Battery

Abstract

A battery according to the present disclosure comprises a unit cell that is provided with: an electrode current collector; an electrode active material layer which is disposed on a main surface of the electrode current collector; an electrolyte layer which is disposed on the reverse side of the electrode active material layer from the electrode current collector; a counter electrode active material layer which is disposed on the reverse side of the electrolyte layer from the electrode active material layer; a counter electrode current collector which is disposed on the reverse side of the counter electrode active material layer from the electrolyte layer; and an insulating member. In a plan view with respect to the main surface of the electrode current collector, the electrode active material layer is larger than the counter electrode active material layer. An end of the electrolyte layer in a first direction, which is a direction from the center of the main surface of the electrode current collector toward the outer edge, is provided with a first region which is not covered with the counter electrode active material layer in the plan view. In the plan view, the insulating member covers at least a part of the first region and a part of the electrode active material layer, and protrudes beyond the electrode active material layer in at least one of the first direction and a second direction that is orthogonal to the first direction in the plan view.

Description

battery

[0001] The present disclosure relates to batteries.

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

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

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

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

[0006] The present disclosure aims to provide a highly reliable battery.

[0007] a counter electrode active material layer disposed on a main surface of the electrode current collector; an electrolyte layer disposed on the side of the electrode active material layer opposite the electrode current collector; a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer; a counter electrode current collector disposed on the side of the counter electrode active material layer opposite the electrolyte layer; and an insulating member, wherein, in a plan view relative to the main surface of the electrode current collector, the electrode active material layer is larger than the counter electrode active material layer, and a first region that is not covered by the counter electrode active material layer in the plan view is provided at an end of the electrolyte layer in a first direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector, and the insulating member covers at least a part of the first region and a part of the electrode active material layer in the plan view and protrudes beyond the electrode active material layer in at least one of the first direction and a second direction that is orthogonal to the first direction in the plan view.

[0008] According to the present disclosure, a highly reliable battery can be provided.

[0009] FIG. 1 is a top view of a battery according to an embodiment. FIG. 2 is a cross-sectional view of a battery according to an embodiment. FIG. 3 is another cross-sectional view of a battery according to an embodiment. FIG. 4 is a cross-sectional view showing another example of the structure of an end portion of a unit cell according to an embodiment. FIG. 5 is a top view of another battery according to an embodiment. FIG. 6 is a cross-sectional view of another battery according to an embodiment. FIG. 7 is a top view of yet another battery according to an embodiment. FIG. 8 is a cross-sectional view of a battery according to a first modified example of the embodiment. FIG. 9 is a cross-sectional view of a battery according to a second modified example of the embodiment. FIG. 10 is another cross-sectional view of a battery according to a second modified example of the embodiment. FIG. 11 is a cross-sectional view illustrating a gap between an insulating member and a counter electrode current collector. FIG. 12 is a cross-sectional view illustrating an insulating member that does not cover side surfaces of an electrode current collector, an electrode active material layer, a solid electrolyte layer, and a counter electrode active material layer. FIG. 13 is a cross-sectional view of a battery according to a third modified example of the embodiment. FIG. 14 is a cross-sectional view illustrating a first modified example of an insulating member arrangement. FIG. 15 is a cross-sectional view illustrating a second modified example of an insulating member arrangement. FIG. 16 is a cross-sectional view illustrating a third modified example of an insulating member arrangement. Fig. 17 is a top view of a battery according to Modification 4 of the embodiment. Fig. 18 is a cross-sectional view of a battery according to Modification 4 of the embodiment. Fig. 19 is a flowchart showing a method for manufacturing a battery according to Modification 4 of the embodiment. Fig. 20 is a top view showing an example of a laminated electrode plate.

[0010] (Findings underlying the present disclosure) Batteries have been proposed that include unit cells having a structure in which an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, and a counter electrode current collector are stacked. Generally, the electrode current collector and electrode active material layer, and the counter electrode current collector and counter electrode active material layer, have electronic conductivity, and therefore contact between these electrodes of opposite polarity leads to conduction, i.e., a short circuit. Therefore, high resistance to short circuits is important for long-term use of batteries. Furthermore, an electrical connection structure such as a terminal may be formed at the end of a battery. While an electrical connection structure can be easily formed by providing a region at the end of the electrode current collector that is not covered by the electrode active material layer, this region is prone to short circuits due to contact between the electrode current collector and the counter electrode active material layer and counter electrode current collector.

[0011] In addition, in such batteries, terminals may be formed at the ends of the battery to extract current. In cases where electrode active material layers are formed on both sides of the same electrode current collector, terminals may be formed in areas of the electrode current collector that are not covered by the electrode active material layers. In these areas, short circuits are likely to occur due to contact between the electrode current collector and the counter electrode active material layer and the counter electrode current collector. Furthermore, when multiple unit cells are stacked, misalignment of the stacked unit cells increases the likelihood of short circuits at the end surfaces. Furthermore, when the electrode active material layer and the counter electrode active material layer differ in size, the active material is likely to collapse at the end of the larger active material layer. Thus, the present inventors focused on the problem of battery reliability being easily reduced at the end of the unit cells.

[0012] Therefore, the present disclosure provides a highly reliable battery.

[0013] (Summary of the Present Disclosure) As an overview of the present disclosure, an example of a battery according to the present disclosure will be described below.

[0014] For example, a battery according to a first aspect of the present disclosure includes a unit cell having an electrode current collector, an electrode active material layer disposed on a main surface of the electrode current collector, an electrolyte layer disposed on the side of the electrode active material layer opposite the electrode current collector, a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, a counter electrode current collector disposed on the side of the counter electrode active material layer opposite the electrolyte layer, and an insulating member, wherein, in a plan view relative to the main surface of the electrode current collector, the electrode active material layer is larger than the counter electrode active material layer, a first region that is not covered by the counter electrode active material layer in the plan view is provided at an end of the electrolyte layer in a first direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector, and the insulating member covers at least a part of the first region and at least a part of the electrode active material layer and protrudes beyond the electrode active material layer in at least one of the first direction and a second direction that is orthogonal to the first direction in the plan view.

[0015] As a result, at the end of the unit cell in the first direction, the insulating member protrudes beyond the electrode active material layer in at least one of the first and second directions, suppressing contact of the counter electrode active material layer with the electrode active material layer and the counter electrode current collector, thereby improving the battery's resistance to short circuits. Furthermore, although the end of the electrode active material layer that is larger than the counter electrode active material layer is prone to collapse, the insulating member protrudes beyond the electrode active material layer in at least one of the first and second directions in a plan view and covers the electrode active material layer, thereby suppressing collapse of the end of the electrode active material layer due to external force. Furthermore, by having the insulating member cover the first region, the end of the solid electrolyte layer that is not covered by the counter electrode active material layer can be suppressed from collapsing due to external force, etc. Therefore, the battery according to this embodiment can improve reliability.

[0016] Furthermore, for example, a battery according to a second aspect of the present disclosure may be a battery according to the first aspect, in which a second region that is not covered by the electrolyte layer in the planar view is provided at an end of the electrode active material layer in the first direction, and the insulating member covers at least a portion of the second region in the planar view.

[0017] As a result, the insulating member covers the second region, thereby preventing the end of the electrode active material layer that is not covered by the solid electrolyte layer from collapsing due to external force, etc. Furthermore, contact between the counter electrode current collector and the counter electrode active material layer and the second region is prevented, improving the battery's resistance to short circuits and thus improving the reliability of the battery.

[0018] Furthermore, for example, a battery according to a third aspect of the present disclosure may be a battery according to the first or second aspect, wherein a third region that is not covered by the electrode active material layer is provided at an end of the main surface of the electrode current collector in the first direction, and the insulating member covers at least a portion of the third region in the planar view.

[0019] This prevents the counter electrode active material layer and the counter electrode current collector from coming into contact with the third region of the electrode current collector by the insulating member, thereby improving the resistance of the battery to short circuits.

[0020] Furthermore, for example, a battery according to a fourth aspect of the present disclosure may be a battery according to any one of the first to third aspects, wherein the length of the insulating member in the second direction is longer than the length of the end of the electrode active material layer in the first direction, and the insulating member may extend beyond the electrode active material layer in the second direction in the planar view.

[0021] As a result, even if the end portion of the electrode active material layer on the second direction side is exposed, the insulating member protrudes beyond the electrode active material layer in the second direction, thereby suppressing contact of the counter electrode active material layer with the counter electrode current collector, and improving the battery's resistance to short circuits.

[0022] Furthermore, for example, a battery according to a fifth aspect of the present disclosure may be a battery according to the fourth aspect, in which the difference between the length of the insulating member in the second direction and the length of the end of the electrode active material layer in the first direction in the second direction is 0.05 mm or more and 5 mm or less.

[0023] By making the difference in length 0.05 mm or more, it is possible to enhance the effect of suppressing contact between the electrode current collector and the electrode active material layer and the counter electrode active material layer and the counter electrode current collector, and the effect of suppressing collapse of the end of the electrode active material layer due to external force. Furthermore, by making the difference in length 5 mm or less, interference between the insulating member and the container that houses the battery or other batteries is unlikely to occur, and it is possible to suppress application of external force to the electrode active material layer via the insulating member, thereby suppressing collapse of the electrode active material layer. Furthermore, it is possible to suppress a decrease in the areal energy density of the battery.

[0024] Furthermore, for example, a battery according to a sixth aspect of the present disclosure may be a battery according to any one of the first to fifth aspects, wherein the insulating member, when viewed in plan, extends beyond the electrode current collector in the first direction.

[0025] This reduces contact between the electrode current collector and the counter electrode active material layer and the counter electrode current collector at the end of the unit cell in the first direction, thereby further improving the resistance of the battery to short circuits.

[0026] Furthermore, for example, a battery according to a seventh aspect of the present disclosure may be a battery according to any one of the first to sixth aspects, wherein the insulating member covers at least a portion of at least one of the side surfaces of the electrode current collector on the first direction side and the side surface on the second direction side.

[0027] This prevents the counter electrode active material layer and the counter electrode current collector from coming into contact with the side surface of the electrode current collector, further improving the resistance of the battery to short circuits.

[0028] Furthermore, for example, a battery according to an eighth aspect of the present disclosure may be the battery according to the seventh aspect, wherein a gap is provided between the insulating member and the at least one side surface of the electrode current collector.

[0029] This can prevent an external force applied to the insulating member from being directly transmitted to the side surface of the electrode current collector.

[0030] Furthermore, for example, a battery according to a ninth aspect of the present disclosure may be a battery according to any one of the first to eighth aspects, wherein the electrode current collector has a protrusion in which a portion of an end of the electrode current collector in the first direction protrudes in the first direction, and the insulating member covers at least a portion of the protrusion in the planar view.

[0031] Although the formation of such a protrusion increases the exposed portion at the end of the electrode current collector in the first direction, the protrusion is covered with the insulating member, which prevents the protrusion from coming into contact with the counter electrode active material layer and the counter electrode current collector, thereby preventing the occurrence of a short circuit and improving the reliability of the battery.

[0032] Furthermore, for example, a battery according to a tenth aspect of the present disclosure may be the battery according to any one of the first to ninth aspects, wherein a fourth region that is not covered by the counter electrode current collector in the plan view is provided at an end of the counter electrode active material layer in the first direction, and the insulating member covers at least a part of the fourth region.

[0033] As a result, the insulating member covers the fourth region, which can prevent the end of the electrode active material layer that is not covered by the counter electrode current collector from collapsing due to external force, etc. This can improve the reliability of the battery.

[0034] Furthermore, for example, a battery according to an eleventh aspect of the present disclosure is the battery according to the tenth aspect, wherein the insulating member does not need to cover the counter electrode current collector in the plan view.

[0035] This prevents the insulating member from riding on the counter electrode current collector and creating additional space when stacking the batteries or housing the batteries in a container, thereby suppressing a decrease in volumetric energy density.

[0036] Furthermore, for example, a battery according to a twelfth aspect of the present disclosure may be the battery according to the tenth or eleventh aspect, wherein the thickness of the portion of the insulating member covering the fourth region is equal to or less than half the thickness of the counter electrode current collector.

[0037] This makes it less likely that the insulating member will interfere with other members and layers, thereby suppressing a decrease in volumetric energy density and external forces due to interference.

[0038] Furthermore, for example, a battery according to a thirteenth aspect of the present disclosure may be the battery according to any one of the first to twelfth aspects, wherein at an end of the unit cell in a direction from the center toward the outer edge of the main surface of the electrode current collector and in a direction different from the first direction, side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer, and the counter electrode active material layer may be flush with each other.

[0039] As a result, at the end of the unit cell in a direction different from the first direction, there are no steps on the side surfaces of the counter electrode active material layer, electrolyte layer, and electrode active material layer stacked on the counter electrode current collector, and no spaces that do not function as a battery are formed due to the steps, thereby improving the effective volumetric energy density of the battery.

[0040] Furthermore, for example, a battery according to a fourteenth aspect of the present disclosure may be the battery according to any one of the first to thirteenth aspects, wherein at an end of the unit cell in a direction from the center toward the outer edge of the main surface of the electrode current collector and in a direction different from the first direction, side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer, the counter electrode active material layer, and the counter electrode current collector may be flush with each other.

[0041] As a result, at the ends of the unit cell in a direction different from the first direction, there are no steps on the side surfaces of each layer, and no spaces that do not function as a battery are formed due to the steps, thereby improving the actual volumetric energy density of the battery.

[0042] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0043] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not described in the independent claims are described as optional components.

[0044] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0045] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel or perpendicular, terms indicating the shape of elements, such as rectangular or circular, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

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

[0047] Furthermore, in this specification, the terms "upper" and "lower" do not refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in a stacked configuration. Furthermore, the terms "upper" and "lower" are used not only when two components are arranged with a gap between them and another component is present between them, but also when two components are arranged closely together and are in contact with each other. In the following description, the negative side of the z axis is referred to as "lower" or "lower side," and the positive side of the z axis is referred to as "upper" or "upper side."

[0048] Furthermore, in this specification, unless otherwise specified, "protruding" means protruding outward from the center of the unit cell in a cross-sectional view perpendicular to the main surface of the electrode current collector. "Element A protrudes from element B" means that the tip of element A protrudes more than the tip of element B in the protruding direction, i.e., the tip of element A is farther from the center of the unit cell than the tip of element B. The "protruding direction" is considered to be a direction parallel to the main surface of the electrode current collector. Furthermore, "protruding portion of element A" means a part of element A that protrudes more than the tip of element B in the protruding direction. Furthermore, element B may be a part other than the protruding portion of element A. Examples of elements include an active material layer, a solid electrolyte layer, an insulating member, and a current collector.

[0049] Furthermore, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing between components of the same type.

[0050] (Embodiment) [1. Configuration] First, the configuration of a battery according to an embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0051] FIG. 1 is a top view of a battery 1 according to the present embodiment. FIG. 2 is a cross-sectional view of the battery 1 according to the present embodiment. FIG. 3 is another cross-sectional view of the battery 1 according to the present embodiment. FIG. 1 shows the planar shape of the battery 1 when viewed from the positive side of the z-axis. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 1. In FIG. 1, the outlines of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 when viewed through an insulating member 80 are indicated by dashed lines.

[0052] As shown in FIGS. 1 to 3 , a battery 1 according to the present embodiment includes 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 80. 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 on the xy plane toward the z axis. Furthermore, an insulating member 80 is disposed at the end of the unit cell 60 so as to cover a portion of the electrode current collector 10, a portion of the electrode active material layer 20, a portion of the solid electrolyte layer 30, and a portion of the counter electrode active material layer 40. As shown in FIG. 2 , the battery 1 is formed from one unit cell 60. The battery 1 is, for example, an all-solid-state battery.

[0053] As shown in Figures 1 to 3, the unit cell 60 has side faces 61 and 62 facing away from each other and side faces 63 and 64 facing away from each other. Side face 61 is the side face of the unit cell 60 facing in the direction moving toward the positive side of the x-axis. Side face 62 is the side face of the unit cell 60 facing in the direction moving toward the negative side of the x-axis. Side face 63 is the side face of the unit cell 60 facing in the direction moving toward the positive side of the y-axis. Side face 64 is the side face of the unit cell 60 facing in the direction moving toward the negative side of the y-axis.

[0054] Hereinafter, the direction along the x-axis toward the positive side will be referred to as the "positive x-axis direction." Hereinafter, the direction along the x-axis toward the negative side will be referred to as the "negative x-axis direction." Hereinafter, the direction along the y-axis toward the positive side will be referred to as the "positive y-axis direction." Hereinafter, the direction along the y-axis toward the negative side will be referred to as the "negative y-axis direction." The positive x-axis direction and the negative x-axis direction are perpendicular to the positive y-axis direction and the negative y-axis direction. The positive x-axis direction and the negative x-axis direction are opposite directions, and the positive y-axis direction and the negative y-axis direction are opposite directions. In this specification, the positive x-axis direction is an example of a first direction, which is a direction from the center toward the outer edge of the main surface 11 of the electrode current collector 10. The positive y-axis direction or the negative y-axis direction is an example of a second direction that is perpendicular to the first direction in a plan view. The negative x-axis direction is a direction from the center toward the outer edge of the main surface 11 of the electrode current collector 10, and is a direction different from the first direction.

[0055] 1 , the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided at the end of the unit cell 60 on the side surface 61 side, but these regions may be provided at the end of the unit cell 60 on the side surface 62 side, the side surface 63 side, or the side surface 64 side. The first region 71, the second region 72, the third region 73, and the fourth region 74 will be described in detail later.

[0056] The planar shape of the battery 1 and the unit cell 60 is rectangular as shown in FIG. 1 . That is, the general shape of the battery 1 and the unit cell 60 is a flattened rectangular parallelepiped. Here, "flat" means that the thickness is shorter than each side or the maximum width of the main surface. Each side or the maximum width of the main surface of the battery 1 and the unit cell 60 is, for example, 10 mm or more and 500 mm or less. The planar shape of the battery 1 and the unit cell 60 may be a polygon, such as a square, hexagon, or octagon, or may be a circle or an ellipse. Note that in the drawings related to this specification, the thickness of each layer is exaggerated to make the layer structure of the unit cell easier to understand. Also, in the drawings related to this specification, the lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 in the positive x-axis direction are exaggerated to make the structure of the unit cell easier to understand.

[0057] The side surfaces 62, 63, and 64 of the unit cell 60 are made up of the side surfaces of 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, excluding the portion where the insulating member 80 is disposed, and at least a portion of each may be a flat plane. When the side surfaces 62, 63, and 64 are flat planes excluding the portion where the insulating member 80 is disposed, on this plane, at least the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are flush with one another and lie on the same flat plane. In other words, at the ends of the unit cell 60 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are flush with one another. Furthermore, at the ends of the unit cell 60 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 may be flush with each other. This results in no steps on the side surfaces of the layers at the ends of the unit cell 60 where the first region 71, the second region 72, the third region 73, and the fourth region 74 are not provided, and no spaces that do not function as a battery due to the steps are formed, thereby improving the volumetric energy density of the battery 1. Furthermore, since the side surfaces of the layers can be flush with each other by cutting the layers together, for example, the battery 1 can be manufactured more easily.

[0058] At least a portion of the side surfaces 62, 63, and 64 are, for example, cut surfaces. Specifically, at least a portion of the side surfaces 62, 63, and 64 are surfaces formed by cutting with a blade such as a cutter, and are surfaces having, for example, cut marks such as fine grooves. By having cut surfaces, the side surfaces of each layer of the unit cell 60 can be easily made flush. Note that the cut marks may be smoothed by polishing, etc. The shape of the cut surfaces is not limited.

[0059] As shown in FIG. 1, when the unit cell 60 has a rectangular shape in plan view, the side surfaces 61, 62, 63, and 64 each form one side of the rectangle of the unit cell 60 in plan view.

[0060] The unit cell 60 has one each of an electrode current collector 10, an electrode active material layer 20, a solid electrolyte layer 30, a counter electrode active material layer 40, and a counter electrode current collector 50. 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 each other.

[0061] 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 or more and 100 μm or less. In this specification, the thickness of the current collector and each layer is the length in the stacking direction, and is the average value of the entire thickness unless otherwise specified.

[0062] Known materials can be used as the material for the electrode current collector 10. For example, a foil, plate, or mesh-like body made of copper, aluminum, nickel, iron, stainless steel, platinum, gold, or an alloy of two or more of these materials can be used for the electrode current collector 10. In addition to the foil, plate, or mesh-like body, the electrode current collector 10 may also include a connection layer that is a layer containing a conductive material and is provided in a portion that contacts the electrode active material layer 20.

[0063] The counter electrode current collector 50 is disposed on the side of the counter electrode active material layer 40 opposite to the solid electrolyte layer 30 side. 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 with the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 interposed therebetween. The thickness of the counter electrode current collector 50 is, for example, 5 μm or more and 100 μm or less.

[0064] Known materials can be used as the material of the counter electrode current collector 50. For example, a foil, plate, or mesh-like body made of copper, aluminum, nickel, iron, stainless steel, platinum, gold, or an alloy of two or more of these metals can be used for the counter electrode current collector 50. Note that, in addition to the foil, plate, or mesh-like body, the counter electrode current collector 50 may also include a connection layer that is a layer containing a conductive material and is provided in a portion that contacts the counter electrode active material layer 40.

[0065] The electrode active material layer 20 is disposed on one main surface 11 of the electrode current collector 10. The surface of the electrode active material layer 20 opposite 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 sandwiched between them. In a plan view, the electrode active material layer 20 is larger than the counter electrode active material layer 40. Therefore, in a plan view, at least a portion of the outer edge of the electrode active material layer 20 is located outside the counter electrode active material layer 40. In the example shown in FIG. 1 , in a plan view, the outer edge of the electrode active material layer 20 in the x-axis positive direction is located outside the counter electrode active material layer 40 (on the x-axis positive side in this case). In other words, in a plan view, the electrode active material layer 20 protrudes in the x-axis positive direction beyond the counter electrode active material layer 40. The thickness of the electrode active material layer 20 is, for example, 5 μm or more and 300 μm or less. The material used for the electrode active material layer 20 will be described later.

[0066] The solid electrolyte layer 30 is disposed on the side of the electrode active material layer 20 opposite to the electrode current collector 10 side. The solid electrolyte layer 30 is located between the electrode active material layer 20 and the counter electrode active material layer 40, and is in contact with 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 or more and 150 μm or less. The materials used for the solid electrolyte layer 30 will be described later.

[0067] The counter electrode active material layer 40 is disposed 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 or more and 300 μm or less. The material used for the counter electrode active material layer 40 will be described later.

[0068] Here, the materials used for the solid electrolyte layer 30, the electrode active material layer 20, and the counter electrode active material layer 40 will be described.

[0069] 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 contain a binder material as necessary. 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 entirely solid electrolyte, except for unavoidable impurities, for example. Note that the electrolyte material used in the solid electrolyte layer 30 may further contain a nonaqueous electrolyte solution, a gel electrolyte solution, or an ionic liquid, as long as it contains a solid electrolyte as a main component. The following describes a case where the electrolyte material contained in the solid electrolyte layer 30 is entirely solid electrolyte.

[0070] As the solid electrolyte, known materials such as lithium ion conductors, sodium ion conductors, magnesium ion conductors, etc. can be used. As the solid electrolyte, for example, a solid electrolyte material such as a sulfide solid electrolyte, a halide solid electrolyte, an oxide solid electrolyte, a polymer solid electrolyte, or a complex hydride solid electrolyte can be used.

[0071] As the sulfide solid electrolyte, in the case of a material capable of conducting lithium ions, for example, lithium sulfide (Li ２ S) and diphosphorus pentasulfide (P ２ S ５ ) is used. As the sulfide solid electrolyte, Li ２ S-SiS ２ , Li ２ S-B ２ S ３ or Li ２ S-GeS ２ Sulfides such as Li may be used as an additive to the sulfides. ３ N, LiCl, LiBr, Li ３ P.O. ４ and Li ４ SiO ４ A sulfide to which at least one of the following is added may be used.

[0072] As the oxide solid electrolyte, in the case of a material that can conduct lithium ions, for example, Li ７ La ３ Zr ２ O1２ (LLZ), Li １．３ Al ０．３ Ti １．７ (P.O. ４ ) ３ (LATP) or (La,Li)TiO ３ (LLTO) and the like are used.

[0073] As the binder material, for example, elastomers such as styrene-based elastomers are used, and organic compounds such as polyvinylidene fluoride, acrylic resin, or cellulose resin may also be used.

[0074] In this embodiment, one of the electrode active material layer 20 and the counter electrode active material layer 40 is a positive electrode active material layer, and the other is a negative electrode active material layer.

[0075] The positive electrode active material layer contains at least a positive electrode active material, and may contain at least one of an electrolyte material such as a solid electrolyte, a conductive additive, and a binder material, as necessary.

[0076] As the positive electrode active material, known materials capable of occluding and releasing (inserting and desorbing, or dissolving and depositing) lithium ions, sodium ions, magnesium ions, etc. can be used. As the positive electrode active material, materials capable of extracting and inserting lithium ions include, for example, transition metal oxides, transition metal fluorides, polyanion materials, fluorinated polyanion materials, transition metal sulfides, transition metal oxysulfides, transition metal oxynitrides, sulfur, and lithium-containing compounds thereof. Examples of lithium-containing transition metal oxides include Li(NiCoAl)O ２ , Li(NiCoMn)O ２ , LiCoO ２ Li(NiCoAl)O ２ means that Ni, Co, and Al are contained in any ratio. Li(NiCoMn)O ２ means that Ni, Co and Mn are contained in any ratio.

[0077] The solid electrolyte may be any of the solid electrolyte materials exemplified above. The conductive material used in the conductive additive may be, for example, acetylene black, carbon black, graphite, carbon fiber, vapor-grown carbon, or conductive carbon such as carbon nanotubes. The binder may be any of the binder materials exemplified above.

[0078] The negative electrode active material layer contains at least a negative electrode active material, and may contain at least one of an electrolyte material such as a solid electrolyte, a conductive additive, and a binder material, as necessary.

[0079] The negative electrode active material may be a known material capable of occluding and releasing (inserting and desorbing, or dissolving and precipitating) lithium ions, sodium ions, magnesium ions, etc. In the case of a material capable of extracting and inserting lithium ions, for example, a carbon material such as natural graphite, artificial graphite, graphite carbon fiber, or resin-baked carbon, metallic lithium, a lithium alloy, silicon (Si), tin (Sn), a silicon compound, a tin compound, or an oxide of lithium and a transition metal element may be used as the negative electrode active material.

[0080] The solid electrolyte may be any of the solid electrolyte materials exemplified above. The conductive additive may be any of the conductive materials exemplified above. The binder material may be any of the binder materials exemplified above.

[0081] Next, the end structure of the unit cell 60 will be described.

[0082] As shown in FIGS. 1 and 2 , in the unit cell 60, a first region 71, a second region 72, a third region 73, and a fourth region 74 that are not covered by the upper layer are provided at the end in the positive x-axis direction (the end along the side surface 61 in the example shown in FIG. 1 ).

[0083] Specifically, a third region 73 that is not covered by the electrode active material layer 20 is provided at an end of the main surface 11 of the electrode current collector 10 in the positive x-axis direction. The third region 73 is not in contact with the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, or the counter electrode current collector 50. A second region 72 that is not covered by the solid electrolyte layer 30 in a plan view is provided at an end of the electrode active material layer 20 in the positive x-axis direction. The second region 72 is not in contact with the solid electrolyte layer 30, the counter electrode active material layer 40, or the counter electrode current collector 50. A first region 71 that is not covered by the counter electrode active material layer 40 in a plan view is provided at an end of the solid electrolyte layer 30 in the positive x-axis direction. The first region 71 is not in contact with the counter electrode active material layer 40 or the counter electrode current collector 50. The first region 71 is farther from the electrode current collector 10 than the second region 72. Furthermore, a fourth region 74 that is not covered by the counter electrode current collector 50 in plan view is provided at the end of the counter electrode active material layer 40 in the positive x-axis direction. The fourth region 74 is farther from the electrode current collector 10 than the first region 71.

[0084] As a result, at the end of the unit cell 60 where the third region 73 is provided and where it is easy to form a terminal on the electrode current collector 10, the second region 72, the first region 71, and the fourth region 74 increase the distance between the electrode current collector 10 and the end of the counter electrode active material layer 40 and the distance between the electrode current collector 10 and the end of the counter electrode active material layer 20 and the end of the counter electrode current collector 50. As a result, short circuits and other problems caused by contact between opposite polarity counter electrodes are less likely to occur. Furthermore, the provision of the first region 71 prevents the counter electrode active material layer 40 from contacting the electrode active material layer 20 and the electrode current collector 10 even if the end of the counter electrode active material layer 40 in the positive x-axis direction collapses or if the position of the end of the counter electrode active material layer 40 in the positive x-axis direction is shifted due to formation accuracy. This improves the reliability of the battery 1.

[0085] 1 , the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided along the side surface 61 in a plan view. The first region 71, the second region 72, the third region 73, and the fourth region 74 are elongated in a plan view, and in the example shown in FIG. 1 , the direction perpendicular to the positive x-axis direction (the y-axis direction) is the longitudinal direction. Furthermore, the fourth region 74, the first region 71, the second region 72, and the third region 73 are arranged in this order along the positive x-axis direction in a plan view.

[0086] The length of the third region 73 is, for example, 1 mm or more and 20 mm or less, which allows the energy density of the battery 1 to be increased while ensuring an area where a terminal can be easily formed on the electrode current collector 10.

[0087] The length of each of the second region 72, the first region 71, and the fourth region 74 is, for example, 0.1 mm or more and 5 mm or less. This allows the above-mentioned distance to be maintained while increasing the energy density of the battery 1. The length of each of the second region 72, the first region 71, and the fourth region 74 may be, for example, 0.5 mm or more and 2 mm or less.

[0088] The lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 may be the same, or at least one of them may be different. In addition, the length of the first region 71 may be longer than the lengths of the second region 72, the third region 73, and the fourth region 74.

[0089] Here, the lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 are lengths in the positive x-axis direction in plan view. The length of the third region 73 is also the distance between the outer edge of the electrode current collector 10 and the outer edge of the electrode active material layer 20 in the positive x-axis direction in plan view. The length of the second region 72 is also the distance between the outer edge of the electrode active material layer 20 and the outer edge of the solid electrolyte layer 30 in the positive x-axis direction in plan view. The length of the first region 71 is also the distance between the outer edge of the solid electrolyte layer 30 and the outer edge of the counter electrode active material layer 40 in the positive x-axis direction in plan view. The length of the fourth region 74 is also the distance between the outer edge of the counter electrode active material layer 40 and the outer edge of the counter electrode current collector 50 in the positive x-axis direction in plan view.

[0090] In the present embodiment, the electrode active material layer 20 may be a negative electrode active material layer, and the counter electrode active material layer 40 may be a positive electrode active material layer. In this case, the fourth region 74 in the counter electrode active material layer 40 that is not covered by the counter electrode current collector 50 becomes a region that is unlikely to function as a positive electrode. Furthermore, since the second region 72 is provided in the electrode active material layer 20 and the first region 71 is provided in the solid electrolyte layer 30, the electrode active material layer 20 becomes relatively larger than the counter electrode active material layer 40. Therefore, metal ions are more easily taken up into the electrode active material layer 20, which is a negative electrode active material layer, and metal precipitation derived from the metal ions is suppressed, thereby further improving the reliability of the battery 1.

[0091] In the example shown in FIG. 2 , 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 form a stepped structure at the end of the unit cell 60 in the positive x-axis direction. The stepped structure can be formed by methods such as lamination, transfer, or cutting, but the method for forming the stepped structure is not particularly limited. Furthermore, the structure of the end of the unit cell 60 is not limited to a stepped structure. FIG. 4 is a cross-sectional view showing another example of the structure of the end of the unit cell 60. FIG. 4 shows a cross section of the unit cell 60 near the end of the unit cell 60 in the positive x-axis direction, taken at a position corresponding to line II-II in FIG. 1 .

[0092] In the example shown in FIG. 4 , the electrode active material layer 20 has, in the second region 72, an inclined surface 21 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction. The entire second region 72 is, for example, the region where the inclined surface 21 is formed. Furthermore, the solid electrolyte layer 30 has, in the first region 71, an inclined surface 31 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction. The entire first region 71 is, for example, the region where the inclined surface 31 is formed. Furthermore, the counter electrode active material layer 40 has, in the fourth region 74, an inclined surface 41 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction. The entire fourth region 74 is, for example, the region where the inclined surface 41 is formed. In the example shown in FIG. 4 , the inclined surface 21 and the inclined surface 31 are connected, and the inclined surface 31 and the inclined surface 41 are connected. In other words, the inclined surfaces 21, 31 and 41 form one continuous inclined surface.

[0093] The formation of the inclined surfaces 21, 31, and 41 makes it difficult for corners to be formed in the electrode active material layer 20 in the second region 72, the solid electrolyte layer 30 in the first region 71, and the counter electrode active material layer 40 in the fourth region 74, and the materials of these layers are less likely to fall off, making it less likely for short circuits to occur, thereby improving the reliability of the battery.

[0094] These inclined surface shapes can be formed, for example, by subjecting a portion including the end of a laminate in which the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are stacked on the electrode current collector 10 to a high-pressure press treatment such as a roll press so that the end is stepped.

[0095] The angle that each of the inclined surfaces 21, 31, and 41 forms with respect to the main surface 11 is, for example, less than 45 degrees. This makes it even more difficult for the layer material to fall off. The angle that each of the inclined surfaces 21, 31, and 41 forms with respect to the main surface 11 may be 30 degrees or less, or may be 10 degrees or less. Furthermore, the angle that each of the inclined surfaces 21, 31, and 41 forms with respect to the main surface 11 is, for example, 1 degree or more.

[0096] In the example shown in FIG. 4 , the electrode active material layer 20 has a recess 22 in the first region 71 where the solid electrolyte layer 30 is recessed. The solid electrolyte layer 30 also has a recess 32 in the fourth region 74 where the counter electrode active material layer 40 is recessed. This increases the bonding strength of the layers stacked above and below at the end in the positive x-axis direction, making the materials of these layers less likely to fall off and suppressing delamination. This reduces the likelihood of short circuits due to contact between oppositely polarized counter electrodes. This recessed shape can be formed, for example, by performing a high-pressure press, such as a roll press, on a portion of the stack including the end of the stack in which the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are stacked on the electrode current collector 10 so that the end is stepped.

[0097] The depth of each of the recesses 22 and 32 is, for example, not less than 1 μm and not more than 10 μm.

[0098] 4 , the surface of the electrode active material layer 20 on the solid electrolyte layer 30 side below the inclined surface 41 (i.e., the position overlapping with the inclined surface 41 in a plan view) has a portion that inclines so as to move away from the electrode current collector 10 as it progresses in the positive x-axis direction. Therefore, at the position of the outer edge of the counter electrode active material layer 40 in the positive x-axis direction in a plan view, the thickness of the electrode active material layer 20 is greater than the thickness of the electrode active material layer 20 on the inside of that position.

[0099] In the batteries according to the embodiments and modifications described below, the end structures of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 in the positive x-axis direction may be a stepped structure as shown in FIG. 2, or may be a structure inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction as shown in FIG. 4.

[0100] Next, the insulating member 80 will be described with reference to FIGS. 1 to 3 again.

[0101] In a plan view, the insulating member 80 covers at least a portion of the first region 71 and at least a portion of the electrode active material layer 20. In the example shown in FIG. 1 , in a plan view, the insulating member 80 covers the entire third region 73, the entire second region 72, the entire first region 71, and a portion of the fourth region 74 on the first region 71 side. In addition, in a plan view, the insulating member 80 protrudes beyond the electrode active material layer 20 in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction. As a result, at the end of the unit cell 60 in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction, the insulating member 80 protrudes beyond the electrode active material layer 20. 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 short-circuit resistance of the battery 1. Furthermore, although the end of the electrode active material layer 20 that is larger than the counter electrode active material layer 40 is prone to collapse, the insulating member 80 protrudes beyond the electrode active material layer 20 in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction in plan view to cover the electrode active material layer 20, thereby suppressing collapse of the end of the electrode active material layer 20 due to external force. Furthermore, the insulating member 80 covers the second region 72 and the third region 73, thereby preventing exposure of the electrode active material layer 20 and the electrode current collector 10. Furthermore, because the insulating member 80 covers the first region 71 together with the second region 72 at the end in the positive x-axis direction, even if the position of the insulating member 80 is slightly misaligned, the risk of exposure of the portion of the electrode active material layer 20 near the first region 71 (specifically, the portion of the second region 72 on the first region 71 side) is reduced. Furthermore, by covering the first region 71 and the second region 72 with the insulating member 80, it is possible to prevent the ends of the solid electrolyte layer 30 and the electrode active material layer 20 that are not covered by the upper layer from collapsing due to an external force, etc. Therefore, the insulating member 80 can improve the reliability of the battery 1.

[0102] Furthermore, in the unit cell 60, the insulating member 80 protrudes beyond the electrode current collector 10 in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction in plan view. This prevents contact between the side surface of the electrode current collector 10 and the counter electrode active material layer 40 and the counter electrode current collector 50 at the end of the unit cell 60 in the positive x-axis direction, thereby further improving the short-circuit resistance of the battery 1.

[0103] Furthermore, in the unit cell 60, the insulating member 80 does not cover a portion of the fourth region 74. Therefore, a gap is provided between the counter electrode current collector 50 and the insulating member 80. The outer edge of the insulating member 80 in the negative x-axis direction is located on the fourth region 74 of the counter electrode active material layer 40. Furthermore, the insulating member 80 is in contact with the entire third region 73, the entire second region 72, the entire first region 71, and a portion of the fourth region 74 on the first region 71 side.

[0104] Furthermore, the insulating member 80 does not cover the counter electrode current collector 50. This prevents the insulating member 80 from riding on the counter electrode current collector 50 and creating additional space when stacking the batteries 1 or housing the batteries 1 in a container, thereby suppressing a decrease in volumetric energy density.

[0105] The insulating member 80 also covers the side surface of the electrode current collector 10 on the positive x-axis direction. This prevents the counter electrode active material layer 40 and the counter electrode current collector 50 from coming into contact with the side surface of the electrode current collector 10. The insulating member 80 also contacts the side surface of the electrode current collector 10 on the positive x-axis direction. The insulating member 80 does not have to cover the side surface of the electrode current collector 10 on the positive x-axis direction. The insulating member 80 may also cover only a portion of the side surface of the electrode current collector 10 on the positive x-axis direction. In the example shown in FIG. 3 , the insulating member 80 also contacts the side surfaces of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 on the positive x-axis direction.

[0106] 3 , the insulating member 80 covers the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 facing in the positive y-axis direction and the negative y-axis direction, respectively. This protects the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. The insulating member 80 also contacts the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 facing in the positive y-axis direction and the negative y-axis direction, respectively. Note that the insulating member 80 does not necessarily have to cover at least one of the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 facing in the positive y-axis direction and the negative y-axis direction.

[0107] In the unit cell 60, the length by which the insulating member 80 protrudes from the electrode current collector 10 in a plan view is, for example, 0.05 mm or more and 5 mm or less in all directions along the positive x-axis, the positive y-axis, and the negative y-axis. Having this length of 0.05 mm or more enhances the effect of suppressing contact between the electrode current collector 10 and the electrode active material layer 20 and the counter electrode active material layer 40 and the counter electrode current collector 50, as well as the effect of suppressing collapse of the end of the electrode active material layer 20 due to external force. Having this length of 5 mm or less reduces interference between the insulating member 80 and the container containing the battery 1, other batteries, etc., suppresses application of external force to the electrode active material layer 20 via the insulating member 80, and suppresses collapse of the electrode active material layer 20. Furthermore, a decrease in the areal energy density of the battery 1 can be suppressed.

[0108] Furthermore, in the unit cell 60, in plan view, the difference between the length of the insulating member 80 in the y-axis positive direction and the length of the electrode active material layer 20 in the y-axis positive direction is, for example, 0.05 mm or more and 5 mm or less. This also enhances the effect of suppressing contact between the electrode active material layer 20 and the counter electrode active material layer 40 and the counter electrode current collector 50, and the effect of suppressing collapse of the end of the electrode active material layer 20 due to an external force.

[0109] At least one of the first region 71, the second region 72, and the third region 73 may have a portion that is not covered with the insulating member 80. For example, if the electrode current collector 10 has a portion that is not covered with the insulating member 80, a terminal such as a tab can be connected to that portion. In addition, the fourth region 74 does not have to be covered with the insulating member 80.

[0110] Furthermore, the height of the insulating member 80 from the main surface 11 (in other words, the distance from the main surface 11 to the surface of the insulating member 80 opposite the electrode current collector 10) is, for example, equal to or less than the distance from the main surface 11 to the counter electrode current collector 50. This allows the space above the insulating member 80 to be used effectively when forming a terminal on the counter electrode current collector 50. Furthermore, when stacking batteries 1 for use, the batteries 1 can be easily stacked.

[0111] The insulating member 80 has electronic and ionic insulating properties. For example, insulating tape or insulating resin is used for the insulating member 80. Examples of resins used for the insulating tape and insulating resin include silicone resin, epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, and polyimide resin. The resin may be a thermosetting resin, an ultraviolet-curing resin, or a thermoplastic resin. The insulating member 80 is formed by, for example, pasting, coating, injection, or extrusion. By including a resin in the insulating member 80, the resin penetrates into the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, thereby enhancing the bonding of the insulating member 80 to the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 through an anchoring effect. In the examples shown in FIGS. 2 to 4 , the insulating member 80 is a film with a uniform thickness, but the shape of the insulating member 80 is not particularly limited. The insulating member 80 may be, for example, a member whose length in the stacking direction increases toward the positive side of the x-axis. The insulating member 80 may be, for example, formed as a single unit, or may be formed in multiple sections.

[0112] In plan view, the insulating member 80 only needs to cover at least a portion of the end of the solid electrolyte layer 30 in the positive x-axis direction (specifically, the first region 71) and at least a portion of the electrode active material layer 20, and to extend beyond the electrode active material layer 20 in at least one of the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction. For example, the insulating member 80 does not need to cover the entire area of ​​at least one of the first region 71, the second region 72, and the third region 73. In plan view, the insulating member 80 may entirely or partially cover the third region 73, the second region 72, and the first region 71 in the longitudinal direction (y-axis direction) of the third region 73, the second region 72, and the first region 71. In plan view, the insulating member 80 does not need to extend beyond the electrode active material layer 20 in one or two of the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction.

[0113] Here, an example will be described in which the arrangement of the insulating member 80 in plan view differs from that of the unit cell 60. FIG. 5 is a top view of another battery 1a according to the present embodiment. FIG. 6 is a cross-sectional view of another battery 1a according to the present embodiment. FIG. 7 is a top view of yet another battery 1b according to the present embodiment. FIGS. 5 and 7 show the planar shapes of the batteries 1a and 1b, respectively, when viewed from the positive side of the z-axis. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. In FIGS. 5 and 7, the outlines of the electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 when viewed through the insulating member 80 are indicated by dashed lines.

[0114] As shown in Figures 5 and 6, the battery 1a includes a unit cell 60a and is formed from one unit cell 60a. As shown in Figure 7, the battery 1b includes a unit cell 60b and is formed from one unit cell 60b.

[0115] 5 and 6 , in the unit cell 60a, the insulating member 80 covers, in a plan view, a portion of the third region 73 on the second region 72 side, the entire second region 72, the entire first region 71, and a portion of the fourth region 74 on the first region 71 side. In the unit cell 60a, the insulating member 80 protrudes beyond the electrode active material layer 20 in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction in a plan view. In the unit cell 60a, the insulating member 80 does not protrude beyond the electrode current collector 10 in the positive x-axis direction. That is, the electrode current collector 10 protrudes beyond the insulating member 80 in a plan view. In the unit cell 60a, the insulating member 80 contacts, in a plan view, a portion of the third region 73 on the second region 72 side, the entire second region 72, the entire first region 71, and a portion of the fourth region 74 on the first region 71 side. The cross-sectional shape of the unit cell 60a taken along the line III-III in FIG. 1 is the same as that shown in FIG. 3, for example.

[0116] The length of the portion where the insulating member 80 and the third region 73 are in contact is, for example, 100 μm or more. This reduces the possibility of exposure of the electrode current collector 10 and the electrode active material layer 20, thereby reducing the possibility of the electrode current collector 10 and the electrode active material layer 20 coming into contact with the counter electrode current collector 50 and the counter electrode active material layer 40, thereby improving the reliability of the battery 1a. The length of the portion where the insulating member 80 and the third region 73 are in contact is the length in the positive x-axis direction in a plan view, and is also the distance in a plan view between the outer edge of the electrode active material layer 20 and the outer edge of the insulating member 80 in the positive x-axis direction.

[0117] 7 , in the unit cell 60b, the insulating member 80 covers the entire third region 73, the entire second region 72, the entire first region 71, and a portion of the fourth region 74 on the first region 71 side, except for the ends in the positive and negative y-axis directions, in a plan view. In the unit cell 60b, the insulating member 80 extends beyond the electrode active material layer 20 and the electrode current collector 10 in the positive x-axis direction, but does not extend beyond the electrode active material layer 20 and the electrode current collector 10 in the positive and negative y-axis directions. The cross-sectional shape of the unit cell 60b at a position corresponding to line II-II in FIG. 1 is the same as that shown in FIG. 2 , for example. In the unit cell 60b, the positions of the outer edges of the insulating member 80 may coincide with the positions of the outer edges of the electrode active material layer 20 and the electrode current collector 10 in the positive and negative y-axis directions. For example, on the side surfaces 63 and 64 of the unit cell 60b, the side surfaces of the insulating member 80, the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 may be flush with each other.

[0118] The insulating members 80 in the batteries according to the embodiments and modifications other than the batteries 1a and 1b may be arranged in the same manner as the insulating members 80 in the unit cell 60a or the unit cell 60b.

[0119] [2. Modifications] The following describes batteries according to modifications of the embodiment. In the following description of the modifications, differences from the embodiment and each modification will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0120] [2-1. Modification 1] In the above-described unit cell 60, the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided, but in the batteries according to the embodiment and each modification, some of these regions may not be provided in the unit cell. Modification 1 of the embodiment will describe an example in which some of the first region 71, the second region 72, the third region 73, and the fourth region 74 are not provided in the unit cell.

[0121] 8 is a cross-sectional view of the battery 101 according to this modification, taken along the line II-II in FIG.

[0122] 8, the battery 101 includes a unit cell 160 and is formed from one unit cell 160. The unit cell 160 differs from the unit cell 60 according to the embodiment in that the second region 72 is not provided.

[0123] 8 , in the unit cell 160, a first region 71, a third region 73, and a fourth region 74 that are not covered by the upper layer are provided at the end portion in the positive x-axis direction. In the unit cell 160, the outer edge of the solid electrolyte layer 30 and the outer edge of the electrode active material layer 20 are at the same position in the positive x-axis direction, and the electrode active material layer 20 is completely covered by the solid electrolyte layer 30 in a plan view. Note that the solid electrolyte layer 30 may extend as far as the electrode active material layer 20 in the positive x-axis direction.

[0124] Even in such a unit cell 160, the insulating member 80 covers at least a portion of the first region 71 and at least a portion of the electrode active material layer 20 in a planar view, and protrudes beyond the electrode active material layer 20 in at least one direction of the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction, thereby improving the reliability of the battery 101.

[0125] In the battery 101, the second region 72 was not provided in the unit cell 160, but among the first region 71, the second region 72, the third region 73 and the fourth region 74, the first region 71 may not be provided, the third region 73 may not be provided, and the fourth region 74 may not be provided.

[0126] [2-2. Modification 2] Next, a battery according to Modification 2 of the embodiment will be described. FIG. 9 is a cross-sectional view of a battery 501 according to this modification. FIG. 10 is another cross-sectional view of the battery 501 according to this modification. FIG. 9 shows a cross-section of the battery 501 near the end of the battery 501 in the positive x-axis direction at a position corresponding to line II-II in FIG. 1. FIG. 10 also shows a cross-section of the battery 501 at a position corresponding to line III-III in FIG. 1.

[0127] 9 and 10 , the battery 501 includes a unit cell 560 and is formed from one unit cell 560. The unit cell 560 differs from the unit cell 60 according to the embodiment in that the unit cell 560 has two of each of the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, the counter electrode current collector 50, and the insulating member 80.

[0128] 9 and 10 , two electrode active material layers 20 are disposed on both main surfaces 11 and 12 of an electrode current collector 10. Two solid electrolyte layers 30 are disposed on each of the two electrode active material layers 20, opposite the electrode current collector 10. Two counter electrode active material layers 40 are disposed on each of the two solid electrolyte layers 30, opposite the electrode active material layer 20. Two counter electrode current collectors 50 are disposed on each of the two counter electrode active material layers 40, opposite the solid electrolyte layer 30.

[0129] 9 and 10 , a third region 73 that is not covered by either of the two electrode active material layers 20 is provided at the end in the positive x-axis direction of each of the main surfaces 11 and 12 of the electrode current collector 10. A second region 72 that is not covered by either of the two solid electrolyte layers 30 is provided at the end in the positive x-axis direction of each of the two electrode active material layers 20. A first region 71 that is not covered by either of the two counter electrode active material layers 40 is provided at the end in the positive x-axis direction of each of the two solid electrolyte layers 30. A fourth region 74 that is not covered by either of the two counter electrode current collectors 50 is provided at the end in the positive x-axis direction of each of the two counter electrode active material layers 40.

[0130] In this way, in the unit cell 560, a structure similar to the laminated structure of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 formed on the main surface 11 of the electrode current collector 10 of the unit cell 60 is also formed upside down on the main surface 12 facing away from the main surface 11 of the electrode current collector 10. Therefore, the unit cell 560 has a laminated structure that is symmetrical with respect to the electrode current collector 10.

[0131] This allows currents of two electrode active material layers 20 to be extracted from one electrode current collector 10, thereby increasing the volumetric energy density. Furthermore, because the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided on both sides of the electrode current collector 10 in the stacking direction, the distance between the electrode current collector 10 and the electrode active material layer 20 and the end of the counter electrode active material layer 40, and the distance between the electrode current collector 10 and the electrode active material layer 20 and the end of the counter electrode current collector 50 are increased, thereby improving the reliability of the battery 501. Furthermore, because a stacked structure of 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 is formed on both main surfaces 11 and 12 of the electrode current collector 10, when the unit cell 560 is densified by pressing or the like, stresses generated on both sides of the electrode current collector 10 in the stacking direction are less likely to differ, and warping of the unit cell 560 can be suppressed. Furthermore, even if stress occurs due to expansion and contraction of the electrode active material layer 20 and the counter electrode active material layer 40 during use of the battery 501, there is little difference in the stress occurring on both sides of the electrode current collector 10 in the stacking direction, and warping of the unit cell 560 can be suppressed.

[0132] 9 and 10 , one of the two insulating members 80 is disposed on the main surface 11 side of the electrode current collector 10, covers the entire third region 73, the entire second region 72, the entire first region 71, and a part of the fourth region 74 on the first region 71 side, and protrudes beyond the electrode active material layer 20 and the electrode current collector 10 in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction in plan view. The other of the two insulating members 80 is disposed on the main surface 12 side of the electrode current collector 10, covers the entire third region 73, the entire second region 72, the entire first region 71, and a part of the fourth region 74 on the first region 71 side, and protrudes beyond the electrode active material layer 20 and the electrode current collector 10 in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction in plan view. Even in the case of battery 501 in which an electrode active material layer 20 or the like is formed on the main surfaces 11 and 12 on both sides of the electrode current collector 10, the insulating member 80 can have the effect of improving the reliability of battery 501, as in the above-mentioned battery 1, etc.

[0133] 9 and 10 , the two insulating members 80 are joined to each other at positions corresponding to the electrode current collector 10, for example, at the end on the positive x-axis direction, the end on the positive y-axis direction, and the end on the negative y-axis direction. The two insulating members 80 may be formed integrally.

[0134] In the example shown in FIG. 9 , each of the two insulating members 80 covers the side surface of the electrode current collector 10 facing the positive x-axis direction. Each of the two insulating members 80 is in contact with the side surface of the electrode current collector 10 facing the positive x-axis direction. Note that each of the two insulating members 80 may cover the side surface of the electrode current collector 10 facing the positive x-axis direction with a gap therebetween, without contacting the side surface. FIG. 11 is a cross-sectional view illustrating a gap 81 between the insulating member 80 and the electrode current collector 10. As shown in FIG. 11 , a gap 81 may be provided between the insulating member 80 and the side surface of the electrode current collector 10 facing the positive x-axis direction. This prevents an external force on the insulating member 80 from being directly transmitted to the side surface of the electrode current collector 10.

[0135] 10 , each of the two insulating members 80 covers the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 facing the positive and negative y-axis directions. Each of the two insulating members 80 is in contact with the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 facing the positive and negative y-axis directions. The insulating member 80 does not necessarily have to cover the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 facing the positive and negative y-axis directions. FIG. 12 is a cross-sectional view illustrating an insulating member 80 that does not cover the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. As shown in FIG. 12 , the insulating member 80 does not bend at the ends in the positive and negative y-axis directions, and does not have to cover the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 in the positive and negative y-axis directions.

[0136] The structure of the insulating member 80 shown in FIG. 11 or FIG. 12 may be applied to batteries according to embodiments other than the battery 501 and to the modifications thereof.

[0137] [2-3. Modification 3] Next, a battery according to Modification 3 of the embodiment will be described. Fig. 13 is a cross-sectional view of a battery 601 according to this modification. Fig. 13 shows a cross section of the battery 601 near the end on the positive x-axis direction at a position corresponding to line II-II in Fig. 1.

[0138] 13 , the battery 601 is a stacked-type battery including a plurality of unit cells 560 according to the second modification of the embodiment, stacked on top of each other. The stacked unit cells 560 make the battery 601 highly reliable. Furthermore, the insulating member 80 prevents contact between opposite polarity portions of adjacent unit cells 560 in the stacking direction.

[0139] The multiple unit cells 560 have the same configuration and are stacked so as to be electrically connectable in parallel. The electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 stacked on both main surfaces of each current collector are stacked in the same order from the current collector. Furthermore, the multiple unit cells 560 are stacked such that the positions of the side surfaces of the unit cells 560 coincide when viewed, for example, from the stacking direction. Therefore, the side surfaces of the multiple unit cells 560 in the negative x-axis direction, positive y-axis direction, and negative y-axis direction are flush with each other.

[0140] In the example shown in FIG. 13, the number of stacked unit cells 560 is two, but it may be three or more.

[0141] 13 , two adjacent unit cells 560 share a counter electrode current collector 50. Note that two adjacent unit cells 560 may not share a counter electrode current collector 50, but may each have an individual counter electrode current collector 50, with two counter electrode current collectors 50 overlapping each other 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.

[0142] In the stacked-type battery according to this modification, the unit cells to be stacked may be unit cells other than the unit cell 560 according to the first embodiment and the modifications described above. Even when unit cells other than the unit cell 560 are stacked, adjacent unit cells may share a current collector, or the unit cells may be stacked such that two separate current collectors overlap without sharing a current collector. Furthermore, when unit cells such as the unit cell 60 are stacked, in which 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 only on one main surface 11 of the electrode current collector 10, the unit cells may be stacked so as to be electrically connected in series. Furthermore, the plurality of unit cells may include unit cells having different configurations.

[0143] Furthermore, in the unit cell 560, the arrangement of the insulating members 80 in the x-axis direction may be different from the arrangement described above. Fig. 14 is a cross-sectional view showing a first example of the arrangement of the insulating members 80. Fig. 15 is a cross-sectional view showing a second example of the arrangement of the insulating members 80. Fig. 16 is a cross-sectional view showing a third example of the arrangement of the insulating members 80.

[0144] 14 and 15 , the insulating member 80 does not cover the fourth region 74 in the counter electrode active material layer 40. In this case, the outer edge of the insulating member 80 in the negative x-axis direction may be located on the boundary between the fourth region 74 in the counter electrode active material layer 40 and the first region 71 in the solid electrolyte layer 30, as shown in Fig. 14 , or may be located on the first region 71 in the solid electrolyte layer 30, as shown in Fig. 15 .

[0145] 16 , the insulating member 80 completely covers the fourth region 74 of the counter electrode active material layer 40 in the x-axis direction. Therefore, the insulating member 80 is in contact with the side surface of the counter electrode current collector 50 on the positive x-axis direction side. In addition, in the example shown in FIG. 16 , the thickness of the portion of the insulating member 80 covering the fourth region 74 is equal to or less than half the thickness of the counter electrode current collector 50. This prevents the insulating members 80 from interfering with each other when the unit cells 560 are stacked, thereby suppressing an increase in the thickness of the battery 601 and also suppressing the generation of a force that separates the unit cells 560 from each other.

[0146] In the unit cells according to the embodiments and modifications other than the unit cell 560 of the battery 601, the insulating member 80 may be arranged in the x-axis direction as shown in any of FIGS.

[0147] [2-4. Modification 4] Next, a battery according to Modification 4 of the embodiment will be described. FIG. 17 is a top view of a battery 701 according to this modification. FIG. 18 is a cross-sectional view of the battery 701 according to this modification. FIG. 17 shows the shape of the battery 701 in plan view when viewed from the positive side of the z-axis. FIG. 18 is a cross-sectional view taken along the line XVIII-XVIII in FIG. 17. In FIG. 17, the outlines of the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30 when viewed through the insulating member 80 are indicated by dashed lines.

[0148] 17 and 18 , battery 701 has a configuration in which unit cell 560 of battery 601 according to the third modification of the embodiment is replaced with unit cell 760. Battery 701 is a stacked battery having a structure in which a plurality of unit cells 760 are stacked. Unit cell 760 differs from unit cell 560 in that it has an electrode current collector 710 and a counter electrode current collector 750 instead of electrode current collector 10 and counter electrode current collector 50.

[0149] As shown in FIGS. 17 and 18 , the electrode current collector 710 has a protrusion 711, which is a portion of the end of the electrode current collector 710 in the positive x-axis direction that protrudes further in the positive x-axis direction than other portions. The electrode current collector 710 has a shape in which a rectangular tab-shaped protrusion 711 is added to the electrode current collector 10, which has a rectangular shape in a plan view. The protrusion 711 functions, for example, as a lead on which a terminal is formed. Another lead material may be bonded to the protrusion 711. In the example shown in FIG. 17 , the third region 73 is also provided inside the protrusion 711 (toward the negative x-axis direction) on the electrode current collector 710, but the main surface 11 in areas other than the protrusion 711 may be covered with the electrode active material layer 20. Note that the electrode current collector 710 does not necessarily have to have the protrusion 711. In other words, the electrode current collector 10 may be used instead of the electrode current collector 710.

[0150] The counter electrode current collector 750 has a protrusion 751, which is a portion of an end of the counter electrode current collector 750 in the x-axis positive direction that protrudes further in the x-axis positive direction than other portions. The counter electrode current collector 750 has a shape in which a rectangular tab-shaped protrusion 751 is added to the counter electrode current collector 50, which has a rectangular shape in a plan view as described above. The protrusion 751 protrudes further in the x-axis positive direction than the insulating member 80 in a plan view. The protrusion 751 functions as, for example, a lead on which a terminal is formed. Another lead material may be joined to the protrusion 751.

[0151] The protrusion 751 faces the electrode current collector 710, the electrode active material layer 20, and the solid electrolyte layer 30 via the insulating member 80. The protrusions 711 and 751 are arranged in positions where they do not overlap in a plan view. The insulating member 80 does not have to be formed in a position where it does not overlap with the protrusion 751 in a plan view.

[0152] Thus, in the battery 701, the protrusion 751, which is a part of the end portion of the counter electrode current collector 750 in the positive x-axis direction, protrudes in the positive x-axis direction beyond the insulating member 80 in a plan view. This makes it possible to form a terminal on the counter electrode current collector 750 at the end portion of the battery 701, making the structure less complicated than when the terminal is formed on the main surface of the counter electrode current collector 750, and enabling the reliability of the battery 701 to be improved.

[0153] In the plurality of unit cells 760, the protrusions 751 and the protrusions 711 protrude in the same direction, specifically, in the positive x-axis direction. The protrusions 751 of the plurality of unit cells 760 and the protrusions 711 of the plurality of unit cells 760 may be bundled together and joined by welding or the like.

[0154] 17 , the insulating member 80 covers a portion of the protrusion 711 in a plan view. By forming the protrusion 711, a larger portion is exposed at the end of the electrode current collector 710 in the positive x-axis direction. However, since the protrusion 711 is covered by the insulating member 80, the protrusion 711 can be prevented from coming into contact with the counter electrode active material layer 40 and the counter electrode current collector 750. This prevents a short circuit from occurring, improving the reliability of the battery 701. Note that the insulating member 80 may cover the entire protrusion 711 in a plan view.

[0155] 17 , the positions of the outer edges of the insulating member 80 in the positive and negative y-axis directions coincide with the positions of the outer edges of the solid electrolyte layer 30, the electrode active material layer 20, and the electrode current collector 710. For example, at the ends of the unit cell 760 in the positive and negative y-axis directions, the side surfaces of the insulating member 80, the electrode current collector 710, the electrode active material layer 20, and the solid electrolyte layer 30 are flush with each other. Note that the arrangement of the insulating member 80 at the ends in the positive and negative y-axis directions may be the same as that of any of the unit cells 60, 60a, and 60b described above in FIGS. 1 , 6, and 7 .

[0156] In unit cells other than the unit cell 760 according to the above-described embodiment and each modified example, an electrode current collector 710 may be used in place of the electrode current collector 10, and a counter electrode current collector 750 may be used in place of the counter electrode current collector 50.

[0157] [3. Manufacturing Method] Next, a method for manufacturing the battery according to the present embodiment and each of the modified examples of the present embodiment will be described. The following mainly describes a method for manufacturing the battery 701 according to the modified example 4 of the embodiment, but other batteries can also be manufactured by appropriately applying the manufacturing method described below. Figure 19 is a flowchart showing a method for manufacturing the battery 701 according to the modified example 4 of the embodiment. Note that the manufacturing method for the battery 701 described below is an example, and the manufacturing method for the battery 701 is not limited to the following example.

[0158] First, in the manufacturing method of the battery 701, an electrode current collector 10 without a protrusion 711 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 so that a third region 73 not covered by the electrode active material layer 20 is provided at the end of each of the main surfaces 11 and 12 in the positive x-axis direction. Note that when manufacturing a battery in which the electrode active material layer 20 or the like is not laminated on the main surface 12 side of the battery 1 or the like, the electrode active material layer 20 is laminated only on the main surface 11.

[0159] 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 so that a second region 72 that is not covered by the solid electrolyte layer 30 is provided at the end of the electrode active material layer 20 in the positive x-axis direction.

[0160] Next, the counter electrode active material layer 40 is laminated on the side of the solid electrolyte layer 30 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 so that a first region 71 that is not covered by the counter electrode active material layer 40 is provided at the end of the solid electrolyte layer 30 in the positive x-axis direction.

[0161] When laminating the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, a high-pressure pressing process (step S15) is performed as necessary after each of steps S12 to S14. This results in a laminated electrode plate 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 to the main surface 12 of the electrode current collector 10.

[0162] The electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are each formed in this order by, for example, a wet coating method. By using the wet coating method, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 can be easily laminated on the electrode current collector 10. As the wet coating method, a coating method such as a die coating method, a doctor blade method, a roll coater method, a screen printing method, or an inkjet method can be used, but the wet coating method is not limited to these methods.

[0163] When the wet coating method is used, a coating step is carried out in which materials for forming the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are appropriately mixed with a solvent to obtain a slurry.

[0164] The solvent used in the paint-making step may be a known solvent used in producing a known all-solid-state battery (for example, a lithium-ion all-solid-state battery).

[0165] The slurries for each layer obtained in the coating process are applied to both main surfaces 11 and 12 of the electrode current collector 10 in the order of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. In this case, the next layer may be applied after the previous layer has been applied, or the next layer may be applied while the previous layer is being applied. In other words, steps S12, S13, and S14 may be performed simultaneously in parallel.

[0166] The slurry for each layer is applied sequentially, and after all layers have been applied, a high-pressure pressing process (step S15) is performed to promote the filling of the material for each layer. The high-pressure pressing process may be performed after each layer is applied. For example, the high-pressure pressing process may be performed after each layer is applied in the coating lamination of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, or may be performed separately after any two layers are applied and after one layer is applied, or may be performed all at once after all three layers are applied. When the high-pressure pressing process is performed two or more times, the pressing may be performed so that the pressure of the final high-pressure pressing process is the highest. For example, a roll press, a plate press, or an isostatic pressing (ISP) may be used for the high-pressure pressing process.

[0167] When the wet coating method is used, a heat treatment is performed to remove the solvent before the high-pressure pressing. The heat treatment is performed, for example, after each application of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, but may also be performed all at once after the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are laminated. At least one of the heat treatment and the high-pressure pressing may not be performed.

[0168] By performing the layered coating method in this manner, it is possible to improve the bonding strength and reduce the interfacial resistance at the interfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. It is also possible to improve the bonding strength and reduce the grain boundary resistance in the powder materials used in the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. That is, good interfaces are formed between the layers 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.

[0169] The above steps S12 to S15 may be performed in a continuous process such as a roll-to-roll process.

[0170] The laminated electrode plate may have a size in plan view corresponding to one unit cell 760, or may be sized in plan view so that it can be divided into individual units and used for multiple unit cells 760. FIG. 20 is a top view showing an example of a laminated electrode plate 90. As shown in FIG. 20 , the laminated electrode plate 90 has a third region 73, a second region 72, and a first region 71 at both ends on the positive and negative sides of the x-axis. The laminated electrode plate 90 also has two electrode active material layers 20, two solid electrolyte layers 30, and two counter electrode active material layers 40, which are arranged on both sides of the electrode current collector 10 in the stacking direction. FIG. 20 shows the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 arranged on one side of the electrode current collector 10 in the stacking direction (the positive side of the z-axis).

[0171] The battery 701 can also be manufactured by using such a laminated electrode plate 90 in the manufacturing process of the battery 701 and dicing the laminated electrode plate 90 into the shape of a single unit cell 760 at any stage before the completion of the battery 701. This can improve manufacturing efficiency. For example, the laminated electrode plate 90 is diced by cutting at least the center of the laminated electrode plate 90 in the x-axis direction along the y-axis direction. This dicing may also be performed by cutting in step S19, which will be described later. After dicing the laminated electrode plate 90, polishing or the like may be performed to adjust the size.

[0172] Next, the electrode current collector 710 is formed by forming a protrusion 711 on the electrode current collector 10 (step S16). The protrusion 711 is formed, for example, by removing a portion of the third region 73. For the removal process, a blade such as a cutter, slitter, cutting machine, or punching machine with a Thomson blade, or a laser or jet may be used, but the method is not limited to these. Alternatively, a separately prepared foil or the like having the shape of the protrusion 711 may be bonded to the electrode current collector 10. For this bonding, a method such as ultrasonic welding, resistance welding, or crimping may be used, but the method is not limited to these. The protrusion 711 may be formed at any stage in the manufacturing of the battery 701. Alternatively, in step S11, the electrode current collector 710 on which the protrusion 711 is formed in advance may be prepared. If a battery including the electrode current collector 10 is manufactured, step S16 is omitted.

[0173] Next, an insulating member 80 is formed to cover a portion of the third region 73 facing the second region 72, the entire second region 72, and a portion of the first region 71 facing the second region 72, and to extend beyond the electrode active material layer 20 and the electrode current collector 10 in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction (step S17). This results in a laminated electrode plate further formed with the insulating member 80. The insulating member 80 is formed, for example, by applying and curing a flowable resin material. The application is performed by inkjet printing, screen printing, extrusion, or by immersing the end surfaces of the laminated electrode plate in the resin material. The curing is performed by drying, heating, cooling, light irradiation, or the like, depending on the resin material used. Furthermore, when forming the insulating member 80, a portion of the third region 73 may be protected by masking with tape or resist treatment to prevent the entire third region 73 of the main surfaces 11 and 12 of the electrode current collector 10 from being insulated. After forming the insulating member 80, the member used for protection described above is removed, thereby ensuring electrical connection in the third region 73. The insulating member 80 may also be formed by attaching insulating tape, but the method is not limited to these. When manufacturing a battery other than the battery 701, the position where the insulating member 80 is formed is adjusted as necessary.

[0174] In manufacturing the battery 701, the same number of laminated electrode plates as the number of unit cells 760 included in the battery 701 are formed by the above steps S11 to S17. The laminated electrode plates may be large laminated electrode plates 90 as shown in Fig. 20 with insulating members 80 formed thereon, or may be laminated electrode plates corresponding to the size of the unit cells 760.

[0175] Next, a counter electrode current collector 750 is stacked on the side of the counter electrode active material layer 40 opposite the solid electrolyte layer 30, and multiple unit cells 760 are stacked together (steps S18 and S19). For example, the multiple laminated electrode plates obtained up to step S17 and multiple counter electrode current collectors 750 are stacked such that the counter electrode current collector 750 is stacked on the side of the counter electrode active material layer 40 opposite the solid electrolyte layer 30. This results in multiple unit cells 760, each having the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 750 stacked in this order on both main surfaces 11 and 12 of the electrode current collector 710. At this time, the counter electrode current collector 750 is stacked on the counter electrode active material layer 40 such that a fourth region 74 not covered by the counter electrode current collector 750 is provided at the end of the counter electrode active material layer 40 in the positive x-axis direction. When manufacturing a battery including the counter electrode current collector 50, 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. When manufacturing a battery formed of one unit cell such as the battery 1, step S19 is omitted.

[0176] In manufacturing the battery 701, for example, the counter electrode current collector 750 and the laminated electrode plates obtained up to step S17 are alternately stacked, so that the counter electrode current collector 750 is shared by adjacent unit cells 760, and the stacking of the counter electrode current collector 750 on the counter electrode active material layer 40 and the stacking of the multiple unit cells 760 are performed. Alternatively, the counter electrode current collector 750 may be stacked on only one of the two counter electrode active material layers 40 of the laminated electrode plate to form a unit cell having a structure in which one counter electrode current collector 750 is removed from the unit cell 760, and this unit cell may be stacked. The counter electrode current collector 750 may also be shared by adjacent unit cells 760 by stacking this unit cell so that the counter electrode active material layers 40 sandwich the counter electrode current collector 750. In this case, after stacking the required number of unit cells, the counter electrode current collector 750 is stacked on the counter electrode active material layer 40 at the end in the stacking direction and thus on which no counter electrode current collector 750 is stacked. At this time, the counter electrode active material layer 40 and the counter electrode current collector 750 are bonded together by, for example, high-pressure pressing. The bonding may also be performed by coating with an adhesive or by attaching an adhesive film. The bonding method is not limited to these methods. Heat treatment may also be performed during or after bonding.

[0177] The counter electrode current collector 750 may be formed to a desired size before stacking, or may be partially removed after stacking. Also, the protrusion 751 may be formed after stacking.

[0178] In addition, when two adjacent unit cells 760 do not share a counter electrode current collector 750 and two counter electrode current collectors 750 are arranged between the counter electrode active material layers 40, in step S18, a laminate (unit cell 760) is obtained in which the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 750 are laminated in this order on both main surfaces 11 and 12 of the electrode current collector 710. Then, in step S19, the obtained unit cells 760 are stacked. At this time, the unit cells 760 are bonded to each other using a conductive adhesive layer formed by coating an adhesive or laminating an adhesive film. However, the bonding method is not limited to these methods. Furthermore, heat treatment and pressing may be performed after bonding.

[0179] Next, the stack of unit cells 760 obtained in step S19 is cut along a direction intersecting the main surface 11 to form cut surfaces as side surfaces 62, 63, and 64 at the respective ends of the unit cells 760 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction (step S20). This cutting results in three sides that define the ends of the unit cells 760 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, different from the ends where the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided, in a planar view. Cutting may be performed using a blade such as a cutter, an ultrasonic cutter, a slitter, a dicer, a cutting machine, a punching machine with a Thomson blade, a laser, or a jet, but is not limited to these methods. Furthermore, to prevent short circuits, the side surfaces 62, 63, and 64 may be polished after cutting to remove burrs and the like.

[0180] In step S20, all of the unit cells 760 are cut together in a direction intersecting the main surface 11. Furthermore, in each unit cell 760, the electrode current collector 710, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 750 are cut together in a direction intersecting the main surface 11. Specifically, the direction intersecting the main surface 11 is a direction perpendicular to the main surface 11, which can also be considered the stacking direction of the unit cells 760. This eliminates the need to stack the electrode current collector 710, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 750 in the shapes after cutting, thereby facilitating the manufacture of the battery 701. Furthermore, because the regions including the first region 71, the second region 72, the third region 73, and the fourth region 74 remain uncut, it is possible to form terminals with a structure that can suppress the occurrence of short circuits. This allows the manufacture of a highly reliable battery 701 with ease. Furthermore, since the capacitance of the unit cell 760 can be adjusted by the position where the unit cell 760 is cut, the capacitance precision can be improved.

[0181] At the cut surface, the respective side surfaces of the electrode current collector 710, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 750 are exposed. After cutting, a sealing member or the like may be disposed to cover these exposed side surfaces in order to protect them. That is, when these side surfaces are covered with another member such as a sealing member, these exposed side surfaces may also be covered with the other member.

[0182] Through the above steps, a battery 701 having a structure in which a plurality of unit cells 760 are stacked is obtained. The obtained battery 701 may be housed in an exterior body or the like. When the battery 701 is housed in an exterior body, the protrusions 711 and 751 are extended to the outside of the exterior body. Furthermore, the obtained battery 701 may be subjected to a process of removing corners (intersections of the side surfaces) in a plan view by cutting or the like. In this case, when removing a corner in the positive x-axis direction, for example, a portion including the first region 71, the second region 72, the third region 73, and the fourth region 74 is removed. This removes corners that are prone to collapse and breakage, thereby further improving the reliability of the battery 701.

[0183] Note that step S20 may be performed before step S18. For example, after step S17, in step S19, the laminated electrode plate obtained up to step S17 is cut along a direction intersecting the main surface 11 to form cut surfaces at the ends of the laminated electrode plate in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction. At this time, the electrode current collector 710, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are cut collectively along a direction intersecting the main surface 11. Then, in steps S18 and S19, the plurality of laminated electrode plates after the cut surfaces are formed are stacked with a plurality of counter electrode current collectors 750 having shapes corresponding to the shapes of the laminated electrode plates after the cut surfaces are formed. This results in a battery 701 having a structure in which a plurality of unit cells 760 are stacked. Also, the formation of the cut surfaces in step S20 may be performed on each of the unit cells 760 before stacking formed in step S18. In this case, in step S19, the unit cells 760 with the cut surfaces formed are stacked to obtain the battery 701.

[0184] Furthermore, in cases where the insulating member 80 is formed so as to extend beyond the electrode active material layer 20 and the electrode current collector 10 in the positive and negative y-axis directions, step S20 may be performed before step S17. For example, after step S16, steps S20, S17, S18, and S19 may be performed in this order.

[0185] While the battery according to the present disclosure has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as the modifications do not deviate from the gist of the present disclosure, modifications that would occur to those skilled in the art and other forms constructed by combining some of the components of the embodiments are also included in the scope of the present disclosure.

[0186] In the above-described embodiment, the battery is composed of 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, or 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 thereto. For example, within the range of allowable battery characteristics, a bonding layer or the like may be provided between each layer of the battery to reduce electrical resistance and improve bonding strength.

[0187] In the above embodiment, the electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer are formed by sequentially stacking them directly on the main surface of the electrode current collector, but this is not limited thereto. For example, the electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may be formed by sequentially stacking them on a sheet-like substrate, and the formed electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may be removed from the substrate and stacked on the main surface of the electrode current collector. Alternatively, the electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may be formed on a sheet-like substrate, and the formed electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may be stacked by sequentially transferring them to the main surface of the electrode current collector.

[0188] Furthermore, various modifications, substitutions, additions, omissions, etc. can be made to each of the above-described embodiments within the scope of the claims or their equivalents.

[0189] The battery according to the present disclosure can be used as a secondary battery such as an all-solid-state battery used in various electronic devices, electrical appliances, automobiles, etc.

[0190] REFERENCE SIGNS LIST 1, 1a, 1b, 101, 501, 601, 701 Battery 10, 710 Electrode current collector 11, 12 Main surface 20 Electrode active material layer 21, 31, 41 Inclined surface 22, 32 Recess 30 Solid electrolyte layer 40 Counter electrode active material layer 50, 750 Counter electrode current collector 60, 60a, 60b, 160, 560, 760 Unit cell 61, 62, 63, 64 Side surface 71 First region 72 Second region 73 Third region 74 Fourth region 80 Insulating member 90 Laminated electrode plate 711, 751 Protruding portion

Claims

1. A battery comprising a unit cell having: an electrode current collector; an electrode active material layer disposed on a main surface of the electrode current collector; an electrolyte layer disposed on the side of the electrode active material layer opposite the electrode current collector; a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer; a counter electrode current collector disposed on the side of the counter electrode active material layer opposite the electrolyte layer; and an insulating member, wherein, in a plan view relative to the main surface of the electrode current collector, the electrode active material layer is larger than the counter electrode active material layer, and a first region that is not covered by the counter electrode active material layer in the plan view is provided at an end of the electrolyte layer in a first direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector, and the insulating member covers at least a part of the first region and a part of the electrode active material layer in the plan view, and protrudes beyond the electrode active material layer in at least one of the first direction and a second direction that is orthogonal to the first direction in the plan view.

2. The battery according to claim 1, wherein a second region that is not covered by the electrolyte layer in the plan view is provided at an end of the electrode active material layer in the first direction, and the insulating member covers at least a portion of the second region in the plan view.

3. The battery according to claim 1, wherein a third region not covered by the electrode active material layer is provided at an end in the first direction of the main surface of the electrode current collector, and the insulating member covers at least a portion of the third region in the plan view.

4. A battery according to any one of claims 1 to 3, wherein the length of the insulating member in the second direction is longer than the length of the end of the electrode active material layer in the first direction, and the insulating member protrudes beyond the electrode active material layer in the second direction in the planar view.

5. The battery according to claim 4, wherein the difference between the length of the insulating member in the second direction and the length of the end of the electrode active material layer in the first direction in the second direction is 0.05 mm or more and 5 mm or less.

6. The battery according to any one of claims 1 to 3, wherein the insulating member protrudes beyond the electrode current collector in the first direction in the plan view.

7. The battery according to any one of claims 1 to 3, wherein the insulating member covers at least a portion of at least one of the side surfaces of the electrode current collector on the first direction side and the side surface on the second direction side.

8. The battery according to claim 7, wherein a gap is provided between the insulating member and the at least one side surface of the electrode current collector.

9. The battery according to any one of claims 1 to 3, wherein the electrode current collector has a protrusion in which a part of an end of the electrode current collector in the first direction protrudes in the first direction, and the insulating member covers at least a part of the protrusion in the plan view.

10. The battery according to any one of claims 1 to 3, wherein a fourth region that is not covered by the counter electrode current collector in the plan view is provided at an end of the counter electrode active material layer in the first direction, and the insulating member covers at least a portion of the fourth region.

11. The battery according to claim 10, wherein the insulating member does not cover the counter electrode current collector in the plan view.

12. The battery according to claim 10, wherein the thickness of the portion of the insulating member covering the fourth region is equal to or less than half the thickness of the counter electrode current collector.

13. The battery according to any one of claims 1 to 3, wherein at an end of the unit cell in a direction from the center toward the outer edge of the main surface of the electrode current collector and in a direction different from the first direction, 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 with each other.

14. The battery according to any one of claims 1 to 3, wherein at an end of the unit cell in a direction from the center toward the outer edge of the main surface of the electrode current collector and in a direction different from the first direction, the side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer, the counter electrode active material layer, and the counter electrode current collector are flush with each other.

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