Battery

Abstract

We provide highly reliable batteries. [Solution] The battery 1 comprises a unit cell 60 having an electrode current collector 10, an electrode active material layer 20, a solid electrolyte layer 30, a counter electrode active material layer 40, a counter electrode current collector 50, and an insulating member 90 covering the electrode active material layer 20 and the solid electrolyte layer 30. At the end of the electrode active material layer 20 in the positive x-axis direction, a first covering region 71 is provided, which is not covered by the solid electrolyte layer 30 but covered by the insulating member 90, in a plan view with respect to the main surface 11 of the electrode current collector 10. At the end of the solid electrolyte layer 30 in the positive x-axis direction, a second covering region 72 is provided, which is not covered by the counter electrode active material layer 40 but covered by the insulating member 90, in a plan view with respect to the main surface 11 of the electrode current collector 10.

Description

[Technical Field]

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

[0002] Patent documents 1 to 4 describe 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 laminated, with insulating members placed at the ends. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2012 / 114497 [Patent Document 2] Japanese Patent Publication No. 2015-125893 [Patent Document 3] Japanese Patent Publication No. 2024-25996 [Patent Document 4] Japanese Patent Publication No. 2024-92485 [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure aims to provide highly reliable batteries. [Means for solving the problem]

[0005] A battery according to one aspect of the present disclosure comprises a unit cell having an electrode current collector, an electrode active material layer disposed on the main surface of the electrode current collector, an electrolyte layer disposed on the side of the electrode active material layer opposite to the electrode current collector, a counter electrode active material layer disposed on the side of the electrolyte layer opposite to the electrode active material layer, a counter electrode current collector disposed on the side of the counter electrode active material layer opposite to the electrolyte layer, and an insulating member covering the electrode active material layer and the electrolyte layer, wherein the end of the electrode active material layer in a first direction toward the outer edge from the center of the main surface of the electrode current collector is provided with a first covering region that is not covered by the electrolyte layer but covered by the insulating member in a plan view with respect to the main surface of the electrode current collector, and the end of the electrolyte layer in the first direction is provided with a second covering region that is not covered by the counter electrode active material layer but covered by the insulating member in a plan view with respect to the main surface of the electrode current collector. [Effects of the Invention]

[0006] According to this disclosure, a highly reliable battery can be provided. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a top view of a battery according to Embodiment 1. [Figure 2] Figure 2 is a cross-sectional view of the battery according to Embodiment 1. [Figure 3] Figure 3 is another cross-sectional view of the battery according to Embodiment 1. [Figure 4] Figure 4 is a top view of a battery according to a modified example 1 of Embodiment 1. [Figure 5] Figure 5 is a cross-sectional view of a battery according to a modified example 1 of Embodiment 1. [Figure 6] Figure 6 is a cross-sectional view of a battery according to a modified example 2 of Embodiment 1. [Figure 7] Figure 7 is another cross-sectional view of the battery according to a modified example 2 of Embodiment 1. [Figure 8] Figure 8 is a flowchart showing a method for manufacturing a battery according to a modified example 2 of Embodiment 1. [Figure 9]FIG. 9 is a top view showing an example of a laminated electrode plate. [Figure 10] FIG. 10 is a cross-sectional view of the battery according to Embodiment 2. [Figure 11] FIG. 11 is a flowchart showing a method for manufacturing the battery according to Embodiment 2.

MODE FOR CARRYING OUT THE INVENTION

[0008] (Knowledge on which the present disclosure is based) As described above, 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 laminated has been proposed. Generally, since the electrode current collector and the electrode active material layer, and the counter electrode current collector and the counter electrode active material layer have electronic conductivity, conduction, that is, short circuit occurs when these different-polarity electrodes contact each other. Therefore, it is important to have high resistance to short circuit in the long-term use of the battery. In particular, at the end of the battery, short circuit is likely to occur due to the contact between the electrode active material layer and the electrode current collector and the counter electrode active material layer and the counter electrode current collector. Further, when the end of the active material layer is exposed, short circuit is likely to occur due to the collapse of the active material. Thus, the inventors have focused on the problem that the reliability of the battery is likely to decrease due to the end of the battery.

[0009] Therefore, in the present disclosure, a highly reliable battery is provided.

[0010] (Summary of the present disclosure) The following shows an example of the battery according to the present disclosure as an overview of the present disclosure.

[0011] A battery according to a first aspect of the present disclosure comprises a unit cell having an electrode current collector, an electrode active material layer disposed on the main surface of the electrode current collector, an electrolyte layer disposed on the side of the electrode active material layer opposite to the electrode current collector, a counter electrode active material layer disposed on the side of the electrolyte layer opposite to the electrode active material layer, a counter electrode current collector disposed on the side of the counter electrode active material layer opposite to the electrolyte layer, and an insulating member covering the electrode active material layer and the electrolyte layer, wherein the end of the electrode active material layer in a first direction, which is the direction from the center of the main surface of the electrode current collector toward the outer edge, is provided with a first covering region that is not covered by the electrolyte layer but covered by the insulating member in a plan view with respect to the main surface of the electrode current collector, and the end of the electrolyte layer in the first direction is provided with a second covering region that is not covered by the counter electrode active material layer but covered by the insulating member in a plan view with respect to the main surface of the electrode current collector.

[0012] As a result, in the first and second coating regions, the ends of the electrode active material layer and the electrolyte layer in the first direction are covered with an insulating material. Therefore, contact between electrodes of opposite polarity with the electrode active material layer can be suppressed, improving the battery's resistance to short circuits. Thus, the reliability of the battery can be increased.

[0013] Furthermore, the provision of a first coating region prevents the end of the electrode active material layer in the first direction from being covered by the electrolyte layer, resulting in a shape where the electrode active material layer protrudes further in the first direction than the electrolyte layer. Similarly, the provision of a second coating region prevents the end of the electrolyte layer in the first direction from being covered by the counter electrode active material layer, resulting in a shape where the electrolyte layer protrudes further in the first direction than the counter electrode active material layer. As a result, at the end of the unit cell in the first direction, the end of the electrolyte layer is supported by the electrode active material layer, and the end of the counter electrode active material layer is supported by the electrolyte layer. Consequently, collapse of the electrolyte layer and the counter electrode active material layer can be suppressed at the end of the unit cell in the first direction, thereby improving the reliability of the battery. Moreover, even if the positional accuracy during the formation of the electrolyte layer and the counter electrode active material layer is not high, it is possible to avoid a structure where the outer edges of the electrolyte layer and the outer edges of the counter electrode active material layer protrude from the electrode active material layer and electrolyte layer, respectively, and are prone to collapse at the end of the unit cell in the first direction, thereby improving productivity.

[0014] Furthermore, for example, a battery according to a second aspect of this disclosure is a battery according to a first aspect, wherein the insulating member is in contact with at least one of the first-direction side surface of the electrolyte layer and the first-direction side surface of the counter electrode active material layer.

[0015] This allows the insulating material to suppress collapse on the sides of at least one of the solid electrolyte layer and the counter electrode active material layer, thereby improving the reliability of the battery.

[0016] Furthermore, for example, a battery according to a third aspect of this disclosure is a battery according to a first aspect, wherein the insulating member is in contact with the side surface of the electrolyte layer on the first direction side and the side surface of the counter electrode active material layer on the first direction side.

[0017] This allows the insulating material to suppress collapse on the sides of the solid electrolyte layer and the counter electrode active material layer, thereby improving the reliability of the battery.

[0018] Furthermore, for example, a battery according to a fourth aspect of the present disclosure is a battery according to any one of the first to third aspects, wherein the insulating member is provided with a first uncovered region that is not covered by the counter electrode current collector in a plan view with respect to the main surface of the electrode current collector.

[0019] This makes it possible to suppress short circuits that occur when the positional accuracy during the formation of the counter electrode current collector is not high, by preventing the portion of the counter electrode current collector that protrudes from the counter electrode active material layer at the end of the unit cell in the first direction from coming into contact with the electrode current collector.

[0020] Furthermore, for example, a battery according to a fifth aspect of the present disclosure is a battery according to any one of the first to fourth aspects, wherein the electrode current collector has a protruding portion at a part of its end in the first direction that protrudes in the first direction, and when the cross-section of the unit cell is viewed in a plan view at the position of a line parallel to the first direction that does not pass through the protruding portion, the side surface of the electrode active material layer on the first direction side and the side surface of the insulating member on the first direction side are aligned in the first direction at the end of the unit cell in the first direction.

[0021] As a result, there is no step between the side surface of the electrode active material layer and the side surface of the insulating material, preventing the formation of spaces that do not function as a battery due to the step, and thus improving the effective volumetric energy density of the battery.

[0022] Furthermore, for example, a battery according to the sixth aspect of the present disclosure is a battery according to any one of the first to fifth aspects, wherein the end of the electrode current collector in the first direction is provided with a second uncovered region that is not covered by the electrode active material layer and the insulating member in a plan view with respect to the main surface of the electrode current collector.

[0023] This exposes a portion of the main surface of the electrode current collector, making it easy to form electrical connection structures such as terminals on the electrode current collector.

[0024] Furthermore, for example, a battery according to the seventh aspect of the present disclosure is a battery according to any one of the first to sixth aspects, wherein the electrode current collector has a protrusion at a part of its end in the first direction that protrudes in the first direction, and when the cross-section of the unit cell is viewed in a plan view at the position of a line parallel to the first direction passing through the protrusion, the electrode active material layer protrudes in the first direction more than the insulating member.

[0025] This makes it possible to reduce the amount of insulating material used.

[0026] Furthermore, for example, a battery according to the eighth aspect of the present disclosure is a battery according to any one of the first to fifth aspects, wherein the electrode current collector has a protruding portion on which a part of the end in the first direction protrudes in the first direction, and the protruding portion is provided with a third covering region that is not covered by the electrode active material layer but is covered by the insulating member, in a plan view with respect to the main surface of the electrode current collector.

[0027] As a result, at the location where the protrusion is formed, the electrode active material layer is covered by the insulating material from the first direction side, thereby suppressing the collapse of the edges of the electrode active material layer in the first direction and improving the reliability of the battery.

[0028] Furthermore, for example, a battery according to the ninth aspect of the present disclosure is a battery according to any one of the first to eighth aspects, wherein the unit cell has two of each of the electrode active material layer, the electrolyte layer, the counter electrode active material layer, the counter electrode current collector and the insulating member, the two electrode active material layers are arranged on both main surfaces of the electrode current collector, the two electrolyte layers are arranged on the opposite side of each of the two electrode active material layers from the electrode current collector, the two counter electrode active material layers are arranged on the opposite side of each of the two electrolyte layers from the electrode active material layer, and the two counter electrode current collector The current body is positioned on the opposite side of each of the two counter electrode active material layers from the electrolyte layer, one of the two insulating members covers the electrode active material layer and the electrolyte layer positioned on the main surface side of one of the electrode current collectors, the other of the two insulating members covers the electrode active material layer and the electrolyte layer positioned on the main surface side of the other electrode current collector, a first covering region is provided at the end of each of the two electrode active material layers in the first direction, and a second covering region is provided at the end of each of the two electrolyte layers in the first direction.

[0029] This allows for the realization of a structure on both main surfaces of the electrode current collector that enhances the reliability of the battery as described above. Furthermore, when the unit cell is densified by pressing or other means, differences in the stress applied to both sides of the electrode current collector in the stacking direction are less likely to occur, thereby suppressing warping of the unit cell.

[0030] Furthermore, for example, a battery according to the tenth aspect of the present disclosure is a battery according to any one of the first to ninth aspects, wherein, at the end of the unit cell in a second direction different from the first direction, in a direction from the center of the main surface of the electrode current collector toward the outer edge, the side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer, and the counter electrode active material layer are flush.

[0031] As a result, a first covering region, etc., can be provided at the end of the unit cell in the first direction. On the other hand, at the end of the unit cell in the second direction, which is different from the first direction, there are no steps on the sides of the electrode active material layer, electrolyte layer, and counter electrode active material layer stacked on the electrode current collector, so that no space that does not function as a battery due to steps is formed. Therefore, the effective volumetric energy density of the battery is improved.

[0032] Furthermore, for example, a battery according to the 11th aspect of the present disclosure is a battery according to any one of the first to 9th aspects, wherein, at the end of the unit cell in a second direction different from the first direction, in a direction from the center of the main surface of the electrode current collector toward the outer edge, the side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer, and the counter electrode active material layer are flush.

[0033] As a result, a first covering region, etc., can be provided at the end of the unit cell in the first direction. On the other hand, at the end of the unit cell in a second direction different from the first direction, there are no steps on the sides of the electrode active material layer, electrolyte layer, counter electrode active material layer, and counter electrode current collector, so that no space that does not function as a battery due to steps is formed. Therefore, the effective volumetric energy density of the battery is improved.

[0034] Furthermore, for example, a battery according to a twelfth aspect of the present disclosure is a battery according to any one of the first to eleventh aspects, wherein at least one selected from the group consisting of the electrode active material layer, the insulating member, and the electrolyte layer includes a sulfide solid electrolyte.

[0035] As a result, a sulfide solid electrolyte with excellent ionic conductivity, moldability, and insulating properties is included in at least one of the electrode active material layer, insulating material, and electrolyte layer, thereby improving battery reliability and enabling higher battery output.

[0036] Furthermore, for example, a battery according to a 13th aspect of this disclosure is a battery according to any one of the 1st to 12th aspects, wherein at least one selected from the group consisting of the electrode active material layer, the insulating member, and the electrolyte layer includes a styrene-based elastomer.

[0037] As a result, since a styrene-based elastomer with excellent flexibility and elasticity is included in at least one of the electrode active material layer, insulating material, and electrolyte layer, the layer containing the styrene-based elastomer becomes less likely to collapse, and the battery's resistance to short circuits can be further improved.

[0038] Furthermore, for example, a battery according to a 14th aspect of this disclosure is a battery according to any one of the 1st to 13th aspects, wherein a portion of the end of the counter electrode current collector in the first direction protrudes in the first direction more than the counter electrode active material layer in the plan view.

[0039] 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, resulting in a less complex structure than when the electrical connection structure is formed on the main surface of the counter electrode current collector.

[0040] Furthermore, for example, a battery according to the 15th aspect of this disclosure is a battery according to any one of the 1st to 14th aspects, comprising a plurality of unit cells, wherein the plurality of unit cells are stacked.

[0041] As a result, the above-mentioned unit cells are stacked, making it possible to realize a highly reliable stacked battery.

[0042] The embodiments of this disclosure will be described below with reference to the drawings.

[0043] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit this disclosure. Furthermore, any components in the following embodiments that are not described in an independent claim will be described as optional components.

[0044] Furthermore, each figure is a schematic diagram and not necessarily a strictly accurate representation. Therefore, for example, the scale may not necessarily match in each figure. Also, in each figure, substantially identical components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0045] Furthermore, in this specification, terms indicating relationships between elements such as parallel or orthogonal, terms indicating the shape of elements such as rectangles or circles, and numerical ranges are not expressions that represent only strict meanings, but also expressions that include substantially equivalent ranges, such as differences of a few percent.

[0046] In this specification and in the drawings, the x, y, and z axes represent the three axes of a three-dimensional Cartesian coordinate system. The x and y axes are parallel to the main surface of the electrode current collector, and the z axis is perpendicular to the main surface of the electrode current collector. The x and y axes are parallel to the first side and the second side perpendicular to the first side of the rectangle, respectively, when the plan view shape of the battery is rectangular. The z axis is the stacking direction of the multiple unit cells contained in the battery. In this specification, the "stacking direction" coincides with the direction normal to the main surface of the current collector and the active material layer. In this specification, unless otherwise specified, "plan view" means a view from a direction perpendicular to the main surface of the electrode current collector.

[0047] Furthermore, unless otherwise specified in this specification, "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 in the protruding direction, the tip of element A protrudes more than the tip of element B, that is, the tip of element A is further from the center of the unit cell than the tip of element B. "Protruding direction" is considered to be the direction parallel to the main surface of the electrode current collector. Also, "protruding portion of element A" means a part of element A that protrudes more than the tip of element B in the protruding direction. Also, element B may be a part other than the protruding portion of element A. Elements are, for example, an active material layer, a solid electrolyte layer, an insulating layer, a current collector, etc.

[0048] Furthermore, in this specification, ordinal numbers such as "first," "second," etc., do not mean the number or order of components unless otherwise specified, but are used to avoid confusion and to distinguish similar components.

[0049] (Embodiment 1) [1. Structure] First, the configuration of the battery according to Embodiment 1 will be explained using Figures 1 and 2.

[0050] Figure 1 is a top view of the battery 1 according to this embodiment. Figure 2 is a cross-sectional view of the battery 1 according to this embodiment. Figure 3 is another cross-sectional view of the battery 1 according to this embodiment. Figure 1 shows the plan view shape of the battery 1 when viewed from the positive z-axis side. Figure 2 is a cross-sectional view at the position indicated by the line II-II in Figure 1. The line II-II is a hypothetical line parallel to the x-axis that does not pass through the protrusion 15 in the plan view. Figure 3 is a cross-sectional view at the position indicated by the line III-III in Figure 1. The line III-III is a hypothetical line parallel to the x-axis that passes through the protrusion 15 in the plan view. In Figure 1, the outline of the solid electrolyte layer 30 when viewed through the insulating member 90, and the outline of the counter electrode active material layer 40 when viewed through the counter electrode current collector 50 are shown by dashed lines.

[0051] As shown in Figures 1 to 3, the battery 1 according to this embodiment comprises a unit cell 60 having an electrode current collector 10, an electrode active material layer 20, a solid electrolyte layer 30, a counter electrode active material layer 40, a counter electrode current collector 50, and an insulating member 90. In the unit cell 60, the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 are stacked in this order along the z-axis. As shown in Figures 2 and 3, the battery 1 is formed from one unit cell 60. The battery 1 is, for example, an all-solid-state battery.

[0052] As shown in Figures 1 and 2, the unit cell 60 has sides 61 and 62 facing away from each other, and sides 63 and 64 facing away from each other. Side 61 is the side of the unit cell 60 in the direction of moving toward the positive x-axis. Side 62 is the side of the unit cell 60 in the direction of moving toward the negative x-axis. Side 63 is the side of the unit cell 60 in the direction of moving toward the positive y-axis. Side 64 is the side of the unit cell 60 in the direction of moving toward the negative y-axis.

[0053] Hereafter, the direction in which movement toward the positive side of the x-axis is referred to as the "positive x-axis direction." Also, hereafter, the direction in which movement toward the negative side of the x-axis is referred to as the "negative x-axis direction." Also, hereafter, the direction in which movement toward the positive side of the y-axis is referred to as the "positive y-axis direction." Also, hereafter, the direction in which movement toward the negative side of the y-axis is referred to as the "negative y-axis direction." The positive and negative x-axis directions and the positive and negative y-axis directions are orthogonal to each other. Furthermore, the positive and negative x-axis directions are opposite to each other, and the positive and negative y-axis directions are opposite to each other. In this specification, the positive x-axis direction is an example of a first direction, which is the direction from the center of the main surface 11 of the electrode current collector 10 toward the outer edge. Also, the negative x-axis direction is an example of a second direction, which is the direction from the center of the main surface 11 of the electrode current collector 10 toward the outer edge, and is different from the first direction. The second direction may be either the positive or negative y-axis direction.

[0054] In Figures 1 to 3, a first covered area 71, a second covered area 72, a first uncovered area 81, a second uncovered area 82, and a third uncovered area 83 are provided at the end of the unit cell 60 on the side surface 61 side. However, these areas may also be provided at the end of the unit cell 60 on the side surface 62, side surface 63, or side surface 64 side. Details of the first covered area 71, the second covered area 72, the first uncovered area 81, the second uncovered area 82, and the third uncovered area 83 will be described later.

[0055] The plan view shape of the battery 1 and unit cell 60 is rectangular, as shown in Figure 1. Here, "rectangular" means substantially rectangular. For example, if the approximate outer shape is rectangular, it may have shapes that protrude from parts of the sides of the rectangle, such as protrusions 15 and 55, and chamfered shapes may be formed on the corners of the rectangle. The general shape of the battery 1 and unit cell 60 is a flattened rectangular parallelepiped. Here, "flattened" means that the thickness is shorter than each side or the maximum width of the main surface. The side or maximum width of each side or the main surface of the battery 1 and unit cell 60 is, for example, 10 mm or more and 500 mm or less. The plan view shape of the battery 1 and unit cell 60 may be a polygon such as a square, hexagon or octagon, or it may be a circle or an ellipse. Note that in the drawings relating to this specification, the thickness of each layer is exaggerated in order to make the layer structure of the unit cell easier to understand. Furthermore, in the drawings relating to this specification, the lengths of the unit cells 60 in the first covered area 71, the second covered area 72, the first uncovered area 81, the second uncovered area 82, and the third uncovered area 83 are exaggerated in the positive x-axis direction as necessary in order to make the structure of the unit cells 60 in the first covered area 71, the second covered area 72, the first uncovered area 81, the second uncovered area 82, and the third uncovered area 83 easier to understand.

[0056] The sides 62, 63, and 64 of the unit cell 60 are composed of the respective sides of the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50, and at least a portion of them may be flat planes. If at least a portion of the sides 62, 63, and 64 are flat planes, then on this plane, at least the respective sides of the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 are flush with each other and located on the same flat plane. In other words, at the ends of the unit cell 60 in the negative x-axis direction, positive y-axis direction, and negative y-axis direction, the sides of the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 are flush. Furthermore, at the ends of the unit cell 60 in the negative x-axis direction, positive y-axis direction, and negative y-axis direction, the sides of the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 may be flush. As a result, at the ends of the unit cell 60 where the first coated region 71, second coated region 72, first uncoated region 81, second uncoated region 82, and third uncoated region 83 are not provided, there are no steps on the sides of each layer, no spaces that do not function as a battery due to steps are formed, and the effective volumetric energy density of the battery 1 is improved. In addition, since the sides of each layer can be made flush by cutting each layer together, the manufacturing of the battery 1 becomes easier.

[0057] Sides 62, 63, and 64 are, for example, cut surfaces. Specifically, side surfaces 62, 63, and 64 are surfaces formed by cutting with a blade such as a cutter, and are, for example, surfaces having cut marks such as fine grooves. Being cut surfaces makes it easy to make the side surfaces of each layer of the unit cell 60 flush. The cut marks may be smoothed by polishing or the like. The shape of the cut surfaces is not limited.

[0058] As shown in Figure 1, when the plan view shape of the unit cell 60 is rectangular, the sides 61, 62, 63, and 64 each constitute one side of the rectangle of the unit cell 60 in plan view.

[0059] Each unit cell 60 has one electrode current collector 10, one electrode active material layer 20, one solid electrolyte layer 30, one counter electrode active material layer 40, one counter electrode current collector 50, and one insulating member 90. In a plan view, the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 overlap.

[0060] The electrode current collector 10 is in contact with the electrode active material layer 20 on one main surface 11. The thickness of the electrode current collector 10 is, for example, 5 μm to 100 μm. In this specification, the thickness of the current collector and each layer is the length in the lamination direction, and unless otherwise specified, it is the average value of the total thickness.

[0061] Any known material can be used as the material for the electrode current collector 10. For example, the electrode current collector 10 may be made of a foil-like body, plate-like body, or mesh-like body made of copper, aluminum, nickel, iron, stainless steel, platinum or gold, or an alloy of two or more of these materials. In addition to the foil-like body, plate-like body, or mesh-like body, the electrode current collector 10 may also include a connecting layer, which is a layer containing a conductive material, provided in the portion that is in contact with the electrode active material layer 20.

[0062] The counter electrode current collector 50 is positioned on the side of the counter electrode active material layer 40 opposite to the solid electrolyte layer 30. The counter electrode current collector 50 is in contact with the upper surface of the counter electrode active material layer 40. The counter electrode current collector 50 faces the electrode current collector 10 via the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. The thickness of the counter electrode current collector 50 is, for example, 5 μm to 100 μm.

[0063] Known materials can be used as the material for the counter electrode current collector 50. For example, the counter electrode current collector 50 may be a foil-like, plate-like, or mesh-like body made of copper, aluminum, nickel, iron, stainless steel, platinum, or gold, or an alloy of two or more of these. In addition to the foil-like, plate-like, or mesh-like body, the counter electrode current collector 50 may also include a connecting layer, which is a layer containing a conductive material, provided in the portion in contact with the counter electrode active material layer 40.

[0064] The electrode active material layer 20 is located on one main surface 11 of the electrode current collector 10. The side of the electrode active material layer 20 opposite to the electrode current collector 10 is in contact with the solid electrolyte layer 30. The electrode active material layer 20 and the counter electrode active material layer 40 face each other with the solid electrolyte layer 30 in between. In a plan view, the area of ​​the electrode active material layer 20 is larger than the area of ​​the counter electrode active material layer 40. The thickness of the electrode active material layer 20 is, for example, between 5 μm and 300 μm. The material used for the electrode active material layer 20 will be described later.

[0065] The solid electrolyte layer 30 is located on the side of the electrode active material layer 20 opposite to the electrode current collector 10. The solid electrolyte layer 30 is situated between the electrode active material layer 20 and the counter electrode active material layer 40, and is in contact with both the electrode active material layer 20 and the counter electrode active material layer 40. The thickness of the solid electrolyte layer 30 is, for example, 5 μm to 150 μm. The material used for the solid electrolyte layer 30 will be described later.

[0066] The counter electrode active material layer 40 is located on the side of the solid electrolyte layer 30 opposite to the electrode active material layer 20. The counter electrode active material layer 40 is laminated on the solid electrolyte layer 30 and faces the electrode active material layer 20. The thickness of the counter electrode active material layer 40 is, for example, 5 μm to 300 μm. The material used for the counter electrode active material layer 40 will be described later.

[0067] The insulating member 90 covers the electrode active material layer 20 and the solid electrolyte layer 30 from the positive z-axis side. The insulating member 90 is in contact with the z-axis positive side surfaces of the electrode active material layer 20 and the solid electrolyte layer 30. The insulating member 90 is arranged in an elongated shape along the positive y-axis direction. In the example shown in Figure 1, the insulating member 90 covers the ends of the electrode active material layer 20 and the solid electrolyte layer 30 in the positive x-axis direction over the entire length in a direction perpendicular to the positive x-axis direction in a plan view.

[0068] The insulating member 90 is in contact with the x-positive side surface 31 of the solid electrolyte layer 30 and the x-positive side surface 41 of the counter electrode active material layer 40. This allows the insulating member 90 to suppress the collapse of the solid electrolyte layer 30 and the counter electrode active material layer 40 at the sides 31 and 41, thereby improving the reliability of the battery 1. However, the insulating member 90 does not necessarily have to be in contact with at least one of the x-positive side surface 31 of the solid electrolyte layer 30 and the x-positive side surface 41 of the counter electrode active material layer 40.

[0069] The height of the insulating member 90 from the main surface 11 (in other words, the distance from the main surface 11 to the surface of the insulating member 90 opposite to the electrode current collector 10) is the same as the height of the counter electrode active material layer 40 from the main surface 11 (in other words, the distance from the main surface 11 to the surface of the counter electrode active material layer 40 opposite to the electrode current collector 10). The surface of the insulating member 90 opposite to the electrode current collector 10 and the surface of the counter electrode active material layer 40 opposite to the electrode current collector 10 are flush.

[0070] Here, we will describe the materials used in the solid electrolyte layer 30, the electrode active material layer 20, the counter electrode active material layer 40, and the insulating member 90.

[0071] The solid electrolyte layer 30 is an example of an electrolyte layer containing an electrolyte material. The solid electrolyte layer 30 contains at least a solid electrolyte as the electrolyte material, and may optionally contain a binder material. The solid electrolyte layer 30 may contain a solid electrolyte having lithium ion conductivity. The electrolyte material contained in the solid electrolyte layer 30 is, for example, entirely a solid electrolyte, excluding unavoidable impurities. The electrolyte material used in the solid electrolyte layer 30 may further contain a non-aqueous electrolyte, a gel electrolyte, or an ionic liquid, as long as it mainly contains a solid electrolyte. The following describes the case where the electrolyte material contained in the solid electrolyte layer 30 is entirely a solid electrolyte.

[0072] As the solid electrolyte, known materials such as lithium ion conductors, sodium ion conductors, or magnesium ion conductors can be used. For the solid electrolyte, for example, solid electrolyte materials such as sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, polymer solid electrolytes, or complex hydride solid electrolytes are used.

[0073] In the case of materials capable of conducting lithium ions as the sulfide solid electrolyte, for example, Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 and the like can be used. To these, LiX, Li2O, MO q , Li p MO q and the like may be added. The element X in "LiX" is at least one selected from the group consisting of F, Cl, Br, and I. The element M in "MO q " and "Li p MO q " is at least one selected from the group consisting of P, Si, Ge, B, Al, Ga, In, Fe, and Zn. The p and q in "MO q " and "Li p MO q " are each independently natural numbers.

[0074] As the sulfide solid electrolyte, for example, Li2S-P2S5-based glass ceramics may be used. To Li2S-P2S5-based glass ceramics, LiX, Li2O, MO q , Li p MO q and the like may be added, and two or more selected from LiCl, LiBr, and LiI may be added. Since Li2S-P2S5-based glass ceramics are relatively soft materials, according to the battery 1 including Li2S-P2S5-based glass ceramics, a battery with high durability can be manufactured.

[0075] Examples of oxide solid electrolytes include NASICON-type solid electrolytes represented by LiTi2(PO4)3 and its elemental substitutions, (LaLi)TiO3-based perovskite-type solid electrolytes, and Li 14 ZnGe4O 16 , LISICON-type solid electrolytes such as Li4SiO4, LiGeO4 and their elemental substitutions, Li7La3Zr2O 12 Garnet-type solid electrolytes, such as those represented by elemental substitutions thereof, Li-BO compounds such as Li3PO4 and its N-substituted counterparts, LiBO2 and Li3BO3, with Li2SO4, Li2CO3, etc. added as a base, as well as glass ceramics, can be used.

[0076] Examples of solid halide electrolytes include Li3Y(Cl,Br,I)6, Li 2.7 Y 1.1 (Cl,Br,I)6, Li2Mg(F,Cl,Br,I)4, Li2Fe(F,Cl,Br,I)4, Li(Al,Ga,In)(F,Cl,Br,I)4, Li3(Al,Ga,In)(F,Cl,Br,I)6, Li3(Ca,Y,Gd)(Cl,Br,I)6, Li 2.7 (Ti,Al)F6, Li 2.5 (Ti,Al)F6, Li(Ta,Nb)O(F,Cl)4, etc., can be used. In this disclosure, when an element in a formula is represented as "(Al,Ga,In)", this notation indicates at least one element selected from the group of elements in 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.

[0077] As a polymeric 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. Polymeric compounds having an ethylene oxide structure can contain a large amount of lithium salt. Therefore, the ionic conductivity can be further improved. Examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), and LiC(SO2CF3)3. A single lithium salt may be used, or two or more may be used in combination.

[0078] Examples of complex hydride solid electrolytes that can be used include LiBH4-LiI and LiBH4-P2S5.

[0079] As the binder material, for example, elastomers such as styrene-based elastomers may be used, and organic compounds such as polyvinylidene fluoride, polytetrafluoroethylene, acrylic resin, or cellulose resin may also be used.

[0080] Styrene-based elastomers refer to elastomers that contain repeating units derived from styrene. These repeating units represent 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 styrene-derived repeating units in styrene-based elastomers is not particularly limited, but is, for example, between 5% and 70% by mass.

[0081] The styrene-based elastomer may be a block copolymer comprising 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 unsaturated bonds such as carbon-carbon double bonds. The block copolymer may have a triblock arrangement composed of two first blocks and one second block. The block copolymer may be an ABA-type triblock copolymer. In this triblock copolymer, block A corresponds to the first block and block B 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.

[0082] 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 also contain SBR or SEBS. A mixture containing two or more of these selected materials may be used as a binder material. Styrene-based elastomers are suitable as binder materials because of their excellent flexibility and elasticity.

[0083] Styrene-based elastomers may also be styrene-based triblock copolymers. 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.

[0084] Styrene-based elastomers may contain modifying groups. A modifying group refers to a functional group that chemically modifies all repeating units in the polymer chain, some repeating units in the polymer chain, or the terminal portion of the polymer chain.

[0085] The binder material may contain 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 contain only a styrene-based elastomer.

[0086] In this embodiment, one of the electrode active material layer 20 and the counter electrode active material layer 40 is the positive electrode active material layer, and the other is the negative electrode active material layer.

[0087] The positive electrode active material layer includes at least a positive electrode active material and may optionally include at least one of an electrolyte material such as a solid electrolyte, a conductive additive, and a binder material.

[0088] As the positive electrode active material, known materials capable of intercalating and releasing (inserting and deintercalating, or dissolving and precipitating) lithium ions, sodium ions, or magnesium ions may be used. Examples of positive electrode active materials that can release and insert lithium ions include transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic 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)O2, Li(NiCoMn)O2, and LiCoO2. Li(NiCoAl)O2 means that Ni, Co, and Al are contained in any ratio. Li(NiCoMn)O2 means that Ni, Co, and Mn are contained in any ratio.

[0089] As the solid electrolyte, the solid electrolyte materials exemplified above may be used. Furthermore, as the conductive material used as the conductive additive, conductive carbon such as acetylene black, carbon black, graphite, carbon fiber, vapor-deposited carbon, or carbon nanotubes may be used. Furthermore, as the binder material, the binder materials exemplified above may be used.

[0090] The negative electrode active material layer includes at least a negative electrode active material and may optionally include at least one of an electrolyte material such as a solid electrolyte, a conductive additive, and a binder material.

[0091] As the negative electrode active material, known materials capable of intercalating and releasing (inserting and deintercalating, or dissolving and precipitating) lithium ions, sodium ions, or magnesium ions may be used. Examples of negative electrode active materials that can release and insert lithium ions include carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, or resin-fired carbon, metallic lithium, lithium alloys, silicon (Si), tin (Sn), silicon compounds, tin compounds, or oxides of lithium with transition metal elements.

[0092] As the solid electrolyte, the solid electrolyte materials exemplified above may be used. Furthermore, as the conductive additive, the conductive materials exemplified above may be used. Furthermore, as the binder material, the binder materials exemplified above may be used.

[0093] The insulating member 90 includes one or more insulating materials having electronic insulating properties.

[0094] An insulating material is a material that exhibits electronic insulation properties, that is, a material with low electronic conductivity. An insulating material may also possess ionic insulation properties. Examples of insulating materials possessing both electronic and ionic insulation properties include metal oxides such as silicon dioxide, titanium dioxide, and aluminum oxide; minerals such as mica and marble; heat dissipation fillers such as boron nitride, aluminum nitride, and beryllium oxide; and resin particles such as latex particles and acrylic particles. Furthermore, resin materials such as silicone resin, epoxy resin, acrylic resin, or polyimide resin may be used as insulating materials possessing both electronic and ionic insulation properties.

[0095] Furthermore, the insulating member 90 may contain a solid electrolyte as an insulating material having electronic insulating properties. As the solid electrolyte, the solid electrolyte materials exemplified above may be used.

[0096] Furthermore, the insulating member 90 may contain a binder material as an insulating material having electronic and ionic insulating properties. The binder material may be one of the binder materials exemplified above. The binder material contained in the insulating member 90 may be the same as the binder material used in the electrode active material layer 20, or it may be a different binder material.

[0097] Furthermore, the insulating material contained in the insulating member 90 may also contain an active material that exhibits electronic insulating properties. Examples of active materials that exhibit electronic insulating properties include lithium iron phosphate, titanium oxide, lithium titanate, niobium titanium oxide, lithium vanadium oxide, and silicon.

[0098] The shape of the insulating material included in the insulating member 90 is not particularly limited. The shape of the insulating material may be needle-shaped, spherical, ellipsoidal, or the like. The shape of the insulating material may also be granular. Alternatively, the insulating member 90 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 granular insulating material is dispersed may be used.

[0099] The insulating member 90 may contain the same material as the solid electrolyte layer 30. Alternatively, the insulating member 90 may have the same material composition as the solid electrolyte layer 30. However, even if the insulating member 90 and the solid electrolyte layer 30 have the same material composition, an interface will be formed between the insulating member 90 and the solid electrolyte layer 30.

[0100] At least one selected from the group consisting of the electrode active material layer 20, the insulating member 90, and the solid electrolyte layer 30 may contain a sulfide solid electrolyte. The counter electrode active material layer 40 may also contain a sulfide solid electrolyte. Since sulfide solid electrolytes have excellent ionic conductivity, moldability, and insulating properties, they can provide high resistance to short circuits and high-efficiency production of the battery 1, as well as enabling higher output power of the battery 1.

[0101] Furthermore, at least one selected from the group consisting of the electrode active material layer 20, the insulating member 90, and the solid electrolyte layer 30 may contain a styrene-based elastomer. The counter electrode active material layer 40 may also contain a styrene-based elastomer. Because styrene-based elastomers have excellent flexibility and elasticity, the layer containing the styrene-based elastomer becomes less likely to collapse, further improving the battery 1's high resistance to short circuits.

[0102] Next, the end structure of the unit cell 60 will be described. Specifically, the end structure of the unit cell 60 in the positive x-axis direction will be described. An electrical connection structure to the outside, such as a terminal, is formed at the end of the unit cell 60 in the positive x-axis direction.

[0103] As shown in Figures 1 to 3, the electrode current collector 10 has a projection 15, which is a portion of the end of the electrode current collector 10 in the positive x-axis direction that protrudes more in the positive x-axis direction than other parts. The plan view shape of the projection 15 is, for example, an elongated rectangle. The projection 15 functions, for example, as a lead on which a terminal is formed. Another lead material may be joined to the projection 15.

[0104] The counter electrode current collector 50 has a protrusion 55, which is a portion of the end of the counter electrode current collector 50 in the positive x-axis direction that protrudes in the positive x-axis direction more than other portions. The shape of the protrusion 55 in plan view is, for example, an elongated rectangle. In plan view, the protrusion 55 protrudes in the positive x-axis direction more than the counter electrode active material layer 40 and the insulating member 90. The protrusion 55 functions, for example, as a lead on which a terminal is formed. Another lead material may be joined to the protrusion 55. Alternatively, the entire end of the counter electrode current collector 50 in the positive x-axis direction may protrude in the positive x-axis direction more than the counter electrode active material layer 40 and the insulating member 90 in plan view without the formation of a protrusion 55. The protrusion 55 faces the electrode current collector 10, the electrode active material layer 20 and the solid electrolyte layer 30 via the insulating member 90. The protrusion 15 and the protrusion 55 are positioned so as not to overlap in plan view.

[0105] Furthermore, as shown in Figures 1 to 3, in the unit cell 60, a first covered area 71, a second covered area 72, a first uncovered area 81, a second uncovered area 82, and a third uncovered area 83 are provided at the end in the positive x-axis direction (the end along the side surface 61 in the example shown in Figure 1).

[0106] Specifically, as shown in Figures 1 to 3, the end of the electrode active material layer 20 in the positive x-axis direction is provided with a first covering region 71, which, in a plan view, is not covered by the solid electrolyte layer 30 but is covered by the insulating member 90. The first covering region 71 is in contact with the insulating member 90. The first covering region 71 is not in contact with the solid electrolyte layer 30, the counter electrode active material layer 40, or the counter electrode current collector 50. Furthermore, the end of the solid electrolyte layer 30 in the positive x-axis direction is provided with a second covering region 72, which, in a plan view, is not covered by the counter electrode active material layer 40 but is covered by the insulating member 90. The second covering region 72 is in contact with the insulating member 90. The second covering region 72 is not in contact with the counter electrode active material layer 40 or the counter electrode current collector 50. The second covering region 72 is further away from the electrode current collector 10 than the first covering region 71. The first covering region 71 and the second covering region 72 are provided along the side surface 61 in a plan view. The first covering region 71 and the second covering region 72 are elongated in plan view, and in the example shown in Figure 1, the longitudinal direction is perpendicular to the positive x-axis direction (y-axis direction). Furthermore, the second covering region 72 and the first covering region 71 are arranged in this order along the positive x-axis direction in plan view.

[0107] The provision of the first covering region 71 and the second covering region 72 ensures that the ends of the electrode active material layer 20 and the solid electrolyte layer 30 in the positive x-axis direction are covered with the insulating member 90. This suppresses contact between the counter electrode active material layer 40 and the counter electrode current collector 50 and the electrode active material layer 20, thereby improving the battery 1's resistance to short circuits. Consequently, the reliability of the battery 1 can be enhanced.

[0108] Furthermore, the provision of the first covering region 71 prevents the end of the electrode active material layer 20 in the positive x-axis direction from being covered by the solid electrolyte layer 30, resulting in a shape where the electrode active material layer 20 protrudes further in the positive x-axis direction than the solid electrolyte layer 30. Additionally, the provision of the second covering region 72 prevents the end of the solid electrolyte layer 30 in the positive x-axis direction from being covered by the counter electrode active material layer 40, resulting in a shape where the solid electrolyte layer 30 protrudes further in the positive x-axis direction than the counter electrode active material layer 40. As a result, at the end of the unit cell 60 in the positive x-axis direction, the end of the solid electrolyte layer 30 is supported by the electrode active material layer 20, and the end of the counter electrode active material layer 40 is supported by the solid electrolyte layer 30. Consequently, collapse of the solid electrolyte layer 30 and the counter electrode active material layer 40 can be suppressed at the end of the unit cell 60 in the positive x-axis direction where electrical connection structures with the outside, such as the protruding portion 15 and the protruding portion 55, are formed. Furthermore, even if the positional accuracy of the solid electrolyte layer 30 and the counter electrode active material layer 40 is not high during formation, it is possible to suppress the solid electrolyte layer 30 and the counter electrode active material layer 40 from protruding from the lower layer. Therefore, it is easier to improve productivity while increasing the reliability of the battery 1.

[0109] As shown in Figures 1 to 3, the insulating member 90 has a first uncovered region 81 in plan view that is not covered by the counter electrode current collector 50. The first uncovered region 81 is further away from the electrode current collector 10 than the second covered region 72. The first uncovered region 81 is provided in the insulating member 90 at locations other than where a protrusion 55 is formed on the counter electrode current collector 50. In the example shown in Figures 1 to 3, in plan view, the end of the insulating member 90 in the negative x-axis direction is covered by the counter electrode current collector 50, but the insulating member 90 does not have to be covered by the counter electrode current collector 50. In other words, the side of the insulating member 90 opposite to the electrode current collector 10 side may be completely exposed. Furthermore, the first uncovered region 81 may also extend to the counter electrode active material layer 40. In other words, there may be a region at the end of the counter electrode active material layer 40 in the positive x-axis direction that is not covered by the counter electrode current collector 50.

[0110] The provision of the first uncovered region 81 prevents short circuits from occurring due to contact between the electrode current collector 10 and the portion of the counter electrode current collector 50 that protrudes from the insulating member 90, even if the positional accuracy of the counter electrode current collector 50 is not high during its formation. Therefore, it is easier to increase productivity while improving the reliability of the battery 1.

[0111] As shown in Figures 1 and 3, the end of the electrode current collector 10 in the positive x-axis direction is provided with a second uncovered region 82 in a plan view, which is not covered by the electrode active material layer 20 and the insulating member 90. The second uncovered region 82 is provided on the protruding portion 15 of the electrode current collector 10. The second uncovered region 82 is not in contact with the electrode active material layer 20, the insulating member 90, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50. By providing the second uncovered region 82, a part of the main surface 11 of the electrode current collector 10 is exposed, and an electrical connection structure such as a terminal can be easily formed on the electrode current collector 10 (specifically the protruding portion 15).

[0112] As shown in Figures 1 and 3, at the end of the electrode active material layer 20 in the positive x-axis direction, the electrode active material layer 20 covers a portion of the protrusion 15 in a plan view. In addition, a third uncovered region 83 is provided in the portion of the electrode active material layer 20 that covers the protrusion 15, which is not covered by the insulating member 90 in a plan view. Therefore, as shown in Figure 3, when viewing a cross-section of the unit cell 60 at the position of line III-III in Figure 1, which is the position passing through the protrusion 15 in a plan view, the electrode active material layer 20 protrudes further in the positive x-axis direction than the insulating member 90. This makes it possible to reduce the amount of insulating member 90 material used. In the example shown in Figures 1 and 3, the third uncovered region 83 is provided over the entire portion of the electrode active material layer 20 that covers the protrusion 15, but a portion of the portion of the electrode active material layer 20 that covers the protrusion 15 may be covered by the insulating member 90 in a plan view.

[0113] The first uncovered region 81, the third uncovered region 83, and the second uncovered region 82 are arranged in this order along the positive x-axis direction in a plan view.

[0114] As shown in Figures 1 and 2, when viewing a cross-section of the unit cell 60 at the position of line II-II in Figure 1, which is a position that does not pass through the protrusion 15 in a plan view, the x-axis positive side surface 21 of the electrode active material layer 20 and the x-axis positive side surface 91 of the insulating member 90 are aligned in the x-axis positive direction at the end of the unit cell 60 in the x-axis positive direction. In other words, in a position where the protrusion 15 is not formed in a plan view, the x-axis positive side surface 21 of the electrode active material layer 20 and the x-axis positive side surface 91 of the insulating member 90 are flush. As a result, there is no step between the side surface 21 and the side surface 91, no space is formed that would prevent the battery from functioning due to the step, and the effective volumetric energy density of the battery 1 is improved.

[0115] Furthermore, as shown in Figures 1 and 2, when viewing a cross-section of the unit cell 60 at the position of line II-II in Figure 1, which is a position that does not pass through the protrusion 15 in a plan view, the x-axis positive side surface 21 of the electrode active material layer 20 and the x-axis positive side surface 13 of the electrode current collector 10 are aligned in the x-axis positive direction at the end of the unit cell 60 in the x-axis positive direction. In other words, in the position where the protrusion 15 is not formed in a plan view, the x-axis positive side surface 21 of the electrode active material layer 20 and the x-axis positive side surface 13 of the electrode current collector 10 are flush. As a result, there is no step between the side surface 21 and the side surface 13, no space is formed that does not function as a battery due to a step, and the effective volumetric energy density of the battery 1 is improved. In addition, since the electrode active material layer 20 is laminated to the end of the electrode current collector 10 in the x-axis positive direction, the area of ​​the electrode active material layer 20 can be increased, and the volumetric energy density of the battery 1 is improved.

[0116] Furthermore, although not shown in the figure, the unit cell 60 may have an insulating tape or insulating resin covering at least a portion of the counter electrode active material layer 40, insulating member 90, electrode active material layer 20, and electrode current collector 10 at its end in the positive x-axis direction. This suppresses the collapse of the portions of the counter electrode active material layer 40, insulating member 90, and electrode active material layer 20 that are covered with insulating tape or insulating resin.

[0117] The length of the second uncovered region 82 is, for example, 1 mm to 20 mm. This makes it possible to increase the energy density of the battery 1 while ensuring a region in which electrical connection structures such as terminals can be easily formed on the electrode current collector 10.

[0118] The lengths of the first covered area 71, the second covered area 72, the first uncovered area 81, and the third uncovered area 83 in the positive x-axis direction in a plan view are, for example, 0.1 mm to 5 mm. This enhances the effect of providing the first covered area 71, the second covered area 72, the first uncovered area 81, and the third uncovered area 83 as described above, and also increases the energy density of the battery 1. The lengths of the first covered area 71, the second covered area 72, the first uncovered area 81, and the third uncovered area 83 in the positive x-axis direction in a plan view may be 0.5 mm to 2 mm.

[0119] The lengths of the first covered region 71, the second covered region 72, the first uncovered region 81, and the third uncovered region 83 in the direction of the positive x-axis in a plan view may be the same as those of each other, or at least one of them may be different.

[0120] In this embodiment, the electrode active material layer 20 may be the negative electrode active material layer, and the counter electrode active material layer 40 may be the positive electrode active material layer. In this embodiment, since the electrode active material layer 20 is larger than the counter electrode active material layer 40, metal ions are more easily incorporated into the electrode active material layer 20, which is the negative electrode active material layer, suppressing the deposition of metal derived from metal ions, making internal short circuits less likely to occur, and further improving the battery 1's resistance to short circuits.

[0121] The above configuration of battery 1 enhances its resistance to short circuits and improves its reliability. Furthermore, it increases the productivity of battery 1.

[0122] [2. Variant] The following describes a modified battery according to this embodiment. In the following description of the modified examples, the differences between Embodiment 1 and each modified example will be the main focus, and the commonalities will be omitted or simplified.

[0123] [2-1. Variation 1] First, a modified example of the battery according to Embodiment 1 will be described. Figure 4 is a top view of the battery 101 according to this modified example. Figure 5 is a cross-sectional view of the battery 101 according to this modified example. Figure 4 shows the plan view shape of the battery 101 when viewed from the positive z-axis side. Figure 5 is a cross-sectional view at the position indicated by the VV line in Figure 4. The VV line is a hypothetical line parallel to the x-axis passing through the protruding portion 15 in the plan view. In Figure 4, the outlines of the electrode active material layer 20 and the solid electrolyte layer 30 when viewed through the insulating member 90, and the outline of the counter electrode active material layer 40 when viewed through the counter electrode current collector 50 are shown by dashed lines.

[0124] As shown in Figures 4 and 5, the battery 101 comprises a unit cell 160, and is formed from one unit cell 160. The unit cell 160 differs from the unit cell 60 according to Embodiment 1 in that the electrode active material layer 20 does not have a third uncoated region 83, and the protruding portion 15 of the electrode current collector 10 has a third coated region 73. Note that the cross-sectional structure of the unit cell 160 along a hypothetical line parallel to the x-axis that does not pass through the protruding portion 15 in a plan view is the same as that of the unit cell 60, and is the structure shown in Figure 2.

[0125] In the unit cell 160, the protruding portion 15 is provided with a third covered area 73 that, in a plan view, is not covered by the electrode active material layer 20 but is covered by the insulating member 90. The third covered area 73 is in contact with the insulating member 90. In the unit cell 160, a second uncovered area 82 is located on the positive x-axis side of the third covered area 73.

[0126] In the battery 101, the provision of the third covering region 73 ensures that the electrode active material layer 20 is covered by the insulating member 90 from the positive x-axis side at the location where the protrusion 15 is formed. This suppresses the collapse of the end of the electrode active material layer 20 in the positive x-axis direction, thereby improving the reliability of the battery 101.

[0127] The length of the third covering region 73 in the positive x-axis direction in a plan view is, for example, 0.1 mm or more and 5 mm or less. This enhances the effect of providing the third covering region 73 as described above, and also increases the energy density of the battery 101. The lengths of the third covering region 73 in the positive x-axis direction in a plan view may be 0.5 mm or more and 2 mm or less.

[0128] The lengths of the first covered region 71, the second covered region 72, the third covered region 73, and the first uncovered region 81 in the positive x-axis direction in a plan view may be the same as those of each other, or at least one of them may be different. Furthermore, the length of the first covered region 71 in the positive x-axis direction in a plan view may be longer than the length of the third covered region 73 in the positive x-axis direction in a plan view.

[0129] Furthermore, in the battery 101, even at the end of the portion of the electrode current collector 10 in the positive x-axis direction where the protruding portion 15 is not formed, a third covering region 73 may be provided that is not covered by the electrode active material layer 20 but is covered by the insulating member 90. Also, in Figures 4 and 5, in a plan view, a part of the electrode active material layer 20 is positioned at a location overlapping with the protruding portion 15, but the electrode active material layer 20 does not necessarily have to be positioned at a location overlapping with the protruding portion 15.

[0130] [2-2. Variation 2] Next, a battery according to a modification 2 of Embodiment 1 will be described. Figure 6 is a cross-sectional view of the battery 201 according to this modification. Figure 7 is another cross-sectional view of the battery 201 according to this modification. The top view of the battery 201 according to this modification is the same as in Figure 1. Figure 6 is a cross-sectional view of the battery 201 at a position corresponding to line II-II in Figure 1, that is, at a position parallel to the x-axis that does not pass through the protrusion 15 in a plan view. Figure 7 is a cross-sectional view of the battery 201 at a position corresponding to line III-III in Figure 1, that is, at a position parallel to the x-axis that passes through the protrusion 15 in a plan view.

[0131] As shown in Figures 6 and 7, the battery 201 comprises a unit cell 260, and is formed from one unit cell 260. The unit cell 260 differs from the unit cell 60 according to Embodiment 1 in that it has two of each of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, counter electrode current collector 50, and insulating member 90.

[0132] As shown in Figures 6 and 7, the two electrode active material layers 20 are located on both main surfaces 11 and 12 of the electrode current collector 10, respectively. The two solid electrolyte layers 30 are located on the opposite side of each of the two electrode active material layers 20 from the electrode current collector 10. The two counter electrode active material layers 40 are located on the opposite side of each of the two solid electrolyte layers 30 from the electrode active material layers 20. The two counter electrode current collectors 50 are located on the opposite side of each of the two counter electrode active material layers 40 from the solid electrolyte layer 30. One of the two insulating members 90 covers the electrode active material layer 20 and solid electrolyte layer 30 located on the main surface 11 side of the electrode current collector 10, from the positive z-axis side. The other of the two insulating members 90 covers the electrode active material layer 20 and solid electrolyte layer 30 located on the main surface 12 side of the electrode current collector 10, from the negative z-axis side.

[0133] Furthermore, at the ends of each of the two electrode active material layers 20 in the positive x-axis direction, a first covered area 71 is provided, in a plan view, which is not covered by the solid electrolyte layer 30 but is covered by the insulating member 90. Also, at the ends of each of the two solid electrolyte layers 30 in the positive x-axis direction, a second covered area 72 is provided, in a plan view, which is not covered by the counter electrode active material layer 40 but is covered by the insulating member 90. Furthermore, at each of the two insulating members 90, a first uncovered area 81 is provided, in a plan view, which is not covered by the counter electrode current collector 50. Also, at the ends of each of the two electrode current collectors 10 in the positive x-axis direction, a second uncovered area 82 is provided, in a plan view, which is not covered by the electrode active material layer 20 and the insulating member 90. Furthermore, at the portions of each of the two electrode active material layers 20 that cover a part of the protruding portion 15, a third uncovered area 83 is provided, in a plan view, which is not covered by the insulating member 90.

[0134] Thus, in the unit cell 260, a structure similar to the laminated structure of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, counter electrode current collector 50, and insulating member 90 formed on the main surface 11 of the electrode current collector 10 of the unit cell 60 is formed on the main surface 12 facing away from the main surface 11 of the electrode current collector 10, but with the top and bottom reversed. Therefore, the unit cell 260 has a symmetrical structure with respect to the electrode current collector 10.

[0135] This makes it possible to extract current from two electrode active material layers 20 from one electrode current collector 10, thereby increasing the volumetric energy density. In addition, since the first coating region 71 and the second coating region 72 are provided on both sides of the electrode current collector 10 in the stacking direction, reliability can also be improved. Furthermore, since the stacked structure of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 is formed on both main surfaces 11 and 12 of the electrode current collector 10, when the unit cell 260 is densified by pressing or the like, differences in stress generated on both sides of the electrode current collector 10 in the stacking direction are less likely to occur, and warping of the unit cell 260 can be suppressed. Moreover, even when the battery 201 is in use, even if stress is generated due to the expansion and contraction of the electrode active material layer 20 and the counter electrode active material layer 40, differences in stress generated on both sides of the electrode current collector 10 in the stacking direction are less likely to occur, and warping of the unit cell 260 can be suppressed.

[0136] In the case of unit cell 260, the laminated structure formed on the main surface 11 of unit cell 60 is also formed on the main surface 12. However, the laminated structure formed on the main surface 11 of unit cell 160 according to the modified example 1 of Embodiment 1 may also be formed on the main surface 12.

[0137] [3. Manufacturing method] Next, the manufacturing methods for batteries according to this embodiment and its various modifications will be described. The following description will focus on the manufacturing method for battery 201 according to Modification 2 of Embodiment 1, but other batteries can also be manufactured by appropriately applying the following manufacturing methods. Figure 8 is a flowchart showing the manufacturing method for battery 201 according to Modification 2 of Embodiment 1. Note that the manufacturing method for battery 201 described below is just one example, and the manufacturing method for battery 201 is not limited to the following example.

[0138] First, in the manufacturing method of the battery 201, an electrode current collector 10 without a protruding portion 15 is prepared (step S11). Next, an electrode active material layer 20 is laminated on both main surfaces 11 and 12 of the electrode current collector 10 (step S12). At this time, the electrode active material layer 20 is laminated on the main surfaces 11 and 12 such that a second uncovered region 82 not covered by the electrode active material layer 20 is provided at the ends of the main surfaces 11 and 12 in the positive x-axis direction. Note that when manufacturing a battery such as battery 1 in which the electrode active material layer 20 is not laminated on the main surface 12 side, the electrode active material layer 20 is laminated only on the main surface 11.

[0139] Next, the solid electrolyte layer 30 is laminated on the electrode active material layer 20 on the side opposite to the electrode current collector 10 (step S13). At this time, the solid electrolyte layer 30 is laminated on the electrode active material layer 20 such that, in a plan view, there is a region at the end of the electrode active material layer 20 in the positive x-axis direction that is not covered by the solid electrolyte layer 30. This region is the region before the first covering region 71 is covered by the insulating member 90. As a result, even if the formation position of the solid electrolyte layer 30 is slightly off, it will not protrude from the electrode active material layer 20, and the solid electrolyte layer 30 can be formed efficiently without excessively increasing the positional accuracy of the solid electrolyte layer 30.

[0140] Next, the counter electrode active material layer 40 is laminated on the solid electrolyte layer 30 on the side opposite to the electrode active material layer 20 (step S14). At this time, the counter electrode active material layer 40 is laminated on the solid electrolyte layer 30 such that, in a plan view, there is a region at the end of the solid electrolyte layer 30 in the positive x-axis direction that is not covered by the counter electrode active material layer 40. This region is the region before the second covering region 72 is covered by the insulating member 90. As a result, even if the formation position of the counter electrode active material layer 40 is slightly off, it will not protrude from the solid electrolyte layer 30, and the counter electrode active material layer 40 can be formed efficiently without excessively increasing the positional accuracy of the counter electrode active material layer 40.

[0141] Next, an insulating member 90 is formed to cover the electrode active material layer 20 and the solid electrolyte layer 30 (step S15). At this time, the area of ​​the first covered region 71 before it is covered by the insulating member 90 and the area of ​​the second covered region 72 before it is covered by the insulating member 90 are covered with the insulating member 90. In addition, the insulating member 90 is formed such that, in a plan view, a third uncovered region 83 is provided at the end of the electrode active material layer 20 in the positive x-axis direction, which is not covered by the insulating member 90. When manufacturing the battery 101, the insulating member 90 is formed such that it covers a part of the electrode current collector 10, providing the third covered region 73. Step S15 may be performed after step S14 or simultaneously with step S14.

[0142] When laminating the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, and when forming the insulating member 90, a high-pressure press treatment (step S16) is performed after each step from step S12 to step S15 as necessary. As a result, a laminated electrode plate is obtained in which the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material 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, and the insulating member 90 is formed.

[0143] The electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the insulating member 90 are each formed sequentially, for example, using a wet coating method. By using a wet coating method, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the insulating member 90 can be easily formed. As a wet coating method, coating methods such as die coating, doctor blade coating, roll coating, screen printing, or inkjet coating can be used, but are not limited to these methods.

[0144] When using a wet coating method, a coating step is performed in which the materials and solvents for forming the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the insulating member 90 are appropriately mixed to obtain a slurry. Instead of the slurry, a liquid resin material may be prepared as the material for the insulating member 90.

[0145] The solvent used in the paint formulation process may be a known solvent used in the manufacture of known solid-state batteries (for example, lithium-ion solid-state batteries).

[0146] The slurry of each layer obtained in the coating process is applied to both main surfaces 11 and 12 of the electrode current collector 10 in the order of electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and insulating member 90. In this case, the next layer may be applied after the coating of the previously applied layer is completed, or the coating of the next layer may be started while the coating of the previously applied layer is in progress. In other words, steps S12, S13, S14, and S15 may be performed in part simultaneously. Furthermore, the counter electrode active material layer 40 and the insulating member 90 may be coated simultaneously. In this case, for example, the counter electrode active material layer 40 and the insulating member 90 are coated simultaneously by using a die capable of dispensing two types of slurry. The coating direction in this case is perpendicular to the direction in which the counter electrode active material layer 40 and the insulating member 90 are aligned.

[0147] The slurry for each layer and insulating member 90 is applied sequentially, and after all layers and insulating members 90 have been applied, a high-pressure press treatment (step S16) is performed to promote the filling of the material in each layer and insulating member 90. The high-pressure press treatment may also be performed after each layer and insulating member 90 has been applied. For example, the high-pressure press treatment may be performed after each application of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and insulating member 90, or it may be performed all at once after all four have been applied. If the high-pressure press treatment is performed two or more times, the pressure of the final high-pressure press treatment may be set to be the highest. For example, a roll press, flat plate press, or isostatic press (ISP) can be used for the high-pressure press treatment.

[0148] Furthermore, when using a wet coating method, a heat treatment is performed to remove the solvent before the high-pressure pressing process. The heat treatment is performed, for example, after each coating of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and insulating member 90, but it may also be performed all at once after the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and insulating member 90 have been laminated. Note that at least one of the heat treatment and high-pressure pressing process may be omitted.

[0149] By laminating each layer using this coating method, the bonding properties and interfacial resistance of each interface between the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 can be improved. Furthermore, the bonding properties and grain boundary resistance of the powder materials used in the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 can be improved. In other words, good interfaces are formed between each layer of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, and between the powder materials within each layer.

[0150] Steps S12 to S16 described above may be carried out in a series of continuous processes, such as a roll-to-roll method.

[0151] Furthermore, the laminated electrode plate may be of a size in plan view corresponding to one battery 201, or it may be of a size in plan view that allows it to be pieced and used for multiple batteries 201. Figure 9 is a top view showing an example of a laminated electrode plate 65. As shown in Figure 9, the laminated electrode plate 65 has a first coated area 71, a second coated area 72, a second uncoated area 82, and a third uncoated area 83 at both the positive and negative ends of the x-axis. The laminated electrode plate 65 also has two of each of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and insulating member 90, and the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and insulating member 90 are arranged on both sides of the electrode current collector 10 in the stacking direction. In Figure 9, the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and insulating member 90 arranged on one side (the positive side of the z-axis) of the electrode current collector 10 in the stacking direction are shown.

[0152] The battery 201 can also be manufactured by using such laminated electrode plates 65 and proceeding with the manufacturing process of the battery 201, and then separating the laminated electrode plates 65 into individual pieces in the shape of a single battery 201 at any stage before the completion of the battery 201. This can increase manufacturing efficiency. For example, the laminated electrode plate 65 can be separated into individual pieces by cutting it along the y-axis direction at least in the center of the x-axis direction. Alternatively, this separation may be performed by cutting in step S19, which will be described later. Furthermore, after separating the laminated electrode plates 65 into individual pieces, polishing or the like may be performed to adjust the size.

[0153] Next, a protrusion 15 is formed on the electrode current collector 10 (step S17). The protrusion 15 is formed, for example, by cutting away the second uncoated region 82 and the third uncoated region 83 in the parts other than the protrusion 15. As a result, in the position where the protrusion 15 is not formed in a plan view, the positions of the side surface 21 of the electrode active material layer 20 and the side surface 91 of the insulating member 90 are aligned in the positive x-axis direction. In the cutting process, a part of the area where the insulating member 90 is placed may also be cut away in a plan view.

[0154] The removal process may involve cutting tools such as cutters, slitters, cutting machines, or die-cutting machines incorporating Thomson blades, as well as lasers or jets, but is not limited to these methods. Alternatively, a foil or the like having the shape of the protrusion 15, prepared separately, may be joined to the electrode current collector 10. This joining may involve ultrasonic welding, resistance welding, or crimping, but is not limited to these methods. The formation of the protrusion 15 may be performed at any stage in the manufacturing of the battery 201. Furthermore, in step S11, an electrode current collector 10 with the protrusion 15 already formed may be prepared.

[0155] Next, the counter electrode current collector 50 is laminated on the side of the counter electrode active material layer 40 opposite to the solid electrolyte layer 30 (step S18). As a result, the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 are laminated in this order on both main surfaces 11 and 12 of the electrode current collector 10, and a laminate (unit cell 260) with an insulating member 90 is obtained. At this time, the counter electrode current collector 50 is laminated on the counter electrode active material layer 40 such that, in a plan view, a first uncovered region 81 is provided in the insulating member 90 that is not covered by the counter electrode current collector 50. At this time, the counter electrode active material layer 40 and the counter electrode current collector 50 are joined by, for example, a high-pressure press treatment. Alternatively, the joining may be performed by using a counter electrode current collector 50 having a connecting layer containing an adhesive binder, by coating with an adhesive, or by laminating an adhesive film. The joining method is not limited to these methods. Furthermore, heat treatment may be performed during or after the joining process.

[0156] The counter electrode current collector 50 may be molded to the desired dimensions before lamination, or it may be partially removed after lamination. Furthermore, the protrusion 55 may be formed after lamination.

[0157] Next, the unit cell 260 obtained in step S18 is cut along a direction intersecting the main surface 11 to form cut surfaces as sides 62, 63, and 64 at the ends of the unit cell 260 in the negative x-axis direction, positive y-axis direction, and negative y-axis direction (step S19). This cutting creates three sides that constitute the ends of the unit cell 260 in the negative x-axis direction, positive y-axis direction, and negative y-axis direction, which are different from the ends where the first covered area 71, second covered area 72, first uncovered area 81, second uncovered area 82, and third uncovered area 83 are provided, in a plan view. Cutting can be performed using cutting tools such as cutters, ultrasonic cutters, slitters, dicers, cutting machines, punching machines incorporating Thomson blades, lasers, or jets, but is not limited to these methods. In addition, to suppress short circuits, the sides 62, 63, and 64 may be polished after cutting to remove burrs and other debris.

[0158] In step S19, the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 are cut together along a direction intersecting the main surface 11. Depending on the cutting position, the insulating member 90 may also be cut together. The direction intersecting the main surface 11 is specifically the direction perpendicular to the main surface 11, and can also be said to be the stacking direction of the unit cell 260. As a result, there is no need to stack the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 in their cut shapes, making it easy to manufacture the battery 201. In addition, the areas where the first coated area 71, second coated area 72, first uncoated area 81, second uncoated area 82, and third uncoated area 83 are provided remain uncut, making it possible to form electrical connection structures such as terminals in a structure that can suppress the occurrence of short circuits. Furthermore, since the capacity of the battery 201 can be adjusted by changing the position where the unit cell 260 is cut, the capacity accuracy can be improved.

[0159] At the cut surface, the sides of the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 are exposed. After cutting, sealing members or the like may be placed to cover these exposed sides in order to protect them. In other words, if these sides are covered with sealing members or other materials, the exposed sides may also be covered by the other materials.

[0160] Through the steps described above, a battery 201 composed of one unit cell 260 is obtained. The above manufacturing method makes it possible to manufacture a battery 201 with high resistance to short circuits with high efficiency. The obtained battery 201 may be housed in an outer casing or the like. When the battery 201 is housed in an outer casing, the protrusions 15 and 55 are extended to the outside of the outer casing. In addition, the obtained battery 201 may be subjected to a process to remove the corners (intersections of the sides) in a plan view by cutting or the like.

[0161] Steps S18 and S19 may be performed in any order. In this case, first, after step S17, in step S19, the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 are laminated together to form a laminate (laminated electrode plate) on which an insulating member 90 is formed. This laminate is then 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, positive y-axis direction, and negative y-axis direction. When the laminated electrode plate 65 is used in the manufacture of the battery 201, the laminated electrode plate 65 is cut into individual pieces before the counter electrode current collector 50 is laminated onto it. At this time, the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 are cut together along a direction intersecting the main surface 11. As a result, there is no need to stack the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 in their cut shapes, making it easy to manufacture the battery 201. Then, in step S18, a counter electrode current collector 50, shaped according to the shape of the stacked electrode plate after the cut surface is formed, is stacked on the side of the counter electrode active material layer 40 opposite to the solid electrolyte layer 30. This results in a battery 201 consisting of one unit cell 260.

[0162] (Embodiment 2) Next, Embodiment 2 will be described. Embodiment 2 describes a stacked battery in which multiple unit cells are stacked. In the following description, the differences from Embodiment 1 and its various modifications will be the main focus, and the explanation of common points will be omitted or simplified as appropriate.

[0163] [1. Structure] First, the configuration of the battery according to Embodiment 2 will be described with reference to the drawings. Figure 10 is a cross-sectional view of the battery 301 according to this embodiment. As shown in Figure 10, the battery 301 has a plurality of unit cells 260 according to Modification 2 of Embodiment 1, and has a structure in which the plurality of unit cells 260 are stacked. In the battery 301, since the above-mentioned unit cells 260 are stacked, it is possible to realize a battery 301 that can achieve both high resistance to short circuits and high-efficiency productivity.

[0164] Multiple unit cells 260 have the same configuration and are stacked so that they can be electrically connected in parallel. The electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40, which are stacked on the main surfaces on both sides of each current collector, are stacked in the same order from the current collector. Furthermore, the multiple unit cells 260 are stacked so that the positions of each side of the unit cell 260 coincide when viewed from the stacking direction. Therefore, the sides of each of the multiple unit cells 260 in the negative x-axis direction, positive y-axis direction, and negative y-axis direction are flush. Also, in the multiple unit cells 260, the protrusions 55 and 15 protrude in the same direction, specifically in the positive x-axis direction. The protrusions 55 of each of the multiple unit cells 260 and the protrusions 15 of each of the multiple unit cells 260 may be bundled together and joined by welding or the like.

[0165] In the example shown in Figure 10, the number of stacked unit cells 260 is 3, but it may be 2, or 4 or more.

[0166] In the example shown in Figure 10, two adjacent unit cells 260 share a counter electrode current collector 50. Alternatively, two adjacent unit cells 260 may each have their own separate counter electrode current collector 50, with two counter electrode current collectors 50 overlapping between the counter electrode active material layers 40. In this case, a conductive adhesive layer may be provided between the two counter electrode current collectors 50.

[0167] In the stacked battery according to this embodiment, instead of unit cell 260, a unit cell other than unit cell 260, as described above in Embodiment 1 or Modification 1 of Embodiment 1, may be used as the unit cell to be stacked. Even when unit cells other than unit cell 260 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 a unit cell such as unit cell 60, in which the electrode active material layer 20 etc. is stacked on only one main surface 11 of the electrode current collector 10, is stacked, the unit cells may be stacked so as to be electrically connected in series. In addition, the multiple unit cells may include unit cells with different configurations from each other. Furthermore, the multiple unit cells may include unit cells with different configurations from the unit cells according to Embodiment 1 and each of its modifications.

[0168] [2. Manufacturing method] Next, the manufacturing method of the battery according to this embodiment will be described. The following description will focus on the manufacturing method of a battery 301 in which a plurality of unit cells 260 are stacked, but batteries in which unit cells other than the unit cells 260 described above in Embodiment 1 and each of its modifications are stacked can also be manufactured by appropriately applying the following manufacturing method. Figure 11 is a flowchart showing the manufacturing method of a battery 301 according to Embodiment 2. Note that the manufacturing method of the battery 301 described below is just one example, and the manufacturing method of the battery 301 is not limited to the following example.

[0169] First, in steps S21 to S27 shown in Figure 11, the same number of laminated electrode plates as the number of unit cells 260 in the battery 301 are formed in the same manner as in steps S11 to S17 shown and explained in Figure 8. The laminated electrode plates may be large laminated electrode plates 65 as shown in Figure 9, or laminated electrode plates formed to correspond to the size of the unit cells 260. Steps S21 to S27 may be omitted, and the same number of laminated electrode plates as the number of unit cells 260 in the battery 301 may be prepared in advance.

[0170] Next, a counter electrode current collector 50 is laminated on the side of the counter electrode active material layer 40 opposite to the solid electrolyte layer 30, and multiple unit cells 260 are laminated at the same time (steps S28 and S29). For example, by alternately laminating the counter electrode current collector 50 and the laminated electrode plate obtained up to step S27, the counter electrode current collector 50 is shared by adjacent unit cells 260, and the lamination of the counter electrode current collector 50 on the counter electrode active material layer 40 and the lamination of multiple unit cells 260 are carried out. Alternatively, by laminating the counter electrode current collector 50 on only one of the two counter electrode active material layers 40 of the laminated electrode plate, a unit cell with a structure in which one counter electrode current collector 50 is omitted from the unit cell 260 is formed, and this unit cell is laminated. By laminating this unit cell so that the counter electrode current collector 50 is sandwiched between the counter electrode active material layers 40, the counter electrode current collector 50 is also shared by adjacent unit cells 260. In this case, after stacking the required number of unit cells, the counter electrode current collector 50 is stacked on the counter electrode active material layer 40 at the end of the stacking direction, where the counter electrode current collector 50 is not stacked.

[0171] During these lamination processes, the counter electrode active material layer 40 and the counter electrode current collector 50 may be joined by high-pressure pressing or the like, similar to step S18. This joining may be performed at an intermediate stage in the lamination of the counter electrode current collector 50 and the laminated electrode plates, or it may be performed all at once after all the counter electrode current collectors 50 and laminated electrode plates have been laminated. If the joining is performed all at once, for example, all of the multiple counter electrode current collectors 50 and multiple laminated electrode plates are laminated and then pressed all at once after lamination.

[0172] Furthermore, similar to step S18, the counter electrode current collector 50 may be molded to the desired dimensions before lamination, or a portion may be removed after lamination. Also, the protrusion 55 may be formed after lamination.

[0173] Furthermore, when manufacturing a battery 301 in which two adjacent unit cells 260 do not share a counter electrode current collector 50, but instead have two counter electrode current collectors 50 stacked between the counter electrode active material layers 40, step S28 is performed in the same way as step S18 above to obtain a laminate (unit cell 260) in which the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 are laminated in this order on both main surfaces 11 and 12 of the electrode current collector 10, and an insulating member 90 is formed. Then, in step S29, the obtained unit cells 260 are laminated. At this time, the unit cells 260 are joined together by a conductive adhesive layer formed by coating with an adhesive or laminating an adhesive film. However, the joining method is not limited to these methods. Also, heat treatment and pressing may be performed after joining. For example, all of the multiple counter electrode current collectors 50 and multiple laminated electrode plates may be laminated by laminating the unit cells 260, and then pressed all at once after lamination.

[0174] Next, the stack of multiple unit cells 260 obtained in step S29 is cut along a direction intersecting the main surface 11 to form cut surfaces as sides 62, 63, and 64 at the respective ends of the multiple unit cells 260 in the negative x-axis direction, positive y-axis direction, and negative y-axis direction (step S30). This cutting creates three sides that, in a plan view, constitute ends of the multiple unit cells 260 that are different from the ends where the first covered area 71, second covered area 72, first uncovered area 81, second uncovered area 82, and third uncovered area 83 are provided. The cutting method can be the same as in step S19 described above. In step S30, all of the multiple unit cells 260 are cut together along a direction intersecting the main surface 11. As a result, there is no need to stack the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 of each of the multiple unit cells 260 in their cut shapes, making it easy to manufacture the battery 301. In addition, since the areas where the first coated area 71, second coated area 72, first uncoated area 81, second uncoated area 82, and third uncoated area 83 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.

[0175] At the cut surface, the sides of each of the electrode current collectors 10, electrode active material layers 20, solid electrolyte layers 30, counter electrode active material layers 40, and counter electrode current collectors 50 of the multiple unit cells 260 are exposed. After cutting, sealing members or the like may be placed to cover these exposed sides in order to protect them. In other words, if these sides are covered with sealing members or other materials, the exposed sides may also be covered by the other materials.

[0176] Through the steps described above, a battery 301 having a structure in which multiple unit cells 260 are stacked is obtained. The obtained battery 301 may be housed in an outer casing or the like. When the battery 301 is housed in an outer casing, the protrusions 15 and 55 are pulled out to the outside of the outer casing. In addition, the obtained battery 301 may be subjected to a process to remove the corners (intersections of the sides) in a plan view by cutting or the like.

[0177] Note that the formation of the cut surface in step S30 may be performed before step S29. For example, step S30 may be performed after step S27 and before step S28. In this case, the battery 301 is obtained by stacking the unit cells on which the cut surfaces have been formed in step S29.

[0178] Furthermore, the laminated electrode plates and counter electrode current collectors 50 stacked in steps S28 and S29 are not limited to configurations corresponding to a plurality of unit cells 260, but may also be laminated electrode plates and counter electrode current collectors having configurations appropriate to the battery being manufactured. For example, the laminated electrode plates and counter electrode current collectors used in steps S28 and S29 may have configurations corresponding to unit cells other than the unit cell 260 described above in Embodiment 1 and each of its modifications.

[0179] (Other embodiments) The battery and battery manufacturing method described above have been explained based on embodiments, but this disclosure is not limited to these embodiments. Within the scope of this disclosure, various modifications to the embodiments that a person skilled in the art could conceive, as long as they do not deviate from the spirit of this disclosure, and other forms constructed by combining some of the components of the embodiments, are also included.

[0180] In the above embodiment, the battery consisted of an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, a counter electrode current collector, and an insulating member, but is not limited to this. For example, a bonding layer or the like for reducing electrical resistance and improving bonding strength may be provided between each layer of the battery, within a range that is acceptable for the battery characteristics.

[0181] Furthermore, in the above embodiment, the electrode active material layer, solid electrolyte layer, and counter electrode active material layer were formed by sequentially laminating them directly from the main surface side of the electrode current collector, but this is not limited to this. For example, the electrode active material layer, solid electrolyte layer, and counter electrode active material layer may be formed by sequentially laminating them on a sheet-like substrate, and the formed electrode active material layer, solid electrolyte layer, and counter electrode active material layer may be removed from the substrate and laminated on the main surface of the electrode current collector. Alternatively, the electrode active material layer, solid electrolyte layer, and counter electrode active material layer may be formed on a sheet-like substrate, and the formed electrode active material layer, solid electrolyte layer, and counter electrode active material layer may be laminated by sequentially transferring them to the main surface of the electrode current collector.

[0182] Furthermore, each of the above embodiments can be modified, replaced, added, or omitted in various ways within the scope of the claims or their equivalents. [Industrial applicability]

[0183] The battery relating to this disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices or automobiles. [Explanation of symbols]

[0184] 1, 101, 201, 301 batteries 10 Electrode current collector 11, 12 Main surfaces 13, 21, 31, 41, 61, 62, 63, 64, 91 Side view 15, 55 protrusion 20 Electrode active material layer 30 Solid electrolyte layer 40 Counter electrode active material layer 50 Counter-pole current collector 60, 160, 260 unit cells 65 Laminated plate 71 First Covering Region 72 Second Covering Region 73 Third Covering Region 81 First Uncovered Region 82 Second Uncovered Region 83 Third Uncovered Area 90 Insulating material

Claims

1. Electrode current collector and An electrode active material layer arranged on the main surface of the electrode current collector, The electrode active material layer comprises an electrolyte layer located on the side opposite to the electrode current collector, The electrolyte layer includes a counter electrode active material layer positioned on the opposite side from the electrode active material layer, A counter electrode current collector is positioned on the opposite side of the counter electrode active material layer from the electrolyte layer, An insulating member covering the electrode active material layer and the electrolyte layer, It comprises a unit cell having, At the end of the electrode active material layer in a first direction, which is the direction from the center of the main surface of the electrode current collector toward the outer edge, a first covering region is provided that, in a plan view with respect to the main surface of the electrode current collector, is not covered by the electrolyte layer but is covered by the insulating member. At the end of the electrolyte layer in the first direction, a second covering region is provided that, in a plan view with respect to the main surface of the electrode current collector, is not covered by the counter electrode active material layer but is covered by the insulating member. battery.

2. The insulating member is in contact with at least one of the first-direction side surface of the electrolyte layer and the first-direction side surface of the counter electrode active material layer. The battery according to claim 1.

3. The insulating member is in contact with the side surface of the electrolyte layer on the first direction side and the side surface of the counter electrode active material layer on the first direction side. The battery according to claim 1.

4. The insulating member is provided with a first uncovered region that is not covered by the counter electrode current collector, in a plan view with respect to the main surface of the electrode current collector. The battery according to claim 1.

5. The electrode current collector has a protruding portion at a part of its end in the first direction that protrudes in the first direction, When viewing a cross-section of the unit cell in a plan view at a position parallel to the first direction and not passing through the protrusion, the side surface of the electrode active material layer on the first direction side and the side surface of the insulating member on the first direction side are aligned in the first direction at the end of the unit cell in the first direction. The battery according to claim 1.

6. At the end of the electrode current collector in the first direction, a second uncovered region is provided that, in a plan view with respect to the main surface of the electrode current collector, is not covered by the electrode active material layer and the insulating member. The battery according to any one of claims 1 to 5.

7. The electrode current collector has a protruding portion at a part of its end in the first direction that protrudes in the first direction, When viewing the cross-section of the unit cell in a plan view at a position parallel to the first direction passing through the protrusion, the electrode active material layer protrudes more in the first direction than the insulating member. The battery according to any one of claims 1 to 5.

8. The electrode current collector has a protruding portion at a part of its end in the first direction that protrudes in the first direction, The protruding portion is provided with a third covering region that, in a plan view with respect to the main surface of the electrode current collector, is not covered by the electrode active material layer but is covered by the insulating member. The battery according to any one of claims 1 to 5.

9. The unit cell has two of each of the electrode active material layer, the electrolyte layer, the counter electrode active material layer, the counter electrode current collector, and the insulating member. The two electrode active material layers are arranged on both main surfaces of the electrode current collector. The two electrolyte layers are arranged on the opposite side of each of the two electrode active material layers from the electrode current collector. The two counter electrode active material layers are positioned on the opposite side of each of the two electrolyte layers from the electrode active material layers. The two counter electrode current collectors are positioned on the opposite side of each of the two counter electrode active material layers from the electrolyte layer. One of the two insulating members covers the electrode active material layer and the electrolyte layer, which are positioned on the main surface side of one of the electrode current collectors. The other of the two insulating members covers the electrode active material layer and the electrolyte layer, which are located on the main surface side of the other electrode current collector. The first coating region is provided at the end of each of the two electrode active material layers in the first direction. The second covering region is provided at the end of each of the two electrolyte layers in the first direction. The battery according to any one of claims 1 to 5.

10. In the unit cell, at the end in a second direction different from the first direction, in the direction from the center of the main surface of the electrode current collector toward the outer edge, the side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer, and the counter electrode active material layer are flush. The battery according to any one of claims 1 to 5.

11. In the unit cell, at the end in a second direction different from the first direction, in a direction from the center of the main surface of the electrode current collector toward the outer edge, the electrode current collector, the electrode active material layer, the electrolyte layer, the counter electrode active material layer, and the side surface of the counter electrode current collector are flush. The battery according to any one of claims 1 to 5.

12. At least one selected from the group consisting of the electrode active material layer, the insulating member, and the electrolyte layer includes a sulfide solid electrolyte. The battery according to any one of claims 1 to 5.

13. At least one selected from the group consisting of the electrode active material layer, the insulating member, and the electrolyte layer includes a styrene-based elastomer. The battery according to any one of claims 1 to 5.

14. A portion of the end of the counter electrode current collector in the first direction protrudes in the first direction more than the counter electrode active material layer in the plan view. The battery according to any one of claims 1 to 5.

15. The unit comprises multiple such units, Multiple of the aforementioned unit cells are stacked. The battery according to any one of claims 1 to 5.

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