Battery and method for manufacturing battery

Abstract

A battery according to the present disclosure is provided with an electrode body which comprises: a current collector; an electrode active material layer that is disposed on a main surface of the current collector; an electrolyte layer that is disposed on the reverse side of the electrode active material layer from the current collector; and a counter electrode active material layer that is disposed on the reverse side of the electrolyte layer from the electrode active material layer. An end portion of the electrode body in a first direction, which is a direction from the center of the main surface of the current collector toward the outer edge, is provided with a protrusion region in which the current collector protrudes beyond the counter electrode active material layer in the first direction in a plan view with respect to the main surface of the current collector, and a chamfered shape is formed in the current collector at a corner portion of the protrusion region in the plan view.

Description

Battery and method for manufacturing the battery

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

[0002] Patent Document 1 discloses a configuration related to a battery having a laminate, and also discloses rounding the corners of the electrodes.

[0003] Japanese Patent Application Laid-Open No. 2018-73583

[0004] In the prior art, there is a demand for improved reliability of batteries having a stacked structure. Therefore, an object of the present disclosure is to provide a highly reliable battery and the like.

[0005] A battery according to one aspect of the present disclosure comprises an electrode body having a current collector, an electrode active material layer disposed on a main surface of the current collector, an electrolyte layer disposed on the side of the electrode active material layer opposite the current collector, and a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, wherein a protruding region is provided at an end of the electrode body in a first direction, which is a direction from the center toward the outer edge of the main surface of the current collector, where the current collector protrudes in the first direction beyond the counter electrode active material layer in a planar view relative to the main surface of the current collector, and a chamfered shape is formed on the current collector at a corner of the protruding region in the planar view.

[0006] A method for manufacturing a battery according to one aspect of the present disclosure includes an electrode body having a current collector, an electrode active material layer disposed on a main surface of the current collector, an electrolyte layer disposed on an opposite side of the electrode active material layer from the current collector, and a counter electrode active material layer disposed on the opposite side of the electrolyte layer from the electrode active material layer, the electrode body having a protruding region at an end of the main surface of the current collector in a first direction, which is a direction from the center of the main surface of the current collector toward an outer edge, where the current collector protrudes in the first direction beyond the counter electrode active material layer in a planar view relative to the main surface of the current collector, the method comprising: performing a first shaping process to define an outer shape of a region where the protruding region is not provided in the planar view; forming a tab portion on the current collector, where a part of the end of the current collector in the first direction protrudes in the first direction beyond other parts of the end; and forming a chamfered shape on the current collector at a corner of the protruding region in the planar view, all at once.

[0007] According to the present disclosure, highly reliable batteries and the like can be provided.

[0008] FIG. 1 is a top view of a battery according to an embodiment. FIG. 2 is a cross-sectional view of the battery according to the embodiment. FIG. 3 is a top view of an electrode assembly included in the battery according to the embodiment. FIG. 4 is a cross-sectional view showing another example of the structure of an end portion of a unit cell according to the embodiment. FIG. 5 is a top view showing another example of a chamfered shape formed at a corner of an electrode assembly according to the embodiment. FIG. 6 is a top view of an electrode assembly according to a first modification of the embodiment. FIG. 7 is a top view of an electrode assembly according to a second modification of the embodiment. FIG. 8 is a top view of an electrode assembly according to a third modification of the embodiment. FIG. 9 is a top view of a battery according to a fourth modification of the embodiment. FIG. 10 is a top view of an electrode assembly according to the fourth modification of the embodiment. FIG. 11 is a top view of another electrode assembly according to the fourth modification of the embodiment. FIG. 12 is a flowchart showing an example of a method for manufacturing a battery according to the fourth modification of the embodiment. FIG. 13 is a top view of an electrode assembly after first forming processing. FIG. 14 is a flowchart showing another example of a method for manufacturing a battery according to the fourth modification of the embodiment.

[0009] (Background to the Achievement of One Aspect of the Present Disclosure) In a battery including an electrode assembly in which an electrode active material layer, an electrolyte layer, and a counter electrode active material layer are stacked on a current collector in this order, short circuits are likely to occur at the end portions due to contact between the active material layers with opposite polarities or between the current collector and the active material layer. Furthermore, in such batteries, the current collector may be made to protrude beyond the counter electrode active material layer to form a terminal at the end portion of the battery in order to extract current. In such a protruding region where the current collector protrudes beyond the counter electrode active material layer, not all layers are stacked on the current collector, making the strength of the laminated structure of the electrode assembly weaker than in other portions, and prone to collapse that could lead to a short circuit.

[0010] The present disclosure has been made in view of these problems, and aims to provide a highly reliable battery and the like.

[0011] (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.

[0012] For example, a battery according to a first aspect of the present disclosure includes an electrode body having a current collector, an electrode active material layer disposed on a main surface of the current collector, an electrolyte layer disposed on the side of the electrode active material layer opposite the current collector, and a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, wherein a protruding region is provided at an end of the electrode body in a first direction, which is a direction from the center toward the outer edge of the main surface of the current collector, where the current collector protrudes in the first direction beyond the counter electrode active material layer in a planar view relative to the main surface of the current collector, and a chamfered shape is formed on the current collector at a corner of the protruding region in the planar view.

[0013] The protruding region is a portion where the end of the current collector protrudes beyond the counter electrode active material layer, and is therefore susceptible to external impacts during the formation and transportation of the electrode body in the manufacture of the battery, as well as after the battery is installed in a product. In the battery according to this embodiment, the current collector is chamfered at the corners of the protruding region in a plan view, thereby preventing the current collector from getting caught on the corners, making it less susceptible to external impacts, and also alleviating stress concentration even if the corners are impacted. This improves the reliability of the battery.

[0014] Furthermore, for example, a battery according to a second aspect of the present disclosure may be the battery according to the first aspect, in which a chamfered shape is formed in the electrode active material layer together with the current collector at the corner of the protruding region in the planar view.

[0015] In the protruding region, the electrode active material layer is prone to collapse due to impact, vibration, etc. during the formation and transportation of the electrode body in the manufacture of the battery, and after the battery is mounted in a product, etc. In the battery according to this embodiment, the electrode active material layer is also chamfered at the corners of the protruding region in a plan view, so that the ends of the electrode active material layer are recessed, making them less likely to collapse due to impact, vibration, etc. This improves the reliability of the battery.

[0016] Furthermore, for example, a battery according to a third aspect of the present disclosure may be the battery according to the first aspect, in which a chamfered shape is formed in the electrode active material layer and the electrolyte layer together with the current collector at the corners of the protruding region in the planar view.

[0017] In the protruding region, the electrode active material layer and the electrolyte layer are prone to collapse due to impact, vibration, etc. during the formation and transportation of the electrode body in the manufacture of the battery, and after the battery is installed in a product, etc. In the battery according to this embodiment, the electrode active material layer and the electrolyte layer are also chamfered at the corners of the protruding region in a plan view, so that the ends of the electrode active material layer and the electrolyte layer are recessed, making them less likely to collapse due to impact, vibration, etc. This improves the reliability of the battery.

[0018] Furthermore, for example, a battery according to a fourth aspect of the present disclosure may be the battery according to any one of the first to third aspects, in which the chamfered shape is a C-chamfered shape.

[0019] This allows the chamfered shape to be formed using a simple method.

[0020] Furthermore, for example, a battery according to a fifth aspect of the present disclosure may be the battery according to any one of the first to third aspects, in which the chamfered shape is a rounded chamfered shape.

[0021] This eliminates sharp corners in the electrode body, effectively reducing stress concentration at the corners.

[0022] Furthermore, for example, a battery according to a sixth aspect of the present disclosure is the battery according to the fifth aspect, wherein the radius of the R-chamfered shape may be 0.05 mm or more and 10 mm or less.

[0023] As a result, the larger the radius, the more effectively stress concentration can be alleviated even when an impact is applied to the corner. This further improves the reliability of the battery. Furthermore, the smaller the radius, the greater the area that contributes to the charging and discharging of the battery, thereby further increasing the energy density of the battery. The radius may be 0.1 mm or more, or 0.3 mm or more, or may be 5 mm or less, 3 mm or less, or 1 mm or less.

[0024] 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 current collector has a tab portion in which a part of an end of the current collector in the first direction protrudes in the first direction more than the other part of the end.

[0025] This allows a chamfered shape to be formed at the end of the current collector on the first direction side where the tab portion is formed, thereby suppressing impact to the end and mitigating stress to the end.

[0026] Furthermore, for example, a battery according to an eighth aspect of the present disclosure may be a battery according to the seventh aspect, wherein the end of the tab portion on the second direction side opposite to the first direction has a length in a third direction perpendicular to the first direction in the planar view that increases as it progresses in the second direction.

[0027] The corners of the notches for forming the tab portion are likely to be the starting points for damage to the current collector due to external forces acting during the manufacture and use of the battery. In the battery according to this aspect, the length in the third direction of the end of the tab portion on the second direction side increases as it progresses in the second direction, which increases the width of the base of the tab portion and causes the corners of the notches for forming the tab portion to curve gently, thereby suppressing damage to the current collector.

[0028] Furthermore, for example, a battery according to a ninth aspect of the present disclosure may be a battery according to any one of the first to eighth aspects, wherein the electrode body has, in the planar view, an insulating layer that covers at least a portion of the electrolyte layer, at least a portion of the electrode active material layer, and at least a portion of the current collector in the protruding region.

[0029] This protects the current collector, electrode active material layer, and electrolyte layer in the protruding region, and can prevent damage to the current collector, electrode active material layer, and electrolyte layer.

[0030] Furthermore, for example, a battery according to a tenth aspect of the present disclosure may be the battery according to the ninth aspect, wherein the insulating layer protrudes outward from a corner of the protruding region in the plan view.

[0031] This allows the corners to be protected by the insulating layer.

[0032] Furthermore, for example, a battery according to an eleventh aspect of the present disclosure may be a battery according to any one of the first to tenth aspects, in which a chamfered shape is formed on the current collector at a corner of the electrode body other than the protruding region in the planar view.

[0033] This prevents the current collector from getting caught on corners of the electrode body other than the protruding area, making it less susceptible to external impacts, and even if an impact is received at the corner, stress concentration can be alleviated.

[0034] Furthermore, for example, a battery according to a twelfth aspect of the present disclosure may be the battery according to any one of the first to eleventh 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 current collector in the first direction, a second region that is not covered by the electrolyte layer in the planar view is provided at the end of the electrode active material layer in the first direction, and a third region that is not covered by the counter electrode active material layer in the planar view is provided at the end of the electrolyte layer in the first direction.

[0035] This allows the second and third regions to increase the distance between the current collector and the electrode active material layer and the counter electrode active material layer at the end of the electrode body in the first direction where the first region is provided and where it is easy to form a terminal on the current collector. As a result, short circuits and the like caused by contact between electrodes of opposite polarity are less likely to occur, thereby 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 electrode body in a direction from the center toward the outer edge of the main surface of the current collector and in a direction different from the first direction, the side surfaces of the 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, a protruding region is provided at the end of the electrode body in the first direction, while at the end of the electrode body in a 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 current collector, and no space that does not function as a battery is formed due to the steps, thereby improving the actual volumetric energy density of the battery.

[0038] Furthermore, for example, a method for manufacturing a battery according to a fourteenth aspect of the present disclosure includes an electrode body having a current collector, an electrode active material layer disposed on a main surface of the current collector, an electrolyte layer disposed on the side of the electrode active material layer opposite the current collector, and a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, the electrode body having a protruding region at an end in a first direction, which is a direction from the center of the main surface of the current collector toward the outer edge, where the current collector protrudes in the first direction beyond the counter electrode active material layer in a plan view relative to the main surface of the current collector, the method including: performing a first shaping process to define an outer shape of a region where the protruding region is not provided in the plan view; forming a tab portion on the current collector, where a part of the end of the current collector in the first direction protrudes in the first direction beyond other parts of the end; and forming a chamfered shape on the current collector at a corner of the protruding region in the plan view, all at once.

[0039] The first molding process defines the shape of the electrode body, which has the protruding region that does not function as a battery, except for the end portion in the first direction, thereby improving the capacity accuracy of the battery. Furthermore, the second molding process simultaneously forms the tab portion and the chamfered shape of the corners of the protruding region, thereby efficiently forming a structure that improves the reliability of the battery.

[0040] Also, for example, a method for manufacturing a battery according to a fifteenth aspect of the present disclosure may be a method for manufacturing a battery according to the fourteenth aspect, in which the second molding process is performed after the first molding process is performed.

[0041] This allows suitable processing jigs and processing conditions to be selected for the first forming process and the second forming process, thereby improving processing quality.

[0042] Furthermore, for example, a method for manufacturing a battery according to a sixteenth aspect of the present disclosure may be the method for manufacturing a battery according to the fourteenth aspect, in which the first molding process and the second molding process are carried out simultaneously.

[0043] This allows for increased productivity of the battery. Furthermore, since the processing of the outer shape of the end of the electrode body in directions other than the first direction and the processing of the corners of the protruding region of the end in the first direction are performed simultaneously, it is possible to prevent the active material layer and the like from collapsing at the end of the electrode body in directions other than the first direction due to stress generated when forming the chamfered shape at the corners.

[0044] Furthermore, 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 any one of the fourteenth to fifteenth aspects, and may include forming an insulating layer that covers, in the planar view, at least a portion of the electrolyte layer, at least a portion of the electrode active material layer, and at least a portion of the current collector in the protruding region, and the first molding process and the second molding process may be performed after forming the insulating layer.

[0045] This allows the first and second molding processes to be carried out with the protruding regions protected by the insulating layer, and prevents the active material layer and the like from collapsing during the processes.

[0046] Also, for example, a method for manufacturing a battery according to an eighteenth aspect of the present disclosure may be a method for manufacturing a battery according to any one of the fourteenth to sixteenth aspects, in which the first molding process and the second molding process are punching processes.

[0047] This improves the uniformity of the processed size and the ease of processing in the first forming process and the second forming process, and also makes it possible to suppress processing damage to the electrode body.

[0048] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] In this specification, the direction along the x-axis toward the positive side is referred to as the "x-axis positive direction." The direction along the x-axis toward the negative side is referred to as the "x-axis negative direction." The direction along the y-axis toward the positive side is referred to as the "y-axis positive direction." The direction along the y-axis toward the negative side is referred to as the "y-axis negative direction." The x-axis positive direction and the x-axis negative direction are perpendicular to the y-axis positive direction and the y-axis negative direction. The x-axis positive direction and the x-axis negative direction are opposite directions, and the y-axis positive direction and the y-axis negative direction are opposite directions.

[0054] 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."

[0055] Furthermore, in this specification, unless otherwise specified, "protruding" means protruding outward from the center of the electrode body in a plan view relative 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, the "protruding portion of element A" means a part of element A that protrudes more than the tip of element B in the protruding direction. Furthermore, element B may be a part other than the protruding portion of element A. The element is, for example, an active material layer, a solid electrolyte layer, an insulating layer, a current collector, etc.

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

[0057] (Embodiment) [1. Configuration] First, the configuration of a battery according to an embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0058] FIG. 1 is a top view of a battery 1 according to this embodiment. FIG. 2 is a cross-sectional view of the battery 1 according to this embodiment. FIG. 3 is a top view of an electrode assembly 70 included in the battery 1 according to this embodiment. FIG. 1 shows the shape of the battery 1 in plan view 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. FIG. 3 shows the shape of the electrode assembly 70 in plan view when viewed from the positive side of the z-axis. FIG. 3 shows a state in which the counter electrode current collector 50 has been removed from the battery 1.

[0059] As shown in FIGS. 1 and 2 , a battery 1 according to the present embodiment includes a unit cell 60 including an electrode assembly 70 having an electrode current collector 10, an electrode active material layer 20, a solid electrolyte layer 30, and 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 electrode assembly 70 includes two of each of the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40. The unit cell 60 also includes one electrode assembly 70 and two counter electrode current collectors 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. 2 , the battery 1 is formed from one unit cell 60. The battery 1 is, for example, an all-solid-state battery. Note that the battery 1 is not limited to a structure formed from one unit cell 60, and may have a structure in which a plurality of unit cells 60 are stacked.

[0060] 1 , a first region 81, a second region 82, a third region 83, and a fourth region 84 are provided at the end of the unit cell 60 in the positive x-axis direction. The positive x-axis direction is an example of a first direction, which is a direction from the center toward the outer edge of the main surface 15 of the electrode current collector 10. The first region 81, the second region 82, the third region 83, and the fourth region 84 may be provided at the end in the negative x-axis direction, the positive y-axis direction, or the negative y-axis direction. Details of the first region 81, the second region 82, the third region 83, and the fourth region 84 will be described later.

[0061] 1 and 2 , in the unit cell 60, counter electrode current collectors 50 are stacked on both the top and bottom sides of the electrode assembly 70. That is, the electrode assembly 70 is sandwiched between the two counter electrode current collectors 50. In the example shown in FIG. 1 , the outer edge of the electrode assembly 70 and the outer edge of the counter electrode current collector 50 coincide in plan view in the negative x-axis direction, the positive y-axis direction, and the negative y-axis direction.

[0062] The planar shapes of the battery 1, unit cell 60, and electrode assembly 70 are rectangular as shown in FIGS. 1 and 3 . Here, "rectangular" means substantially rectangular. As long as the approximate outer shape is rectangular, protruding shapes such as tab portions 11 and 51 and chamfered shapes such as corners 76 may be partially included. The battery 1, unit cell 60, and electrode assembly 70 have two parallel sides and two perpendicular sides that form the outer edges in planar view. The battery 1, unit cell 60, and electrode assembly 70 are generally shaped like a flattened rectangular parallelepiped. Here, "flat" means that the thickness is shorter than each side or the maximum width of the main surface. The sides or the maximum width of the main surface of the battery 1, unit cell 60, and electrode assembly 70 are, for example, 10 mm or more and 500 mm or less. The planar shapes of the battery 1, unit cell 60, and electrode assembly 70 may be polygonal, such as a square, hexagon, or octagon. In the drawings related to this specification, the thickness of each layer is exaggerated to make the layer structure of the battery easier to understand. Also, in the drawings related to this specification, the lengths of the first region 81, the second region 82, the third region 83, and the fourth region 84 in the positive x-axis direction are exaggerated to make the structure of the unit cell in the first region 81, the second region 82, the third region 83, and the fourth region 84 easier to understand.

[0063] 3, the electrode body 70 has side surfaces 71 and 72 facing back to back, and side surfaces 73 and 74 facing back to back. Side surface 71 is the side surface of the electrode body 70 on the positive x-axis direction. Side surface 72 is the side surface of the electrode body 70 on the negative x-axis direction. Side surface 73 is the side surface of the electrode body 70 on the positive y-axis direction. Side surface 74 is the side surface of the electrode body 70 on the negative y-axis direction.

[0064] The side surfaces 72, 73, and 74 of the electrode assembly 70 may be composed of the side surfaces of the electrode current collector 10, the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40, and at least a portion of each may be a flat plane. When the side surfaces 72, 73, and 74 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 free of steps and lie on the same flat plane. In other words, at the ends of the electrode assembly 70 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 each other. As a result, the side surfaces 72, 73, and 74 of the electrode assembly 70 are free of steps on the side surfaces of the layers, and no spaces that do not function as a battery due to the steps are formed, thereby improving the volumetric energy density of the actual battery 1. Furthermore, the side surfaces of the layers can be made flush by cutting the layers together, for example, facilitating the manufacture of the battery 1. Furthermore, at the ends of the unit cell 60 in the negative x-axis direction, positive y-axis direction, and negative y-axis direction, the 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.

[0065] The side surfaces 72, 73, and 74 are, for example, cut surfaces. Specifically, the side surfaces 72, 73, and 74 are surfaces formed by cutting with a cutter or a punching blade, and are, for example, surfaces having cut marks such as fine grooves. By being cut surfaces, the side surfaces of the layers of the electrode body 70 can easily be made flush. The cut marks may be smoothed by polishing, for example.

[0066] As shown in FIG. 3, when the shape of the electrode body 70 is rectangular in plan view, the side surfaces 71, 72, 73, and 74 each form one side of the rectangle of the electrode body 70 in plan view.

[0067] 1 and 2 , a laminated structure of an electrode active material layer 20, a solid electrolyte layer 30, a counter electrode active material layer 40, and a counter electrode current collector 50 is formed on each of both main surfaces 15 and 16 of the electrode current collector 10. A structure similar to the laminated structure of the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 formed on the main surface 15 of the electrode current collector 10 is also formed upside down on the main surface 16 of the electrode current collector 10 facing away from the main surface 15. Therefore, the unit cell 60 and the electrode assembly 70 have a symmetrical laminated structure with the electrode current collector 10 sandwiched between them. This makes it possible to extract currents from two electrode active material layers 20 from one electrode current collector 10, thereby increasing the volumetric energy density. Furthermore, due to the symmetrical stacking structure, when the unit cells 60 and the electrode assembly 70 are 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, thereby suppressing warping of the unit cells 60 and the electrode assembly 70. Furthermore, even if stresses are generated due to expansion and contraction of the electrode active material layer 20 and the counter electrode active material layer 40 during use of the battery 1, stresses generated on both sides of the electrode current collector 10 in the stacking direction are less likely to differ, thereby suppressing warping of the unit cells 60 and the electrode assembly 70. The stacking structure of the electrode active material layer 20, solid electrolyte layer 30, counter electrode active material layer 40, and counter electrode current collector 50 may be formed on only one main surface of the electrode current collector 10.

[0068] Two electrode active material layers 20 are disposed on both main surfaces 15 and 16 of the electrode current collector 10. Two solid electrolyte layers 30 are disposed on each of the two electrode active material layers 20, on the side opposite the electrode current collector 10. Two counter electrode active material layers 40 are disposed on each of the two solid electrolyte layers 30, on the side opposite the electrode active material layer 20. Two counter electrode current collectors 50 are disposed on each of the two counter electrode active material layers 40, on the side opposite the solid electrolyte layer 30.

[0069] The electrode current collector 10 is an example of a current collector, and is in contact with the electrode active material layer 20 on each of its main surfaces 15 and 16. The thickness of the electrode current collector 10 is, for example, 5 μm or more and 100 μm or less. In this specification, the thickness of the current collector and each layer is the length in the stacking direction, and is the average value of the overall thickness unless otherwise specified.

[0070] Known materials can be used as the material 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.

[0071] 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.

[0072] Known materials can be used as the material of the counter electrode current collector 50. For example, a foil, plate, or mesh-like body made of copper, aluminum, nickel, iron, stainless steel, platinum, gold, or an alloy of two or more of these 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.

[0073] The electrode active material layer 20 is disposed on the main surfaces 15 and 16 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 material used for the electrode active material layer 20 will be described later. In a plan view, the area of ​​the electrode active material layer 20 may be the same as the area of ​​the counter electrode active material layer 40, or may be smaller than the area of ​​the counter electrode active material layer 40.

[0074] 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 material used for the solid electrolyte layer 30 will be described later. The solid electrolyte layer 30 may be formed to be larger than the electrode active material layer 20 and the counter electrode active material layer 40 in a plan view, and the solid electrolyte layer 30 may cover the side surfaces of the electrode active material layer 20 and the counter electrode active material layer 40 on the positive x-axis direction.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] Next, the end structures of the unit cell 60 and the electrode assembly 70 will be described.

[0090] As shown in FIGS. 1 to 3 , the electrode current collector 10 has a tab portion 11, which is a protrusion at a portion of the end of the electrode current collector 10 in the positive x-axis direction that protrudes further in the positive x-axis direction than the remaining portion of the end. The tab portion 11 has, for example, a rectangular shape in a plan view. The tab portion 11 functions, for example, as a lead on which a terminal is formed. Another lead material may be bonded to the tab portion 11. Because the tab portion 11 is a protruding portion of the end of the electrode current collector 10, it is possible to suppress short circuits caused by contact between the electrode current collector 10 and the counter electrode current collector 50 and the counter electrode active material layer 40, compared to when the entire end of the electrode current collector 10 protrudes. In the example shown in FIGS. 1 and 3 , a portion of the first region 81 of the electrode current collector 10 protrudes in the positive x-axis direction to form the tab portion 11. Note that the main surfaces 15 and 16 other than the tab portion 11 may be entirely covered by the electrode active material layer 20. Alternatively, a portion of the tab portion 11 may be covered by the electrode active material layer 20. Furthermore, the electrode current collector 10 does not necessarily have to have the tab portion 11 .

[0091] The counter electrode current collector 50 has a tab portion 51, which is a protrusion at a portion of an end of the counter electrode current collector 50 in the x-axis positive direction that protrudes further in the x-axis positive direction than the remaining portion of the end. The tab portion 51 has, for example, a rectangular shape in a plan view. The tab portion 51 protrudes further in the x-axis positive direction than the electrode active material layer 20 in a plan view. The tab portion 51 functions, for example, as a lead on which a terminal is formed. Another lead material may be bonded to the tab portion 51. The tab portion 51 may be formed not at the end of the counter electrode current collector 50 in the x-axis positive direction, but at the end of the counter electrode current collector 50 in the x-axis negative direction, the y-axis positive direction, or the y-axis negative direction. In other words, the tab portion 11 and the tab portion 51 may protrude in different directions. Alternatively, the tab portion 51 may not be formed, and the counter electrode current collector 50 may protrude in any direction beyond the electrode active material layer 20 in a plan view.

[0092] 1 and 2, the tab portion 51 faces, with a gap therebetween, the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30. The tab portion 11 and the tab portion 51 are arranged at positions where they do not overlap in a plan view.

[0093] As shown in FIGS. 1 to 3 , a protruding region 75 is provided at the end of the electrode assembly 70 in the positive x-axis direction (the end along the side surface 71 in plan view), where the electrode current collector 10 protrudes in the positive x-axis direction beyond the counter electrode active material layer 40 in plan view. In the example shown in FIGS. 1 to 3 , the electrode active material layer 20 and the solid electrolyte layer 30 also protrude in the positive x-axis direction beyond the counter electrode active material layer 40 in the protruding region 75 in plan view. Because the counter electrode active material layer 40 is not disposed in the protruding region 75, the protruding region 75 is a region of the electrode assembly 70 that does not function as a battery. Furthermore, because the electrode current collector 10 protrudes in the positive x-axis direction beyond the counter electrode active material layer 40 in the protruding region 75, current can be easily extracted from the electrode active material layer 20. The thickness of the electrode assembly 70 in the protruding region 75 is smaller than the thickness of the electrode assembly 70 in regions other than the protruding region 75. In the examples shown in FIGS. 1 to 3, in the protruding region 75, the number of layers stacked on the electrode current collector 10 decreases as the region moves in the positive x-axis direction, and therefore the thickness decreases.

[0094] In the unit cell 60, a first region 81, a second region 82, a third region 83, and a fourth region 84 that are not covered by the upper layer are provided at the end in the positive x-axis direction.

[0095] Specifically, a first region 81 that is not covered by the electrode active material layer 20 is provided at an end of the main surface 15 of the electrode current collector 10 in the positive x-axis direction. The first region 81 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 82 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 82 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 83 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 83 is not in contact with the counter electrode active material layer 40 or the counter electrode current collector 50. The third region 83 is farther from the electrode current collector 10 than the second region 82. Furthermore, a fourth region 84 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 84 is farther from the electrode current collector 10 than the third region 83.

[0096] Thus, the provision of the first region 81 makes it easier to form a terminal on the electrode current collector 10. Furthermore, the second region 82, the third region 83, and the fourth region 84 increase the distance between the electrode current collector 10 and the electrode active material layer 20 and the end of the counter electrode active material layer 40, as well as the distance between the electrode current collector 10 and the electrode active material layer 20 and the end of the counter electrode current collector 50. As a result, short circuits and the like caused by contact between electrodes of opposite polarity are less likely to occur. This makes it possible to improve the reliability of the battery 1.

[0097] 1 , the first region 81, the second region 82, the third region 83, and the fourth region 84 are provided along the side surface of the unit cell 60 on the x-axis positive side in a plan view. The first region 81, the second region 82, the third region 83, and the fourth region 84 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 84, the third region 83, the second region 82, and the first region 81 are arranged in this order along the x-axis positive direction in a plan view.

[0098] Here, the lengths of the first region 81, the second region 82, the third region 83, and the fourth region 84 will be described. In the following description, the lengths of the first region 81, the second region 82, the third region 83, and the fourth region 84 are lengths in the positive x-axis direction in a plan view. The length of the first region 81 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 a plan view. The length of the second region 82 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 a plan view. The length of the third region 83 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 a plan view. The length of the fourth region 84 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 a plan view.

[0099] The length of the first region 81 is, for example, 1 mm or more and 20 mm or less. This makes it possible to increase the energy density of the battery 1 while ensuring an area where a terminal can be easily formed on the electrode current collector 10. The length of the first region 81 here is the maximum length of the first region 81, and specifically, the length of the first region 81 in the portion where the tab portion 11 is formed. The length of the first region in the portion where the tab portion 11 is not formed is, for example, 0 mm or more and 5 mm or less, and may be 0.2 mm or more and 2 mm or less.

[0100] The length of each of the second region 82, the third region 83, and the fourth region 84 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 82, the third region 83, and the fourth region 84 may be, for example, 0.5 mm or more and 2 mm or less.

[0101] The lengths of the first region 81, the second region 82, the third region 83, and the fourth region 84 may be the same, or at least one of them may be different. In addition, the length of the first region 81 may be longer than the lengths of the second region 82, the third region 83, and the fourth region 84.

[0102] 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 84 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 82 is provided in the electrode active material layer 20 and the third region 83 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.

[0103] 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. 4 is a cross-sectional view showing another example of the structure of the end of the unit cell 60.

[0104] In the example shown in FIG. 4 , the electrode active material layer 20 has, in the second region 82, 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 82 is, for example, the region where the inclined surface 21 is formed. Furthermore, the solid electrolyte layer 30 has, in the third region 83, 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 83 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 84, 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 84 is, for example, the region where the inclined surface 41 is formed. In the example shown in FIG. 4 , the inclined surface 21 and the inclined surface 31 are connected, and the inclined surface 31 and the inclined surface 41 are connected. In other words, the inclined surfaces 21, 31 and 41 form one continuous inclined surface.

[0105] 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 82, the solid electrolyte layer 30 in the third region 83, and the counter electrode active material layer 40 in the fourth region 84, and the materials of these layers are less likely to fall off, making short circuits less likely to occur. This improves the reliability of the battery 1.

[0106] 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 has a stepped shape.

[0107] The angle that each of the inclined surfaces 21, 31, and 41 forms with respect to the main surface 15 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 15 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 15 is, for example, 1 degree or more.

[0108] In the example shown in FIG. 4 , the electrode active material layer 20 has a recess 22 in the third region 83 where the solid electrolyte layer 30 is recessed. The solid electrolyte layer 30 also has a recess 32 in the fourth region 84 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.

[0109] The depth of each of the recesses 22 and 32 is, for example, not less than 1 μm and not more than 10 μm.

[0110] 4 , the surface of the electrode active material layer 20 on the solid electrolyte layer 30 side below the inclined surface 41 (i.e., the position overlapping with the inclined surface 41 in a plan view) has a portion that inclines so as to move away from the electrode current collector 10 as it progresses in the positive x-axis direction. Therefore, at the position of the outer edge of the counter electrode active material layer 40 in the positive x-axis direction in a plan view, the thickness of the electrode active material layer 20 is greater than the thickness of the electrode active material layer 20 on the inside of that position.

[0111] 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. 4 may also be included in batteries according to the modifications described below.

[0112] 1 and 3 again, the shape of the corners 76 of the electrode body 70 will be described.

[0113] As shown in FIGS. 1 and 3 , a chamfered shape is formed on the electrode current collector 10 at a corner 76 of the protruding region 75 in a plan view. The corner 76 is a portion where two sides extending in intersecting directions of the outer edge of the electrode body 70 are connected in a plan view. The chamfered shape is a shape processed so that the corner 76 does not have an angle that is less than the angle formed by a virtual line extending from the two sides connected by the corner 76 in a plan view. In the example shown in FIG. 3 , the corner 76 is a portion that connects the side surface 71 and the side surface 74 in a plan view. In addition, in the example shown in FIG. 3 , the corner 76 is located at the end of the protruding region 75 in the y-axis negative direction. In addition, in the example shown in FIG. 3 , a tab portion 11 is not formed on the electrode current collector 10 at the corner 76.

[0114] Because the end of the electrode current collector 10 protrudes beyond the counter electrode active material layer 40, the protruding region 75 is a portion that is susceptible to external impacts during the formation and transportation of the electrode body 70 in the manufacture of the battery 1, as well as after the battery 1 is mounted in a product. In the battery 1, the electrode current collector 10 is chamfered at the corners 76 of the protruding region 75 in a plan view. This prevents the electrode current collector 10 from getting caught on other components at the corners 76, making it less susceptible to external impacts, and also alleviates stress concentration even if an impact is received at the corners 76. This improves the reliability of the battery 1.

[0115] 1 and 3 , at corners 76 of protruding regions 75 in a plan view, chamfered shapes are formed in the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30. At corners 76, a chamfered shape is formed in a first region 81 of the electrode current collector 10, a chamfered shape is formed in a second region 82 of the electrode active material layer 20, and a chamfered shape is formed in a third region 83 of the solid electrolyte layer 30. In other words, the chamfered shape at corners 76 extends not only to the first region 81 but also to the second region 82 and the third region 83.

[0116] As shown in the figure, the protruding region 75 may be exposed and not covered by the counter electrode active material layer 40, making it a portion where structural strength is relatively low against impact, vibration, and the like. Therefore, in the protruding region 75, the electrode active material layer 20 and the solid electrolyte layer 30 are likely to collapse due to impact, vibration, and the like during the formation and transportation of the electrode body 70 in the manufacture of the battery 1, and after the battery 1 is installed in a product. In the battery 1, the electrode active material layer 20 and the solid electrolyte layer 30 are also chamfered at the corners 76 of the protruding region 75 in a planar view. This recesses the ends of the electrode active material layer 20 and the solid electrolyte layer 30, making them less likely to collapse due to impact, vibration, and the like. This improves the reliability of the battery 1.

[0117] The chamfered shape formed at the corners 76 is an R-chamfered shape. That is, the corners 76 are rounded in plan view. This eliminates sharp edges at the corners 76 of the electrode body 70, effectively preventing the corners 76 from getting caught on other components and effectively suppressing stress concentration at the corners 76. The R-chamfered shape is formed by, for example, punching, but may also be formed by cutting, laser processing, or the like.

[0118] In the example shown in FIGS. 1 and 3 , the chamfered shape formed at the corner 76 does not extend to the counter electrode active material layer 40. In other words, the length L1 of the chamfered shape formed at the corner 76 in the positive x-axis direction is set to a length that does not result in a chamfered shape being formed in the counter electrode active material layer 40. This allows the chamfered shape to be formed without reducing the capacity of the battery. The length L1 is the length in the positive x-axis direction of a portion that is recessed from an imaginary line extending from two sides connected by the corner 76 in a plan view. When the chamfered shape formed at the corner 76 is an R-chamfered shape, the length L1 is the same as the R amount of the chamfered shape (the radius of the arc of the chamfered shape). Note that the chamfered shape formed at the corner 76 may also extend to the counter electrode active material layer 40. Furthermore, the electrode active material layer 20 and the solid electrolyte layer 30, or the solid electrolyte layer 30, do not need to have a chamfered shape at their ends in the positive x-axis direction.

[0119] The chamfered shape formed at the corner 76 is not limited to an R-chamfered shape. FIG. 5 is a top view showing another example of a chamfered shape formed at the corner 76 of the electrode body 70. The chamfered shape formed at the corner 76 may be a C-chamfered shape as shown in FIG. 5. That is, at the corner 76 of the electrode body 70, a flat surface inclined relative to each of the side surfaces 71 and 74 is formed. This allows the chamfered shape to be formed using a simple construction method. Furthermore, there is a high degree of freedom in determining the extent and timing of the chamfered shape. Furthermore, because the angle of the corner 76 is an obtuse angle, it is possible to prevent the corner 76 from catching on other components and to suppress stress concentration at the corner 76. The C-chamfered shape is formed by, for example, a cutting process, but may also be formed by punching, cutting, laser processing, or the like.

[0120] The chamfered shape formed at the corners of the electrode body according to each of the modified examples described below is not limited to an R-chamfered shape, but may also be a C-chamfered shape.

[0121] [2. Modifications] Modifications of the present embodiment will be described below. In the following description of the modifications, differences from the embodiment and each modification will be mainly described, and descriptions of commonalities will be omitted or simplified. In the following description, the electrode assembly included in the battery according to each modification may be illustrated, but the electrode assembly according to each modification has counter electrode current collectors 50 stacked on both the top and bottom of the electrode assembly, similar to the battery 1 according to the above embodiment.

[0122] [2-1. Modification 1] First, modification 1 of the embodiment will be described. Fig. 6 is a top view of an electrode body 170 according to this modification. Fig. 6 shows the shape of the electrode body 170 in plan view when viewed from the positive side of the z-axis. The battery according to this modification has a configuration in which the electrode body 70 of the battery 1 according to the embodiment is replaced with the electrode body 170. Fig. 6 shows a state in which the counter electrode current collector 50 has been removed from the battery according to this modification.

[0123] 6 , the electrode body 170 differs from the electrode body 70 according to the embodiment in that, in plan view, chamfered shapes are formed at corners 77, 78, and 79 in addition to corner 76. Note that the electrode body 170 does not necessarily have to have chamfered shapes formed at one or two of the corners 77, 78, and 79.

[0124] In the electrode body 170, a chamfer is formed on the electrode current collector 10 not only at the corner 76 of the protruding region 75 in plan view but also at the corner 77. In the example shown in FIG. 6 , the corner 77 is a portion that connects the side surface 71 and the side surface 73 in plan view. Also, in the example shown in FIG. 6 , the corner 77 is located at the end of the protruding region 75 in the y-axis positive direction. Also, no tab portion 11 is formed on the electrode current collector 10 at the corner 77. Also, in the example shown in FIG. 6 , a chamfer is formed on the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30 at the corner 77 of the protruding region 75 in plan view. The chamfered shape at the corner 76 and the chamfered shape at the corner 77 have, for example, the same size and shape. For example, the length in the x-axis positive direction of the chamfered shape formed at the corner 77 is the same as the length L1 in the x-axis positive direction of the chamfered shape formed at the corner 76.

[0125] Furthermore, in the electrode body 170, the electrode current collector 10 is chamfered at corners 78 and 79 of the electrode body 170 other than the protruding region 75 in a plan view. This prevents the current collector from getting caught at the corners 78 and 79, making them less susceptible to external impacts, and also alleviates stress concentration even if the corners 78 and 79 are impacted. The corners 78 and 79 are corners at the end of the electrode body 170 in the negative x-axis direction in a plan view. In the example shown in FIG. 6 , the corner 78 is a portion connecting the side surface 72 and the side surface 74 in a plan view, and the corner 79 is a portion connecting the side surface 72 and the side surface 73 in a plan view. In the example shown in FIG. 6 , 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 chamfered at the corners 78 and 79. The chamfered shape at the corner 78 and the chamfered shape at the corner 79 have, for example, the same size and shape.

[0126] 6, the length L2 in the x-axis positive direction of the chamfered shape formed at corner 78 is shorter than the length L1 in the x-axis positive direction of the chamfered shape formed at corner 76. This reduces the amount of recession of electrode body 170 at corner 78, thereby suppressing a decrease in the energy capacity of the battery.

[0127] In addition, in electrode bodies according to other modified examples described below, there may be a plurality of corners formed with chamfered shapes.

[0128] [2-2. Modification 2] Next, Modification 2 of the embodiment will be described. Fig. 7 is a top view of an electrode body 270 according to this modification. Fig. 7 shows the planar shape of the electrode body 270 when viewed from the positive side of the z-axis. The battery according to this modification has a configuration in which the electrode body 70 of the battery 1 according to the embodiment is replaced with the electrode body 270. Fig. 7 shows a state in which the counter electrode current collector 50 has been removed from the battery according to this modification.

[0129] As shown in FIG. 7 , the electrode assembly 270 differs from the electrode assembly 70 according to the embodiment in that it has an electrode current collector 210 instead of the electrode current collector 10 .

[0130] The electrode current collector 210 includes a current collecting foil 210 a and a connection layer 210 b that covers the current collecting foil 210 a. The connection layer 210 b is disposed between the current collecting foil 210 a and the electrode active material layer 20 and is in contact with the current collecting foil 210 a and the electrode active material layer 20.

[0131] The current collecting foil 210a is a metal foil made of, for example, copper, aluminum, nickel, iron, stainless steel, platinum, gold, or an alloy of two or more of these metals. The connection layer 210b is, for example, a conductive carbon coating layer containing conductive carbon.

[0132] 7 , the current collecting foil 210a has an area in the tab portion 11 that is not covered by the connection layer 210b. The current collecting foil 210a is entirely covered by the connection layer 210b except for the tab portion 11. In addition, at corners 76 of the protruding region 75 in plan view, the current collecting foil 210a is covered by the connection layer 210b in the electrode current collector 210. Therefore, at corners 76 of the protruding region 75 in plan view, a chamfered shape is formed in the current collecting foil 210a and the connection layer 210b.

[0133] The electrode current collector according to the embodiment or a modification other than this modification may include the connection layer 210b.

[0134] [2-3. Modification 3] Next, Modification 3 of the embodiment will be described. Fig. 8 is a top view of an electrode body 370 according to this modification. Fig. 8 shows the planar shape of the electrode body 370 when viewed from the positive side of the z-axis. The battery according to this modification has a configuration in which the electrode body 70 of the battery 1 according to the embodiment is replaced with the electrode body 370. Fig. 8 shows a state in which the counter electrode current collector 50 has been removed from the battery according to this modification.

[0135] As shown in FIG. 8 , the electrode assembly 370 differs from the electrode assembly 70 according to the embodiment in that the electrode current collector 10 has a tab portion 311 instead of the tab portion 11 .

[0136] The length of the x-axis negative end 312 of the tab portion 311 (in other words, the base portion of the tab portion 311 protruding in the x-axis positive direction) increases in the y-axis positive direction as it progresses in the x-axis negative direction. In the example shown in FIG. 8 , in plan view, the angle of the rise of the side extending in the x-axis positive direction of the x-axis negative end 312 of the tab portion 311 is gentle, and it can also be said that the corners of the notch for forming the tab portion 311 have a chamfered shape. In the example shown in FIG. 8 , in plan view, the chamfered shape of the corners of the notch for forming the tab portion 311 is an R-chamfer, but it may also be a C-chamfer. In other words, the length of the end 312 in the y-axis positive direction may increase in a curved or linear manner as it progresses in the x-axis negative direction. In this modification, the x-axis negative direction is an example of the second direction, and the y-axis positive direction is an example of the third direction.

[0137] The corners of the notch for forming the tab portion 311 are likely to be the starting points for damage to the electrode current collector 10 due to external forces acting during the manufacture and use of the battery. If the electrode current collector 10 is damaged by tearing or cutting, there are concerns about reduced yield and reduced reliability due to current concentration in undamaged portions. In this modification, the length of the end 312 of the tab portion 311 in the negative x-axis direction increases in the positive y-axis direction as it progresses in the negative x-axis direction, so that the corners of the notch for forming the tab portion 311 are gently curved, thereby suppressing damage to the electrode current collector 10.

[0138] The tab portion 51 of the counter electrode current collector 50 may have a structure similar to that of the tab portion 311 at its end in the negative x-axis direction.

[0139] [2-4. Modification 4] Next, Modification 4 of the embodiment will be described. Fig. 9 is a top view of a battery 401 according to this modification. Fig. 10 is a top view of an electrode assembly 470 according to this modification. Fig. 9 shows the shape of the battery 401 in plan view when viewed from the positive side of the z axis. Fig. 10 also shows the shape of the electrode assembly 470 in plan view when viewed from the positive side of the z axis. Fig. 10 shows a state in which the counter electrode current collector 50 has been removed from the battery 401 according to this modification.

[0140] 9, the battery 401 includes a unit cell 460 having an electrode assembly 470 and a counter electrode current collector 50, and is formed from one unit cell 460. Also, as shown in FIGS. 9 and 10, the electrode assembly 470 differs from the electrode assembly 370 according to the third modified example of the embodiment in that it further includes an insulating layer 90. In other words, the electrode assembly 470 has a configuration in which the insulating layer 90 is added to the electrode assembly 370.

[0141] In a plan view, the insulating layer 90 covers at least a portion of the electrode current collector 10, at least a portion of the electrode active material layer 20, and at least a portion of the solid electrolyte layer 30 in the protruding region 75. In the example shown in FIG. 10 , the insulating layer 90 covers a portion of the first region 81 on the second region 82 side, the entire second region 82, and the entire third region 83 in a plan view. The insulating layer 90 is in contact with a portion of the first region 81 on the second region 82 side, the entire second region 82, and the entire third region 83. In a plan view, the insulating layer 90 does not cover a portion of the tab portion 311. In addition, in the battery 401, the tab portion 51 of the counter electrode current collector 50 faces the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30, with the insulating layer 90 interposed therebetween.

[0142] The insulating layer 90 protects the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30 in the protruding region 75 from external forces from the z-axis direction, and can suppress damage to the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30. It can also suppress the occurrence of a short circuit due to contact between the electrode current collector 10 and the electrode active material layer 20 and the counter electrode active material layer 40 and the counter electrode current collector 50.

[0143] Furthermore, the insulating layer 90 protrudes outward from the corners 76 of the protruding regions 75 in a plan view. As a result, the insulating layer 90 protrudes beyond the electrode current collector 10 at the corners 76 in a plan view, and the corners 76 can be effectively protected by the insulating layer 90. The chamfered shapes formed at the corners 76 of the protruding regions 75 in a plan view are completely covered by the insulating layer 90 in a plan view. Furthermore, the insulating layer 90 protrudes in a plan view in the positive x-axis direction, the positive y-axis direction, and the negative y-axis direction beyond the electrode active material layer 20 and the electrode current collector 10 other than the tab portions 311.

[0144] In the examples shown in FIGS. 9 and 10 , the insulating layer 90 does not cover the counter electrode active material layer 40 in a plan view. The insulating layer 90 may cover the end of the counter electrode active material layer 40 in the x-axis positive direction (e.g., at least a portion of the fourth region 84) in a plan view. The insulating layer 90 may completely cover the third region 83 in a plan view, but may not cover at least a portion of the third region 83, forming a gap between the insulating layer 90 and the counter electrode active material layer 40. The insulating layer 90 may not entirely cover the first region 81, the second region 82, and the third region 83 in the y-axis direction in a plan view. For example, the insulating layer 90 may not be formed in a portion that does not overlap with the tab portion 51 in a plan view.

[0145] Furthermore, the insulating layer 90 may cover the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30 from the sides in the protruding region 75. Furthermore, the insulating layer 90 may be disposed in a region other than the protruding region 75. For example, the insulating layer 90 may be disposed on the side surfaces 72, 73, and 74.

[0146] The insulating layer 90 has, for example, electronic insulation and ionic insulation. For example, an insulating tape or an insulating resin is used for the insulating layer 90. Examples of resins used for the insulating tape and the insulating resin include silicone resin, epoxy resin, acrylic resin, and polyimide resin. The resin may be a thermosetting resin or an ultraviolet-curable resin. The insulating layer 90 may also contain a solid electrolyte. The above-listed solid electrolyte materials may be used as the solid electrolyte. The same solid electrolyte material as that used for the solid electrolyte layer 30 may also be used as the solid electrolyte.

[0147] In addition, the insulating layer 90 does not have to protrude outward from the corners 76 of the protruding regions 75 in a plan view. Fig. 11 is a top view of another electrode body 470A according to this modification. The other battery according to this modification has a configuration in which the electrode body 70 of the battery 1 according to the embodiment is replaced with the electrode body 470A.

[0148] The electrode body 470A has a configuration in which the insulating layer 90 of the electrode body 470 is replaced with an insulating layer 90A. In plan view, the insulating layer 90A does not protrude outward from the corners 76 of the protruding regions 75, and the position of the outer edge of the insulating layer 90A at the corners 76 coincides with the position of the outer edge of the electrode current collector 10. Therefore, a chamfered shape is formed in the insulating layer 90A together with the electrode current collector 10 at the corners 76 of the protruding regions 75 in plan view. Furthermore, in plan view, the insulating layer 90A does not protrude outward from the electrode current collector 10 in any part other than the corners 76 of the protruding regions 75, and the position of the outer edge of the insulating layer 90A overlaps the outer edge of the electrode current collector 10. This can increase the areal energy density of the battery.

[0149] The electrode body 70, 170 or 270 may have the insulating layer 90 or 90A.

[0150] [3. Manufacturing Method] Next, a method for manufacturing batteries according to the present embodiment and each of the modified examples of the present embodiment will be described. The following mainly describes a method for manufacturing battery 401 according to modified example 4 of the embodiment, but other batteries can also be manufactured by appropriately applying the manufacturing method described below. Figure 12 is a flowchart showing an example of a method for manufacturing battery 401 according to modified example 4 of the embodiment. Note that the manufacturing methods for batteries according to the present embodiment and each of the modified examples described below are merely examples and are not limited to the following example.

[0151] First, an electrode current collector 10 without a tab portion 311 is prepared (step S11). Next, electrode active material layers 20 are laminated on both main surfaces 15 and 16 of the electrode current collector 10 (step S12). At this time, the electrode active material layers 20 are laminated on the main surfaces 15 and 16 so that first regions 81 that are not covered by the electrode active material layers 20 are provided at the ends of the main surfaces 15 and 16 in the positive x-axis direction.

[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 82 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 83 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 press treatment (step S15) is performed as necessary after each of steps S12 to S14. This results in an electrode body 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 15 and 16 side on both main surfaces 15 and 16 of the electrode current collector 10, and in which a protruding region 75 is provided at the end on the positive side of the x-axis.

[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 15 and 16 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] The above steps S12 to S15 may be performed in a continuous process such as a roll-to-roll process.

[0162] Furthermore, the electrode body formed up to step S15 may have a size in plan view sufficient to form one battery 401, or may have a size in plan view sufficient to be singulated and used for multiple batteries 401. When singulating the electrode body, the singulation may be performed by the first molding process described below.

[0163] Next, a first shaping process is performed to define the outer shape of the electrode body in a plan view where the protruding region 75 is not provided (step S16). In the first shaping process, the positions of the electrode body's end portions other than the end portion in the x-axis positive direction in a plan view are defined. FIG. 13 is a top view of the electrode body 80 after the first shaping process. FIG. 13 shows the electrode body 80 after the first shaping process and before the second shaping process described below. For example, in the first shaping process, the end portions of the electrode body obtained up to step S15 in the x-axis negative direction, the y-axis positive direction, and the y-axis negative direction are cut off along a direction intersecting (specifically, perpendicular to) the main surface 15 to form cut surfaces as side surfaces 72, 73, and 74. This defines the outer shape of the end portions in the direction other than the x-axis positive direction where the protruding region 75 is provided, thereby obtaining an electrode body 80 with a defined area of ​​the region that functions as a battery.

[0164] On the cut surface, 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 exposed. After the first shaping process, an insulating layer or the like may be disposed to cover these exposed side surfaces in order to protect these side surfaces. That is, when these side surfaces are covered with another member such as an insulating layer, these exposed side surfaces may also be covered with the other member.

[0165] The first shaping process is, for example, a punching process. For example, the electrode body obtained up to step S15 is punched using a punching die provided with a punching blade shaped so that the area of ​​the region functioning as a battery in the electrode body 80 is the desired area. By performing the punching process, the electrode body can be easily processed into the desired shape. Furthermore, by performing the punching process, an electrode body 80 with the same area can be obtained each time the first shaping process is performed, thereby improving the capacitance accuracy of the electrode body 80. The first shaping process is not limited to punching, and other processing methods such as cutting, cutting, or laser processing may also be used. Furthermore, to prevent short circuits, foreign matter adhering to the side surfaces 72, 73, and 74 after the first shaping process may be removed by cleaning. Examples of cleaning methods include non-contact removal methods such as air blowing or suction, or contact removal methods using adhesive tape.

[0166] Next, a second shaping process is performed (step S17), which simultaneously forms the tab portion 311 on the electrode current collector 10 and chamfers the corners 76 of the protruding region 75 in a plan view of the electrode current collector 10. In the second shaping process, the electrode current collector 10, the electrode active material layer 20, and the solid electrolyte layer 30 are chamfered along with the electrode current collector 10. In the second shaping process, the tab portion 311 is formed such that its length in the positive y-axis direction increases as its end 312 in the negative x-axis direction advances in the negative x-axis direction, as described with reference to FIG. 8 and other figures. The second shaping process defines the outline of the protruding region 75 in a plan view. For example, in the second shaping process, a portion of the protruding region 75 of the electrode assembly 80 shown in FIG. 13 is cut off to form the shapes of the tab portion 311 and the corners 76 in a plan view. This results in the electrode assembly 370 shown in FIG. 8.

[0167] The second shaping process is, for example, a punching process. For example, the electrode body 80 shown in FIG. 13 is punched using a punching die provided with a punching blade shaped to correspond to the tab portion 311 and the corner portion 76 in a plan view. By performing the punching process, the electrode body 80 can be easily processed into the desired shape. Furthermore, by performing the punching process, the punching blade does not penetrate into areas other than those that require processing, thereby reducing processing damage to the electrode body 370. For example, forming the tab portion 311 by punching can prevent notches from being created at the base of the tab portion 311 due to processing. The second shaping process is not limited to punching, and other processing methods such as cutting, cutting, or laser processing may also be used. Furthermore, to prevent short circuits, foreign matter adhering to the side surface of the protruding region 75 after the second shaping process may be removed by cleaning. Examples of cleaning methods include non-contact removal methods such as air blowing or suction, or contact removal methods using adhesive tape.

[0168] 12 , the second shaping process is performed after the first shaping process, which processes the region where the electrode active material layer 20, the solid electrolyte layer 30, and the counter electrode active material layer 40 are all laminated on the electrode current collector 10, and the second shaping process which processes the protruding region 75 where the counter electrode active material layer 40 is not present. This allows for selecting suitable jigs, processing conditions, and the like for each process, thereby improving processing quality.

[0169] Instead of step S17, the steps of forming the tab portion 311 on the electrode current collector 10 and forming a chamfered shape on the electrode current collector 10 at the corner 76 of the protruding region 75 in a plan view may be performed separately.

[0170] Next, an insulating layer 90 is formed to cover, in a plan view, at least a portion of the electrode current collector 10, at least a portion of the electrode active material layer 20, and at least a portion of the solid electrolyte layer 30 in the protruding region 75 (step S18). This results in an electrode assembly 470 with the insulating layer 90 formed in the protruding region 75. The insulating layer 90 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 dipping the end surface of the laminated electrode plate in the resin material. The curing is performed by drying, heating, or light irradiation, depending on the resin material used. Furthermore, when forming the insulating layer 90, a protective process may be performed using masking tape or a resist treatment to prevent a portion of the tab portion 311 from being covered by the insulating layer 90. After forming the insulating layer 90, the protective material may be removed to ensure electrical connection at the tab portion 311. The insulating layer 90 may also be formed by applying insulating tape or the like.

[0171] Next, a counter electrode current collector 50 is laminated on the side of the counter electrode active material layer 40 opposite the solid electrolyte layer 30 (step S19). This results in a unit cell 460 including a laminate in which the electrode active material layer 20, the solid electrolyte layer 30, the counter electrode active material layer 40, and the counter electrode current collector 50 are laminated in this order on both main surfaces 15 and 16 of the electrode current collector 10. The counter electrode current collector 50 is laminated on the counter electrode active material layer 40 so that a fourth region 84 not covered by the counter electrode current collector 50 is provided at the end of the counter electrode active material layer 40 in the positive x-axis direction. The counter electrode active material layer 40 and the counter electrode current collector 50 are bonded to each other by, for example, high-pressure pressing. The bonding may also be performed by using a counter electrode current collector 50 having a connection layer containing an adhesive binder, by coating with an adhesive, or by attaching an adhesive film. The bonding method is not limited to these methods. Heat treatment may also be performed during or after bonding.

[0172] The counter electrode current collector 50 may be formed to a desired size before stacking, or may be partially removed after stacking. Also, the tab portion 51 may be formed after stacking.

[0173] Through the steps described above, a battery 401 composed of one unit cell 460 is obtained. The obtained battery 401 may be housed in an exterior body or the like. When the battery 401 is housed in an exterior body, the tab portion 311 and the tab portion 51 are drawn out to the outside of the exterior body.

[0174] Furthermore, the formed unit cells 460 may be stacked along the z-axis direction to manufacture a stacked battery. In this case, the unit cells 460 adjacent to each other in the stacking direction may share one counter electrode current collector 50. For example, by alternately stacking the electrode assemblies 470 and the counter electrode current collectors 50, the counter electrode current collector 50 is shared by the unit cells 460 adjacent to each other in the stacking direction.

[0175] Next, a description will be given of another example of a method for manufacturing the battery 401. Fig. 14 is a flowchart showing another example of a method for manufacturing the battery 401 according to the fourth modification of the embodiment.

[0176] In the example shown in FIG. 14 , steps S11 to S15 are the same as those in the example shown in FIG. 12 . After step S15, the first and second shaping processes are performed simultaneously (step S20). That is, the shape of the end portion in a direction other than the positive x-axis direction in plan view is defined, the tab portion 311 is formed on the electrode current collector 10, and a chamfer is formed on the electrode current collector 10 at the corner 76 of the protruding region 75 in plan view. This increases the productivity of the battery 401. Furthermore, because the processing of the side surface 74 and the processing of the corner 76 connected to the side surface 74 are performed simultaneously, the collapse of the active material layer and the like at the side surface 74 due to stress generated when forming the chamfered shape at the corner 76 can be suppressed.

[0177] The combined forming process of the first and second forming processes in step S20 is, for example, a punching process, in which the electrode body obtained up to step S15 is punched using a punching die provided with a punching blade having the same shape as the electrode body 370 in a plan view.

[0178] While the above describes a manufacturing method for battery 401 according to the fourth embodiment, batteries according to other embodiments and variations can also be manufactured by adjusting the materials and processed shape in the above manufacturing method. Furthermore, when manufacturing a battery including electrode assembly 470A, step S18 is performed after step S15, and then step S16 or step S20 is performed. That is, after forming the insulating layer, the first and second molding processes are performed. This allows the first and second molding processes to be performed while the protruding region 75 is protected by the insulating layer, thereby preventing the active material layer and other components from collapsing during processing. Furthermore, the insulating layer is also processed by the first and second molding processes to form insulating layer 90A having the shape shown in FIG. 11 .

[0179] 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.

[0180] 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.

[0181] 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.

[0182] In the above embodiment, the unit cell is provided with the first region, the second region, the third region, and the fourth region, but this is not limiting. For example, at least one of the first region, the second region, the third region, and the fourth region may not be provided.

[0183] In the above embodiment, the battery includes a counter electrode current collector, but this is not limiting. For example, the function of the counter electrode current collector may be realized by an external component, such as by mounting the electrode assembly on a substrate or the like that has a function of collecting current from the counter electrode active material layer.

[0184] 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.

[0185] The battery according to the present disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices or automobiles.

[0186] 1, 401 Battery 10, 210 Electrode current collector 11, 51, 311 Tab portion 15, 16 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 Counter electrode current collector 60, 460 Unit cell 70, 80, 170, 270, 370, 470, 470A Electrode body 71, 72, 73, 74 Side surface 75 Protruding region 76, 77, 78, 79 Corner portion 81 First region 82 Second region 83 Third region 84 Fourth region 90, 90A Insulating layer 210a Current collecting foil 210b Connection layer 312 End

Claims

1. A battery comprising an electrode body having: a current collector; an electrode active material layer disposed on a main surface of the current collector; an electrolyte layer disposed on the side of the electrode active material layer opposite the current collector; and a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, wherein a protruding region is provided at an end of the electrode body in a first direction, which is a direction from the center toward the outer edge of the main surface of the current collector, where the current collector protrudes in the first direction beyond the counter electrode active material layer in a planar view relative to the main surface of the current collector; and a chamfered shape is formed on the current collector at a corner of the protruding region in the planar view.

2. The battery according to claim 1, wherein a chamfered shape is formed on the electrode active material layer together with the current collector at the corners of the protruding region in the plan view.

3. The battery according to claim 1, wherein the current collector, the electrode active material layer, and the electrolyte layer are chamfered at corners of the protruding region in the plan view.

4. The battery according to claim 1, wherein the chamfered shape is a C-chamfered shape.

5. The battery according to claim 1, wherein the chamfered shape is an R-chamfered shape.

6. The battery according to claim 5, wherein the radius of the R-chamfered shape is 0.05 mm or more and 10 mm or less.

7. The battery according to claim 1, wherein the current collector has a tab portion at one end of the current collector in the first direction that protrudes in the first direction beyond the other portion of the end.

8. The battery described in claim 7, wherein the end of the tab portion on the second direction side opposite the first direction has a length in a third direction perpendicular to the first direction in the plan view that increases as the end advances in the second direction.

9. The battery according to claim 1, wherein the electrode body has an insulating layer that covers, in the plan view, at least a portion of the electrolyte layer, at least a portion of the electrode active material layer, and at least a portion of the current collector in the protruding region.

10. The battery according to claim 9, wherein the insulating layer protrudes outward from the corners of the protruding region in the plan view.

11. The battery according to claim 1, wherein the current collector is chamfered at corners of the electrode body other than the protruding region in the plan view.

12. The battery according to any one of claims 1 to 11, wherein an end of the main surface of the current collector in the first direction 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 the planar view, 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.

13. The battery according to any one of claims 1 to 11, wherein at an end of the electrode body in a direction from the center toward the outer edge of the main surface of the current collector and in a direction different from the first direction, the side surfaces of the current collector, the electrode active material layer, the electrolyte layer, and the counter electrode active material layer are flush with each other.

14. A method for manufacturing a battery, comprising: an electrode body having a current collector, an electrode active material layer disposed on a main surface of the current collector, an electrolyte layer disposed on the side of the electrode active material layer opposite the current collector, and a counter electrode active material layer disposed on the side of the electrolyte layer opposite the electrode active material layer, wherein the electrode body has a protruding region at an end in a first direction, which is a direction from the center of the main surface of the current collector toward the outer edge, where the current collector protrudes in the first direction beyond the counter electrode active material layer in a planar view relative to the main surface of the current collector; performing a first shaping process to define the outer shape of a region where the protruding region is not provided in the planar view; and performing a second shaping process to form a tab portion on the current collector, where a part of the end of the current collector in the first direction protrudes in the first direction beyond the rest of the end, and to form a chamfered shape on the current collector at a corner of the protruding region in the planar view, all at once.

15. The method for manufacturing a battery according to claim 14, wherein the second molding process is carried out after the first molding process is carried out.

16. The method for manufacturing a battery according to claim 14, wherein the first molding process and the second molding process are carried out simultaneously.

17. A method for manufacturing a battery as described in claim 14, comprising forming an insulating layer that covers, in the plan view, at least a portion of the electrolyte layer, at least a portion of the electrode active material layer, and at least a portion of the current collector in the protruding region, and performing the first molding process and the second molding process after forming the insulating layer.

18. A method for manufacturing a battery according to any one of claims 14 to 17, wherein the first forming process and the second forming process are punching processes.

Images