Battery and battery manufacturing method

Abstract

A battery (1) comprises a unit cell (60) that has: an electrode current collector (10); an electrode active material layer (20) provided on the main surface of the electrode current collector (10); a solid electrolyte layer (30) provided to the electrode active material layer (20) on the side opposite the electrode current collector (10); a counter electrode active material layer (40) provided to the solid electrolyte layer (30) on the side opposite the electrode active material layer (20); and a counter electrode current collector (50) provided to the counter electrode active material layer (40) on the side opposite the solid electrolyte layer (30). A first region (71) that is not covered by the electrode active material layer (20) is provided at a first-direction end of the main surface (11) of the electrode current collector (10). A second region (72) that is not covered by the solid electrolyte layer (30) is provided, in plan view, at a first-direction end of the electrode active material layer (20). A third region (73) that is not covered by the counter electrode active material layer (40) is provided, in plan view, at a first-direction end of the solid electrolyte layer (30).

Description

Battery and method for manufacturing the battery

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

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

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

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

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

[0006] In the prior art, there is a demand for improved reliability of batteries. Therefore, an object of the present disclosure is to provide a highly reliable battery and the like.

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

[0008] A method for manufacturing a battery according to one aspect of the present disclosure includes stacking a plurality of stacks, each stack 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, and a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, and a plurality of counter electrode current collectors, such that the counter electrode current collector is stacked on the side of the counter electrode active material layer opposite the electrolyte layer, and then pressing the stacked stack together.

[0009] According to the present disclosure, highly reliable batteries and the like can be provided.

[0010] FIG. 1 is a top view of a battery according to embodiment 1. FIG. 2 is a cross-sectional view of the battery according to embodiment 1. FIG. 3 is a cross-sectional view showing another example of the structure of an end portion of a unit cell according to embodiment 1. FIG. 4 is a cross-sectional view of a battery according to modified example 1 of embodiment 1. FIG. 5 is a cross-sectional view of a battery according to modified example 2 of embodiment 1. FIG. 6 is a cross-sectional view of another battery according to modified example 2 of embodiment 1. FIG. 7 is a cross-sectional view of a battery according to modified example 3 of embodiment 1. FIG. 8 is a cross-sectional view of another battery according to modified example 3 of embodiment 1. FIG. 9 is a top view of a battery according to modified example 4 of embodiment 1. FIG. 10 is a cross-sectional view of a battery according to modified example 4 of embodiment 1. FIG. 11 is a cross-sectional view of another battery according to modified example 4 of embodiment 1. FIG. 12 is a cross-sectional view of a battery according to modified example 5 of embodiment 1. FIG. 13 is a cross-sectional view of another battery according to modified example 5 of embodiment 1. FIG. 14 is a cross-sectional view of yet another battery according to modified example 5 of embodiment 1. FIG. 15 is a flowchart showing a manufacturing method of a battery according to modified example 5 of embodiment 1. FIG. 16 is a top view showing an example of a laminated electrode plate. Fig. 17 is a cross-sectional view of a battery according to embodiment 2. Fig. 18 is a cross-sectional view of another battery according to embodiment 2. Fig. 19 is a flowchart showing a method for manufacturing a battery according to embodiment 2.

[0011] (Background to the Achievement of One Aspect of the Present Disclosure) In a battery including a unit cell in which a solid electrolyte layer containing a solid electrolyte is provided and 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, short circuits are likely to occur due to contact between the edge of the electrode active material layer and the counter electrode active material layer or the counter electrode current collector, or between the edge of the counter electrode active material layer and the electrode active material layer or the electrode current collector. In addition, in such batteries, terminals may be formed at the edges of the battery to extract current. In cases where electrode active material layers are formed on both sides of the same electrode current collector, terminals may be formed in areas of the edge of the electrode current collector that are not covered by the electrode active material layer. In these areas, short circuits are likely to occur due to contact between the electrode current collector and the counter electrode active material layer and the counter electrode current collector. Furthermore, when multiple unit cells are stacked, misalignment of the stacked unit cells increases the likelihood of short circuits at the edges. Furthermore, if the edges of the active material layer are exposed, short circuits are more likely to occur due to active material shedding. Thus, the present inventors have focused on the problem that battery reliability is likely to decrease when terminals are formed at the ends of unit cells, and have also focused on the fact that the decrease in battery reliability can be suppressed by the battery manufacturing method.

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

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

[0014] A battery according to a first aspect of the present disclosure includes a unit cell having an electrode current collector, an electrode active material layer disposed on a main surface of the electrode current collector, an electrolyte layer disposed on the side of the electrode active material layer opposite the electrode current collector, a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, and a counter electrode current collector disposed on the side of the counter electrode active material layer opposite the electrolyte layer, wherein 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 that is a direction from the center toward the outer edge of the main surface of the electrode current collector, a second region that is not covered by the electrolyte layer is provided at the end of the electrode active material layer in the first direction in a plan view relative to the main surface of the electrode current collector, and a third region that is not covered by the counter electrode active material layer in the plan view.

[0015] 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 and the counter electrode current collector at the end of the unit cell in the first direction where the first region is provided and where it is easy to form a terminal on the electrode current collector. As a result, short circuits caused by contact between electrodes of opposite polarity are less likely to occur, thereby improving the reliability of the battery.

[0016] and the first region is provided at an end in the first direction of each of the two main surfaces of the electrode current collector, the second region is provided at an end in the first direction of each of the two electrode active material layers, the second region is provided at an end in the first direction of each of the two electrode active material layers, and the third region is provided at an end in the first direction of each of the two electrolyte layers.

[0017] This allows currents of two electrode active material layers to be extracted from one electrode current collector, thereby increasing the volumetric energy density. Furthermore, at the end of the unit cell in the first direction, the distance between the electrode current collector and the electrode active material layer and the counter electrode active material layer and the counter electrode current collector is increased on both main surface sides of the electrode current collector, making it less likely that a short circuit will occur and improving the reliability of the battery.

[0018] Furthermore, for example, a battery according to a third aspect of the present disclosure may be the battery according to the first aspect, wherein a fourth region that is not covered by the counter electrode current collector in the plan view is provided at an end of the counter electrode active material layer in the first direction.

[0019] As a result, at the end of the unit cell in the first direction where the first region is provided and it is easy to form a terminal on the electrode current collector, 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.

[0020] and the first region is provided at an end in the first direction of each of the two electrode active material layers on both main surfaces of the electrode current collector, the second region is provided at an end in the first direction of each of the two electrode active material layers, the third region is provided at an end in the first direction of each of the two electrolyte layers, and the fourth region is provided at an end in the first direction of each of the two counter electrode active material layers.

[0021] This allows currents of two electrode active material layers to be extracted from one electrode current collector, thereby increasing the volumetric energy density. Furthermore, at the end of the unit cell in the first direction, the distance between the electrode current collector and the electrode active material layer and the counter electrode active material layer and the counter electrode current collector is increased on both main surface sides of the electrode current collector, making it less likely that a short circuit will occur and improving the reliability of the battery.

[0022] Furthermore, for example, a battery according to a fifth aspect of the present disclosure may be a battery according to any one of the first to fourth aspects, wherein the 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.

[0023] 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.

[0024] Furthermore, for example, a battery according to a sixth aspect of the present disclosure may be the battery according to the third or fourth 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 that materials from these layers will fall off, thereby reducing the likelihood of short circuits, thereby improving the reliability of the battery.

[0026] Furthermore, for example, a battery according to a seventh aspect of the present disclosure may be a battery according to any one of the first to sixth aspects, wherein the electrode active material layer has a recess in which the electrolyte layer in the third region is recessed.

[0027] 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.

[0028] Furthermore, for example, a battery according to an eighth aspect of the present disclosure may be the battery according to any one of the third, fourth, and sixth aspects, wherein the electrode active material layer is provided with a recess into which the electrolyte layer in the third region is recessed, and the electrolyte layer is provided with a recess into which the counter electrode active material layer in the fourth region is recessed.

[0029] 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.

[0030] For example, a battery according to a ninth aspect of the present disclosure is the battery according to any one of the first to eighth aspects, wherein the unit cell may further include an insulating layer covering 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. For example, a battery according to a tenth aspect of the present disclosure is the battery according to any one of the third, fourth, sixth, and eighth aspects, wherein the unit cell may further include an insulating layer covering 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.

[0031] As a result, the electrode current collector and the electrode active material layer are covered in the first and second regions by the insulating layer that extends to the third region, which significantly reduces the possibility of a short circuit due to contact between the electrode current collector and the electrode active material layer and the counter electrode current collector and the counter electrode active material layer, thereby improving the reliability of the battery.

[0032] Furthermore, for example, a battery according to an eleventh aspect of the present disclosure is the battery according to the tenth aspect, wherein the insulating layer further covers at least a portion of the fourth region.

[0033] This makes it difficult for the electrolyte layer to fall off, and even if the electrolyte layer does fall off, exposure of the electrode active material layer can be avoided, making it difficult for a short circuit to occur due to contact between the counter electrode current collector and the counter electrode active material layer and the electrode current collector and the electrode active material layer.

[0034] Furthermore, for example, a battery according to a twelfth aspect of the present disclosure is the battery according to any one of the ninth to eleventh aspects, wherein a part of an end portion of the counter electrode current collector in the first direction may protrude in the first direction beyond the insulating layer in the plan view.

[0035] This makes it possible to form a terminal on the counter electrode current collector at the end of the battery in the first direction, making the structure less complicated than when the terminal is formed on the main surface of the counter electrode current collector and improving the reliability of the battery.

[0036] Furthermore, for example, a battery according to a thirteenth aspect of the present disclosure may be the battery according to any one of the first to twelfth aspects, wherein at an end of the unit cell in a second direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector and that is different from the first direction, side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer, and the counter electrode active material layer may be flush with each other.

[0037] As a result, while a first region or the like is provided at the end of the unit cell in the first direction, at the end of the unit cell in the second direction different from the first direction, there are no steps on the side surfaces of the electrode active material layer, electrolyte layer, and counter electrode active material layer stacked on the electrode current collector, and no spaces that do not function as a battery are formed due to the steps, thereby improving the effective volumetric energy density of the battery.

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

[0039] This ensures reliability by suppressing short circuits at the ends of the unit cells in the first direction, where it is easy to form terminals, while at the ends of the unit cells in the second direction, there are no steps on the side surfaces of each layer, and no spaces that do not function as a battery are formed due to the steps, thereby improving the actual volumetric energy density of the battery.

[0040] Furthermore, for example, a battery according to a fifteenth aspect of the present disclosure may be a battery according to any one of the first to thirteenth aspects, and may include a plurality of the unit cells, and the plurality of unit cells may be stacked.

[0041] As a result, unit cells that are less likely to short-circuit at the ends in the first direction are stacked, making it possible to achieve a highly reliable stacked battery.

[0042] Furthermore, for example, a method for manufacturing a battery according to a sixteenth aspect of the present disclosure includes stacking a plurality of stacks, each stack 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, and a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, and a plurality of counter electrode current collectors, such that the counter electrode current collector is stacked on the side of the counter electrode active material layer opposite the electrolyte layer, and then pressing the stacked stack together.

[0043] This allows the multiple stacked electrode plates and the multiple counter electrode current collectors to be pressed together, reducing the number of handling steps, and as a result, preventing foreign matter from being trapped between the multiple stacked electrode plates and the multiple counter electrode current collectors, allowing for the production of a highly reliable battery.

[0044] Also, for example, a method for manufacturing a battery according to a seventeenth aspect of the present disclosure may be a method for manufacturing a battery according to the sixteenth aspect, in which at least one of the plurality of laminates has only the electrode current collector as a current collector.

[0045] This makes it possible to stack the counter electrode current collectors so that one counter electrode current collector is shared by adjacent laminated electrode plates without overlapping them, thereby increasing the volumetric energy density.

[0046] Furthermore, for example, a manufacturing method of a battery according to an eighteenth aspect of the present disclosure may be the manufacturing method of a battery according to the sixteenth or seventeenth aspect, wherein each of the plurality of laminates has two of each of the electrode active material layer, the electrolyte layer, and the counter electrode active material layer, the two electrode active material layers are disposed on both main surfaces of the electrode current collector, the two electrolyte layers are disposed on the side of each of the two electrode active material layers opposite the electrode current collector, and the two counter electrode active material layers are disposed on the side of each of the two electrolyte layers opposite the electrode active material layer.

[0047] This allows currents from two electrode active material layers to be extracted from one electrode current collector, thereby increasing the volumetric energy density.

[0048] Furthermore, for example, a manufacturing method of a battery according to a 19th aspect of the present disclosure may be the manufacturing method of a battery according to any one of the 16th to 18th aspects, wherein 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 that is a direction from the center toward the outer edge of the main surface of the electrode current collector, a second region that is not covered by the electrolyte layer in a plan view with respect to the main surface of the electrode current collector, and a third region that is not covered by the counter electrode active material layer in a plan view with respect to the main surface of the electrode current collector.

[0049] 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 and the counter electrode current collector at the end of the unit cell in the first direction where the first region is provided and where it is easy to form a terminal on the electrode current collector. As a result, short circuits caused by contact between electrodes of opposite polarity are less likely to occur, thereby improving the reliability of the battery.

[0050] Furthermore, for example, a method for manufacturing a battery according to a twentieth aspect of the present disclosure may be the method for manufacturing a battery according to the nineteenth aspect, in which the counter electrode current collector has a protrusion in which a part of an end portion in the first direction protrudes in the first direction.

[0051] This makes it possible to form a terminal on the counter electrode current collector at the end of the battery in the first direction, making the structure less complicated than when the terminal is formed on the main surface of the counter electrode current collector and improving the reliability of the battery.

[0052] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] In this specification and the drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional Cartesian coordinate system. The x-axis and y-axis are directions parallel to the main surface of the electrode current collector, and the z-axis is a direction perpendicular to the main surface of the electrode current collector. When the shape of the battery in a plan view is rectangular, the x-axis and y-axis are directions parallel to a first side of the rectangle and a second side perpendicular to the first side, respectively. The z-axis is the stacking direction of the multiple unit cells included in the battery. In this specification, the "stacking direction" coincides with the direction normal to the main surfaces of the current collector and the active material layer. In this specification, the term "plan view" refers to a view perpendicular to the main surface of the electrode current collector, unless otherwise specified.

[0057] 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."

[0058] Furthermore, in this specification, unless otherwise specified, "protruding" means protruding outward from the center of the unit cell in a cross-sectional view perpendicular to the main surface of the electrode current collector. "Element A protrudes from element B" means that the tip of element A protrudes more than the tip of element B in the protruding direction, i.e., the tip of element A is farther from the center of the unit cell than the tip of element B. The "protruding direction" is considered to be a direction parallel to the main surface of the electrode current collector. Furthermore, "protruding portion of element A" means a part of element A that protrudes more than the tip of element B in the protruding direction. Furthermore, element B may be a part other than the protruding portion of element A. The element is, for example, an active material layer, a solid electrolyte layer, an insulating layer, a current collector, etc.

[0059] Furthermore, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing between components of the same type.

[0060] First Embodiment [1. Configuration] First, the configuration of a battery according to a first embodiment will be described with reference to FIGS. 1 and 2. FIG.

[0061] Fig. 1 is a top view of a battery 1 according to this embodiment. Fig. 2 is a cross-sectional view of the battery 1 according to this embodiment. Fig. 1 shows the planar shape of the battery 1 when viewed from the positive side of the z-axis. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1.

[0062] 1 and 2 , a battery 1 according to the present embodiment includes a unit cell 60 having an electrode current collector 10, an electrode active material layer 20, a solid electrolyte layer 30, a counter electrode active material layer 40, 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. As shown in FIG. 2 , the battery 1 is formed from one unit cell 60. The battery 1 is, for example, an all-solid-state battery.

[0063] As shown in Figures 1 and 2, the unit cell 60 has side faces 61 and 62 facing away from each other and side faces 63 and 64 facing away from each other. Side face 61 is the side face of the unit cell 60 facing in the direction moving toward the positive side of the x-axis. Side face 62 is the side face of the unit cell 60 facing in the direction moving toward the negative side of the x-axis. Side face 63 is the side face of the unit cell 60 facing in the direction moving toward the positive side of the y-axis. Side face 64 is the side face of the unit cell 60 facing in the direction moving toward the negative side of the y-axis.

[0064] Hereinafter, the direction along the x-axis toward the positive side will be referred to as the "positive x-axis direction." Hereinafter, the direction along the x-axis toward the negative side will be referred to as the "negative x-axis direction." Hereinafter, the direction along the y-axis toward the positive side will be referred to as the "positive y-axis direction." Hereinafter, the direction along the y-axis toward the negative side will be referred to as the "negative y-axis direction." The positive x-axis direction and the negative x-axis direction are perpendicular to the positive y-axis direction and the negative y-axis direction. The positive x-axis direction and the negative x-axis direction are opposite directions, and the positive y-axis direction and the negative y-axis direction are opposite directions. In this specification, the positive x-axis direction is an example of a first direction, which is a direction from the center toward the outer edge of the main surface 11 of the electrode current collector 10. The negative x-axis direction is a direction from the center toward the outer edge of the main surface 11 of the electrode current collector 10 and is an example of a second direction different from the first direction. The positive y-axis direction or the negative y-axis direction may be the second direction.

[0065] 1 , the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided at the end of the unit cell 60 on the side surface 61 side, but these regions may be provided at the end of the unit cell 60 on the side surface 62 side, the side surface 63 side, or the side surface 64 side. The first region 71, the second region 72, the third region 73, and the fourth region 74 will be described in detail later.

[0066] The planar shape of the battery 1 and the unit cell 60 is rectangular as shown in FIG. 1 . That is, the general shape of the battery 1 and the unit cell 60 is a flattened rectangular parallelepiped. Here, "flat" means that the thickness is shorter than each side or the maximum width of the main surface. Each side or the maximum width of the main surface of the battery 1 and the unit cell 60 is, for example, 10 mm or more and 500 mm or less. The planar shape of the battery 1 and the unit cell 60 may be a polygon, such as a square, hexagon, or octagon, or may be a circle or an ellipse. Note that in the drawings related to this specification, the thickness of each layer is exaggerated to make the layer structure of the unit cell easier to understand. Also, in the drawings related to this specification, the lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 in the positive x-axis direction are exaggerated to make the structure of the unit cell easier to understand.

[0067] 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 planes. When the side surfaces 62, 63, and 64 are flat planes, at least the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are flush with one another and lie on the same flat plane. In other words, at the ends of the unit cell 60 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are flush with one another. Furthermore, at the ends of the unit cell 60 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction, the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 may be flush with each other. This results in no steps on the side surfaces of the layers at the ends of the unit cell 60 where the first region 71, the second region 72, the third region 73, and the fourth region 74 are not provided, and no spaces that do not function as a battery due to the steps are formed, thereby improving the volumetric energy density of the battery 1. Furthermore, since the side surfaces of the layers can be flush with each other by cutting the layers together, for example, the battery 1 can be manufactured more easily.

[0068] The side surfaces 62, 63, and 64 are, for example, cut surfaces. Specifically, the side surfaces 62, 63, and 64 are surfaces formed by cutting with a blade such as a cutter, and are surfaces having, for example, cut marks such as fine grooves. By being cut surfaces, the side surfaces of each layer of the unit cell 60 can be easily made flush. The cut marks may be smoothed by polishing, etc. The shape of the cut surfaces is not limited.

[0069] As shown in FIG. 1, when the unit cell 60 has a rectangular shape in plan view, the side surfaces 61, 62, 63, and 64 each form one side of the rectangle of the unit cell 60 in plan view.

[0070] The unit cell 60 has one each of an electrode current collector 10, an electrode active material layer 20, a solid electrolyte layer 30, a counter electrode active material layer 40, and a counter electrode current collector 50. In a plan view, the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 overlap each other.

[0071] The electrode current collector 10 is in contact with the electrode active material layer 20 on one main surface 11. The thickness of the electrode current collector 10 is, for example, 5 μm or more and 100 μm or less. In this specification, the thickness of the current collector and each layer is the length in the stacking direction, and is the average value of the entire thickness unless otherwise specified.

[0072] 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.

[0073] The counter electrode current collector 50 is disposed on the side of the counter electrode active material layer 40 opposite to the solid electrolyte layer 30 side. The counter electrode current collector 50 is in contact with the upper surface of the counter electrode active material layer 40. The counter electrode current collector 50 faces the electrode current collector 10 with the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 interposed therebetween. The thickness of the counter electrode current collector 50 is, for example, 5 μm or more and 100 μm or less.

[0074] 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.

[0075] The electrode active material layer 20 is disposed on one main surface 11 of the electrode current collector 10. The surface of the electrode active material layer 20 opposite the electrode current collector 10 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] The solid electrolyte layer 30 is an example of an electrolyte layer containing an electrolyte material. The solid electrolyte layer 30 contains at least a solid electrolyte as the electrolyte material, and may contain a binder material as necessary. The solid electrolyte layer 30 may contain a solid electrolyte having lithium ion conductivity. The electrolyte material contained in the solid electrolyte layer 30 is entirely solid electrolyte, except for unavoidable impurities, for example. Note that the electrolyte material used in the solid electrolyte layer 30 may further contain a nonaqueous electrolyte solution, a gel electrolyte solution, or an ionic liquid, as long as it contains a solid electrolyte as a main component. The following describes a case where the electrolyte material contained in the solid electrolyte layer 30 is entirely solid electrolyte.

[0080] 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.

[0081] As the sulfide solid electrolyte, in the case of a material capable of conducting lithium ions, for example, lithium sulfide (Li ２ S) and diphosphorus pentasulfide (P ２ S ５ ) is used. As the sulfide solid electrolyte, Li ２ S-SiS ２ , Li ２ S-B ２ S ３ or Li ２ S-GeS ２ Sulfides such as Li may be used as an additive to the sulfides. ３ N, LiCl, LiBr, Li ３ P.O. ４ and Li ４ SiO ４ A sulfide to which at least one of the following is added may be used.

[0082] As the oxide solid electrolyte, in the case of a material that can conduct lithium ions, for example, Li ７ La ３ Zr ２ O1 ２ (LLZ), Li １．３ Al ０．３ Ti １．７ (P.O. ４ ) ３ (LATP) or (La,Li)TiO ３ (LLTO) and the like are used.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] As the positive electrode active material, known materials capable of occluding and releasing (inserting and desorbing, or dissolving and depositing) lithium ions, sodium ions, magnesium ions, etc. can be used. As the positive electrode active material, materials capable of extracting and inserting lithium ions include, for example, transition metal oxides, transition metal fluorides, polyanion materials, fluorinated polyanion materials, transition metal sulfides, transition metal oxysulfides, transition metal oxynitrides, sulfur, and lithium-containing compounds thereof. Examples of lithium-containing transition metal oxides include Li(NiCoAl)O ２ , Li(NiCoMn)O ２ , LiCoO ２ Li(NiCoAl)O ２ means that Ni, Co, and Al are contained in any ratio. Li(NiCoMn)O ２ means that Ni, Co and Mn are contained in any ratio.

[0087] 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.

[0088] 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.

[0089] The negative electrode active material may be a known material capable of occluding and releasing (inserting and desorbing, or dissolving and precipitating) lithium ions, sodium ions, magnesium ions, etc. In the case of a material capable of extracting and inserting lithium ions, for example, a carbon material such as natural graphite, artificial graphite, graphite carbon fiber, or resin-baked carbon, metallic lithium, a lithium alloy, silicon (Si), tin (Sn), a silicon compound, a tin compound, or an oxide of lithium and a transition metal element may be used as the negative electrode active material.

[0090] 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.

[0091] Next, the end structure of the unit cell 60 will be described.

[0092] As shown in FIGS. 1 and 2 , in the unit cell 60, a first region 71, a second region 72, a third region 73, and a fourth region 74 that are not covered by the upper layer are provided at the end in the positive x-axis direction (the end along the side surface 61 in the example shown in FIG. 1 ).

[0093] Specifically, a first region 71 that is not covered by the electrode active material layer 20 is provided at an end of the main surface 11 of the electrode current collector 10 in the positive x-axis direction. The 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 an end of the electrode active material layer 20 in the positive x-axis direction. The second region 72 is not in contact with the solid electrolyte layer 30, the counter electrode active material layer 40, or the counter electrode current collector 50. A third region 73 that is not covered by the counter electrode active material layer 40 in a plan view is provided at an end of the solid electrolyte layer 30 in the positive x-axis direction. The 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.

[0094] As a result, at the end of the unit cell 60 where the first region 71 is provided and where it is easy to form a terminal on the electrode current collector 10, the second region 72, the third region 73, and the fourth region 74 increase the distance between the electrode current collector 10 and the end of the counter electrode active material layer 40, and the distance between the electrode current collector 10 and the end of the counter electrode active material layer 20 and the end of the counter electrode current collector 50. As a result, short circuits caused by contact between electrodes of opposite polarity are less likely to occur. This improves the reliability of the battery 1. On the other hand, conventional batteries are prone to short circuits because they do not have a structure in which the first region 71 to the fourth region 74 are provided. For example, in the battery disclosed in Patent Document 3, the electrode current collector has a region corresponding to the first region 71, and the solid electrolyte layer has a region corresponding to the third region 73, but the electrode current collector and the counter electrode current collector are prone to contact because they do not have regions corresponding to the second region 72 and the fourth region 74. Furthermore, in the battery disclosed in Patent Document 3, an insulating layer is provided on the main surface of the counter electrode current collector facing the electrode current collector in order to prevent short circuits. However, in a battery having such a configuration, unless the positional precision of the insulating layer is improved, it is difficult to obtain a sufficient effect of preventing short circuits, and it is also difficult to improve the manufacturing efficiency of the battery.

[0095] 1 , the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided along the side surface 61 in a plan view. The first region 71, the second region 72, the third region 73, and the fourth region 74 are elongated in a plan view, and in the example shown in FIG. 1 , the direction perpendicular to the x-axis positive direction (the y-axis direction) is the longitudinal direction. Furthermore, the fourth region 74, the third region 73, the second region 72, and the first region 71 are arranged in this order along the x-axis positive direction in a plan view.

[0096] The length of the first region 71 is, for example, 1 mm or more and 20 mm or less, which allows the energy density of the battery 1 to be increased while ensuring an area where a terminal can be easily formed on the electrode current collector 10.

[0097] The length of each of the second region 72, the third region 73, and the fourth region 74 is, for example, 0.1 mm or more and 5 mm or less. This allows the above distance to be increased while increasing the energy density of the battery 1. The length of each of the second region 72, the third region 73, and the fourth region 74 may be, for example, 0.5 mm or more and 2 mm or less.

[0098] The lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 may be the same, or at least one of them may be different. In addition, the length of the first region 71 may be longer than the lengths of the second region 72, the third region 73, and the fourth region 74.

[0099] Here, the lengths of the first region 71, the second region 72, the third region 73, and the fourth region 74 are lengths in the positive x-axis direction in plan view. The length of the first region 71 is also the distance between the outer edge of the electrode current collector 10 and the outer edge of the electrode active material layer 20 in the positive x-axis direction in plan view. The length of the second region 72 is also the distance between the outer edge of the electrode active material layer 20 and the outer edge of the solid electrolyte layer 30 in the positive x-axis direction in plan view. The length of the third region 73 is also the distance between the outer edge of the solid electrolyte layer 30 and the outer edge of the counter electrode active material layer 40 in the positive x-axis direction in plan view. The length of the fourth region 74 is also the distance between the outer edge of the counter electrode active material layer 40 and the outer edge of the counter electrode current collector 50 in the positive x-axis direction in plan view.

[0100] In the present embodiment, the electrode active material layer 20 may be a negative electrode active material layer, and the counter electrode active material layer 40 may be a positive electrode active material layer. In this case, the fourth region 74 in the counter electrode active material layer 40 that is not covered by the counter electrode current collector 50 becomes a region that is unlikely to function as a positive electrode. Furthermore, since the second region 72 is provided in the electrode active material layer 20 and the 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 more easily taken up into the electrode active material layer 20, which is a negative electrode active material layer, and metal precipitation derived from the metal ions is suppressed, thereby further improving the reliability of the battery 1.

[0101] 1 and 2, the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 form a stepped structure at the end of the unit cell 60 in the positive x-axis direction, but this is not limiting. Fig. 3 is a cross-sectional view showing another example of the structure of the end of the unit cell 60.

[0102] In the example shown in FIG. 3 , the electrode active material layer 20 has, in the second region 72, an inclined surface 21 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction. The entire second region 72 is, for example, the region where the inclined surface 21 is formed. Furthermore, the solid electrolyte layer 30 has, in the 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 x-axis direction. The entire third region 73 is, for example, the region where the inclined surface 31 is formed. Furthermore, the counter electrode active material layer 40 has, in the fourth region 74, an inclined surface 41 that is inclined so as to approach the electrode current collector 10 as it progresses in the positive x-axis direction. The entire fourth region 74 is, for example, the region where the inclined surface 41 is formed. In the example shown in FIG. 3 , 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.

[0103] 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 it less likely for short circuits to occur, thereby improving the reliability of the battery.

[0104] These inclined surface shapes can be formed, for example, by subjecting a portion including the end of a laminate in which the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are stacked on the electrode current collector 10 to a high-pressure press treatment such as a roll press so that the end is stepped.

[0105] The angle that each of the inclined surfaces 21, 31, and 41 forms with respect to the main surface 11 is, for example, less than 45 degrees. This makes it even more difficult for the layer material to fall off. The angle that each of the inclined surfaces 21, 31, and 41 forms with respect to the main surface 11 may be 30 degrees or less, or may be 10 degrees or less. Furthermore, the angle that each of the inclined surfaces 21, 31, and 41 forms with respect to the main surface 11 is, for example, 1 degree or more.

[0106] In the example shown in FIG. 3 , 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 above and below at the end in the positive x-axis direction, making the materials of these layers less likely to fall off and suppressing delamination. This reduces the likelihood of short circuits due to contact between electrodes of opposite polarity. This recessed shape can be formed, for example, by performing a high-pressure press, such as a roll press, on a portion of the stack including the end of the stack in which the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are stacked on the electrode current collector 10 so that the end is stepped.

[0107] The depth of each of the recesses 22 and 32 is, for example, not less than 1 μm and not more than 10 μm.

[0108] 3 , the surface of the electrode active material layer 20 on the solid electrolyte layer 30 side below the inclined surface 41 (i.e., the position overlapping with the inclined surface 41 in a plan view) has a portion that inclines so as to move away from the electrode current collector 10 as it progresses in the positive x-axis direction. Therefore, at the position of the outer edge of the counter electrode active material layer 40 in the positive x-axis direction in a plan view, the thickness of the electrode active material layer 20 is greater than the thickness of the electrode active material layer 20 on the inside of that position.

[0109] The structures of 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 shown in FIG. 3 may be included in the batteries according to the embodiments and modifications described below.

[0110] [2. Modifications] The following describes batteries according to modifications of the present embodiment. In the following description of the modifications, differences from the first embodiment and each modification will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0111] [2-1. Modification 1] First, a description will be given of a battery according to Modification 1 of Embodiment 1. Fig. 4 is a cross-sectional view of a battery 101 according to this modification.

[0112] 4 , the battery 101 includes a unit cell 160 and is formed from one unit cell 160. The unit cell 160 differs from the unit cell 60 according to the first embodiment in that the unit cell 160 has 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.

[0113] 4 , two electrode active material layers 20 are disposed on both main surfaces 11 and 12 of an electrode current collector 10. Two solid electrolyte layers 30 are disposed on each of the two electrode active material layers 20, opposite the electrode current collector 10. Two counter electrode active material layers 40 are disposed on each of the two solid electrolyte layers 30, opposite the electrode active material layer 20. Two counter electrode current collectors 50 are disposed on each of the two counter electrode active material layers 40, opposite the solid electrolyte layer 30.

[0114] 4 , a first region 71 that is not covered by either of the two electrode active material layers 20 is provided at the end in the positive x-axis direction of each of the main surfaces 11 and 12 of the electrode current collector 10. A second region 72 that is not covered by either of the two solid electrolyte layers 30 is provided at the end in the positive x-axis direction of each of the two electrode active material layers 20. A third region 73 that is not covered by either of the two counter electrode active material layers 40 is provided at the end in the positive x-axis direction of each of the two solid electrolyte layers 30. A fourth region 74 that is not covered by either of the two counter electrode current collectors 50 is provided at the end in the positive x-axis direction of each of the two counter electrode active material layers 40.

[0115] In this way, in the unit cell 160, a structure similar to the laminated structure of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 formed on the main surface 11 of the electrode current collector 10 of the unit cell 60 is also formed upside down on the main surface 12 facing away from the main surface 11 of the electrode current collector 10. Therefore, the unit cell 160 has a laminated structure that is symmetrical with respect to the electrode current collector 10.

[0116] This makes it possible to extract currents of two electrode active material layers 20 from one electrode current collector 10, thereby increasing the volumetric energy density. Furthermore, because the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided on both sides of the electrode current collector 10 in the stacking direction, the distance between the electrode current collector 10 and the electrode active material layer 20 and the end of the counter electrode active material layer 40, and the distance between the electrode current collector 10 and the electrode active material layer 20 and the end of the counter electrode current collector 50 are increased, thereby ensuring reliability. Furthermore, because a stacked structure of the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 is formed on both main surfaces 11 and 12 of the electrode current collector 10, when the unit cell 160 is densified by pressing or the like, stresses generated on both sides of the electrode current collector 10 in the stacking direction are less likely to differ, and warping of the unit cell 160 can be suppressed. Furthermore, even if stress occurs due to expansion and contraction of the electrode active material layer 20 and the counter electrode active material layer 40 during use of the battery 101, 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 160 can be suppressed.

[0117] [2-2. Modification 2] Next, a description will be given of a battery according to Modification 2 of Embodiment 1. Fig. 5 is a cross-sectional view of a battery 201 according to this modification.

[0118] 5, the battery 201 includes a unit cell 260 and is formed from one unit cell 260. The unit cell 260 differs from the unit cell 60 according to the first embodiment in that it further includes an insulating layer 80.

[0119] 5 , the insulating layer 80 covers a part of the first region 71 on the second region 72 side, the entire second region 72, and a part of the third region 73 on the second region 72 side. As a result, the electrode current collector 10 and the electrode active material layer 20 are covered by the insulating layer 80 extending to the third region 73 in the first region 71 and the second region 72, which significantly reduces the possibility that the electrode current collector 10 and the electrode active material layer 20 will come into contact with the counter electrode current collector 50 and the counter electrode active material layer 40. This allows the reliability of the battery 201 to be improved.

[0120] The insulating layer 80 does not cover a part of the first region 71 or a part of the third region 73. A gap is provided between the counter electrode active material layer 40 and the insulating layer 80. The electrode current collector 10 protrudes from the end face of the insulating layer 80 in the positive x-axis direction. 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, and a part of the third region 73 on the second region 72 side. The insulating layer 80 is also in contact with the end faces of the electrode active material layer 20 and the solid electrolyte layer 30 in the positive x-axis direction.

[0121] The length of the portion where the insulating layer 80 and the first region 71 are in contact is, for example, 100 μm or more. This reduces the possibility of exposure of the electrode current collector 10 and the electrode active material layer 20, thereby reducing the possibility of the electrode current collector 10 and the electrode active material layer 20 coming into contact with the counter electrode current collector 50 and the counter electrode active material layer 40, and improving the reliability of the battery 201. The length of the portion where the insulating layer 80 and the first region 71 are in contact is the length in the positive x-axis direction in a plan view, and is also the distance in a plan view between the outer edge of the electrode active material layer 20 and the outer edge of the insulating layer 80 in the positive x-axis direction.

[0122] 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 when forming a terminal on the counter electrode current collector 50. Furthermore, when batteries 201 are stacked for use, they can be easily stacked.

[0123] Note that 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 may cover the entire area of ​​at least one of the first region 71 and the third region 73 in the positive x-axis direction, or may not cover a portion of the second region 72. Furthermore, the insulating layer 80 may cover the entire area of ​​the first region 71, the second region 72, and the third region 73 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 the first region 71, the second region 72, and the third region 73.

[0124] The insulating layer 80 has, for example, electronic insulation and ionic insulation. For example, insulating tape or insulating resin is used for the insulating layer 80. Examples of resins used for the insulating tape and insulating resin include silicone resin, epoxy resin, acrylic resin, and polyimide resin. The resin may be a thermosetting resin or an ultraviolet-curing resin. 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.

[0125] The fourth region 74 may also be covered with an insulating layer. Fig. 6 is a cross-sectional view of another battery 201a according to this modification.

[0126] The battery 201a includes a unit cell 260a and is formed from one unit cell 260a. The unit cell 260a has a configuration in which the insulating layer 80 of the unit cell 260 is replaced with an insulating layer 80a. The insulating layer 80a covers the fourth region 74 in addition to the region covered by the insulating layer 80.

[0127] 6 , the insulating layer 80a covers 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. This makes it difficult for the solid electrolyte layer 30 to fall off, and even if the solid electrolyte layer 30 falls off, exposure of the electrode active material layer 20 can be avoided, making it difficult for a short circuit to occur due to contact between the counter electrode current collector 50 and the counter electrode active material layer 40 and the electrode current collector 10 and the electrode active material layer 20.

[0128] The insulating layer 80a does not cover a portion of the first region 71 or a portion of the fourth region 74. A gap is provided between the counter electrode current collector 50 and the insulating layer 80a. The electrode current collector 10 protrudes in the positive x-axis direction beyond the end face of the insulating layer 80a facing the positive x-axis. The insulating layer 80a is in contact with the end faces of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 facing the positive x-axis.

[0129] Note that it is sufficient that the insulating layer 80a covers at least a portion of the first region 71, at least a portion of the second region 72, at least a portion of the third region 73, and at least a portion of the fourth region 74. For example, the insulating layer 80a may cover the entire area of ​​at least one of the first region 71 and the fourth region 74 in the positive x-axis direction, or may not cover at least one of a portion of the second region 72 and a portion of the third region 73. Furthermore, the insulating layer 80a may cover the entire area 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, the third region 73, and the fourth region 74 in a plan view, or may cover only a portion of the first region 71, the second region 72, the third region 73, and the fourth region 74.

[0130] [2-3. Modification 3] Next, a battery according to Modification 3 of the first embodiment will be described.

[0131] The effect of improving reliability by the insulating layers 80 and 80a in the batteries 201 and 201a according to the above-described modified example 2 is similarly exhibited in the case where the electrode active material layers 20 are formed on the main surfaces 11 and 12 on both sides of the electrode current collector 10, as in the battery 101 according to modified example 1. Fig. 7 is a cross-sectional view of a battery 301 according to this modified example. Fig. 8 is a cross-sectional view of another battery 301a according to this modified example.

[0132] 7 , the battery 301 includes a unit cell 360 and is formed from one unit cell 360. The unit cell 360 differs from the unit cell 160 according to the first modification in that it further includes two insulating layers 80. One of the two insulating layers 80 is disposed on the main surface 11 side of the electrode current collector 10 and 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. The other of the two insulating layers 80 is disposed on the main surface 12 side of the electrode current collector 10 and 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.

[0133] 8 , the battery 301a includes a unit cell 360a formed from one unit cell 360a. The unit cell 360a differs from the unit cell 160 according to the first modification in that it further includes two insulating layers 80a. One of the two insulating layers 80a is disposed on the main surface 11 side of the electrode current collector 10 and covers at least a portion of the first region 71, at least a portion of the second region 72, at least a portion of the third region 73, and at least a portion of the fourth region 74. The other of the two insulating layers 80a is disposed on the main surface 12 side of the electrode current collector 10 and covers at least a portion of the first region 71, at least a portion of the second region 72, at least a portion of the third region 73, and at least a portion of the fourth region 74.

[0134] [2-4. Modification 4] Next, a battery according to Modification 4 of Embodiment 1 will be described. FIG. 9 is a top view of battery 401 according to this modification. FIG. 10 is a cross-sectional view of battery 401 according to this modification. FIG. 9 shows the planar shape of battery 401 when viewed from the positive side of the z-axis. FIG. 10 is also a cross-sectional view taken along line X-X in FIG. 9. In FIG. 9, the outlines of electrode active material layer 20 and solid electrolyte layer 30 when viewed through insulating layer 80 are indicated by dashed lines.

[0135] 9 and 10 , the battery 401 includes a unit cell 460 and is formed from one unit cell 460. The unit cell 460 differs from the unit cell 260 according to the second modification in that the unit cell 460 has an electrode current collector 410 and a counter electrode current collector 450 instead of the electrode current collector 10 and the counter electrode current collector 50.

[0136] The electrode current collector 410 has a protrusion 411, which is a portion of the end of the electrode current collector 410 in the positive x-axis direction that protrudes further in the positive x-axis direction than other portions. The electrode current collector 410 has a shape in which a rectangular tab-shaped protrusion 411 is added to the electrode current collector 10, which has a rectangular shape in a plan view. The protrusion 411 functions, for example, as a lead on which a terminal is formed. Another lead material may be bonded to the protrusion 411. In the example shown in FIG. 9 , the first region 71 is also provided inside the protrusion 411 on the electrode current collector 410, but the main surface 11 in a portion other than the protrusion 411 may be covered by the electrode active material layer 20. In the example shown in FIG. 9 , the portion of the first region 71 between the protrusion 411 and the electrode active material layer 20 in a plan view is not covered by the insulating layer 80, but this portion may be covered by the insulating layer 80. Note that the electrode current collector 410 does not necessarily have to have the protrusion 411. That is, the electrode current collector 10 may be used in place of the electrode current collector 410 .

[0137] The counter electrode current collector 450 has a protrusion 451, which is a portion of the end of the counter electrode current collector 450 in the x-axis positive direction that protrudes further in the x-axis positive direction than other portions. The counter electrode current collector 450 has a shape obtained by adding a rectangular tab-shaped protrusion 451 to the counter electrode current collector 50, which has a rectangular shape in a plan view. The protrusion 451 protrudes further in the x-axis positive direction than the insulating layer 80 in a plan view. The protrusion 451 functions as, for example, a lead on which a terminal is formed. Another lead material may be joined to the protrusion 451. Alternatively, the protrusion 451 may not be formed and the entire end of the counter electrode current collector 450 in the x-axis positive direction may protrude further in the x-axis positive direction than the insulating layer 80 in a plan view.

[0138] The protrusion 451 faces the electrode current collector 410, the electrode active material layer 20, and the solid electrolyte layer 30 via the insulating layer 80. The protrusions 411 and 451 are arranged in positions where they do not overlap in a planar view. The insulating layer 80 does not have to be formed in a position where it does not overlap with the protrusion 451 in a planar view.

[0139] Thus, in battery 401, protrusion 451, which is a part of the end portion of counter electrode current collector 450 in the positive x-axis direction, protrudes in the positive x-axis direction beyond insulating layer 80 in plan view. This makes it possible to form a terminal on counter electrode current collector 450 at the end portion of battery 401, making the structure less complicated than when a terminal is formed on the main surface of counter electrode current collector 450, and enabling the reliability of battery 401 to be improved.

[0140] Instead of the unit cell 260 according to the second modification, another unit cell 260a according to the second modification may have the electrode current collector 410 and the counter electrode current collector 450. Fig. 11 is a cross-sectional view of another battery 401a according to this modification.

[0141] The battery 401a includes a unit cell 460a, and is formed from one unit cell 460a. The unit cell 460a differs from the unit cell 260a according to the second modification in that the unit cell 460a has an electrode current collector 410 and a counter electrode current collector 450 instead of the electrode current collector 10 and the counter electrode current collector 50.

[0142] In the unit cell 460 a , the fourth region 74 is covered with the insulating layer 80 a , so that a portion of the protrusion 451 is bent and rides up onto the insulating layer 80 a that covers the fourth region 74 .

[0143] [2-5. Modification 5] Next, a battery according to Modification 5 of the first embodiment will be described.

[0144] The effect achieved when a portion of the counter electrode current collector 450 protrudes in the positive x-axis direction beyond the insulating layer 80 as in the batteries 401 and 401a according to the above-described modified example 4 is similarly achieved in the case where the electrode active material layers 20 and the like are formed on both main surfaces of the electrode current collector 10 as in the batteries 301 and 301a according to modified example 3. Fig. 12 is a cross-sectional view of a battery 501 according to this modified example. Fig. 13 is a cross-sectional view of another battery 501a according to this modified example.

[0145] 12 , the battery 501 includes a unit cell 560 and is formed from one unit cell 560. The unit cell 560 differs from the unit cell 360 according to Modification 3 in that the unit cell 560 has an electrode current collector 410 and two counter electrode current collectors 450 instead of the electrode current collector 10 and two counter electrode current collectors 50. The protrusions 451 of the two counter electrode current collectors 450 face each other with two insulating layers 80 interposed therebetween.

[0146] 13 , the battery 501a includes a unit cell 560a, which is formed from one unit cell 560a. The unit cell 560a differs from the unit cell 360a according to Modification 3 in that the unit cell 560a has an electrode current collector 410 and two counter electrode current collectors 450 instead of the electrode current collector 10 and two counter electrode current collectors 50. The protrusions 451 of the two counter electrode current collectors 450 face each other with two insulating layers 80a interposed therebetween.

[0147] When the counter electrode current collector 450 has a protrusion 451, a portion of the electrode current collector 410 that overlaps with the protrusion 451 in a plan view may be covered with an insulating layer. Fig. 14 is a cross-sectional view of yet another battery 501b according to this modification.

[0148] 14, the battery 501b includes a unit cell 560b, and is formed from one unit cell 560b. The unit cell 560b has a configuration in which the two insulating layers 80 of the unit cell 560 are replaced with an insulating layer 80b.

[0149] In addition to the region covered by the insulating layer 80, the insulating layer 80b covers the end face of the electrode current collector 410 in the positive x-axis direction except for the portion where the protrusion 411 is formed. This further reduces short circuits caused by contact between the protrusion 451 and the electrode current collector 410. In the example shown in FIG. 14 , the insulating layer 80b integrally covers the end face of the electrode current collector 410 in the positive x-axis direction and the first region 71, the second region 72, and the third region 73 on both main surfaces 11 and 12 of the electrode current collector 410. Note that the insulating layer 80b does not need to cover other portions of the end face of the electrode current collector 410 in the positive x-axis direction as long as it covers the portion that overlaps with the protrusion 451 in a plan view. Furthermore, unit cell 560b may have a configuration including insulating layer 80 and another insulating layer that covers insulating layer 80 and the end face in the x-axis positive direction of electrode current collector 410, instead of insulating layer 80b that integrally covers the end face in the x-axis positive direction of electrode current collector 410 and first region 71, second region 72, and third region 73 on both main surfaces 11 and 12 of electrode current collector 410. Furthermore, in the above-described unit cells 460, 460a, and 560a, the end face in the x-axis positive direction of electrode current collector 410 may also be covered with an insulating layer.

[0150] [3. Manufacturing Method] Next, a method for manufacturing a battery according to the present embodiment and each of the modifications of the present embodiment will be described. The following mainly describes a method for manufacturing a battery 501 according to the fifth modification of the first embodiment, but other batteries can also be manufactured by appropriately applying the following manufacturing method. Figure 15 is a flowchart showing a method for manufacturing a battery 501 according to the fifth modification of the first embodiment. Note that the method for manufacturing a battery 501 described below is an example, and the method for manufacturing a battery 501 is not limited to the following example.

[0151] First, in the manufacturing method of the battery 501, an electrode current collector 10 without a protrusion 411 is prepared (step S11). Next, an electrode active material layer 20 is laminated on both main surfaces 11 and 12 of the electrode current collector 10 (step S12). At this time, the electrode active material layer 20 is laminated on the main surfaces 11 and 12 so that a 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 in the positive x-axis direction. Note that when manufacturing a battery such as the battery 1 in which the electrode active material layer 20 is not laminated on the main surface 12 side, the electrode active material layer 20 is laminated only on the main surface 11.

[0152] 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.

[0153] 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.

[0154] When laminating the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, a high-pressure pressing process (step S15) is performed as necessary after each of steps S12 to S14. This results in a laminated electrode plate in which the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are laminated in this order from the main surface 11 to the main surface 12 of the electrode current collector 10.

[0155] 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.

[0156] 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.

[0157] 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).

[0158] The slurries for each layer obtained in the coating process are applied to both main surfaces 11 and 12 of the electrode current collector 10 in the order of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. In this case, the next layer may be applied after the previous layer has been applied, or the next layer may be applied while the previous layer is being applied. In other words, steps S12, S13, and S14 may be performed simultaneously in parallel.

[0159] The slurry for each layer is applied sequentially, and after all layers have been applied, a high-pressure pressing process (step S15) is performed to promote the filling of the material for each layer. The high-pressure pressing process may be performed after each layer is applied. For example, the high-pressure pressing process may be performed after each layer is applied in the coating lamination of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, or may be performed separately after any two layers are applied and after one layer is applied, or may be performed all at once after all three layers are applied. When the high-pressure pressing process is performed two or more times, the pressing may be performed so that the pressure of the final high-pressure pressing process is the highest. For example, a roll press, a plate press, or an isostatic pressing (ISP) may be used for the high-pressure pressing process.

[0160] When the wet coating method is used, a heat treatment is performed to remove the solvent before the high-pressure pressing. The heat treatment is performed, for example, after each application of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, but may also be performed all at once after the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are laminated. At least one of the heat treatment and the high-pressure pressing may not be performed.

[0161] By performing the layered coating method in this manner, it is possible to improve the bonding strength and reduce the interfacial resistance at the interfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. It is also possible to improve the bonding strength and reduce the grain boundary resistance in the powder materials used in the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. That is, good interfaces are formed between the layers of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 and between the powder materials within each layer.

[0162] The above steps S12 to S15 may be performed in a continuous process such as a roll-to-roll process.

[0163] The laminated electrode plate may have a size in plan view corresponding to one battery 501, or may be sized in plan view so that it can be divided into individual pieces and used for multiple batteries 501. FIG. 16 is a top view showing an example of a laminated electrode plate 90. As shown in FIG. 16, the laminated electrode plate 90 has a first region 71, a second region 72, and a third region 73 at both positive and negative ends of the x-axis. The laminated electrode plate 90 also has two electrode active material layers 20, two solid electrolyte layers 30, and two counter electrode active material layers 40, which are arranged on both sides of the electrode current collector 10 in the stacking direction. FIG. 16 shows the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 arranged on one side of the electrode current collector 10 in the stacking direction (the positive side of the z-axis).

[0164] The battery 501 can also be manufactured by using such a laminated electrode plate 90 in the manufacturing process of the battery 501 and dicing the laminated electrode plate 90 into individual batteries 501 at any stage until the completion of the battery 501. This can improve manufacturing efficiency. For example, the laminated electrode plate 90 is diced by cutting at least the center of the laminated electrode plate 90 in the x-axis direction along the y-axis direction. This dicing may also be performed by cutting in step S19, which will be described later. After dicing the laminated electrode plate 90, polishing or the like may be performed to adjust the size.

[0165] Next, the electrode current collector 410 is formed by forming the protrusions 411 on the electrode current collector 10 (step S16). The protrusions 411 are formed, for example, by removing a portion of the first region 71. For the removal process, a blade such as a cutter, slitter, cutting machine, or punching machine with a Thomson blade, or a laser or jet may be used, but the method is not limited to these. Alternatively, a foil or the like having the shape of the protrusions 411 that is separately prepared may be bonded to the electrode current collector 10. For this bonding, a method such as ultrasonic welding, resistance welding, or crimping may be used, but the method is not limited to these. The protrusions 411 may be formed at any stage in the manufacturing process of the battery 501. Alternatively, in step S11, the electrode current collector 410 on which the protrusions 411 have been formed may be prepared in advance.

[0166] Next, an insulating layer 80 is formed in the x-axis positive direction to cover a portion of the first region 71 facing the second region 72, the entire second region 72, and a portion of the third region 73 facing the second region 72 (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 using an inkjet method, a screen printing method, or by immersing (dipping) the end surfaces 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 portion of the first region 71 may be protected by masking with tape or resist treatment to prevent the entire first region 71 of the main surfaces 11 and 12 of the electrode current collector 10 from being insulated. After forming the insulating layer 80, the protective material can be removed to ensure electrical connection in the first region 71. Furthermore, the insulating layer 80 may be formed by attaching insulating tape, but is not limited to these methods. When manufacturing a battery having the insulating layer 80a, such as the battery 501a, the insulating layer 80a is formed so as to cover the entire third region 73 and a part of the fourth region 74 on the third region 73 side. When manufacturing the battery 501b, the insulating layer 80b is formed so as to cover the end face of the electrode current collector 410 in addition to the region covered by the insulating layer 80.

[0167] Next, a counter electrode current collector 450 is laminated on the side of the counter electrode active material layer 40 opposite the solid electrolyte layer 30 (step S18). This results in a laminate (unit cell 560) in which the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 450 are laminated in this order on both main surfaces 11 and 12 of the electrode current collector 410. The counter electrode current collector 450 is laminated on the counter electrode active material layer 40 so that a fourth region 74 not covered by the counter electrode current collector 450 is provided at the end of the counter electrode active material layer 40 in the positive x-axis direction. The counter electrode active material layer 40 and the counter electrode current collector 450 are bonded to each other by, for example, high-pressure pressing. The bonding may also be performed by using a counter electrode current collector 450 having a connection layer containing an adhesive binder, by coating with an adhesive, or by attaching an adhesive film. The bonding method is not limited to these methods. Furthermore, a heat treatment may be performed during or after the joining.

[0168] The counter electrode current collector 450 may be formed to a desired size before stacking, or may be partially removed after stacking. Also, the protrusion 451 may be formed after stacking.

[0169] Next, the unit cell 560 obtained in step S18 is cut along a direction intersecting the main surface 11 to form cut surfaces as side surfaces 62, 63, and 64 at the ends of the unit cell 560 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction (step S19). This cutting results in three sides of the unit cell 560 that, in a planar view, constitute the ends 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. 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.

[0170] In step S19, the electrode current collector 410, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 450 are cut together in a direction intersecting the main surface 11. Specifically, the direction intersecting the main surface 11 is a direction perpendicular to the main surface 11, which can also be considered the stacking direction of the unit cells 560. This eliminates the need to stack the electrode current collector 410, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 450 in the shape after cutting, making it easy to manufacture the battery 501. Furthermore, because the regions including the first region 71, the second region 72, the third region 73, and the fourth region 74 remain uncut, it is possible to form terminals with a structure that suppresses the occurrence of short circuits. This makes it easy to manufacture a highly reliable battery 501. Furthermore, the capacity of the unit cells 560 can be adjusted by the position at which the unit cells 560 are cut, thereby improving capacity accuracy.

[0171] At the cut surface, the respective side surfaces of the electrode current collector 410, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 450 are exposed. After cutting, a sealing member or the like may be disposed to cover these exposed side surfaces in order to protect them. That is, when these side surfaces are covered with another member such as a sealing member, these exposed side surfaces may also be covered with the other member.

[0172] Through the above steps, a battery 501 composed of one unit cell 560 is obtained. The obtained battery 501 may be housed in an exterior body or the like. When the battery 501 is housed in an exterior body, the protrusions 411 and 451 are extended to the outside of the exterior body. Furthermore, the obtained battery 501 may be subjected to a process of removing corners (intersections of the side surfaces) in a plan view by cutting or the like. In this case, when removing a corner in the positive x-axis direction, for example, a portion including the first region 71, the second region 72, the third region 73, and the fourth region 74 is removed. This removes corners that are prone to collapse and breakage, thereby further improving the reliability of the battery 501.

[0173] The order of steps S18 and S19 may be reversed. In this case, first, after step S17, in step S19, a laminate (laminated electrode plate) in which the electrode current collector 410, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are stacked is cut along a direction intersecting the main surface 11 to form cut surfaces at the ends of the laminated electrode plate in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction. At this time, the electrode current collector 410, 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 the main surface 11. This eliminates the need to stack the electrode current collector 410, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 in the shapes after cutting, thereby facilitating the manufacture of the battery 501. Thereafter, in step S18, a counter electrode current collector 450 having a shape corresponding to the shape of the laminated electrode plate after the cut surface is formed is laminated on the side of counter electrode active material layer 40 opposite to solid electrolyte layer 30. In this way, a battery 501 composed of one unit cell 560 is obtained.

[0174] (Embodiment 2) Next, embodiment 2 will be described. In embodiment 2, a stacked type stacked battery in which a plurality of unit cells are stacked will be described. In the following description, differences from embodiment 1 and the modifications will be mainly described, and descriptions of commonalities will be omitted or simplified as appropriate.

[0175] [1. Configuration] First, the configuration of a battery according to embodiment 2 will be described with reference to the drawings. Fig. 17 is a cross-sectional view of a battery 601 according to this embodiment. As shown in Fig. 17, the battery 601 includes a plurality of unit cells 560 according to variation 5 of embodiment 1, and has a structure in which the plurality of unit cells 560 are stacked. Since the battery 601 includes the unit cells 560 stacked, a highly reliable battery 601 can be realized.

[0176] The multiple unit cells 560 have the same configuration and are stacked so as to be electrically connected in parallel. The electrode active material layer 20, the solid electrolyte layer 30, and the 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. The multiple unit cells 560 are stacked such that the positions of the side surfaces of the unit cells 560 coincide when viewed from the stacking direction. Therefore, the side surfaces of the multiple unit cells 560 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction are flush with each other. In the multiple unit cells 560, the protrusions 451 and the protrusions 411 (not shown) protrude in the same direction, specifically, in the positive x-axis direction. The protrusions 451 of the multiple unit cells 560 and the protrusions 411 of the multiple unit cells 560 may be bundled together and joined by welding or the like.

[0177] In the example shown in FIG. 17, the number of stacked unit cells 560 is four, but it may be two or three, or may be five or more.

[0178] 17 , two adjacent unit cells 560 share a counter electrode current collector 450. Note that two adjacent unit cells 560 may not share a counter electrode current collector 450, but may each have an individual counter electrode current collector 450, with two counter electrode current collectors 450 overlapping each other between the counter electrode active material layers 40. In this case, a conductive adhesive layer may be provided between the two counter electrode current collectors 450.

[0179] In the stacked-type battery according to the present embodiment, the unit cells to be stacked may be unit cells other than the unit cell 560 according to the first embodiment and each of the modifications described above. Even when unit cells other than the unit cell 560 are stacked, adjacent unit cells may share a current collector, or the unit cells may be stacked such that two separate current collectors overlap without sharing a current collector. Furthermore, when unit cells such as the unit cell 60 are stacked, in which the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 or 450 are stacked only on one main surface 11 of the electrode current collector 10 or 410, the unit cells may be stacked so as to be electrically connected in series. Furthermore, the plurality of unit cells may include unit cells having different configurations. Furthermore, the plurality of unit cells may include unit cells having different configurations from the unit cells according to the first embodiment and each of the modifications. For example, the multiple unit cells in this case may include a unit cell in which 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 flush with each other on all side surfaces.

[0180] An example of a battery in which unit cells other than unit cell 560 are stacked will be described with reference to Fig. 18. Fig. 18 is a cross-sectional view of another battery 601a according to the present embodiment. Fig. 18 shows battery 601a in which a plurality of unit cells 560a are stacked.

[0181] 18 , the battery 601a has a configuration in which the plurality of unit cells 560 of the battery 601 are replaced with a plurality of unit cells 560a. Furthermore, in the battery 601a, pressing or the like is performed to stack and bond the plurality of unit cells 560a to each other. As a result, in the portion where the protruding portion 451 of the counter electrode current collector 450 and the insulating layer 80a overlap in a planar view, the protruding portion 451 and the insulating layer 80a are rolled, and the gap between the counter electrode current collector 450 and the insulating layer 80a provided in the example shown in FIG. 11 is filled with the insulating layer 80a. The bottom and top of the battery 601a may have a structure in which the protruding portion 451 rides on the insulating layer 80a, as shown in FIG. 11 .

[0182] [2. Manufacturing Method] Next, a method for manufacturing a battery according to this embodiment will be described. The following mainly describes a method for manufacturing a battery 601 formed by stacking a plurality of unit cells 560. However, batteries formed by stacking unit cells according to the first embodiment and each of the modifications other than the unit cell 560 described above can also be manufactured by appropriately applying the manufacturing method described below. Figure 19 is a flowchart showing a method for manufacturing a battery 601 according to the second embodiment. Note that the manufacturing method for the battery 601 described below is an example, and the manufacturing method for the battery 601 is not limited to the following example.

[0183] First, in steps S21 to S27 shown in Fig. 19, laminated electrode plates are formed in the same number as the unit cells 560 included in the battery 601 by a method similar to steps S11 to S17 shown and described with reference to Fig. 15. The laminated electrode plates may be large-sized laminated electrode plates 90 as shown in Fig. 16 with insulating layers 80 formed thereon, or may be laminated electrode plates corresponding to the size of the unit cells 560. Note that steps S21 to S27 may be omitted, and the same number of laminated electrode plates as the number of unit cells 560 included in the pre-formed battery 601 may be prepared.

[0184] Next, a counter electrode current collector 450 is stacked on the side of the counter electrode active material layer 40 opposite the solid electrolyte layer 30, and multiple unit cells 560 are stacked together (steps S28 and S29). For example, the multiple laminated electrode plates obtained up to step S27 and multiple counter electrode current collectors 450 are stacked such that the counter electrode current collector 450 is stacked on the side of the counter electrode active material layer 40 opposite the solid electrolyte layer 30. The laminated electrode plate has only the electrode current collector 410 as a current collector and does not have a counter electrode current collector 450. Therefore, when stacking multiple laminated electrode plates and multiple counter electrode current collectors 450, the counter electrode current collectors 450 do not overlap, and one counter electrode current collector 450 can be shared by adjacent unit cells 560.

[0185] In manufacturing the battery 601, the counter electrode current collector 450 and the laminated electrode plates obtained up to step S27 are alternately stacked, so that the counter electrode current collector 450 is shared by adjacent unit cells 560, and stacking of the counter electrode current collector 450 on the counter electrode active material layer 40 and stacking of multiple unit cells 560 are performed. Alternatively, a unit cell having a structure in which one counter electrode current collector 450 is removed from the unit cell 560 may be formed by stacking the counter electrode current collector 450 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 450 is also shared by adjacent unit cells 560 by stacking these unit cells so that the counter electrode active material layers 40 sandwich the counter electrode current collector 450. In this case, after stacking the required number of unit cells, the counter electrode current collector 450 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 450 has not been stacked.

[0186] During these laminations, the counter electrode active material layer 40 and the counter electrode current collector 450 may be bonded by high-pressure pressing or the like, as in step S18. This bonding may be performed during the lamination of the counter electrode current collector 450 and the laminated electrode plate, or may be performed all at once after all of the counter electrode current collectors 450 and the laminated electrode plates have been laminated. When the bonding is performed all at once, for example, all of the plurality of counter electrode current collectors 450 and the plurality of laminated electrode plates are laminated and then pressed all at once after lamination. This makes it possible to reduce the number of handling steps, suppress the inclusion of foreign matter when laminating the plurality of laminated electrode plates and the plurality of counter electrode current collectors 450, and produce a highly reliable battery.

[0187] Similarly to step S18, the counter electrode current collector 450 may be formed to a desired size before stacking, or a portion of the counter electrode current collector 450 may be removed after stacking. Also, the protrusion 451 may be formed after stacking.

[0188] In addition, when two adjacent unit cells 560 do not share a counter electrode current collector 450 and two counter electrode current collectors 450 are arranged between the counter electrode active material layers 40, a process similar to step S18 described above is performed in step S28 to obtain a laminate (unit cell 560) in which the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 450 are laminated in this order on both main surfaces 11 and 12 of the electrode current collector 410. Then, in step S29, the obtained unit cells 560 are stacked. At this time, the unit cells 560 are bonded to each other using a conductive adhesive layer formed by coating an adhesive or laminating an adhesive film. However, the bonding method is not limited to these methods. Furthermore, heat treatment and pressing may be performed after bonding. For example, all of the multiple counter electrode current collectors 450 and multiple laminated electrode plates may be stacked by stacking the unit cells 560, and then the stacked electrodes may be pressed together.

[0189] Next, the stack of the unit cells 560 obtained in step S29 is cut along a direction intersecting the main surface 11 to form cut surfaces as side surfaces 62, 63, and 64 at each end of the unit cells 560 in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction (step S30). This cutting forms three sides that constitute the end of each of the unit cells 560, different from the end where the first region 71, the second region 72, the third region 73, and the fourth region 74 are provided, in a plan view. The cutting method can be performed using the same method as in step S19. In step S30, all of the unit cells 560 are cut simultaneously along a direction intersecting the main surface 11. This eliminates the need to stack the electrode current collector 410, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 450 of each of the unit cells 560 in the shapes after cutting, thereby facilitating the production of the battery 601. Furthermore, since the regions including the first region 71, the second region 72, the third region 73, and the fourth region 74 remain uncut, it is possible to form the terminals in a structure that can suppress the occurrence of short circuits, thereby facilitating the manufacture of a highly reliable battery 601.

[0190] At the cut surface, the side surfaces of the electrode current collector 410, the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 450 of each of the plurality of unit cells 560 are exposed. After cutting, a sealing member or the like may be disposed to cover these exposed side surfaces in order to protect them. That is, when these side surfaces are covered with another member such as a sealing member, these exposed side surfaces may also be covered with the other member.

[0191] Through the steps described above, a battery 601 having a structure in which a plurality of unit cells 560 are stacked is obtained. The obtained battery 601 may be housed in an exterior body or the like. When the battery 601 is housed in an exterior body, the protrusions 411 and 451 are extended to the outside of the exterior body. Furthermore, the obtained battery 601 may be subjected to a process of removing corners (intersections of the side surfaces) in a plan view by cutting or the like.

[0192] The formation of the cut surfaces in step S30 may be performed before step S29. In this case, in step S29, the unit cells with the cut surfaces formed are stacked to obtain the battery 601.

[0193] Furthermore, the laminated electrode plates and counter electrode current collector 450 laminated in steps S28 and S29 are not limited to configurations corresponding to the plurality of unit cells 560, and may be laminated electrode plates and counter electrode current collectors having configurations corresponding to the battery to be manufactured. For example, the laminated electrode plates and counter electrode current collectors used in steps S28 and S29 may have configurations corresponding to the unit cells according to the first embodiment and each of the modified examples described above, other than unit cell 560. Furthermore, for example, the plurality of laminated electrode plates used in steps S28 and S29 may include laminated electrode plates in which the side surfaces of electrode current collector 10, electrode active material layer 20, solid electrolyte layer 30, and counter electrode active material layer 40 are flush with each other on all sides.

[0194] While the battery according to the present disclosure has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as the modifications do not deviate from the gist of the present disclosure, modifications that would occur to those skilled in the art and other forms constructed by combining some of the components of the embodiments are also included in the scope of the present disclosure.

[0195] In the above-described embodiment, the battery is composed of an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, and a counter electrode current collector, or an electrode current collector, an electrode active material layer, a solid electrolyte layer, a counter electrode active material layer, a counter electrode current collector, and an insulating layer, but is not limited thereto. For example, within the range of allowable battery characteristics, a bonding layer or the like may be provided between each layer of the battery to reduce electrical resistance and improve bonding strength.

[0196] In the above embodiment, the electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer are formed by sequentially stacking them directly on the main surface of the electrode current collector, but this is not limited thereto. For example, the electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may be formed by sequentially stacking them on a sheet-like substrate, and the formed electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may be removed from the substrate and stacked on the main surface of the electrode current collector. Alternatively, the electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may be formed on a sheet-like substrate, and the formed electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may be stacked by sequentially transferring them to the main surface of the electrode current collector.

[0197] In the above embodiment, the unit cell is provided with the first, second, third, and fourth regions, but this is not limiting. For example, the counter electrode active material layer may completely cover the counter electrode current collector, eliminating the fourth region.

[0198] 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.

[0199] 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.

[0200] DESCRIPTION OF SYMBOLS 1, 101, 201, 201a, 301, 301a, 401, 401a, 501, 501a, 501b, 601, 601a Battery 10, 410 Electrode current collector 11, 12 Main surface 20 Electrode active material layer 21, 31, 41 Inclined surface 22, 32 Recess 30 Solid electrolyte layer 40 Counter electrode active material layer 50, 450 Counter electrode current collector 60, 160, 260, 260a, 360, 360a, 460, 460a, 560, 560a, 560b Unit cell 61, 62, 63, 64 Side surface 71 First region 72 Second region 73 Third region 74 Fourth region 80, 80a, 80b Insulating layer 90 Laminated electrode plate 411, 451 Projection part

Claims

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

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

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

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

5. The battery described in claim 1, 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.

6. The battery according to claim 3, 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.

7. The battery according to any one of claims 1 to 6, wherein the electrode active material layer is provided with a recess into which the electrolyte layer in the third region is recessed.

8. The battery according to any one of claims 3, 4 and 6, wherein the electrode active material layer is provided with a recess into which the electrolyte layer in the third region is recessed, and the electrolyte layer is provided with a recess into which the counter electrode active material layer in the fourth region is recessed.

9. The battery according to claim 1, wherein the unit cell further comprises an insulating layer covering 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.

10. The battery according to claim 3, wherein the unit cell further comprises an insulating layer covering 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.

11. The battery of claim 10, wherein the insulating layer further covers at least a portion of the fourth region.

12. The battery according to any one of claims 9 to 11, wherein a portion of an end portion in the first direction of the counter electrode current collector protrudes in the first direction beyond the insulating layer in the plan view.

13. The battery according to claim 12, wherein at an end of the unit cell in a second direction that is a direction from the center toward the outer edge of the main surface of the electrode current collector and different from the first direction, side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer and the counter electrode active material layer are flush with each other.

14. The battery according to claim 12, wherein at an end of the unit cell in a second direction that is a direction from the center toward the outer edge of a main surface of the electrode current collector and different from the first direction, side surfaces of the electrode current collector, the electrode active material layer, the electrolyte layer, the counter electrode active material layer and the counter electrode current collector are flush with each other.

15. The battery according to claim 12, comprising a plurality of the unit cells, the plurality of unit cells being stacked.

16. A method for manufacturing a battery, comprising stacking a plurality of laminated electrode plates each having an electrode current collector, an electrode active material layer arranged on a main surface of the electrode current collector, an electrolyte layer arranged on the side of the electrode active material layer opposite the electrode current collector, and a counter electrode active material layer arranged on the side of the electrolyte layer opposite the electrode active material layer, together with a plurality of counter electrode current collectors, such that the counter electrode current collector is stacked on the side of the counter electrode active material layer opposite the electrolyte layer, and then pressing the stacked plates together.

17. The method for manufacturing a battery according to claim 16, wherein at least one of the plurality of laminated electrode plates has only the electrode current collector as a current collector.

18. A method for manufacturing a battery as described in claim 16 or 17, wherein each of the plurality of laminated electrode plates has two of each of the electrode active material layers, the electrolyte layers and the counter electrode active material layers, the two electrode active material layers are disposed on both main surfaces of the electrode collector, the two electrolyte layers are disposed on the side opposite the electrode collector from each of the two electrode active material layers, and the two counter electrode active material layers are disposed on the side opposite the electrode active material layers from each of the two electrolyte layers.

19. A method for manufacturing a battery as described in claim 16 or 17, wherein an end of a main surface of the electrode collector in a first direction, which is a direction from the center toward the outer edge of the main surface of the electrode collector, is provided with a first region that is not covered by the electrode active material layer, an end of the electrode active material layer in the first direction is provided with a second region that is not covered by the electrolyte layer in a planar view relative to the main surface of the electrode collector, and an end of the electrolyte layer in the first direction is provided with a third region that is not covered by the counter electrode active material layer in the planar view.

20. The method for manufacturing a battery according to claim 19, wherein the counter electrode current collector has a protrusion in which a part of an end portion in the first direction protrudes in the first direction.

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