Battery

Abstract

To provide a battery having high reliability and capable of improving energy density.SOLUTION: The battery 1 includes a container 95, an electrode group 5 housed in the container 95, and a lead wire 91 electrically connected to the electrode group 5. The electrode group 5 includes a unit cell 60 including 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. A first region 71 that is not covered with the electrode active material layer 20 is provided at an end of the main surface 11 of the electrode current collector 10. The unit cell 60 has an insulating layer 80 that covers at least a part of the electrode current collector 10, at least a part of the electrode active material layer 20, and at least a part of the solid electrolyte layer 30 at the end portion. The electrode collector 10 has a joint part 16 joined to the lead wire 91. Joint portion 16 is located at a portion where the end portion of electrode collector 10 is folded back, and overlaps insulating layer 80 in plan view.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[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. In the battery described in Patent Document 1, non-facing portions are provided at the ends of the electrode active material layer and the solid electrolyte layer.

[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, steps are provided in the electrode active material layer and the counter electrode active material layer, and an insulating layer is disposed on the counter electrode current collector.

[0004] Patent Document 3 describes a battery in which a battery element is wrapped in an exterior film. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-129519 [Patent Document 2] Japanese Patent Publication No. 2022-104137 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-251855 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a battery that is highly reliable and can improve energy density. [Means for solving the problem]

[0007] a first lead wire partly disposed within the container and electrically connected to the electrode group within the container, the electrode group 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 opposite side of the electrode active material layer from the electrode current collector, a counter electrode active material layer disposed on the opposite side of the electrolyte layer from the electrode active material layer, and a counter electrode current collector disposed on the opposite side of the counter electrode active material layer from the electrolyte layer, a first region that is not covered by the electrode active material layer is provided at an end of a main surface of the electrode current collector in a first direction, which is a direction toward the electrode; and the unit cell has an insulating layer that covers at least a part of the electrode current collector, at least a part of the electrode active material layer, and at least a part of the electrolyte layer at the end in the first direction, and one of the electrode current collector and the counter electrode current collector has a first joint portion joined to the first lead wire, and the first joint portion is located at a portion where the end of the one current collector in the first direction is folded back, and overlaps with the insulating layer in the plan view. [Effects of the Invention]

[0008] According to the present disclosure, a battery that is highly reliable and can improve energy density can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a top view of a battery according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the battery according to the embodiment. [Figure 3] FIG. 3 is another cross-sectional view of the battery according to the embodiment. [Figure 4] FIG. 4 is a bottom view of the electrode group according to the embodiment. [Figure 5] FIG. 5 is a cross-sectional view of a unit cell according to the embodiment. [Figure 6]FIG. 6 is a cross-sectional view of another unit cell according to the embodiment. [Figure 7] FIG. 7 is a cross-sectional view of yet another unit cell according to the embodiment. [Figure 8] FIG. 8 is a flowchart showing a method for manufacturing a battery according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (How one aspect of the present disclosure was achieved) In a battery equipped with an electrode group having unit cells each having a stacked structure 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, contact between electrodes of opposite polarity at the end of the unit cell can cause conduction, i.e., a short circuit. Therefore, high resistance to short circuits is important for long-term use of the battery. Furthermore, an electrical connection structure may be formed at the end of the unit cell. 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] Also, batteries are known in which the electrode group is housed in a container to protect the electrode group from the atmosphere, moisture, and the like. However, housing the electrode group in a container increases the area of ​​the battery. Furthermore, when viewed from above, if the ratio of the area occupied by the electrode active material layer and the counter electrode active material layer in the container decreases, the volumetric energy density of the battery may decrease. Furthermore, in order to extract current from the electrode group in the container, a lead wire may be electrically connected to the electrode group and drawn out from the container. In such cases, the connection portion between the lead wire and the electrode group occupies a certain area within the container, further increasing the area of ​​the battery and potentially decreasing the energy density of the battery.

[0012] The present disclosure has been made in view of these problems, and aims to provide a battery that is highly reliable and capable of improving energy density.

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

[0014] A battery according to a first aspect of the present disclosure includes a container, an electrode group housed in the container, and a first lead wire partially disposed within the container and electrically connected to the electrode group within the container, the electrode group including 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, and a counter electrode current collector disposed on the side of the counter electrode active material layer opposite the electrolyte layer, A first 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 a first direction, which is a direction toward the edge, and the unit cell has an insulating layer that covers at least a portion of the electrode current collector, at least a portion of the electrode active material layer, and at least a portion of the electrolyte layer at the end in the first direction, and one of the electrode current collector and the counter electrode current collector has a first joint portion joined to the first lead wire, and the first joint portion is located at a portion where the end of the one current collector in the first direction is folded back, and overlaps the insulating layer in the planar view.

[0015] This allows the insulating layer to protect the ends of the unit cells, which are prone to collapse and contact with components of opposite polarity, thereby improving the reliability of the battery. Furthermore, the first joint portion, located where the end of one current collector in the first direction is folded back, overlaps with the insulating layer in a plan view, allowing the first joint portion to be positioned closer to the center of the electrode assembly. As a result, the distances between the electrode active material layer, electrolyte layer, and counter electrode active material layer and the position where the first lead wire is drawn out to the outside of the container can be shortened, preventing the battery from becoming larger, thereby improving the energy density of the battery.

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

[0017] This allows the second and third regions to increase the distance between the electrode current collector and the electrode active material layer and the counter electrode active material layer at the ends of the unit cell in the first direction. As a result, short circuits caused by contact between electrodes of opposite polarity are less likely to occur. This improves the reliability of the battery. Furthermore, the insulating layer prevents the materials of the electrode active material layer and electrolyte layer from collapsing in the second and third regions.

[0018] Furthermore, for example, a battery according to a third aspect of the present disclosure may be the battery according to the second aspect, wherein the electrode active material layer has an inclined surface in the second region that is inclined so as to approach the electrode current collector as it progresses in the first direction, and the electrolyte layer has an inclined surface in the third region that is inclined so as to approach the electrode current collector as it progresses in the first direction.

[0019] This reduces the likelihood of corners forming in the electrode active material layer in the second region and the electrolyte layer in the third region, making it less likely for the materials in these layers to fall off, and therefore reducing the likelihood of short circuits, thereby improving the reliability of the battery.

[0020] Furthermore, for example, a battery according to a fourth aspect of the present disclosure may be a battery according to the second or third aspect, in which the electrode active material layer has a recess in the third region into which the electrolyte layer is recessed.

[0021] This increases the bonding strength between the electrode active material layer and the electrolyte layer at the end of the unit cell in the first direction, making it less likely that the materials of these layers will fall off and less likely that short circuits will occur due to contact between electrodes of opposite polarity.

[0022] Furthermore, for example, a battery according to a fifth aspect of the present disclosure may be the battery according to the second aspect, wherein a fourth region that is not covered by the counter electrode current collector in the plan view is provided at an end of the counter electrode active material layer in the first direction, and the insulating layer further covers at least a portion of the fourth region.

[0023] As a result, at the end of the unit cell in the first direction, the fourth region can further increase the distance between the electrode current collector and the electrode active material layer and the counter electrode current collector, making it even less likely that a short circuit will occur and improving the reliability of the battery.

[0024] Furthermore, for example, a battery according to a sixth aspect of the present disclosure may be the battery according to the fifth aspect, wherein the electrode active material layer has, in the second region, an inclined surface that is inclined so as to approach the electrode current collector as it progresses in the first direction; the electrolyte layer has, in the third region, an inclined surface that is inclined so as to approach the electrode current collector as it progresses in the first direction; and the counter electrode active material layer has, in the fourth region, an inclined surface that is inclined so as to approach the electrode current collector as it progresses in the first direction.

[0025] This reduces the likelihood of corners forming in the electrode active material layer in the second region, the electrolyte layer in the third region, and the counter electrode active material layer in the fourth region, making it less likely for the materials in these layers to fall off, thereby reducing the likelihood of short circuits, thereby improving the reliability of the battery.

[0026] For example, a battery according to a seventh aspect of the present disclosure may be the battery according to the fifth or sixth aspect, wherein the electrode active material layer has a recess in the third region into which the electrolyte layer is recessed, and the electrolyte layer has a recess in the fourth region into which the counter electrode active material layer is recessed.

[0027] This increases the bonding strength between the electrode active material layer and the electrolyte layer and between the electrolyte layer and the counter electrode active material layer at the ends of the unit cell in the first direction, making it less likely that the materials of these layers will fall off and less likely that short circuits will occur due to contact between electrodes of opposite polarity.

[0028] Furthermore, for example, a battery according to an eighth aspect of the present disclosure is a battery according to any one of the second to seventh aspects, wherein the first bonding portion may overlap with at least one of the electrode active material layer, the electrolyte layer, and the counter electrode active material layer when viewed from the first direction side.

[0029] This makes it possible to suppress an increase in the thickness of the electrode group and a decrease in the volumetric energy density of the battery, even when the first joint portion overlaps with the insulating layer in a plan view.

[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 first joint portion is located at a portion where a part of an end portion of one of the current collectors in the first direction protrudes in the first direction more than the other part of the end portion and is folded back.

[0031] This limits the area where the first joint portion is provided to a part of the end of one current collector, making it possible to prevent the end of one current collector from coming into contact with a member of the opposite polarity, making it less likely that a short circuit will occur.

[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, in which the one current collector is the electrode current collector.

[0033] This bonds the first lead wire to the electrode current collector.

[0034] Furthermore, for example, a battery according to an eleventh aspect of the present disclosure is the battery according to any one of the first to ninth aspects, and the one current collector may be the counter electrode current collector.

[0035] This bonds the first lead wire to the counter electrode current collector.

[0036] Also, for example, a battery according to a twelfth aspect of the present disclosure may be a battery according to any one of the first to eleventh aspects, wherein the container is made of one or more laminate films and has a sealed portion in which the one or more laminate films sandwich and seal the first lead wire.

[0037] This allows the electrode group to be sealed by the container.

[0038] Furthermore, for example, a battery according to a thirteenth aspect of the present disclosure may be a battery according to any one of the first to twelfth aspects, comprising a second lead wire, a portion of which is disposed within the container and electrically connected to the electrode group within the container, and the other current collector of the electrode collector and the counter electrode collector has a second joint portion joined to the second lead wire, the second joint portion being located at a portion where an end of the other current collector in the first direction is folded back, and overlapping with the insulating layer in the planar view.

[0039] This allows the second joint portion, located where the end of the other current collector in the first direction is folded back, to overlap with the insulating layer in a plan view, allowing the second joint portion to be positioned closer to the center of the electrode assembly. As a result, the distances between the electrode active material layer, electrolyte layer, and counter electrode active material layer and the position where the second lead wire is drawn out to the outside of the container can be shortened, preventing the battery from becoming larger in area, and improving the energy density of the battery.

[0040] Furthermore, for example, a battery according to a fourteenth aspect of the present disclosure may be a battery according to the thirteenth aspect, wherein the first joint portion is located at a portion where a part of an end portion of one of the current collectors in the first direction protrudes in the first direction more than the other part of the end portion and is folded back, and the second joint portion is located at a portion where a part of an end portion of the other current collector in the first direction protrudes in the first direction more than the other part of the end portion and is folded back.

[0041] This limits the area where the first joint portion is provided to a portion of the end of one current collector, preventing the end of one current collector from contacting a member of the opposite polarity, making short circuits less likely to occur.Furthermore, by limiting the area where the second joint portion is provided to a portion of the end of the other current collector, preventing the end of the other current collector from contacting a member of the opposite polarity, making short circuits less likely to occur.

[0042] Hereinafter, the embodiments will be specifically 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 the present specification and drawings, the x-axis, y-axis, and z-axis refer to the three axes of a three-dimensional Cartesian coordinate system. The x-axis and y-axis are parallel to the main surface of the electrode current collector, and the z-axis is perpendicular to the main surface of the electrode current collector. When the battery has a rectangular shape in plan view, the x-axis and y-axis are parallel to the first side of the rectangle and the second side perpendicular to the first side, respectively. The z-axis is the stacking direction of each layer of the unit cell and multiple unit cells. In the present specification, the "stacking direction" corresponds to the normal direction of the main surfaces of the current collector and the active material layer. In the present specification, unless otherwise specified, the term "plan view" refers to a view from a direction perpendicular to the main surface of the electrode group (the z-axis direction). In the case of a flat member such as a plate, layer, foil, film, or a laminate containing any of these, the "main surface" refers to the main surface of the member, for example, the surface with the largest area, or the surface located opposite the surface with the largest area and having an area equivalent to the surface with the largest area.

[0047] In this specification, the direction along the x-axis toward the positive side is referred to as the "x-axis positive direction." In the following, the direction along the x-axis toward the negative side is referred to as the "x-axis negative direction." In the following, the direction along the y-axis toward the positive side is referred to as the "y-axis positive direction." In the following, the direction along the y-axis toward the negative side is referred to as the "y-axis negative direction." The x-axis positive direction and the x-axis negative direction are perpendicular to each other, and the y-axis positive direction and the y-axis negative direction are opposite to each other.

[0048] 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."

[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 to avoid confusion between and distinguish between components of the same type.

[0050] (Embodiment) [1. Configuration] First, the configuration of the battery according to the embodiment will be described.

[0051] [1-1. Overall structure] 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. 4 is a bottom view of an electrode group 5 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 of the vicinity of the end of the battery 1 on the positive side of the x-axis, within the position indicated by line II-II in FIG. 1. FIG. 3 is a cross-sectional view of the vicinity of the end of the battery 1 on the positive side of the x-axis, within the position indicated by line III-III in FIG. 1. FIG. 4 shows the planar shape of the electrode group 5 together with lead wires 91 and 92 when viewed from the negative side of the z-axis after removing the adhesive protective film 93 and the container 95 from the battery 1.

[0052] In FIG. 1, the outlines of the electrode group 5 and the lead wires 91 and 92 in the container 95 are shown by dashed lines. For ease of understanding, a dotted pattern is applied to the area corresponding to the seal portion 95S in FIG. 1. In FIG. 4, the outlines of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 that overlap the insulating layer 80 are shown by dashed lines. In FIG. 4, the outlines of the protrusion 15 that overlaps the lead wire 91 and the protrusion 55 that overlaps the lead wire 92 are shown by dashed lines. In FIG. 4, the outlines of the areas corresponding to the joint portions 16 and 56 are shown by dashed lines for ease of understanding.

[0053] As shown in FIGS. 1 to 4 , the battery 1 includes a container 95, an electrode group 5 housed in the container 95, lead wires 91 and 92 electrically connected to the electrode group 5 within the container 95, and an adhesive protective film 93. The electrode group 5 is sealed inside the container 95. Portions of the lead wires 91 and 92 are disposed within the container 95, and other portions are drawn out to the outside of the container 95 and protrude from the container 95. The lead wire 91 is an example of one of the first lead wire and the second lead wire. The lead wire 92 is an example of the other of the first lead wire and the second lead wire.

[0054] The electrode group 5 includes a plurality of unit cells 60 stacked on top of one another. In the example shown in Figures 2 and 3, the electrode group 5 includes two unit cells 60, but this is not particularly limited. The number of unit cells included in the electrode group 5 may be one, or three or more.

[0055] The planar shapes of the battery 1, electrode group 5, and unit cell 60 are rectangular as shown in FIG. 1 . Here, "rectangular" means substantially rectangular. As long as the approximate outer shape is rectangular, parts of the outer edges may have protrusions, chamfers, or the like. The general shape of the battery 1, electrode group 5, and 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 electrode group 5 is, for example, 10 mm or more and 500 mm or less. The planar shapes of the battery 1, electrode group 5, and unit cell 60 may be polygonal, such as a square, hexagon, or octagon, or may be circular or elliptical. In the drawings related to this specification, the thickness of each layer of the unit cell 60 is exaggerated to make the structure of the battery 1 easier to understand.

[0056] [1-2. Unit cell] The unit cell 60 will be described below with reference to FIG. 5. FIG. 5 is a cross-sectional view of the unit cell 60 according to this embodiment. FIG. 5 shows a cross section of the unit cell 60 near the end of the unit cell 60 in the x-axis positive direction when the unit cell 60 is cut along the xz plane. FIG. 5 also shows a cross section of the unit cell 60 at a position where the protrusions 15 and 55 are not formed.

[0057] 2 to 5 , a unit cell 60 includes 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 the unit cell 60, the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 are stacked in this order along the z-axis. In the example shown, the unit cell 60 includes one electrode current collector 10, and two of each 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. 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. The unit cell 60 also has an insulating layer 80 at the end on the positive x-axis direction that covers at least a portion of the electrode current collector 10, at least a portion of the electrode active material layer 20, at least a portion of the solid electrolyte layer 30, and at least a portion of the counter electrode active material layer 40.

[0058] The multiple unit cells 60 have the same configuration and are stacked so as to be electrically connected 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. In the illustrated example, two adjacent unit cells 60 share a counter electrode current collector 50. Alternatively, two adjacent unit cells 60 may not share a counter electrode current collector 50, but each have their own counter electrode current collector 50, with two counter electrode current collectors 50 overlapping between the counter electrode active material layers 40. In this case, a conductive adhesive layer may be provided between the two counter electrode current collectors 50.

[0059] A first region 71, a second region 72, a third region 73, and a fourth region 74 are provided at the end of the unit cell 60 in the positive x-axis direction. The positive x-axis direction is an example of a first direction, which is a direction from the center of the electrode current collector 10 toward the outer edge in a plan view. In addition, 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 60 in the first region 71, the second region 72, the third region 73, and the fourth region 74 easier to understand. Details of the first region 71, the second region 72, the third region 73, and the fourth region 74 will be described later.

[0060] 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 on the positive x-axis side. Side face 62 is the side face of the unit cell 60 on the negative x-axis side. Side face 63 is the side face of the unit cell 60 on the positive y-axis side. Side face 64 is the side face of the unit cell 60 on the negative y-axis side.

[0061] The side surfaces 62, 63, and 64 of the unit cell 60 are composed of the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50, and at least a portion of each may be flat. When the side surfaces 62, 63, and 64 are flat, 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 surface. 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 electrode group 5. Furthermore, since the side surfaces of the layers can be flush by cutting the layers together, for example, the electrode group 5 can be manufactured more easily.

[0062] The side surfaces 62, 63, and 64 are, for example, cut surfaces. Specifically, the side surfaces 62, 63, and 64 are surfaces formed by cutting with a blade such as a cutter, and are surfaces having cut marks such as fine grooves. By being cut surfaces, the side surfaces of each layer of the unit cell 60 can be easily made flush. The cut marks may be smoothed by polishing, for example. The shape of the cut surfaces is not limited.

[0063] As shown in FIG. 4, when the shape of unit cell 60 is rectangular in plan view, side surfaces 61, 62, 63, and 64 each form one side of the rectangle of unit cell 60 in plan view.

[0064] Furthermore, the multiple unit cells 60 are stacked so that the positions of the side surfaces of the unit cells 60 coincide when viewed from the stacking direction. Therefore, the side surfaces 62, 63, and 64 of the multiple unit cells 60 are flush with each other.

[0065] In the unit cell 60, a laminated structure of 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 is formed on each of the main surfaces 11 and 12 of the electrode current collector 10. A structure similar to the laminated 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 formed on the main surface 11 of the electrode current collector 10 is also formed upside down on the main surface 12 of the electrode current collector 10 opposite the main surface 11. Therefore, the unit cell 60 has a laminated structure symmetrical with respect to the electrode current collector 10. This makes it possible to extract current from two electrode active material layers 20 from one electrode current collector 10, thereby increasing the volumetric energy density. Furthermore, the symmetrical laminated structure makes it less likely that stress will be different on both sides of the electrode current collector 10 in the stacking direction when the unit cell 60 is densified by pressing or the like, thereby suppressing warping of the unit cell 60. 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 1, 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 60 can be suppressed.

[0066] Two electrode active material layers 20 are disposed on both main surfaces 11 and 12 of the electrode current collector 10. Two solid electrolyte layers 30 are disposed on each of the two electrode active material layers 20, on the side opposite the electrode current collector 10. Two counter electrode active material layers 40 are disposed on each of the two solid electrolyte layers 30, on the side 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, on the side opposite the solid electrolyte layer 30.

[0067] The electrode current collector 10 is in contact with the electrode active material layer 20 on each of its main surfaces 11 and 12. 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 average value of the entire thickness unless otherwise specified.

[0068] 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.

[0069] 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 counter electrode active material layer 40. The counter electrode current collector 50 shared by the two unit cells 60 is sandwiched between the two counter electrode active material layers 40 and is in contact with each of the two counter electrode active material layers 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.

[0070] 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.

[0071] The electrode active material layer 20 is disposed on both main surfaces 11 and 12 of the electrode current collector 10. The surface of the electrode active material layer 20 opposite the electrode current collector 10 side 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 area of ​​the electrode active material layer 20 is larger than the area of ​​the counter electrode active material layer 40. The thickness of the electrode active material layer 20 is, for example, 5 μm or more and 300 μm or less. The materials used for the electrode active material layer 20 will be described later.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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 an 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.

[0076] 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.

[0077] As the sulfide solid electrolyte, for example, a composite of lithium sulfide (Li2S) and diphosphorus pentasulfide (P2S5) is used in the case of a material capable of conducting lithium ions. Alternatively, sulfides such as Li2S-SiS2, Li2S-B2S3, or Li2S-GeS2 may be used as the sulfide solid electrolyte, or sulfides obtained by adding at least one of Li3N, LiCl, LiBr, Li3PO4, and Li4SiO4 as an additive to the above sulfides may be used.

[0078] As oxide solid electrolytes, materials that can conduct lithium ions include, for example, Li7La3Zr2O12 (LLZ), Li 1.3 Al 0.3 Ti 1.7 (PO4)3(LATP) or (La,Li)TiO3(LLTO) are used.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] Positive electrode active materials may be known materials capable of absorbing and releasing (inserting and desorbing, or dissolving and depositing) lithium ions, sodium ions, or magnesium ions. Positive electrode active materials capable of extracting and inserting lithium ions include, for example, transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal oxysulfides, transition metal oxynitrides, sulfur, and lithium-containing compounds thereof. Examples of lithium-containing transition metal oxides include Li(NiCoAl)O2, Li(NiCoMn)O2, and LiCoO2. Li(NiCoAl)O2 refers to a material containing Ni, Co, and Al in any ratio. Li(NiCoMn)O2 refers to a material containing Ni, Co, and Mn in any ratio.

[0083] 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.

[0084] 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.

[0085] 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, the negative electrode active material may be, 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.

[0086] 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.

[0087] Next, the end structure of the unit cell 60 will be described.

[0088] 2 to 5, 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 an upper or lower 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. 4). In addition, in the unit cell 60, the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided on both the main surface 11 side and the main surface 12 side of the electrode current collector 10.

[0089] Specifically, a first region 71 that is not covered by the electrode active material layer 20 is provided at the end of each of the main surfaces 11 and 12 of the electrode current collector 10 in the positive x-axis direction. The first region 71 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 the 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 third region 73 that is not covered by the counter electrode active material layer 40 in a plan view is provided at the end of the solid electrolyte layer 30 in the positive x-axis direction. The third region 73 is not in contact with the counter electrode active material layer 40 or the counter electrode current collector 50. The third region 73 is farther from the electrode current collector 10 than the second region 72. 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 third region 73.

[0090] Thus, the provision of the first region 71 facilitates electrical connection between the electrode current collector 10 and the lead wire 91. Furthermore, it is possible to prevent the material of the electrode active material layer 20 from crumbling and coming into contact with the counter electrode current collector 50 and the lead wire 92 electrically connected to the counter electrode current collector 50. Furthermore, the second region 72, the third region 73, and the fourth region 74 increase 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, as well as 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. As a result, short circuits and the like caused by contact between electrodes of opposite polarity are less likely to occur. This improves the reliability of the battery 1.

[0091] 4, first region 71, second region 72, third region 73, and fourth region 74 are provided along side surface 61 in plan view. First region 71, second region 72, third region 73, and fourth region 74 are elongated in plan view, and in the example shown in Fig. 4, the direction perpendicular to the x-axis positive direction (y-axis direction) is the longitudinal direction. Furthermore, fourth region 74, third region 73, second region 72, and first region 71 are arranged in this order along the x-axis positive direction in plan view.

[0092] The length in the positive x-axis direction of the portion of first region 71 where protrusion 15 is not formed, second region 72, third region 73, and fourth region 74 is, for example, not less than 0.1 mm and not more than 5 mm. This allows both the energy density and reliability of battery 1 to be achieved. The length in the positive x-axis direction of the portion of first region 71 where protrusion 15 is not formed, second region 72, third region 73, and fourth region 74 may be, for example, not less than 0.5 mm and not more than 2 mm.

[0093] 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 of 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 third region 73 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 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.

[0094] As shown in FIG. 5 and other drawings, 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 direction of the x-axis. The entire second region 72 is, for example, the region where the inclined surface 21 is formed. The solid electrolyte layer 30 has, in the third region 73, an inclined surface 31 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive direction of the x-axis. The entire third region 73 is, for example, the region where the inclined surface 31 is formed. 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 direction of the x-axis. The entire fourth region 74 is, for example, the region where the inclined surface 41 is formed. In the example shown in FIG. 5 and other drawings, 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.

[0095] 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 third region 73, 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 short circuits less likely to occur. This improves the reliability of the battery 1.

[0096] These inclined surface shapes can be formed, for example, by performing a high-pressure pressing process such as a roll press on 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 so that the first region 71, the second region 72, and the third region 73 are formed at the end.

[0097] The angle that each of the inclined surfaces 21, 31, and 41 forms with respect to the main surfaces 11 and 12 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 surfaces 11 and 12 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 surfaces 11 and 12 is, for example, 1 degree or more.

[0098] As shown in FIG. 5 and other figures, the electrode active material layer 20 has a recess 22 in the third region 73 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 vertically at the end portion 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 electrodes of opposite polarity. This recessed shape can be formed, for example, by performing a high-pressure press, such as a roll press, on a portion of the stack including the end portion of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 stacked on the electrode current collector 10 so that the first region 71, the second region 72, and the third region 73 are formed at the end portion.

[0099] The depth of each of the recesses 22 and 32 is, for example, not less than 1 μm and not more than 10 μm.

[0100] 5 and other examples, 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 in the positive x-axis direction. Therefore, at the outer edge position 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.

[0101] The first region 71, the second region 72, the third region 73, and the fourth region 74 may be provided at the end of the unit cell 60 in the negative x-axis direction, the positive y-axis direction, or the negative y-axis direction in addition to or instead of the end of the unit cell 60 in the positive x-axis direction. For example, the first region 71, the second region 72, the third region 73, and the fourth region 74 may be provided at both the end of the unit cell 60 in the positive x-axis direction and the end of the unit cell 60 in the negative x-axis direction.

[0102] Next, the insulating layer 80 disposed at the end of the unit cell 60 in the x-axis positive direction will be described.

[0103] As shown in FIGS. 2 to 5 , the insulating layer 80 covers a portion of the first region 71 on the second region 72 side, the entire second region 72, the entire third region 73, and a portion of the fourth region 74 on the third region 73 side. This allows the electrode current collector 10 and the electrode active material layer 20 to be covered by the insulating layer 80 extending from the first region 71 and the second region 72 to the fourth region 74, significantly 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. This improves the reliability of the battery 1. Furthermore, because the insulating layer 80 covers the ends 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, the ends of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 can be prevented from collapsing due to external force, etc.

[0104] The insulating layer 80 is in contact with a part of the first region 71 on the second region 72 side, the entire second region 72, the entire third region 73, and a part of the fourth region 74 on the third region 73 side. The insulating layer 80 covers the entire first region 71 except for the protruding portion 15. The insulating layer 80 does not cover the protruding portion 15, but may cover a part of the protruding portion 15. The insulating layer 80 does not cover the counter electrode current collector 50. In the unit cell 60, the insulating layer 80 is disposed on both the main surface 11 side and the main surface 12 side of the electrode current collector 10.

[0105] Furthermore, the height of the insulating layer 80 from the main surface 11 (in other words, the distance from the main surface 11 to the surface of the insulating layer 80 opposite the electrode current collector 10) is equal to or less than the distance from the main surface 11 to the main surface of the counter electrode current collector 50 facing the electrode current collector 10. This allows the space above the insulating layer 80 to be used effectively. The height of the insulating layer 80 from the main surface 12 is the same as the height from the main surface 11.

[0106] It is sufficient that the insulating layer 80 covers at least a portion of the first region 71, at least a portion of the second region 72, and at least a portion of the third region 73. For example, the insulating layer 80 does not have to cover the fourth region 74. Furthermore, the insulating layer 80 may cover the entirety of the first region 71, the second region 72, the third region 73, and the fourth region 74 in the longitudinal direction (y-axis direction) of the first region 71, the second region 72, and the third region 73 in a plan view, or may cover only a portion of them.

[0107] The insulating layer 80 has electronic insulation properties. The insulating layer 80 may also have electronic insulation properties and ionic insulation properties. For example, an insulating tape or an insulating resin is used for the insulating layer 80. Examples of resins used for the insulating tape and the insulating resin include silicone resin, epoxy resin, acrylic resin, and polyimide resin. The resin may be a thermosetting resin or an ultraviolet-curing resin. By including a resin in the insulating layer 80, the bonding strength of the insulating layer 80 to the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30 can be improved by, for example, an anchor effect in which the resin penetrates into the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30. The insulating layer 80 may also include a solid electrolyte. The solid electrolyte may be any of the solid electrolyte materials exemplified above. The solid electrolyte may be the same material as the solid electrolyte material used for the solid electrolyte layer 30.

[0108] The insulating layer 80 is, for example, a film having a uniform thickness, but the thickness of the insulating layer 80 does not have to be uniform. The insulating layer 80 may have a thickness that increases in the positive x-axis direction, for example.

[0109] Next, the end structures of the electrode current collector 10 and the counter electrode current collector 50 in the unit cell 60 will be described with reference to FIGS.

[0110] 2 to 4, the electrode current collector 10 has a protrusion 15, which is a portion of an end of the electrode current collector 10 in the positive x-axis direction that protrudes further in the positive x-axis direction than the remaining portion of the end and is folded back in the negative x-axis direction. The protrusion 15 is folded back so that the tip of the protrusion 15 overlaps the insulating layer 80 in a plan view. The protrusion 15 protrudes further in the positive x-axis direction than the electrode active material layer 20. In the illustrated example, a portion of the first region 71 of the electrode current collector 10 protrudes in the positive x-axis direction to form the protrusion 15. The protrusions 15 of the electrode current collectors 10 included in the electrode group 5 are positioned at the same position in the y-axis direction and overlap in a plan view.

[0111] The counter electrode current collector 50 has a protruding portion 55, which is a portion of an end portion of the counter electrode current collector 50 in the positive x-axis direction that protrudes in the positive x-axis direction further than the remaining portion of the end portion and is folded back in the negative x-axis direction. The protruding portion 55 is folded back so that the tip of the protruding portion 55 overlaps the insulating layer 80 in plan view. The protruding portion 55 protrudes in the positive x-axis direction further than the counter electrode active material layer 40, and further protrudes in the positive x-axis direction further than the electrode active material layer 20. The protruding portions 55 of the counter electrode current collectors 50 included in the electrode group 5 are positioned at the same position in the y-axis direction and overlap in plan view.

[0112] The protrusion 55 faces the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30 via the insulating layer 80. The protrusion 15 and the protrusion 55 are arranged in positions that do not overlap in a plan view.

[0113] Furthermore, the protrusions 15 and 55 in each unit cell 60 protrude in the same direction, specifically in the positive x-axis direction. The length of each of the protrusions 15 and 55 is, for example, 5 mm or more and 20 mm or less.

[0114] The electrode current collector 10 has a joint portion 16 joined to the lead wire 91. The joint portion 16 is an example of one of a first joint portion and a second joint portion. The joint portion 16 is joined to the lead wire 91 so as to overlap the lead wire 91 in a plan view. The joint portion 16 is located at the protrusion 15. In FIG. 2, the joint portion 16 is the portion of the protrusion 15 surrounded by a two-dot chain line. The protrusions 15 of each electrode current collector 10 of the multiple unit cells 60 are folded back toward the negative x-axis side and bundled together at the joint portion 16. At the joint portion 16, the surface of the protrusion 15 of the electrode current collector 10 is bonded to the lead wire 91 directly or via the protrusion 15 of another electrode current collector 10. The bundled protrusions 15 are also bonded together at the joint portion 16. In the example shown in FIG. 2, the joint portion 16 is arranged so as not to be sandwiched between the multiple unit cells 60.

[0115] The bonding portion 16 is located within the container 95 and overlaps with the insulating layer 80 in a planar view. In the example shown in FIGS. 2 and 4 , the bonding portion 16 entirely overlaps with the insulating layer 80 in a planar view. The bonding portion 16 also overlaps with the electrode current collector 10 and the electrode active material layer 20 (more specifically, the first region 71 and the second region 72) in a planar view. The bonding portion 16 may also overlap with the solid electrolyte layer 30 (more specifically, the third region 73). The bonding portion 16 does not overlap with the counter electrode active material layer 40 (more specifically, the fourth region 74) in a planar view, for example. The bonding portion 16 faces the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 with the insulating layer 80 interposed therebetween.

[0116] In this way, the joint portion 16 located at the protruding portion 15, which is the portion that protrudes further in the x-axis positive direction than the electrode active material layer 20 and is folded back, overlaps with the insulating layer 80 in a plan view, allowing the joint portion 16 to be positioned closer to the center of the electrode group 5. As a result, in a plan view, the distances between the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 and the position where the lead wire 91 is drawn out to the outside of the container 95 can be shortened, preventing the battery 1 from becoming larger in area, thereby improving the energy density of the battery 1. Furthermore, the joint portion 16 overlaps with at least one of the first region 71, the second region 72, and the third region 73 in which at least one of the electrode active material layer 20 and the counter electrode active material layer 40 is not disposed in a plan view, thereby overlapping regions that do not contribute to power generation within the container 95, thereby preventing a decrease in energy density.

[0117] Furthermore, the joint portion 16 overlaps with at least one of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 when viewed from the positive side of the x-axis. As a result, even when the joint portion 16 overlaps with the insulating layer 80 in a plan view, the spaces above the first region 71, the second region 72, and the third region 73 can be effectively utilized to suppress an increase in the thickness of the electrode group 5. This prevents a decrease in the volumetric energy density of the battery 1. The total thickness of the protrusions 15 bundled together at the joint portion 16 is smaller than, for example, the total thickness of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40.

[0118] The counter electrode current collector 50 has a joint portion 56 joined to the lead wire 92. The joint portion 56 is an example of the other of the first joint portion and the second joint portion. The joint portion 56 is joined to the lead wire 92 so as to overlap the lead wire 92 in a plan view. The joint portion 56 is located at the protruding portion 55. In FIG. 3 , the joint portion 56 is the portion of the protruding portion 55 surrounded by a two-dot chain line. The protruding portions 55 of each counter electrode current collector 50 of the multiple unit cells 60 are folded back toward the negative x-axis side and bundled together at the joint portion 56. At the joint portion 56, the surface of the protruding portion 55 of the counter electrode current collector 50 is bonded to the lead wire 92 directly or via the protruding portion 55 of another counter electrode current collector 50. The bundled protruding portions 55 are also bonded together at the joint portion 56. In the example shown in FIG. 3 , the joint portion 56 is arranged so as not to be sandwiched between the multiple unit cells 60. The joint portion 16 and the joint portion 56 are, for example, at the same position in the positive x-axis direction.

[0119] The joint portion 56 is located within the container 95 and overlaps with the insulating layer 80 in a planar view. In the example shown in FIGS. 3 and 4 , the joint portion 56 entirely overlaps with the insulating layer 80 in a planar view. The joint portion 56 also overlaps with the electrode current collector 10 and the electrode active material layer 20 (more specifically, the first region 71 and the second region 72) in a planar view. The joint portion 56 may also overlap with the solid electrolyte layer 30 (more specifically, the third region 73). For example, the joint portion 56 does not overlap with the counter electrode active material layer 40 (more specifically, the fourth region 74) in a planar view. The joint portion 56 faces the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 with the insulating layer 80 interposed therebetween.

[0120] In this way, the joint portion 56 located at the protruding portion 55, which is the portion that protrudes further in the x-axis positive direction than the counter electrode active material layer 40 and is folded back, overlaps with the insulating layer 80 in a plan view, allowing the joint portion 56 to be positioned closer to the center of the electrode group 5. As a result, in a plan view, the distances between the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 and the position where the lead wire 92 is drawn out to the outside of the container 95 can be shortened, preventing the battery 1 from becoming larger in area, thereby improving the energy density of the battery 1. Furthermore, the joint portion 56 overlaps with at least one of the first region 71, the second region 72, and the third region 73 in which at least one of the electrode active material layer 20 and the counter electrode active material layer 40 is not disposed in a plan view, allowing the regions that do not contribute to power generation in the container 95 to overlap, thereby preventing a decrease in energy density.

[0121] Furthermore, when viewed from the positive side of the x-axis, the joint portion 56 overlaps with at least one of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. As a result, even when the joint portion 56 overlaps with the insulating layer 80 in a plan view, the spaces above the first region 71, the second region 72, and the third region 73 can be effectively utilized to suppress an increase in the thickness of the electrode group 5. This prevents a decrease in the volumetric energy density of the battery 1. The total thickness of the protrusions 55 bundled together at the joint portion 56 is smaller than, for example, the total thickness of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40.

[0122] [1-3. Lead wire, adhesive protective film and container] The lead wires 91 and 92 are each a long plate- or foil-shaped member made of a metal such as nickel, stainless steel, aluminum, or copper. The thickness of the lead wires 91 and 92 is greater than the thickness of the electrode current collector 10 and the counter electrode current collector 50, for example.

[0123] A portion of each of lead wires 91 and 92 is disposed within container 95 and is drawn out from the end of container 95 facing the positive x-axis direction. Lead wire 91 is electrically connected to electrode current collector 10 at joint portion 16. Lead wire 91 is joined to joint portion 16 at the end facing the negative x-axis direction and extends in the positive x-axis direction. Lead wire 92 is electrically connected to counter electrode current collector 50 at joint portion 56. Lead wire 92 is joined to joint portion 56 at the end facing the negative x-axis direction and extends in the positive x-axis direction.

[0124] Adhesive protective film 93 surrounds lead wires 91 and 92 at positions where lead wires 91 and 92 are pulled out from container 95, and is disposed between lead wire 91 and container 95 and between lead wire 92 and container 95. Adhesive protective film 93 is made of an insulating material that can be heat-sealed to both lead wires 91 and 92 and container 95. By disposing adhesive protective film 93 between lead wire 91 and container 95 and between lead wire 92 and container 95, it is possible to ensure the airtightness of container 95 and the insulation between lead wires 91 and 92 and container 95.

[0125] The container 95 is made up of, for example, one or more laminate films. In the example shown in FIGS. 1 to 3 , the container 95 is made up of two laminate films. The two laminate films are arranged to sandwich the electrode group 5 and the lead wires 91 and 92. The container 95 has a seal portion 95S formed by heat-sealing two laminate films together around the periphery of the container 95 in a plan view. The seal portion 95S seals the container 95 with the electrode group 5 housed in it. At the end on the positive x-axis direction, the seal portion 95S seals the two laminate films, sandwiching the lead wires 91 and 92 with an adhesive protective film 93 interposed between them. Note that the container 95 may also be made up of a single laminate film. In this case, the single laminate film is folded to sandwich the electrode group 5 and the lead wires 91 and 92, and the seal portion 95S is formed in areas other than the folded portion. Therefore, the periphery of container 95 other than the end in the x-axis positive direction from which lead wires 91 and 92 are drawn out may have a portion where seal portion 95S is not disposed.

[0126] A known laminate film can be used for the laminate film. The laminate film has a laminate structure of, for example, a resin layer made of a thermoplastic resin such as a polyethylene resin or a polypropylene resin and a metal layer made of a metal such as aluminum. In the laminate structure, both ends in the stacking direction are made of resin layers, and a metal layer is disposed between the resin layers on both ends. Note that the laminate structure of the laminate film is not shown in each drawing.

[0127] The container 95 is not limited to a laminate film, and may be a battery container made of other materials.

[0128] [1-4. Another example of a unit cell] In the unit cell 60 described above, a laminated 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 each of the main surfaces 11 and 12 of the electrode current collector 10, but this is not limited to this. FIG. 6 is a cross-sectional view of another unit cell 60a according to this embodiment. FIG. 6 shows a cross-section of the unit cell 60a near the end of the unit cell 60a in the x-axis positive direction when the unit cell 60a is cut along the xz plane. FIG. 6 also shows a cross-section of the unit cell 60a at a position where the protrusions 15 and 55 are not formed.

[0129] In the unit cell 60a, a laminated 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 only on one main surface 11 of the electrode current collector 10. The laminated structure formed on the main surface 11 of the electrode current collector 10 in the unit cell 60a is the same as the laminated structure formed on the main surface 11 of the electrode current collector 10 in the unit cell 60 described above. As a unit cell constituting the electrode group 5, instead of multiple unit cells 60, a single unit cell 60a may be used, or multiple unit cells 60a stacked on top of each other may be used. When the unit cell 60a is used as a unit cell constituting the electrode group 5, for example, the protrusions 15 and 55 are folded back so that the joint portions 16 and 56 are positioned on the main surface 11 side of the electrode current collector 10.

[0130] In the unit cell 60a, the insulating layer 80 also covers the end face of the electrode current collector 10 in the positive x-axis direction other than the location where the protrusion 15 is formed. Note that, in the unit cell 60a, as in the unit cell 60, the end face of the electrode current collector 10 in the positive x-axis direction does not have to be covered. In the unit cell 60, the insulating layer 80 may also cover the end face of the electrode current collector 10 in the positive x-axis direction.

[0131] Furthermore, in the unit cells 60 and 60a, the structure of the end portion in the positive x-axis direction is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction, but this is not limited to this. FIG. 7 is a cross-sectional view of yet another unit cell 60b according to this embodiment. FIG. 7 shows a cross-section of the unit cell 60b near the end portion in the positive x-axis direction of the unit cell 60b when the unit cell 60b is cut in the xz plane. FIG. 7 also shows a cross-section of the unit cell 60b at a position where the protrusions 15 and 55 are not formed.

[0132] As shown in FIG. 7 , the unit cell 60b has a stepped structure at its end in the positive x-axis direction, which is formed by 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. As the unit cells constituting the electrode group 5, instead of the multiple unit cells 60, a single unit cell 60b may be used, or multiple unit cells 60b stacked on top of each other may be used. Furthermore, the stacked structure stacked on the main surface 11 of the unit cell 60b may also be stacked on the main surface 12. In other words, the end of the unit cell 60 in the positive x-axis direction may have a stepped structure like the unit cell 60b.

[0133] [2. Manufacturing method] Next, a method for manufacturing the battery 1 according to the present embodiment will be described. Fig. 8 is a flowchart showing the method for manufacturing the battery 1 according to embodiment 1. Note that the method for manufacturing the battery 1 described below is an example, and the method for manufacturing the battery 1 is not limited to the following example.

[0134] First, in the method for manufacturing the battery 1, an electrode current collector 10 on which no protrusions 15 are formed is prepared (step S11). Next, electrode active material layers 20 are laminated on both main surfaces 11 and 12 of the electrode current collector 10 (step S12). At this time, the electrode active material layers 20 are laminated on the main surfaces 11 and 12 so that first regions 71 that are not covered by the electrode active material layer 20 are provided at the ends of the main surfaces 11 and 12 in the positive x-axis direction. When manufacturing a battery having unit cells such as the unit cell 60a on which the electrode active material layer 20 is not laminated on the main surface 12 side, the electrode active material layer 20 is laminated only on the main surface 11.

[0135] 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.

[0136] 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 third region 73 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.

[0137] 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 after each of steps S12 to S14 as necessary. 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 and 12 side on both main surfaces 11 and 12 of the electrode current collector 10. In addition, the high-pressure pressing process forms inclined surfaces 21, 31, and 41.

[0138] 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.

[0139] 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.

[0140] 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).

[0141] 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 electrode active material layer 20, solid electrolyte layer 30, and 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.

[0142] The slurry for each layer is applied sequentially, and after all layers are applied, a high-pressure pressing process (step S15) is performed to promote 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. Furthermore, 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, and then again after all three layers are applied. When the high-pressure pressing process is performed two or more times, the pressure in the final high-pressure pressing process may be the highest. For the high-pressure pressing process, for example, a roll press, a plate press, or an isostatic pressing (ISP) may be used.

[0143] 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 laminating the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. Note that at least one of the heat treatment and the high-pressure pressing may not be performed.

[0144] 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, electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40. It is also possible to improve the bonding strength and reduce the grain boundary resistance of the powder materials used in the electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40. That is, good interfaces are formed between the electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 and between the powder materials within each layer.

[0145] The above steps S12 to S15 may be performed in a continuous process such as a roll-to-roll method.

[0146] Furthermore, the laminated electrode plate formed up to step S15 may be of a size in plan view sufficient to form one unit cell 60, or may be of a size in plan view sufficient to be diced into individual pieces and used to form multiple unit cells 60.

[0147] Next, protrusions 15 are formed on the electrode current collector 10 (step S16). The protrusions 15 are formed, for example, by removing a portion of the first region 71. This results in the formation of protrusions 15 in an unfolded state. 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. Note that the formation of the protrusions 15 may be performed at any stage in the manufacture of the battery 1, as long as it is before the formation of the bonding portion 16. Alternatively, in step S11, an electrode current collector 10 on which the protrusions 15 have been formed in advance may be prepared.

[0148] Next, an insulating layer 80 is formed at the end portion in the positive x-axis direction to cover at least a portion of the electrode current collector 10, at least a portion of the electrode active material layer 20, at least a portion of the solid electrolyte layer 30, and at least a portion of the counter electrode active material layer 40 (step S17). This results in a laminated electrode plate further formed with the insulating layer 80. The insulating layer 80 is formed, for example, by applying and curing a flowable resin material. The application is performed by an inkjet method, a screen printing method, or by dipping the end surface of the laminated electrode plate in the resin material. The curing is performed by drying, heating, or light irradiation, depending on the resin material used. Furthermore, when forming the insulating layer 80, a protective process may be performed by masking with tape or resist treatment on the areas where the insulating layer 80 is not to be formed, so that only the desired areas are covered with the insulating layer 80. After the insulating layer 80 is formed, the protective member used above is removed. The insulating layer 80 may also be formed by applying insulating tape. The method for forming the insulating layer 80 is not limited to these methods.

[0149] In manufacturing the battery 1, the same number of laminated electrode plates as the number of unit cells 60 included in the battery 1 are formed by the above steps S11 to S17.

[0150] Next, a counter electrode current collector 50 is stacked on the side of the counter electrode active material layer 40 opposite the solid electrolyte layer 30, and multiple unit cells 60 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 50 are stacked such that the counter electrode current collector 50 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 60, each having the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 stacked in this order on both main surfaces 11 and 12 of the electrode current collector 10. At this time, the counter electrode current collector 50 is stacked on the counter electrode active material layer 40 such that a fourth region 74 not covered by the counter electrode current collector 50 is provided at the end of the counter electrode active material layer 40 in the positive x-axis direction.

[0151] In manufacturing the battery 1, for example, the counter electrode current collector 50 and the laminated electrode plate obtained up to step S17 are alternately stacked, so that the counter electrode current collector 50 is shared between two adjacent unit cells 60, and the counter electrode current collector 50 is stacked on the counter electrode active material layer 40 and multiple unit cells 60 are stacked. At this time, the counter electrode active material layer 40 and the counter electrode current collector 50 are bonded together by, for example, a high-pressure press process. The bonding method is not limited to these methods. Heat treatment may also be performed during or after the bonding. Alternatively, a unit cell having a structure in which one counter electrode current collector 50 is removed from the unit cell 60 may be formed by stacking the counter electrode current collector 50 only on one of the two counter electrode active material layers 40 of the laminated electrode plate, and then stacking these unit cells. The counter electrode current collector 50 may also be shared between the adjacent unit cells 60 by stacking these unit cells so that the counter electrode active material layers 40 sandwich the counter electrode current collector 50. In this case, after stacking the required number of unit cells, the counter electrode current collector 50 is stacked on the counter electrode active material layer 40 at the end in the stacking direction and therefore on which the counter electrode current collector 50 is not stacked.

[0152] Counter electrode current collector 50 may be formed to the desired dimensions and shape before lamination, or a portion of counter electrode current collector 50 may be removed after lamination. Also, protrusion 55 may be formed after lamination. In step S19, counter electrode current collector 50 is used without protrusion 55 being folded back.

[0153] Next, the stack of unit cells 60 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 60 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 constitute the ends of the unit cells 60 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.

[0154] In step S20, all of the unit cells 60 are cut together in a direction intersecting the main surface 11. Furthermore, in each 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 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 as the stacking direction of the unit cells 60. This eliminates the need to stack 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 in the shapes after cutting, thereby facilitating the manufacture of the battery 1. Furthermore, the capacity of the unit cells 60 can be adjusted by the position at which the unit cells 60 are cut, thereby improving capacity accuracy.

[0155] At the cut surface, 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 are exposed. After cutting, a sealing member or the like may be placed to cover these exposed side surfaces in order to protect them. That is, when these side surfaces are covered with another member such as a sealing member, these exposed side surfaces may also be covered with the other member.

[0156] Next, a lead wire 91 is joined to the electrode current collector 10 to form a joint portion 16, and a lead wire 92 is joined to the counter electrode current collector 50 to form a joint portion 56 (step S21). This results in an electrode group 5 in which the lead wires 91 and 92 are electrically connected. Specifically, the protrusions 15 of the electrode current collectors 10 of the multiple unit cells 60 are bundled near their tips, and the bundled protrusions 15 are joined to the lead wire 91 to form the joint portion 16. The protrusions 15 on which the joint portion 16 is formed are then folded back toward the negative x-axis direction so that the joint portion 16 overlaps the insulating layer 80 in a plan view. The protrusions 55 of the counter electrode current collectors 50 of the multiple unit cells 60 are bundled near their tips, and the bundled protrusions 55 are joined to the lead wire 92 to form the joint portion 56. The protrusions 55 on which the joint portion 56 is formed are then folded back toward the negative x-axis direction so that the joint portion 56 overlaps the insulating layer 80 in a plan view. The lead wires 91 and 92 are used with, for example, adhesive protective film 93 wrapped around predetermined positions in advance.

[0157] A welding method such as ultrasonic welding is used to join the lead wires 91 and 92 to the electrode current collector 10 and the counter electrode current collector 50. The joining method is not particularly limited, and for example, they may be joined using an adhesive, solder, or the like, or may be joined by crimping.

[0158] Next, the electrode group 5 is housed in the container 95 (step S22). For example, the electrode group 5 is sandwiched between two laminate films that make up the container 95 so that a portion of the lead wires 91 and 92 is exposed, and the peripheral portion of the container 95 in a plan view is heat-sealed to form a sealed portion 95S and seal the container 95. If necessary, a portion of the sealed portion 95S may be removed to adjust the area of ​​the container 95.

[0159] Through the steps described above, the battery 1 is obtained.

[0160] Note that step S20 may be performed before step S18. For example, after step S17, in step S20, the laminated electrode plate obtained up to step S17 is cut along a direction intersecting with 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 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are cut all at once along a direction intersecting with the main surface 11. Thereafter, in steps S18 and S19, the plurality of laminated electrode plates after the cut surfaces have been formed are stacked with a plurality of counter electrode current collectors 50 having a shape corresponding to the shape of the laminated electrode plate after the cut surfaces have been formed. This results in an electrode group 5 having a structure in which a plurality of unit cells 60 are stacked.

[0161] Also, at least one of steps S21 and S22 may be performed before step S20.

[0162] (Other embodiments) 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 they do not deviate from the gist of the present disclosure, various modifications conceivable by those skilled in the art to the embodiments and other forms constructed by combining some of the components of the embodiments are also included in the scope of the present disclosure.

[0163] In the above embodiment, the unit cells 60, 60a, and 60b are provided with the first region 71, the second region 72, the third region 73, and the fourth region 74, but this is not limiting. For example, at least one of the second region 72, the third region 73, and the fourth region 74 may not be provided.

[0164] In the above embodiment, both of the joint portions 16 and 56 overlap the insulating layer 80 at the end of the unit cell 60 facing the positive x-axis direction, and both of the lead wires 91 and 92 are extended from the container 95 in the positive x-axis direction. However, this is not limiting. For example, one of the joint portions 16 and 56 may overlap the insulating layer 80 at the end of the unit cell 60 facing the negative x-axis direction, and one of the lead wires 91 and 92 may be extended from the container 95 in the negative x-axis direction. In this case, the end of the unit cell 60 facing the negative x-axis direction also has a structure similar to that of the end of the unit cell 60 facing the positive x-axis direction, and the insulating layer 80 is disposed thereon. In this case, the electrode current collector 10 and the counter electrode current collector 50 do not necessarily need to have the protrusions 15 and 55. For example, the joint portion 16 may be located at a portion where the entire end of the electrode current collector 10 protrudes outward from the electrode active material layer 20 and is folded back. Furthermore, for example, the joint portion 56 may be located at a portion where the entire end portion of the counter electrode current collector 50 protrudes outward beyond the counter electrode active material layer 40 and is folded back.

[0165] In the above embodiment, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are formed by sequentially stacking them directly on the main surface of the electrode current collector 10, but this is not limiting. For example, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 may be formed by sequentially stacking them on a sheet-like substrate, and the formed electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 may be removed from the substrate and stacked on the main surface of the electrode current collector 10. Alternatively, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 may be formed on a sheet-like substrate, and the formed electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 may be stacked by sequentially transferring them onto the main surface of the electrode current collector 10.

[0166] 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. [Industrial Applicability]

[0167] 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. [Explanation of symbols]

[0168] 1 battery 5 electrode group 10 Electrode current collector 11, 12 Main surfaces 15, 55 protrusion 16, 56 joint part 20 Electrode active material layer 21, 31, 41 Slope 22, 32 recess 30 Solid electrolyte layer 40 Counter electrode active material layer 50 Counter electrode current collector 60, 60a, 60b unit cells 61, 62, 63, 64 Side 71 First area 72 Second area 73 Third area 74 4th area 80 insulating layer 91, 92 Lead wires 93 Adhesive protective film 95 Container

Claims

1. A container and an electrode group housed in the container; a first lead wire, a portion of which is disposed within the container and electrically connected to the electrode group within the container; The electrode group includes: 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 opposite side of the electrode active material layer from the electrode current collector; a counter electrode active material layer disposed on the opposite side of the electrolyte layer from the electrode active material layer; a counter electrode current collector disposed on the opposite side of the counter electrode active material layer from the electrolyte layer; a unit cell having a first region that is not covered with the electrode active material layer is provided at an end of the main surface of the electrode current collector in a first direction that is a direction from the center toward the outer edge of the electrode current collector in a plan view of the main surface of the electrode group, the unit cell has an insulating layer at an end in the first direction that covers at least a portion of the electrode current collector, at least a portion of the electrode active material layer, and at least a portion of the electrolyte layer; one of the electrode current collector and the counter electrode current collector has a first joint portion joined to the first lead wire; The first joint portion is the first current collector is located at a portion where an end portion in the first direction of the first current collector is folded back, overlapping the insulating layer in the plan view; battery.

2. 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; a third 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 the first direction, the insulating layer covers at least a portion of the first region, at least a portion of the second region, and at least a portion of the third region; The battery of claim 1 .

3. the electrode active material layer has, in the second region, an inclined surface that is inclined so as to approach the electrode current collector as it advances in the first direction, the electrolyte layer has, in the third region, an inclined surface that is inclined so as to approach the electrode current collector as it progresses in the first direction; The battery of claim 2.

4. the electrode active material layer is provided with a recess into which the electrolyte layer in the third region is recessed; The battery of claim 2.

5. a fourth region that is not covered by the counter electrode current collector in the plan view is provided at an end portion of the counter electrode active material layer in the first direction, the insulating layer further covers at least a portion of the fourth region; The battery of claim 2.

6. the electrode active material layer has, in the second region, an inclined surface that is inclined so as to approach the electrode current collector as it advances in the first direction, the electrolyte layer has, in the third region, an inclined surface that is inclined so as to approach the electrode current collector as it advances in the first direction, the counter electrode active material layer has, in the fourth region, an inclined surface that is inclined so as to approach the electrode current collector as it progresses in the first direction; The battery of claim 5.

7. the electrode active material layer is provided with a recess into which the electrolyte layer in the third region is recessed, the electrolyte layer is provided with a recess into which the counter electrode active material layer in the fourth region is recessed; The battery of claim 5.

8. the first bonding portion overlaps with at least one of the electrode active material layer, the electrolyte layer, and the counter electrode active material layer when viewed from the first direction side; The battery of claim 2.

9. the first joint portion is located at a portion where a part of an end portion of the one current collector in the first direction protrudes in the first direction more than the other part of the end portion and is folded back. The battery of any one of claims 1 to 8.

10. The one current collector is the electrode current collector. The battery of any one of claims 1 to 8.

11. The one current collector is the counter electrode current collector. The battery of any one of claims 1 to 8.

12. The container comprises: It consists of one or more laminate films, the one or more laminate films have a seal portion where the first lead wire is sandwiched and sealed; The battery of any one of claims 1 to 8.

13. a second lead wire, a portion of which is disposed within the container and electrically connected to the electrode group within the container; the other current collector of the electrode current collector and the counter electrode current collector has a second joint portion joined to the second lead wire, The second joint portion is the other current collector is located at a portion where an end portion in the first direction of the other current collector is folded back, overlapping the insulating layer in the plan view; The battery of any one of claims 1 to 8.

14. the first joint portion is located at a portion where a part of an end portion of the one current collector in the first direction protrudes in the first direction more than another part of the end portion and is folded back, the second joint portion is located at a portion where a part of an end portion of the other current collector in the first direction protrudes in the first direction more than the other part of the end portion and is folded back.

14. The battery of claim 13.

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