press, a plate press, or an isostatic press (ISP) may be used for the high-pressure press treatment.

[0197] When the wet coating method is used, a heat treatment is performed to remove the solvent before the high-pressure pressing. The heat treatment is performed, for example, after each coating of the first layer 20, the second layer 30, and the third layer 40, but may also be performed all at once after laminating the first layer 20, the second layer 30, and the third layer 40. Note that at least one of the heat treatment and the high-pressure pressing may not be performed.

[0198] By performing the layer coating method in this manner, it is possible to improve the bonding strength and reduce the interfacial resistance at the interfaces of the electrode current collector 10, the first layer 20, the second layer 30, and the third layer 40. It is also possible to improve the bonding strength and reduce the grain boundary resistance in the powder materials used in the first layer 20, the second layer 30, and the third layer 40. That is, good interfaces are formed between the first layer 20, the second layer 30, and the third layer 40 and between the powder materials within each layer.

[0199] The above steps S12 to S15 may be performed in a continuous process such as a roll-to-roll process.

[0200] The laminated electrode plate may have a size in plan view corresponding to one battery 501, or may be sized in plan view so that it can be divided into individual pieces and used for multiple batteries 501. FIG. 15 is a top view showing an example of a laminated electrode plate 90. As shown in FIG. 15, the laminated electrode plate 90 has a first region 71, a second region 72, and a third region 73 at both positive and negative ends of the x-axis. The first insulating layer 22 of the first layer 20 is located at both positive and negative ends of the first layer 20 along the x-axis. The laminated electrode plate 90 also has two of each of the first layer 20, the second layer 30, and the third layer 40, which are arranged on both sides of the electrode current collector 10 in the stacking direction. FIG. 15 shows the first layer 20, the second layer 30, and the third layer 40 arranged on one side of the electrode current collector 10 in the stacking direction (the positive side of the z-axis).

[0201] The battery 501 can also be manufactured by using such a laminated electrode plate 90 in the manufacturing process of the battery 501 and dicing the laminated electrode plate 90 into individual batteries 501 at any stage before the completion of the battery 501. This can improve manufacturing efficiency. For example, the laminated electrode plate 90 is diced by cutting at least the center of the laminated electrode plate 90 in the x-axis direction along the y-axis direction. This dicing may also be performed by cutting in step S18, which will be described later. After dicing the laminated electrode plate 90, polishing or the like may be performed to adjust the size.

[0202] Next, the electrode current collector 110 is formed by forming the protrusions 111 on the electrode current collector 10 (step S16). The protrusions 111 are formed, for example, by removing a portion of the first region 71. For the removal, a blade such as a cutter, slitter, cutting machine, or punching machine with a Thomson blade, or a laser or jet may be used, but the method is not limited to these. Alternatively, a foil or the like having the shape of the protrusions 111 that is separately prepared may be bonded to the electrode current collector 10. For this bonding, a method such as ultrasonic welding, resistance welding, or crimping may be used, but the method is not limited to these. The protrusions 111 may be formed at any stage in the manufacturing of the battery 501. Alternatively, in step S11, the electrode current collector 110 on which the protrusions 111 have been formed in advance may be prepared.

[0203] Next, the counter electrode current collector 150 is laminated on the third layer 40 on the side opposite the second layer 30 (step S17). This results in a laminate (unit cell 560) in which the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150 are laminated in this order on both main surfaces 11 and 12 of the electrode current collector 110. The counter electrode current collector 150 is laminated on the third layer 40 so that a fourth region 74 not covered by the counter electrode current collector 150 is provided at the end of the third layer 40 in the positive x-axis direction. The third layer 40 and the counter electrode current collector 150 are bonded together by, for example, high-pressure pressing. The bonding may also be performed by using a counter electrode current collector 150 having a connection layer containing an adhesive binder, by coating with an adhesive, or by attaching an adhesive film. The bonding method is not limited to these methods. Heat treatment may also be performed during or after bonding.

[0204] The counter electrode current collector 150 may be formed to a desired size before stacking, or may be partially removed after stacking. Alternatively, the protrusion 151 may be formed after stacking.

[0205] Next, the unit cell 560 obtained in step S17 is cut along a direction intersecting the main surface 11 to form cut surfaces as side surfaces 62, 63, and 64 at the ends of the unit cell 560 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction (step S18). This cutting creates three sides that define the ends of the unit cell 560 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, different from the ends where the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided, in a planar view. Cutting may be performed using a blade such as a cutter, an ultrasonic cutter, a slitter, a dicer, a cutting machine, a punching machine with a Thomson blade, a laser, or a jet, but is not limited to these methods. Furthermore, to prevent short circuits, the side surfaces 62, 63, and 64 may be polished after cutting to remove burrs and the like.

[0206] In step S18, the electrode current collector 110, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150 are cut together in a direction intersecting the main surface 11. Specifically, the direction intersecting the main surface 11 is a direction perpendicular to the main surface 11, which can also be considered the stacking direction of the unit cells 560. This eliminates the need to stack the electrode current collector 110, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150 in the shape they will have after cutting, making it easy to manufacture the battery 501. Furthermore, because the regions including the first region 71, the second region 72, the third region 73, and the fourth region 74 remain uncut, it is possible to form an electrical connection structure, such as a terminal, in a structure that can suppress the occurrence of a short circuit. Furthermore, the capacity of the battery 501 can be adjusted by adjusting the position at which the unit cells 560 are cut, thereby improving capacity accuracy.

[0207] At the cut surface, the side surfaces of the electrode current collector 110, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150 are exposed. After cutting, a sealing member or the like may be placed to cover these exposed side surfaces in order to protect them. That is, when these side surfaces are covered with another member such as a sealing member, these exposed side surfaces may also be covered with the other member.

[0208] Through the above steps, a battery 501 composed of one unit cell 560 is obtained. The above manufacturing method allows for the efficient manufacture of a battery 501 with high resistance to short circuits. The obtained battery 501 may be housed in an exterior body or the like. When the battery 501 is housed in an exterior body, the protrusions 111 and 151 are extended to the exterior of the exterior body. The obtained battery 501 may also be subjected to a process for removing corners (intersections of the side surfaces) in a plan view by cutting or the like. In this case, when removing a corner in the positive x-axis direction, for example, a portion including the first region 71, the second region 72, the third region 73, and the fourth region 74 is removed. This removes corners that are prone to collapse and breakage, thereby further improving the short-circuit resistance of the battery 501.

[0209] The order of steps S17 and S18 may be reversed. In this case, first, after step S16, in step S18, the laminate (laminated electrode plate) in which the electrode current collector 110, the first layer 20, the second layer 30, and the third layer 40 are stacked is cut along a direction intersecting the main surface 11 to form cut surfaces at the ends of the laminated electrode plate in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction. At this time, the electrode current collector 110, the first layer 20, the second layer 30, and the third layer 40 are cut all at once along a direction intersecting the main surface 11. This eliminates the need to stack the electrode current collector 110, the first layer 20, the second layer 30, and the third layer 40 in the shapes after cutting, thereby facilitating the manufacture of the battery 501. Thereafter, in step S17, a counter electrode current collector 150 having a shape corresponding to the shape of the laminated electrode plate after the cut surface is formed is laminated on the opposite side of the third layer 40 from the second layer 30. In this way, a battery 501 composed of one unit cell 560 is obtained.

[0210] (Embodiment 2) Next, embodiment 2 will be described. In embodiment 2, a stacked type stacked battery in which a plurality of unit cells are stacked will be described. In the following description, differences from embodiment 1 and the modifications will be mainly described, and descriptions of commonalities will be omitted or simplified as appropriate.

[0211] [1. Configuration] First, the configuration of a battery according to embodiment 2 will be described with reference to the drawings. Fig. 16 is a cross-sectional view of a battery 701 according to this embodiment. As shown in Fig. 16, the battery 701 includes a plurality of unit cells 560 according to variation 5 of embodiment 1, and has a structure in which the plurality of unit cells 560 are stacked. Because the unit cells 560 are stacked in the battery 701, it is possible to realize the battery 701 that can achieve both high resistance to short circuits and highly efficient productivity.

[0212] The multiple unit cells 560 have the same configuration and are stacked so as to be electrically connected in parallel. The first layer 20, the second layer 30, and the third layer 40 stacked on both main surfaces of each current collector are stacked in the same order from the current collector. The multiple unit cells 560 are stacked such that the positions of the side surfaces of the unit cells 560 coincide when viewed from the stacking direction. Therefore, the side surfaces of the multiple unit cells 560 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction are flush with each other. In the multiple unit cells 560, the protrusions 151 and the protrusions 111 protrude in the same direction, specifically, in the positive x-axis direction. The protrusions 151 of the multiple unit cells 560 and the protrusions 111 of the multiple unit cells 560 may be bundled together and joined by welding or the like.

[0213] In the example shown in FIG. 16, the number of stacked unit cells 560 is four, but it may be two or three, or may be five or more.

[0214] 16 , two adjacent unit cells 560 share a counter electrode current collector 150. Note that two adjacent unit cells 560 may not share a counter electrode current collector 150, but may each have an individual counter electrode current collector 150, with two counter electrode current collectors 150 overlapping each other between the third layers 40. In this case, a conductive adhesive layer may be provided between the two counter electrode current collectors 150.

[0215] In the stacked-type battery according to the present embodiment, the unit cells to be stacked may be unit cells other than the unit cell 560 according to the first embodiment and each of the modifications described above. Even when unit cells other than the unit cell 560 are stacked, adjacent unit cells may share a current collector, or the unit cells may be stacked so that two separate current collectors overlap without sharing a current collector. Furthermore, when unit cells in which the first layer 20 or the like is stacked only on one main surface 11 of the electrode current collector 10 or 110, such as the unit cell 60, are stacked, the unit cells may be stacked so that they are electrically connected in series. Furthermore, the multiple unit cells may include unit cells with different configurations. Furthermore, the multiple unit cells may include unit cells with different configurations from the unit cells according to the first embodiment and each of the modifications.

[0216] [2. Manufacturing Method] Next, a method for manufacturing a battery according to this embodiment will be described. The following mainly describes a method for manufacturing a battery 701 formed by stacking a plurality of unit cells 560. However, batteries formed by stacking unit cells according to the first embodiment and each of the modifications other than the unit cell 560 described above can also be manufactured by appropriately applying the manufacturing method described below. Figure 17 is a flowchart showing a method for manufacturing a battery 701 according to the second embodiment. Note that the manufacturing method for the battery 701 described below is an example, and the manufacturing method for the battery 701 is not limited to the following example.

[0217] First, in steps S21 to S26 shown in Fig. 17, laminated electrode plates in the same number as the number of unit cells 560 included in the battery 701 are formed by a method similar to steps S11 to S16 shown and described with reference to Fig. 14. The laminated electrode plates may be large-sized laminated electrode plates 90 as shown in Fig. 15, or may be laminated electrode plates formed to correspond to the size of the unit cells 560. Note that steps S21 to S26 may be omitted, and the same number of laminated electrode plates as the number of unit cells 560 included in the pre-formed battery 701 may be prepared.

[0218] Next, a counter electrode current collector 150 is stacked on the third layer 40 on the side opposite the second layer 30, and multiple unit cells 560 are stacked (steps S27 and S28). For example, by alternately stacking the counter electrode current collectors 150 and the laminated electrode plates obtained up to step S26, the counter electrode current collector 150 is shared by adjacent unit cells 560, and the stacking of the counter electrode current collector 150 on the third layer 40 and the stacking of multiple unit cells 560 are performed. Alternatively, a counter electrode current collector 150 may be stacked on only one of the two third layers 40 of the laminated electrode plate to form a unit cell with a structure in which one counter electrode current collector 150 is removed from the unit cell 560, and this unit cell may then be stacked. This unit cell may also be stacked so that the counter electrode current collector 150 is sandwiched between the third layers 40, allowing the counter electrode current collector 150 to be shared by adjacent unit cells 560. In this case, after stacking the required number of unit cells, the counter electrode current collector 150 is stacked on the third layer 40 at the end in the stacking direction and therefore on which no counter electrode current collector 150 is stacked.

[0219] When these layers are stacked, the third layer 40 and the counter electrode current collector 150 may be bonded by high-pressure pressing or the like, as in step S17. This bonding may be performed during the process of stacking the counter electrode current collector 150 and the laminated electrode plate, or may be performed all at once after all of the counter electrode current collectors 150 and the laminated electrode plates have been stacked. When the bonding is performed all at once, for example, all of the counter electrode current collectors 150 and the laminated electrode plates are stacked and then pressed all at once after stacking.

[0220] As in step S17, the counter electrode current collector 150 may be formed to a desired size before stacking, or a portion of the counter electrode current collector 150 may be removed after stacking. Also, the protrusion 151 may be formed after stacking.

[0221] In addition, when manufacturing a battery 701 in which two adjacent unit cells 560 do not share a counter electrode current collector 150 but have two counter electrode current collectors 150 stacked between the third layers 40, step S27 is performed in the same manner as step S17 described above to obtain a stack (unit cell 560) in which the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150 are stacked in this order on both main surfaces 11 and 12 of the electrode current collector 110. Then, in step S28, the obtained unit cells 560 are stacked. The unit cells 560 are bonded to each other using a conductive adhesive layer formed by coating an adhesive or laminating an adhesive film. However, the bonding method is not limited to these methods. Furthermore, heat treatment and pressing may be performed after bonding. For example, all of the counter electrode current collectors 150 and the laminated electrode plates may be stacked by stacking the unit cells 560, and then the stacked electrodes may be pressed together.

[0222] Next, the stack of the unit cells 560 obtained in step S28 is cut along a direction intersecting the main surface 11 to form cut surfaces as side surfaces 62, 63, and 64 at each end of the unit cells 560 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction (step S29). This cutting forms three sides that constitute the end of each of the unit cells 560, different from the end where the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided, in a plan view. The cutting method can be the same as that of step S18. In step S29, all of the unit cells 560 are cut collectively along a direction intersecting the main surface 11. This eliminates the need to stack the electrode current collector 110, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150 of each of the unit cells 560 in the cut shapes, thereby facilitating the production of the battery 701. Furthermore, since the areas where the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided remain uncut, it is possible to form electrical connection structures such as terminals in a structure that can suppress the occurrence of short circuits.

[0223] At the cut surface, the side surfaces of the electrode current collector 110, the first layer 20, the second layer 30, the third layer 40, and the counter electrode current collector 150 of each of the plurality of unit cells 560 are exposed. After cutting, a sealing member or the like may be disposed to cover these exposed side surfaces in order to protect them. That is, when these side surfaces are covered with another member such as a sealing member, these exposed side surfaces may also be covered with the other member.

[0224] Through the steps described above, a battery 701 having a structure in which a plurality of unit cells 560 are stacked is obtained. The obtained battery 701 may be housed in an exterior body or the like. When the battery 701 is housed in an exterior body, the protrusions 111 and 151 are extended to the outside of the exterior body. Furthermore, the obtained battery 701 may be subjected to a process of removing corners (intersections of the side surfaces) in a plan view by cutting or the like.

[0225] The formation of the cut surfaces in step S29 may be performed before step S28. In this case, the unit cells with the cut surfaces formed thereon are stacked in step S28 to obtain the battery 701.

[0226] Furthermore, the laminated electrode plate and counter electrode current collector 150 laminated in steps S27 and S28 are not limited to configurations corresponding to the plurality of unit cells 560, and may be laminated electrode plates and counter electrode current collectors having configurations according to the battery to be manufactured. For example, the laminated electrode plate and counter electrode current collector used in steps S27 and S28 may have configurations corresponding to unit cells other than unit cells 560 according to the first embodiment and each of the modified examples described above.

[0227] While the battery and the method for manufacturing the battery according to the present disclosure have been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications that a person skilled in the art can make to the embodiments and other forms constructed by combining some of the components of the embodiments are also included in the scope of the present disclosure.

[0228] In the above embodiment, the battery is composed of an electrode current collector, a first layer, a second layer, a third layer, and a counter electrode current collector, or an electrode current collector, a first layer, a second layer, a third layer, a counter electrode current collector, and an insulating member, but is not limited to this. For example, within the range of allowable battery characteristics, a bonding layer or the like may be provided between each layer of the battery to reduce electrical resistance and improve bonding strength.

[0229] In the above embodiment, the first, second, and third layers are formed by sequentially stacking them directly on the main surface of the electrode current collector. However, this is not limiting. For example, the first, second, and third layers may be formed by sequentially stacking them on a sheet-like substrate, and the formed first, second, and third layers may be removed from the substrate and stacked on the main surface of the electrode current collector. Alternatively, the first, second, and third layers may be formed on a sheet-like substrate, and the formed first, second, and third layers may be sequentially transferred to the main surface of the electrode current collector.

[0230] Furthermore, the first insulating layer and the second insulating layer, or the second insulating layer and the third insulating layer, may be combined into one insulating layer, i.e., there may be no boundary between the first insulating layer and the second insulating layer, or no boundary between the second insulating layer and the third insulating layer.

[0231] Furthermore, the first insulating layer, the second insulating layer, and the third insulating layer may be combined into one insulating layer, i.e., there may be no boundaries between the first insulating layer, the second insulating layer, and the third insulating layer.

[0232] Furthermore, various modifications, substitutions, additions, omissions, etc. can be made to each of the above-described embodiments within the scope of the claims or their equivalents.

[0233] The battery according to the present disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices or automobiles.

[0234] DESCRIPTION OF SYMBOLS 1, 1a, 101, 201, 301, 301a, 401, 501, 501a, 601, 701 Battery 10, 110 Electrode current collector 11, 12 Main surface 20, 420 First layer 21, 421 Electrode active material layer 22, 422 First insulating layer 25, 35, 45 Inclined surface 26, 36 Recess 30, 230 Second layer 31 Solid electrolyte layer 32 Second insulating layer 40, 340 Third layer 41 Counter electrode active material layer 42 Third insulating layer 50, 150 Counter electrode current collector 60, 60a, 160, 260, 360, 360a, 460, 560, 560a, 660 Unit cell 61, 62, 63, 64 Side surface 71 First region 72 second region 73 third region 74 fourth region 80 insulating member 90 laminated electrode plate 111, 151 protrusion

Claims

1. A unit cell having: an electrode current collector; a first layer arranged on a main surface of the electrode current collector; a second layer arranged on the side of the first layer opposite the electrode current collector; a third layer arranged on the side of the second layer opposite the first layer; and a counter electrode current collector arranged on the side of the third layer opposite the second layer; the first layer includes an electrode active material layer and a first insulating layer having electronic insulation that is aligned with the electrode active material layer along a first direction that is a direction from the center to the outer edge of the main surface of the electrode current collector and is arranged at an end of the first layer in the first direction; the second layer includes an electrolyte layer; and the third layer includes a counter electrode active material layer; a first region that is not covered by the first layer is provided at an end of the main surface of the electrode current collector in the first direction; and a second region that is not covered by the second layer in a plan view with respect to the main surface of the electrode current collector. a third region that is not covered by the third layer in the plan view is provided at an end of the second layer in the first direction.

2. The battery according to claim 1, wherein the unit cell has two of each of the first layer, the second layer, the third layer and the counter electrode current collector, the two first layers being disposed on both main surfaces of the electrode current collector, the two second layers being disposed on the side of each of the two first layers opposite the electrode current collector, the two third layers being disposed on the side of each of the two second layers opposite the first layer, the two counter electrode current collectors being disposed on the side of each of the two third layers opposite the second layer, the first region being provided at an end in the first direction of each of both main surfaces of the electrode current collector, the second region being provided at an end in the first direction of each of the two first layers, and the third region being provided at an end in the first direction of each of the two second layers.

3. The battery according to claim 1, wherein an end portion of the third layer in the first direction is provided with a fourth region that is not covered by the counter electrode current collector in the plan view.

4. The battery according to claim 3, wherein the unit cell has two of each of the first layer, the second layer, the third layer and the counter electrode current collector, the two first layers being arranged on both main surfaces of the electrode current collector, the two second layers being arranged on the side of each of the two first layers opposite the electrode current collector, the two third layers being arranged on the side of each of the two second layers opposite the first layer, the two counter electrode current collectors being arranged on the side of each of the two third layers opposite the second layer, the first region being provided at an end in the first direction of each of both main surfaces of the electrode current collector, the second region being provided at an end in the first direction of each of the two first layers, the third region being provided at an end in the first direction of each of the two second layers, and the fourth region being provided at an end in the first direction of each of the two third layers.

5. The battery according to claim 1, wherein the second layer further includes a second insulating layer having electronic insulation properties aligned with the electrolyte layer along the first direction and disposed at an end of the second layer in the first direction.

6. The battery of claim 1, wherein the third region is part of the electrolyte layer.

7. The battery according to claim 3, wherein the third layer further includes a third insulating layer having electronic insulation properties, aligned with the counter electrode active material layer along the first direction and disposed at an end of the third layer in the first direction.

8. The battery according to any one of claims 1 to 7, wherein at an end of the unit cell in a second direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector and that is different from the first direction, side surfaces of the electrode current collector, the first layer, the second layer and the third layer are flush with each other.

9. The battery according to any one of claims 1 to 7, wherein at an end of the unit cell in a second direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector and different from the first direction, side surfaces of the electrode current collector, the first layer, the second layer, the third layer and the counter electrode current collector are flush with each other.

10. The battery according to any one of claims 1 to 7, wherein at least one selected from the group consisting of the electrode active material layer, the first insulating layer and the electrolyte layer contains a sulfide solid electrolyte.

11. The battery according to any one of claims 1 to 7, wherein at least one selected from the group consisting of the electrode active material layer, the first insulating layer and the electrolyte layer contains a styrene-based elastomer.

12. The battery according to any one of claims 1 to 7, wherein a portion of an end portion in the first direction of the counter electrode current collector protrudes in the first direction beyond the third layer in the plan view.

13. The battery according to any one of claims 1 to 7, comprising a plurality of the unit cells, the plurality of unit cells being stacked.

14. A method for producing an electrode current collector, comprising: preparing an electrode current collector; laminating a first layer on a main surface of the electrode current collector such that a first region not covered by the first layer is provided at an end of the main surface of the electrode current collector in a first direction, which is a direction from the center toward the outer edge of the main surface of the electrode current collector; laminating the second layer on a side opposite the electrode current collector of the first layer such that a second region not covered by the second layer is provided at an end of the first layer in the first direction, in a plan view with respect to the main surface of the electrode current collector; laminating the third layer on a side opposite the first layer to the first layer such that a third region not covered by the third layer is provided at an end of the second layer in the first direction, in the plan view; and laminating a counter electrode current collector on the side opposite the second layer to the second layer, the second layer includes an electrolyte layer, and the third layer includes a counter electrode active material layer.

15. The method for manufacturing a battery according to claim 14, wherein, in stacking the counter electrode current collector, the counter electrode current collector is stacked on the third layer such that a fourth region that is not covered by the counter electrode current collector in the plan view is provided at an end of the third layer in the first direction.

16. A method for manufacturing a battery as described in claim 14 or 15, further comprising cutting the electrode collector, the first layer, the second layer, and the third layer collectively along a direction intersecting a main surface of the electrode collector, to form a cut surface at an end of a laminate in which the electrode collector, the first layer, the second layer, and the third layer are stacked, in a second direction that is a direction from the center toward the outer edge of the main surface of the electrode collector and that is different from the first direction.

17. A method for manufacturing a battery according to claim 14 or 15, further comprising cutting the electrode current collector, the first layer, the second layer, the third layer, and the counter electrode current collector collectively along a direction intersecting a main surface of the electrode current collector, to form a cut surface at an end of a laminate in which the electrode current collector, the first layer, the second layer, the third layer, and the counter electrode current collector are stacked, in a second direction that is a direction from the center to an outer edge of the main surface of the electrode current collector and that is different from the first direction.

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