Battery

Abstract

This battery sequentially comprises in the following order: an electrode collector; two electrode active material layers that are arranged on both surfaces of the electrode collector; two solid electrolyte layers that are respectively arranged on the two electrode active material layers; two counter electrode active material layers that are respectively arranged on the two solid electrolyte layers; and two counter electrode collectors that are respectively arranged on the two counter electrode active material layers. This battery is provided with a first insulating layer that covers the lateral surfaces of the two counter electrode collectors, the two counter electrode active material layers, the two solid electrolyte layers and the two electrode active material layers. The edges of both main surfaces of the electrode collector are provided with first regions that are not covered by either of the two electrode active material layers; the edges of the counter electrode collector-side main surfaces of the two counter electrode active material layers are provided with second regions that are not covered by either of the two counter electrode collectors; the first insulating layer covers the second regions; and the electrode collector protrudes from the outer surface of the first insulating layer.

Description

battery

[0001] The present disclosure relates to batteries.

[0002] Patent Documents 1 and 2 disclose batteries equipped with insulating members.

[0003] JP 2015-233003 A JP 2020-13729 A

[0004] In the prior art, there is a need for improved reliability of batteries. Therefore, an object of the present disclosure is to provide a highly reliable battery.

[0005] A battery according to one aspect of the present disclosure includes an electrode current collector, two electrode active material layers disposed on both main surfaces of the electrode current collector, two solid electrolyte layers disposed on the side opposite the electrode current collector of each of the two electrode active material layers, two counter electrode active material layers disposed on the side opposite the electrode active material layer of each of the two solid electrolyte layers, two counter electrode current collectors disposed on the side opposite the solid electrolyte layer of each of the two counter electrode active material layers, and a first insulating layer covering the side surfaces of the two counter electrode current collectors, the two counter electrode active material layers, the two solid electrolyte layers, and the two electrode active material layers. A first region not covered by either of the two electrode active material layers is provided at the end of each main surface of the electrode current collector facing the counter electrode current collector. A second region not covered by either of the two counter electrode current collectors is provided at the end of each main surface of the two counter electrode active material layers facing the counter electrode current collector. The first insulating layer covers the second region. The electrode current collector protrudes from the outer surface of the first insulating layer.

[0006] According to the present disclosure, a highly reliable battery can be provided.

[0007] FIG. 1 is a schematic top view showing an example of a battery according to embodiment 1. FIG. 2 is a schematic cross-sectional view of the battery according to embodiment 1, taken along the line II-II in FIG. 1 . FIG. 3 is a schematic cross-sectional view of a battery according to modification 1 of embodiment 1. FIG. 4 is a schematic top view of a battery according to modification 2 of embodiment 1. FIG. 5 is a schematic cross-sectional view of the battery according to modification 2 of embodiment 1, taken along the line V-V in FIG. 4 . FIG. 6 is a flowchart showing a method for manufacturing a battery according to embodiment 1. FIG. 7 is a schematic cross-sectional view showing an example of a battery according to embodiment 2. FIG. 8A is a flowchart showing an example of a method for manufacturing a battery according to embodiment 2. FIG. 8B is a flowchart showing another example of a method for manufacturing a battery according to embodiment 2.

[0008] The present inventors have investigated forming a terminal at an end of a battery such as an all-solid-state battery having a solid electrolyte layer containing a solid electrolyte in order to extract current. Specifically, when electrode active material layers are formed on both sides of the same electrode current collector, the inventors have attempted to form a terminal in a region of the end of the electrode current collector that is not covered by the electrode active material layer.

[0009] In this case, the inventors have found that if the counter electrode current collector protrudes beyond the counter electrode active material layer, an end-face short circuit is likely to occur due to contact with the electrode current collector. Furthermore, when multiple unit cells are stacked, the possibility of end-face short circuiting increases due to misalignment of the stacked cells. Furthermore, if the end of the active material layer is exposed, a short circuit is likely to occur due to the active material falling off. These problems reduce the reliability of the battery.

[0010] Therefore, the present disclosure provides a highly reliable battery.

[0011] A battery according to one aspect of the present disclosure includes an electrode current collector, two electrode active material layers disposed on both main surfaces of the electrode current collector, two solid electrolyte layers disposed on the side opposite the electrode current collector of each of the two electrode active material layers, two counter electrode active material layers disposed on the side opposite the electrode active material layer of each of the two solid electrolyte layers, two counter electrode current collectors disposed on the side opposite the solid electrolyte layer of each of the two counter electrode active material layers, and a first insulating layer covering the side surfaces of the two counter electrode current collectors, the two counter electrode active material layers, the two solid electrolyte layers, and the two electrode active material layers. A first region not covered by either of the two electrode active material layers is provided at the end of each main surface of the electrode current collector facing the counter electrode current collector. A second region not covered by either of the two counter electrode current collectors is provided at the end of each main surface of the two counter electrode active material layers facing the counter electrode current collector. The first insulating layer covers the second region. The electrode current collector protrudes from the outer surface of the first insulating layer.

[0012] As a result, the counter electrode current collector is recessed from the counter electrode active material layer, making it less likely that end-surface short circuits will occur due to contact between the counter electrode current collector and the electrode active material layer or the electrode current collector. Furthermore, the formation of the first insulating layer prevents exposure of the electrode active material layer and the counter electrode active material layer. This reduces the likelihood of damage or short circuits due to contact between the electrode active material layer and the counter electrode active material layer and other components. This improves the reliability of the battery.

[0013] Furthermore, for example, in a plan view, the length of the second region on a line connecting a point on the outer edge of the battery to the center of the battery and intersecting the second region may be 100 μm or more.

[0014] As a result, even if the counter electrode current collector is damaged, it is less likely to protrude from the counter electrode active material layer in a plan view, making it less likely that an end-face short circuit will occur due to contact with the electrode active material layer or the electrode current collector, thereby improving the reliability of the battery.

[0015] Furthermore, for example, in a plan view, the length of the first region on a line connecting a point on the outer edge of the battery to the center of the battery and intersecting the first region may be 1 mm or more.

[0016] This allows for easy formation of a terminal in the region of the end of the electrode current collector that is not covered by the electrode active material layer. This improves the connection between the terminal and the electrode current collector, thereby reducing the connection resistance. The reduced connection resistance improves the large-current characteristics of the battery, enabling, for example, rapid charging.

[0017] Furthermore, for example, the thickness of the portion of the first insulating layer that covers the second region may be greater than the thickness of the counter electrode current collector.

[0018] As a result, even if the counter electrode current collector is damaged, it is less likely to protrude from the counter electrode active material layer in a plan view, making it less likely that an end-face short circuit will occur due to contact with the electrode active material layer or the electrode current collector, thereby improving the reliability of the battery.

[0019] Alternatively, for example, the electrode active material layer may contain a negative electrode active material, and the counter electrode active material layer may contain a positive electrode active material. That is, the electrode current collector and the electrode active material layer may be a negative electrode current collector and a negative electrode active material layer, respectively, and the counter electrode current collector and the counter electrode active material layer may be a positive electrode current collector and a positive electrode active material layer, respectively.

[0020] As a result, the region of the positive electrode active material layer that is covered by the positive electrode current collector and functions as a positive electrode is smaller than that of the negative electrode active material layer. Therefore, the capacity of the negative electrode active material layer tends to be larger than that of the positive electrode active material layer. This suppresses the deposition of metal derived from metal ions that are not incorporated into the negative electrode active material layer, further improving the reliability of the battery.

[0021] Furthermore, for example, the first insulating layer may include a resin.

[0022] This allows the resin contained in the first insulating layer to have an anchor effect by penetrating into each of the electrode current collector, counter electrode current collector, electrode active material layer, and counter electrode active material layer, thereby improving the bonding between the first insulating layer and each current collector and each active material layer and suppressing peeling between the first insulating layer and the current collector and active material layer.

[0023] Furthermore, for example, the first insulating layer may include a metal oxide.

[0024] This makes the first insulating layer hard, so that even if the first insulating layer is formed thin during battery manufacturing, the first insulating layer is less likely to deform, and a thin first insulating layer of uniform thickness can be formed.

[0025] Furthermore, for example, the solid electrolyte layer may include a solid electrolyte having lithium ion conductivity.

[0026] This makes it possible to improve the reliability of a lithium ion battery containing a solid electrolyte.

[0027] Furthermore, for example, the battery may have a rectangular shape in plan view, and the first insulating layer may be provided on at least one side of the battery in plan view.

[0028] This ensures reliability on the sides where terminals are formed, while enabling the sides where no terminals are formed to be cut off all at once, for example, allowing for efficient battery production.

[0029] Furthermore, for example, the side surface on which the first insulating layer is not provided may be a cut surface.

[0030] As a result, since the side surface of the battery is a cut surface, the side surface of the electrode layer, the side surface of the counter electrode layer, and the side surface of the solid electrolyte layer can be easily made flush with each other.

[0031] Furthermore, for example, the shape of the cut surface may be rectangular or trapezoidal.

[0032] This makes the edges of the cut surfaces straight, eliminating any spaces that would not contribute to the charge / discharge performance of the resulting battery due to the non-straight edges, thereby preventing a substantial decrease in the energy density of the battery and increasing the energy density of the battery.

[0033] Furthermore, for example, the electrode current collector, the two electrode active material layers, the two solid electrolyte layers, the two counter electrode active material layers, and the two counter electrode current collectors may constitute a unit cell, and a plurality of the unit cells may be stacked.

[0034] As a result, since the unit cells are stacked, a highly reliable stacked battery can be realized.

[0035] Furthermore, for example, the battery may include a second insulating layer covering each of the side surfaces of the two counter electrode current collectors, the two counter electrode active material layers, the two solid electrolyte layers, and the two electrode active material layers that are not covered by the first insulating layer, and at least one of the plurality of counter electrode current collectors may protrude from an outer surface of the second insulating layer.

[0036] This makes it easy to form a counter electrode terminal for extracting current from the counter electrode layer in a region of the counter electrode current collector that is not covered by the second insulating layer, excluding the outermost shell of the stacked battery, in a stacked battery that can be connected in parallel. Furthermore, exposure of the electrode active material layer and the counter electrode active material layer is suppressed on the side surface from which the counter electrode current collector protrudes. This reduces the likelihood of damage or short circuits due to contact between the electrode active material layer and the counter electrode active material layer and other components. This improves the reliability of the battery.

[0037] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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. When the shape of the power generating element 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 power generating element. 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, unless otherwise specified.

[0042] 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."

[0043] Furthermore, in this specification, unless otherwise specified, "protruding" means protruding outward from the center of the unit cell in a cross-sectional view perpendicular to the main surface of the unit cell. "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 unit cell. Furthermore, "protruding portion of element A" means a part of element A that protrudes more than the tip of element B in the protruding direction. Examples of elements include an electrode layer, an active material layer, a solid electrolyte layer, and a current collector.

[0044] 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.

[0045] First Embodiment [1. Overview] First, an overview of a battery according to a first embodiment will be described with reference to FIGS. 1 and 2. FIG.

[0046] Fig. 1 is a schematic top view showing an example of a battery 1 according to the present embodiment. In Fig. 1, the planar shapes of the components of the battery 1 are shown by solid and dashed lines. Fig. 2 is a schematic cross-sectional view of the battery 1 according to the present embodiment taken along line II-II in Fig. 1.

[0047] 1 and 2 , a battery 1 according to this embodiment includes an electrode layer 10, a counter electrode layer 20 disposed opposite the electrode layer 10, and a solid electrolyte layer 30 located between the electrode layer 10 and the counter electrode layer 20. The battery 1 includes two counter electrode layers 20 and two solid electrolyte layers 30. One counter electrode layer 20 and one solid electrolyte layer 30 are disposed on each main surface of the electrode layer 10. The electrode layer 10, the two counter electrode layers 20, and the two solid electrolyte layers 30 constitute a unit cell 2.

[0048] The electrode layer 10 has an electrode current collector 11 and an electrode active material layer 12 located between the electrode current collector 11 and the solid electrolyte layer 30. The electrode layer 10 has two electrode active material layers 12. The two electrode active material layers 12 are disposed on both main surfaces of the electrode current collector 11. An end portion of the main surface 11a of the electrode current collector 11 is provided with a region 51a that is not covered by the upper electrode active material layer 12. An end portion of the main surface 11b of the electrode current collector 11 is provided with a region 51b that is not covered by the lower electrode active material layer 12. The regions 51a and 51b are each an example of a first region that is not covered by either of the two electrode active material layers 12.

[0049] The counter electrode layer 20 has a counter electrode current collector 21 and a counter electrode active material layer 22 located between the counter electrode current collector 21 and the solid electrolyte layer 30. A region 52a that is not covered by the upper counter electrode current collector 21 is provided at an end of the main surface 22a of the upper counter electrode active material layer 22. A region 52b that is not covered by the lower counter electrode current collector 21 is provided at an end of the main surface 22b of the lower counter electrode active material layer 22. The regions 52a and 52b are each an example of a second region that is not covered by either of the two counter electrode current collectors 21.

[0050] The battery 1 further includes an insulating layer 40 that covers the side surfaces of the two electrode active material layers 12, the two solid electrolyte layers 30, the two counter electrode active material layers 22, and the two counter electrode current collectors 21. The insulating layer 40 is an example of a first insulating layer. Specifically, as shown in FIG. 2 , the insulating layer 40 covers the side surfaces 21c of the two counter electrode current collectors 21, the side surfaces 22c of the two counter electrode active material layers 22, the side surfaces 30c of the two solid electrolyte layers 30, and the side surfaces 12c of the two electrode active material layers 12. For example, the side surfaces 21c, 22c, 30c, and 12c are completely covered by the insulating layer 40 and are not exposed. The side surfaces 21c, 22c, 30c, and 12c are, for example, flat planes. The side surfaces 22c, 30c, and 12c are, for example, flush with each other, i.e., form the same flat plane without any steps.

[0051] The electrode current collector 11 has both a region that is covered with the insulating layer 40 and a region that is not covered with the insulating layer 40. In other words, the electrode current collector 11 protrudes from the outer surface 40c of the insulating layer 40. That is, the electrode current collector 11 has a protrusion 13 that protrudes outward from the outer surface 40c. In the region of the electrode current collector 11 that is not covered with the insulating layer 40, it is easy to form an electrode terminal that extracts current from the electrode layer 10.

[0052] The shape of the battery 1 in plan view is rectangular as shown in Fig. 1, but is not limited to this. The shape of the battery 1 in plan view may be a polygon such as a square, hexagon, or octagon, or may be a circle, ellipse, or the like.

[0053] As shown in Fig. 1, the battery 1 has side surfaces 1c and 1d facing back to back, and side surfaces 1e and 1f facing back to back. Side surfaces 1c and 1d form the short sides of the rectangular battery 1 in a plan view. Side surfaces 1e and 1f form the long sides of the rectangular battery 1 in a plan view. As shown in Fig. 1, the side surface 1c of the battery 1 is formed by the side surface 11c of the electrode current collector 11 and the outer surface 40c of the insulating layer 40.

[0054] In FIG. 1, the electrode current collector 11 has a structure on the side of side 1c that has a protruding portion 13 that protrudes from the outer surface 40c of the insulating layer 40, but this protruding portion 13 may be on the side of side 1d, side 1e, or side 1f.

[0055] The battery 1 is, for example, an all-solid-state battery. Furthermore, the side surfaces 1d, 1e, and 1f of the electrode current collector 11 of the battery 1 that do not have the protrusion 13 are each flat planes. On each of these flat side surfaces, the side surface of the electrode layer 10, the side surface of the counter electrode layer 20, and the side surface of the solid electrolyte layer 30 are flush with each other, i.e., there are no steps, and they are located on the same flat plane. As a result, on the side surface of the electrode current collector 11 of the battery 1 that does not have the protrusion 13, there are no steps on the side surfaces of the layers, and no unevenness is present. Therefore, no spaces that do not function as a battery due to unevenness are formed, and the volumetric energy density of the battery 1 is effectively improved. Furthermore, the side surfaces of each layer can be flush by cutting each layer together, for example, which facilitates the manufacture of the battery 1.

[0056] Each of the side surfaces 1d, 1e, and 1f of the electrode current collector 11 of the battery 1 that does not have the protrusion 13 is, for example, a cut surface. Specifically, each of the side surfaces 1d, 1e, and 1f is a surface formed by cutting with a blade such as a cutter. Each of the side surfaces 1d, 1e, and 1f has, for example, a cut mark such as a fine groove. Since each side surface is a cut surface, the side surface of the electrode layer 10, the side surface of the counter electrode layer 20, and the side surface of the solid electrolyte layer 30 can be easily made flush with each other. The cut mark may be smoothed by polishing or the like. The planar shape of the cut surface is not limited, but in the case of the battery 1, it is rectangular. The cut surface is, for example, parallel to the stacking direction (z-axis direction) of the battery 1.

[0057] The electrode current collector 11 is in contact with the electrode active material layer 12 on both main surfaces 11a and 11b. As described above, regions 51a and 51b that are not covered with the electrode active material layer 12 are provided at the end of at least one side of the electrode current collector 11 in a plan view. Furthermore, the region 51a has both a region that is covered with the insulating layer 40 and a region that is not covered with the insulating layer 40. In a plan view, the region that is not covered with the insulating layer 40 corresponds to the protrusion 13.

[0058] The following description will be focused on the upper surface side region 51a, but the lower surface side region 51b also has a similar configuration.

[0059] To facilitate the formation of a terminal in the region 51a at the end of the electrode current collector 11 that is not covered by the electrode active material layer 12, the length of the region 51a is, for example, 1 mm or more. Also, for example, the length of the region 51a is 20 mm or less. This prevents the terminal portion from becoming too large, making it possible to reduce the portion that does not function as a battery, and improving the volumetric energy density of the battery 1.

[0060] The length of region 51a is the length of a straight line connecting a point on the outer edge of battery 1 to the center of battery 1 and intersecting region 51a in a planar view. For example, the point on the outer edge is a point on the side surface 11c of the electrode current collector 11 in a planar view. The center of battery 1 is the geometric center of battery 1 in a planar view. For example, if the shape of battery 1 in a planar view is rectangular, the center of battery 1 is the intersection of diagonal lines in a planar view. The straight line connecting a point on the outer edge of battery 1 to the center of battery 1 and intersecting region 51a is, for example, line II-II shown in FIG. 1. In other words, the length of region 51a is the length along the x-axis direction. In this embodiment, region 51a is a rectangular region elongated in the y-axis direction, but is not limited to this.

[0061] The length of the region 51a is equal to the length of the region 51b, but is not limited to this. The length of the region 51a and the length of the region 51b may be different.

[0062] The thickness of the electrode current collector 11 is, for example, 5 μm or more and 100 μm or less, but is not limited to this range.

[0063] Known materials can be used as the material for the electrode current collector 11. For example, the electrode current collector 11 is a foil, plate, or mesh-like material made of copper, aluminum, nickel, iron, stainless steel, platinum, gold, or an alloy of two or more of these metals.

[0064] The upper counter electrode current collector 21 is in contact with the main surface 22a of the counter electrode active material layer 22. In a plan view, an area 52a that does not cover the main surface 22a of the counter electrode active material layer 22 is provided at an end of at least one side of the counter electrode current collector 21. In other words, the side surface of the counter electrode current collector 21 is recessed relative to the counter electrode active material layer 22. In other words, the side surface 21c of the counter electrode current collector 21 is closer to the center of the battery 1 than the side surface 22c of the counter electrode active material layer 22 in a plan view.

[0065] The same applies to the lower counter electrode current collector 21. The following description will be focused on the upper region 52a, but the same also applies to the lower region 52b.

[0066] By preventing a portion of the counter electrode current collector 21 from protruding from the counter electrode active material layer 22 in a plan view when the portion is damaged, it is possible to suppress the occurrence of a short circuit on the side surface 1 c of the battery 1. To this end, the length of the region 52 a is, for example, 100 μm or more. Also, for example, the length of the region 52 a is 2 mm or less. This prevents the area of ​​the counter electrode current collector 21 from becoming too small, making it possible to sufficiently secure a portion that functions as a battery, and improving the volumetric energy density of the battery 1.

[0067] The length of region 52a is the length of a straight line connecting a point on the outer edge of battery 1 to the center of battery 1 and intersecting region 52a in a plan view. For example, the point on the outer edge, the center, and the line intersecting region 52a are the same as those in region 51a. In other words, the length of region 52a is the length along line II-II shown in FIG. 1, for example, and the length along the x-axis direction. In this embodiment, region 52a is a rectangular region elongated in the y-axis direction, but is not limited to this.

[0068] The length of the region 52a is equal to the length of the region 52b, but is not limited to this. The length of the region 52a and the length of the region 52b may be different.

[0069] Furthermore, the recessed side surface 21c of the counter electrode current collector 21 is in contact with the portion of the insulating layer 40 that covers the region 52a. In this embodiment, the upper surface of the upper counter electrode current collector 21 is flush with the upper surface of the insulating layer 40. Furthermore, the lower surface of the lower counter electrode current collector 21 is flush with the lower surface of the insulating layer 40. This allows the unit cells 2 to be easily stacked to form a stacked battery. A specific example of a stacked battery will be described later in embodiment 2.

[0070] The thickness of the counter electrode current collector 21 is, for example, 5 μm or more and 100 μm or less, but is not limited to this range.

[0071] Known materials can be used as the material of the counter electrode current collector 21. 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 as the counter electrode current collector 21.

[0072] The electrode active material layer 12 is disposed on both the main surfaces 11a and 11b of the electrode current collector 11. The surface of the electrode active material layer 12 opposite the electrode current collector 11 is in contact with the solid electrolyte layer 30. The electrode active material layer 12 and the counter electrode active material layer 22 face each other with the solid electrolyte layer 30 interposed therebetween. A side surface 12c of the electrode active material layer 12 is in contact with the insulating layer 40. In addition, the electrode active material layer 12 and the counter electrode active material layer 22 have the same shape and position in a plan view. The thickness of the electrode active material layer 12 is, for example, 5 μm or more and 300 μm or less. The materials used for the electrode active material layer 12 will be described later.

[0073] The counter electrode active material layer 22 is stacked on the solid electrolyte layer 30 and disposed opposite the electrode active material layer 12. The surface of the counter electrode active material layer 22 opposite to the solid electrolyte layer 30 is in contact with the counter electrode current collector 21. As described above, the end of at least one side of the counter electrode active material layer 22 in a plan view has a region 52a or 52b that is not in contact with the counter electrode current collector 21. The thickness of the counter electrode active material layer 22 is, for example, 5 μm or more and 300 μm or less. The materials used for the counter electrode active material layer 22 will be described later.

[0074] The solid electrolyte layer 30 is located between the electrode active material layer 12 and the counter electrode active material layer 22. The thickness of the solid electrolyte layer 30 is, for example, 5 μm or more and 150 μm or less, but is not limited to this range.

[0075] The solid electrolyte layer 30 includes at least a solid electrolyte and may include a binder material as needed. The solid electrolyte layer 30 may include a solid electrolyte having lithium ion conductivity.

[0076] As the solid electrolyte, known materials such as lithium ion conductors, sodium ion conductors, or magnesium ion conductors can be used. As the solid electrolyte, for example, a solid electrolyte material such as a sulfide solid electrolyte, a halogen-based solid electrolyte, or an oxide solid electrolyte can be used. 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.

[0077] As the oxide solid electrolyte, in the case of a material that can conduct lithium ions, for example, Li ７ La ３ Zr ２ O １２ (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.

[0078] As the binder material, for example, elastomers are used, and organic compounds such as polyvinylidene fluoride, acrylic resin, or cellulose resin may also be used.

[0079] 1 and 2 , the insulating layer 40 is in contact with the side surface 12 c of the electrode active material layer 12, the side surface 30 c of the solid electrolyte layer 30, the side surface 22 c of the counter electrode active material layer 22, and the side surface 21 c of the counter electrode current collector 21 on the side surface in the direction in which the protrusion 13 exists in a plan view. The insulating layer 40 also covers parts of the main surfaces 11 a and 11 b of the electrode current collector 11.

[0080] The insulating layer 40 includes, for example, at least one of a resin and a metal oxide. Examples of the resin include silicone resin, epoxy resin, acrylic resin, and polyimide resin. The resin may be a thermosetting resin or a UV-curable resin. When the insulating layer 40 includes a resin, the resin penetrates into the electrode current collector 11, the electrode active material layer 12, the solid electrolyte layer 30, the counter electrode active material layer 22, and the counter electrode current collector 21, thereby enhancing the bonding of the insulating layer 40 to each layer and each current collector. Examples of the metal oxide include silicon oxide, titanium oxide, and aluminum oxide. The metal oxide in the insulating layer 40 makes the insulating layer 40 hard. Therefore, even when the insulating layer 40 is formed thin during the manufacturing of the battery 1, the insulating layer 40 is less likely to deform, and a thin insulating layer 40 with a uniform thickness can be formed.

[0081] In the present embodiment, one of the electrode layer 10 including the electrode active material layer 12 and the counter electrode layer 20 including the counter electrode active material layer 22 is a positive electrode layer including a positive electrode active material layer, and the other is a negative electrode layer including a negative electrode active material layer. For example, the electrode layer 10 is a negative electrode layer, and the counter electrode layer 20 is a positive electrode layer. In other words, the electrode current collector 11 is a negative electrode current collector, and the electrode active material layer 12 is a negative electrode active material layer. The counter electrode current collector 21 is a positive electrode current collector, and the counter electrode active material layer 22 is a positive electrode active material layer.

[0082] The positive electrode active material layer contains at least a positive electrode active material, and may contain at least one of a solid electrolyte, a conductive additive, and a binder material, as necessary.

[0083] As the positive electrode active material, known materials capable of absorbing and releasing (e.g., inserting and desorbing, or dissolving and depositing) lithium ions, sodium ions, or magnesium ions can be used. As the positive electrode active material, in the case of a material capable of extracting and inserting lithium ions, for example, lithium cobalt oxide composite oxide (LCO), lithium nickel oxide composite oxide (LNO), lithium manganese oxide composite oxide (LMO), lithium-manganese-nickel composite oxide (LMNO), lithium-manganese-cobalt composite oxide (LMCO), lithium-nickel-cobalt composite oxide (LNCO), or lithium-nickel-manganese-cobalt composite oxide (LNMCO) can be used.

[0084] The solid electrolyte may be any of the above-described solid electrolyte materials. The conductive additive may be, for example, a conductive material such as acetylene black, carbon black, graphite, or carbon fiber. The binder may be any of the above-described binder materials.

[0085] The negative electrode active material layer contains at least a negative electrode active material, and may contain, as necessary, at least one of a solid electrolyte, a conductive additive, and a binder material, similar to those of the positive electrode active material layer.

[0086] As the negative electrode active material, a known material capable of occluding and releasing (e.g., inserting and desorbing, or dissolving and precipitating) lithium ions, sodium ions, or magnesium ions can be used. As the negative electrode active material, 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, or an oxide of lithium and a transition metal element can be used.

[0087] As described above, in the battery 1, regions 51a and 51b that are not covered by the electrode active material layer 12 are provided at the ends of the main surfaces 11a and 11b of the electrode current collector 11, respectively. Furthermore, a region 52a that is not covered by the upper counter electrode current collector 21 is provided at the end of the main surface 22a of the upper counter electrode active material layer 22. A region 52b that is not covered by the lower counter electrode current collector 21 is provided at the end of the main surface 22b of the lower counter electrode active material layer 22. Furthermore, the battery 1 includes an insulating layer 40 that covers the side surface 21c of the counter electrode current collector 21, the side surface 22c of the counter electrode active material layer 22, the side surface 30c of the solid electrolyte layer 30, and the side surface 12c of the electrode active material layer 12. The electrode current collector 11 protrudes from the outer surface 40c of the insulating layer 40.

[0088] As a result, the counter electrode current collector 21 is recessed from the counter electrode active material layer 22, making it less likely that an end-surface short circuit will occur due to contact between the counter electrode current collector 21 and the electrode active material layer 12 or the electrode current collector 11. Furthermore, the provision of the insulating layer 40 prevents exposure of the electrode active material layer 12 and the counter electrode active material layer 22. This makes it less likely that damage or a short circuit will occur due to contact between the electrode active material layer 12 and the counter electrode active material layer 22 and other members. This can improve the reliability of the battery 1.

[0089] Furthermore, when the length of the region 52a at the end of the counter electrode active material layer 22 that is not covered by the counter electrode current collector 21 is set to 100 μm or more, even if the counter electrode current collector 21 is damaged, it is less likely to protrude from the counter electrode active material layer 22 in a plan view. This makes it less likely that an end-face short circuit will occur due to contact with the electrode active material layer 12 or the electrode current collector 11. This can improve the reliability of the battery.

[0090] Furthermore, when the length of the region 51a at the end of the electrode current collector 11 that is not covered with the electrode active material layer 12 is set to 1 mm or more, this region 51a can be used to easily form a terminal.

[0091] Furthermore, when the electrode layer 10 is used as the negative electrode layer and the counter electrode layer 20 is used as the positive electrode layer, the region of the positive electrode active material layer that is covered by the positive electrode current collector and functions as a positive electrode is smaller than the negative electrode active material layer. This makes it easier for the capacity of the negative electrode active material layer to be larger than the capacity of the positive electrode active material layer. This suppresses the deposition of metal derived from metal ions that are not incorporated into the negative electrode active material layer, further improving the reliability of the battery 1.

[0092] [2. Modifications] Modifications of the battery 1 according to the present embodiment will be described below. In the following description of the modifications, differences from the first embodiment will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0093] [2-1. Modification 1] First, a battery according to Modification 1 will be described with reference to Fig. 3. Fig. 3 is a schematic cross-sectional view of a battery 1A according to this modification.

[0094] The battery 1A shown in Fig. 3 differs from the battery 1 shown in Fig. 2 in that it includes an insulating layer 40A instead of the insulating layer 40. As shown in Fig. 3, the thickness t2 of the portion of the insulating layer 40A covering the region 52a is greater than the thickness t1 of the counter electrode current collector 21. Specifically, the insulating layer 40A covers the edge of the top surface of the upper counter electrode current collector 21.

[0095] In this way, when the thickness t2 of the portion of the insulating layer 40A covering the region 52a is made larger than the thickness t1 of the counter electrode current collector 21, even if the counter electrode current collector 21 is damaged, it is less likely to protrude from the counter electrode active material layer 22 in a plan view. This makes it less likely that an end-face short circuit will occur due to contact between the counter electrode current collector 21 and the electrode active material layer 12 or the electrode current collector 11. This can improve the reliability of the battery 1A.

[0096] In this modification, the same applies to the lower counter electrode current collector 21 and the portion of the insulating layer 40A that covers the region 52b. This makes it less likely that the lower counter electrode current collector 21 will protrude from the counter electrode active material layer 22 in a plan view, making it less likely that an end-face short circuit will occur due to contact with the electrode active material layer 12 or the electrode current collector 11. This can improve the reliability of the battery 1A.

[0097] The thickness t2 of the insulating layer 40A does not have to be large on one of the upper and lower sides. For example, the lower surface of the lower counter electrode current collector 21 and the lower surface of the insulating layer 40A may be flush with each other, as in the first embodiment.

[0098] [2-2. Modification 2] Next, a battery according to Modification 2 will be described with reference to FIGS. 4 and 5. FIG.

[0099] Fig. 4 is a schematic top view of the battery 1B according to this modification. In Fig. 4, the planar shapes of the components of the battery 1B are indicated by solid and dashed lines. Fig. 5 is a schematic cross-sectional view of the battery 1B according to this modification, taken along the line V-V in Fig. 4.

[0100] 4 and 5 , battery 1B differs from battery 1 of embodiment 1 in that battery 1B includes an electrode layer 10B and a counter electrode layer 20B instead of electrode layer 10 and counter electrode layer 20. Battery 1B also includes an insulating layer 41.

[0101] The electrode layer 10B includes an electrode current collector 11B instead of the electrode current collector 11. The electrode current collector 11B protrudes from the outer surface 40c of the insulating layer 40 and the outer surface 41d of the insulating layer 41 on two sides of the battery 1B. That is, the electrode current collector 11B has a protrusion 13 on the side surface 1c side and a protrusion 14 on the side surface 1d side. The specific configuration of the protrusion 14 is the same as that of the protrusion 13.

[0102] For example, on the side surface 11d side of the electrode current collector 11B, an end portion of the main surface 11a of the electrode current collector 11B is provided with a region 53a that is not covered by the upper electrode active material layer 12. On the side surface 11d side, an end portion of the main surface 11b of the electrode current collector 11B is provided with a region 53b that is not covered by the lower electrode active material layer 12. The regions 53a and 53b are each an example of a first region that is not covered by either of the two electrode active material layers 12. The lengths of the regions 53a and 53b are, for example, the same as the lengths of the regions 51a and 51b, but may be different.

[0103] The counter electrode layer 20B includes a counter electrode current collector 21B instead of the counter electrode current collector 21. The counter electrode current collector 21B is recessed from each of the side surfaces 22c and 22d of the counter electrode active material layer 22 on two sides of the battery 1B. Specifically, on the side surface 21d side of the counter electrode current collector 21B, a region 54a that is not covered by the upper counter electrode current collector 21B is provided at an end of the main surface 22a of the upper counter electrode active material layer 22. On the side surface 21d side, a region 54b that is not covered by the lower counter electrode current collector 21B is provided at an end of the main surface 22b of the lower counter electrode active material layer 22. The regions 54a and 54b are each an example of a second region that is not covered by either of the two counter electrode current collectors 21B. The lengths of the regions 54a and 54b are, for example, the same as the lengths of the regions 52a and 52b, but may be different.

[0104] The insulating layer 41 is an example of a second insulating layer. The insulating layer 41 covers the side surfaces 21d of the two counter electrode current collectors 21B, the side surfaces 22d of the two counter electrode active material layers 22, the side surfaces 30d of the two solid electrolyte layers 30, and the side surfaces 12d of the two electrode active material layers 12. For example, the side surfaces 21d, 22d, 30d, and 12d are completely covered by the insulating layer 41 and are not exposed. The side surfaces 21d, 22d, 30d, and 12d are, for example, flat planes. The side surfaces 22d, 30d, and 12d are, for example, flush with each other, i.e., form the same flat plane without any steps.

[0105] The insulating layer 41 may be formed integrally with the insulating layer 40. Specifically, an insulating layer covering the side surfaces 1 e and 1 f of the battery 1 may be provided, and may be integrally formed and connected to the insulating layers 40 and 41.

[0106] Thus, the battery 1B according to this modification includes not only the insulating layer 40 but also the insulating layer 41 that covers the side surface 21 d of the counter electrode current collector 21B, the side surface 22 d of the counter electrode active material layer 22, the side surface 30 d of the solid electrolyte layer 30, and the side surface 12 d of the electrode active material layer 12. In addition, on two sides of the battery 1B in a plan view, the electrode current collector 11B protrudes from each of the outer surface 40 c of the insulating layer 40 and the outer surface 41 d of the insulating layer 41.

[0107] This allows the formation of insulating layers on two sides of the battery 1B to prevent end-surface short circuits. Furthermore, terminals can be easily formed in the regions 51 a, 51 b, 53 a, and 53 b at the ends of the electrode current collector 11B that are not covered by the electrode active material layer 12.

[0108] Although the example in which the protrusions 13 and 14 are provided on two opposing sides of the battery 1B has been shown, they may also be provided on two intersecting sides. For example, the protrusion 14 may be provided on the side surface 1e or 1f.

[0109] [3. Manufacturing Method] Next, a method for manufacturing batteries 1, 1A, and 1B according to the present embodiment and each of the modified examples will be described using the flowchart shown in Fig. 6. Fig. 6 is a flowchart showing a method for manufacturing battery 1 according to the present embodiment. Note that the method for manufacturing battery 1 described below is an example, and the method for manufacturing battery 1 is not limited to the following example.

[0110] The manufacturing method of the battery 1 includes (1) a power generating element stacking step (steps S11 to S14), (2) a counter electrode current collector stacking step (steps S15 to S17), (3) a cutting step (step S18), and (4) an insulating layer forming step (step S19). Each step will be described in detail below.

[0111] (1) Power-Generating Element Lamination Step In the power-generating element lamination step, first, an electrode current collector 11 is prepared (step S11). Next, a power-generating element portion consisting of an electrode active material layer 12, a solid electrolyte layer 30, and a counter electrode active material layer 22 is laminated in this order on both main surfaces 11a and 11b of the prepared electrode current collector 11 (steps S12, S13, and S14). When laminating each layer, heat treatment and / or high-pressure pressing treatment is performed in each step as necessary. This results in a laminated electrode plate in which a power-generating element portion is laminated on both main surfaces 11a and 11b of the electrode current collector 11.

[0112] At this time, regions 51a and 51b that are not covered with the electrode active material layer 12 are formed at the ends of each of the main surfaces 11a and 11b of the electrode current collector 11. In other words, the electrode active material layer 12 is not formed over the entire surfaces of the main surfaces 11a and 11b of the electrode current collector 11, but is formed so that only the ends are exposed. This makes it possible to easily form the protrusions 13 of the electrode current collector 11 in a later step.

[0113] In the power-generating element lamination step, the electrode active material layer 12 may be formed to cover the entire surfaces of the principal surfaces 11 a and 11 b. In this case, a step of exposing each end of the principal surfaces 11 a and 11 b may be performed in the counter electrode current collector lamination step or cutting step described later.

[0114] The electrode active material layer 12, solid electrolyte layer 30, and counter electrode active material layer 22 that constitute the power generating element are each formed in this order by, for example, a wet coating method. By using the wet coating method, the power generating element can be easily laminated on the electrode current collector 11. Examples of wet coating methods that can be used include die coating, doctor blade coating, roll coating, screen printing, and inkjet coating, but are not limited to these methods.

[0115] When the wet coating method is used, a coating step is carried out in which materials for forming the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22 are appropriately mixed with a solvent to obtain a slurry.

[0116] The solvent used in the coating process may be, for example, a known solvent used in producing a known all-solid-state battery such as a lithium ion all-solid-state battery.

[0117] The slurries for each layer obtained in the coating process are applied to the electrode current collector 11 in the order of the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22. In this case, the next layer may be applied after the previous layer has been applied. Alternatively, 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. After the slurries for each layer are applied sequentially and all layers are applied, a heat treatment to remove the solvent and binder material and a high-pressure press treatment to promote filling of the materials for each layer are performed, for example.

[0118] Heat treatment and high-pressure pressing may be performed after each coating of each layer. The heat treatment and high-pressure pressing may be performed for each coating layer of the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22, or may be performed separately after coating any two layers and after coating one layer, or may be performed all at once after coating all three layers. For the high-pressure pressing, a roll press, a flat plate press, or the like may be used. At least one of the heat treatment and the high-pressure pressing may not be performed.

[0119] By performing the layered coating method in this manner, it is possible to improve the bonding strength and reduce the interfacial resistance at the interfaces of the electrode current collector 11, the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22. It is also possible to improve the bonding strength and reduce the grain boundary resistance in the powder materials used in the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22. In other words, good interfaces are formed between the layers of the power generation element and between the powder materials within each layer.

[0120] The power generating element lamination step may be carried out as a series of continuous processes such as a roll-to-roll method.

[0121] (2) Counter Electrode Current Collector Laminating Step Next, the counter electrode current collector laminating step will be described. In the counter electrode current collector laminating step, counter electrode current collectors 21 are laminated on both sides of the laminated electrode plate in which power generating element portions are laminated on both sides of electrode current collector 11 (step S15). Specifically, counter electrode current collectors 21 are laminated on each of the main surface 22a of the upper counter electrode active material layer 22 and the main surface 22b of the lower counter electrode active material layer 22. At this time, they are bonded by high-pressure pressing or the like (step S16).

[0122] Thereafter, the end of the counter electrode current collector 21 is removed so as to expose the counter electrode active material layer 22 at the end of the side from which the electrode current collector 11 is to be protruded (step S17), thereby forming the unit cell 2 shown in FIG.

[0123] At least a portion of the removal is performed by cutting with a blade, laser, or jet. In this case, portions of the counter electrode active material layer 22, the solid electrolyte layer 30, and the electrode active material layer 12 may be removed simultaneously. However, the cutting is performed to a stop so as not to cut off the electrode current collector 11 that should be protruding. Alternatively, the removal may be performed by grinding, laser trimming, plasma etching, or chemical etching instead of cutting. Alternatively, the removal may be performed by a combination of these methods. The removal method is not limited to these methods.

[0124] In the power-generating element lamination step, if the ends of the main surfaces 11a and 11b of the electrode current collector 11 are not exposed, the ends of the counter electrode active material layer 22, the solid electrolyte layer 30, and the electrode active material layer 12 are removed by cutting to the nearest inch, polishing, or the like. This exposes the ends of the main surfaces 11a and 11b of the electrode current collector 11, and allows the regions 51a and 51b to be formed.

[0125] In the counter electrode current collector lamination step, a counter electrode current collector 21 formed in advance to a desired size may be prepared, and may be laminated on both sides of a laminated electrode plate in which power generating element parts are laminated on both sides of an electrode current collector 11, and bonded by high-pressure pressing, etc. In this case, the step of removing a portion of the counter electrode current collector (step S17) may be omitted.

[0126] (3) Cutting Step Next, the cutting step will be described. In the cutting step, the end of the unit cell 2 is cut so as to leave the protruding portion 13 of the electrode current collector 11 (step S18). Specifically, part or all of the sides other than the side on which the protruding portion 13 is provided are cut using a blade, a laser, a jet, or the like.

[0127] The electrode current collector 11, electrode active material layer 12, solid electrolyte layer 30, counter electrode active material layer 22, and counter electrode current collector 21 are stacked on the edge to be cut, but these are cut all at once. This eliminates the need to stack the layers of the power generating element in the shape after cutting, making it easy to manufacture the battery 1. The cut edge exposes the side surfaces of the electrode current collector 11, electrode active material layer 12, solid electrolyte layer 30, counter electrode active material layer 22, and counter electrode current collector 21. After cutting, a sealing member or the like may be placed to cover the exposed side surfaces to protect them. In other words, when the side surfaces are covered with another member such as a sealing member, the exposed side surfaces may also be covered with the other member.

[0128] (4) Insulating Layer Forming Step Next, the insulating layer forming step will be described. In the insulating layer forming step, an insulating layer 40 is formed at the end of the side where the electrode current collector 11 should protrude, so as to cover the side surface 12c of the electrode active material layer 12, the side surface 30c of the solid electrolyte layer 30, the side surface 22c of the counter electrode active material layer 22, and the side surface 21c of the counter electrode current collector 21 (step S19). The insulating layer 40 is formed, for example, by applying a fluid resin material and curing it. The application is performed by inkjet printing or screen printing, or by immersing (dipping) the end surface of the unit cell in the resin material. The curing is performed by drying, heating, light irradiation, or the like, depending on the resin material used.

[0129] Furthermore, when forming the insulating layer 40, the protrusions 13 of the electrode current collector 11 may be protected by masking with tape or resist treatment so as not to insulate the protrusions 13. After the insulating layer 40 is disposed, the material protecting the protrusions 13 is removed, thereby ensuring the conductivity of the protrusions 13.

[0130] (5) Other Manufacturing Methods The manufacturing method of the battery 1 according to this embodiment is not limited to the above-described example, and may be, for example, the manufacturing method shown below.

[0131] First, an electrode current collector 11 is prepared in the shape shown in Figures 1 and 2. Then, using a coating process or the like, the electrode active material layer 12 and the solid electrolyte layer 30 are laminated in this order on the electrode current collector 11 by layer coating in the shape shown in Figures 1 and 2 to obtain an electrode plate.

[0132] Next, a counter electrode current collector 21 is prepared in the shape shown in Fig. 1 and Fig. 2. Then, using a coating process or the like, the counter electrode active material layer 22 and the solid electrolyte layer 30 are laminated in this order on the counter electrode current collector 21 by layer coating in the shape shown in Fig. 1 and Fig. 2 to obtain a counter electrode plate.

[0133] Next, the obtained electrode plate and counter electrode plate are stacked so that their solid electrolyte layers 30 are in contact with each other. The stacked stack, i.e., the unit cell 2, is subjected to a high-pressure pressing process from both sides in the stacking direction using a flat press. Thereafter, a portion of the counter electrode current collector 21 is removed (step S17), a portion of the unit cell 2 is cut (step S18), and an insulating layer 40 is formed (step S19), thereby obtaining the battery 1.

[0134] In step S19, the insulating material is applied thickly to cover the end of the counter electrode current collector 21, thereby forming the battery 1A shown in FIG.

[0135] In step S12, regions 53a and 53b that are not covered with the electrode active material layer 12 are formed not only on the side surface 11c of the electrode current collector 11 but also on the end portion on the side surface 11d. In step S17, not only on the side surface 21c of the counter electrode current collector 21 but also on the end portion on the side surface 21d is removed. This allows the formation of the battery 1B shown in FIGS. 4 and 5.

[0136] (Embodiment 2) Next, embodiment 2 will be described. In embodiment 2, a stacked battery will be described in which unit cells of the battery according to embodiment 1 are stacked. In the following description, differences from embodiment 1 will be mainly described, and descriptions of commonalities will be omitted or simplified as appropriate.

[0137] [1. Overview] First, the configuration of a stacked battery according to embodiment 2 will be described with reference to Fig. 7. Fig. 7 is a schematic cross-sectional view showing an example of a stacked battery 101 according to this embodiment.

[0138] 7 , the stacked battery 101 includes a plurality of unit cells 3. The plurality of unit cells 3 are stacked in the stacking direction of the layers constituting each unit cell. The plurality of unit cells 3 are electrically connected in parallel.

[0139] The plurality of unit cells 3 have the same configuration. The unit cell 3 differs from the unit cell 2 according to the first embodiment in that the unit cell 3 includes counter electrode layers 20B and 120 instead of the two counter electrode layers 20. The counter electrode layer 20B is the same as the counter electrode layer 20B of the battery 1B according to the second modification of the first embodiment. The unit cell 3 also includes an insulating layer 41.

[0140] The counter electrode layer 120 includes a counter electrode current collector 121 and a counter electrode active material layer 22. An end portion of the counter electrode current collector 121 has a region that is not covered with the counter electrode active material layer 22. The counter electrode current collector 121 protrudes from the outer surface 41d of the insulating layer 41. In other words, the counter electrode current collector 121 has a protruding portion 123 that protrudes outward from the outer surface 41d. In a plan view, the region that is not covered with the insulating layer 41 corresponds to the protruding portion 123.

[0141] Furthermore, because the counter electrode current collector 121 protrudes from the outer surface 41d of the insulating layer 41, it is easy to form a counter electrode terminal for extracting current from the counter electrode layers 20B and 120 in an area of ​​the counter electrode current collector 121 that is not covered by the insulating layer 41. Furthermore, the provision of the insulating layer 41 prevents the electrode active material layer 12 and the counter electrode active material layer 22 from being exposed, making it less likely that damage or a short circuit will occur due to contact between the electrode active material layer 12 and the counter electrode active material layer 22 and other components. This improves the reliability of the stacked battery 101.

[0142] In this embodiment, the protrusion 13 of the electrode current collector 11 and the protrusion 123 of the counter electrode current collector 121 are provided on different side surfaces of the stacked battery 101. For example, if the stacked battery 101 has a rectangular shape in a plan view, the side surface on which the protrusion 13 is provided and the side surface on which the protrusion 123 is provided are side surfaces that face each other. This allows the protrusion 13 and the protrusion 123 to be separated from each other, making it possible to prevent short circuits and the like due to contact.

[0143] Furthermore, on the side of the stacked battery 101 where the protruding portion 13 of the electrode current collector 11 is provided, the counter electrode current collectors 21B and 121 are recessed from the counter electrode active material layer 22. This makes it less likely that an end-face short circuit will occur due to contact between each of the counter electrode current collectors 21B and 121 and the electrode active material layer 12 or the electrode current collector 11. Furthermore, the provision of the insulating layer 40 prevents exposure of the electrode active material layer 12 and the counter electrode active material layer 22, making it less likely that damage or a short circuit will occur due to contact between the electrode active material layer 12 and the counter electrode active material layer 22 and other components. This improves the reliability of the stacked battery 101.

[0144] In the example shown in FIG. 7, the number of stacked unit cells 3 is four, but it may be two, three, or five or more.

[0145] No current collector is shared between two adjacent unit cells 3. In other words, two counter electrode current collectors 21B and 121 of the same polarity are arranged one on top of the other. In this case, an adhesive layer may be provided between the current collectors. The adhesive layer preferably has high conductivity.

[0146] Furthermore, the unit cell 3 may include a counter electrode current collector 121 instead of the counter electrode current collector 21B. In other words, two counter electrode current collectors 121 may be arranged in an overlapping manner.

[0147] 8A and 8B , a method for manufacturing the stacked battery 101 according to the present embodiment will be described. Note that the method for manufacturing the stacked battery 101 described below is an example, and the method for manufacturing the stacked battery 101 is not limited to the following example.

[0148] The manufacturing method of the stacked battery 101 includes (1) a power generating element stacking step (steps S21 to S24), (2) a counter electrode current collector stacking step (steps S25 to S27), (3) a cutting step (step S28), (4) an insulating layer forming step (step S29), and (5) a unit cell stacking step (step S30). In each of FIGS. 8A and 8B , the steps up to step S28 are the unit cell manufacturing steps. (1) The power generating element stacking steps of steps S21, 22, 23, and 24 are common to steps S11, 12, 13, and 14 of the manufacturing method in embodiment 1, and therefore will not be described here. The steps from the counter electrode current collector stacking step onwards will be described in detail below.

[0149] (2) Counter Electrode Current Collector Laminating Step In the counter electrode current collector laminating step, counter electrode current collectors 21B and 121 are laminated on both sides of the laminated electrode plate in which the power generating element parts are laminated on both sides of the electrode current collector 11 (step S25). Specifically, counter electrode current collector 21B is laminated on the main surface 22a of the upper counter electrode active material layer 22. Counter electrode current collector 121 is laminated on the main surface 22b of the lower counter electrode active material layer 22. At this time, they are bonded by high-pressure pressing or the like (step S26).

[0150] Thereafter, the ends of the counter electrode current collectors 21B and 121 are removed so as to expose the counter electrode active material layer 22 at the end of the side from which the electrode current collector 11 is to be protruded (step S27), thereby forming the unit cell 3 shown in FIG.

[0151] At least a portion of the removal is performed by cutting with a blade, laser, or jet. In this case, portions of the counter electrode active material layer 22, the solid electrolyte layer 30, and the electrode active material layer 12 may be removed simultaneously. However, the cutting is performed to a stop so as not to cut off the electrode current collector 11 that should be protruding. Alternatively, the removal may be performed by grinding, laser trimming, plasma etching, or chemical etching instead of cutting. Alternatively, the removal may be performed by a combination of these methods. The removal method is not limited to these methods.

[0152] Furthermore, at the end of the side where the counter electrode current collector 121 is to protrude, the end of the counter electrode current collector 21B is removed so that the counter electrode active material layer 22 is exposed on only one side of the unit cell 3. In the example shown in FIG. 7 , the end of the counter electrode current collector 21B is removed so that the upper counter electrode active material layer 22 is exposed. At least a portion of the removal is performed by cutting with a blade, laser, or jet. At this time, portions of the counter electrode active material layer 22, the solid electrolyte layer 30, the electrode active material layer 12, and the electrode current collector 11 may be removed simultaneously, but the cutting is performed to a stop so as not to cut off the counter electrode current collector 121 that is to protrude. Alternatively, the removal may be performed by polishing, laser trimming, plasma etching, or chemical etching instead of cutting. Alternatively, the removal may be performed by a combination of these methods. The removal method is not limited to these methods.

[0153] In the counter electrode current collector lamination step, counter electrode current collectors 21B and 121 formed to desired dimensions in advance may be prepared, and may be laminated on both sides of a laminated electrode plate in which power generating element portions are laminated on both sides of electrode current collector 11, and bonded by high-pressure pressing, etc. In this case, the step of removing a portion of counter electrode current collector 21B or 121 (step S27) may be omitted.

[0154] (3) Cutting Step Next, the cutting step will be described. In the cutting step, the end of the unit cell 3 is cut so as to leave the protruding portion 13 of the electrode current collector 11 and the protruding portion 123 of the counter electrode current collector 121 (step S28). Specifically, part or all of the sides other than the side on which the protruding portion 13 and the side on which the protruding portion 123 are provided are cut using a blade, a laser, a jet, or the like.

[0155] The electrode current collector 11, electrode active material layer 12, solid electrolyte layer 30, counter electrode active material layer 22, and counter electrode current collectors 21B and 121 are stacked on the edge to be cut, but these are cut all at once. This eliminates the need to stack the layers of the power generating element in the shape after cutting, making it easy to manufacture the unit cell 3. The cut edge exposes the side surfaces of the electrode current collector 11, electrode active material layer 12, solid electrolyte layer 30, counter electrode active material layer 22, and counter electrode current collectors 21B and 121. After cutting, a sealing member or the like may be placed to cover the exposed side surfaces to protect them. In other words, if the side surfaces are covered with another member such as a sealing member, the exposed side surfaces may also be covered with the other member.

[0156] (4) Insulating Layer Forming Step Next, the insulating layer forming step will be described. In the insulating layer forming step, an insulating layer 40 is formed at the end of the side from which the electrode current collector 11 should protrude, covering the side surface 12 c of the electrode active material layer 12, the side surface 30 c of the solid electrolyte layer 30, the side surface 22 c of the counter electrode active material layer 22, and the side surfaces 21 c of the counter electrode current collectors 21B and 121 (step S29). Furthermore, an insulating layer 41 is formed at the end of the side from which the counter electrode current collector 121 should protrude, covering the side surface 21 d of the counter electrode current collector 21B, the side surface 22 d of the counter electrode active material layer 22, the side surface 30 d of the solid electrolyte layer 30, the side surface 12 d of the electrode active material layer 12, and the side surface 11 d of the electrode current collector 11. The insulating layers 40 and 41 are arranged, for example, by applying and curing a fluid resin material. The coating is performed by inkjet or screen printing, or by dipping the end faces of the unit cells into the resin material, etc. The curing is performed by drying, heating, light irradiation, etc. depending on the resin material used.

[0157] Furthermore, when forming the insulating layers 40 and 41, the protrusions 13 and 123 may be protected by masking with tape or resist treatment so as not to insulate the protrusions 13 and 123 of the electrode current collector 11 and the counter electrode current collector 121. After the insulating layers 40 and 41 are disposed, the member protecting the protrusions 13 and 123 is removed, thereby ensuring the conductivity of the protrusions 13 and 123.

[0158] (5) Unit Cell Stacking Step Next, the unit cell stacking step will be described. In the unit cell stacking step, a plurality of unit cells 3 are stacked in the same orientation (step S30). Specifically, the unit cells 3 are bonded together so that the surface on which the counter electrode active material layer 22 is exposed and the surface on which the counter electrode active material layer 22 is not exposed are adjacent to each other. At this time, it is preferable that the unit cells 3 are stacked so that they have the same shape and position in a plan view. The unit cells 3 are bonded together by applying an adhesive or by bonding an adhesive film, but the bonding method is not limited to these methods. Furthermore, a heat treatment or pressing step may be performed after bonding.

[0159] As shown in FIG. 8B, the step of forming insulating layers 40 and 41 (step S29) may be performed after the step of stacking unit cells (step S30).

[0160] While the battery and its manufacturing method according to the present disclosure have been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications conceivable by those skilled in the art to the embodiments and other forms constructed by combining some of the components of different embodiments are also included in the scope of the present disclosure.

[0161] In the above 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, a counter electrode current collector, and an insulating layer, but is not limited to this. 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.

[0162] Furthermore, for example, in the above-described embodiment, when the battery is surrounded by a case or a substrate, and a part of the case or the substrate functions as a current collector, the battery does not need to have a current collector on the counter electrode active material layer side. In other words, the counter electrode layer may be composed of the counter electrode active material layer.

[0163] In the above embodiment, the electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer have the same shape and position in a plan view, but this is not limiting. At least one of the electrode active material layer, the solid electrolyte layer, and the counter electrode active material layer may have a different shape or position in a plan view.

[0164] In the above embodiment, the power generating element is formed by sequentially stacking an electrode active material layer, a solid electrolyte layer, and a counter electrode active material layer on a current collector in the power generating element stacking step, but this is not limiting. For example, the power generating element may be formed by sequentially stacking an electrode active material layer, a solid electrolyte layer, and a counter electrode active material layer on a sheet-like substrate in the power generating element stacking step, and the formed power generating element may be removed from the substrate and stacked on an electrode current collector.

[0165] 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.

[0166] The battery according to the present disclosure can be used as a secondary battery such as an all-solid-state battery used in various electronic devices, electrical appliances, automobiles, etc.

[0167] DESCRIPTION OF SYMBOLS 1, 1A, 1B Battery 1c, 1d, 1e, 1f, 11c, 11d, 12c, 12d, 21c, 21d, 22c, 22d, 30c, 30d Side surface 2, 3 Unit cell 10, 10B Electrode layer 11, 11B Electrode current collector 11a, 11b, 22a, 22b Main surface 12 Electrode active material layer 13, 14, 123 Protrusion 20, 20B, 120 Counter electrode layer 21, 21B, 121 Counter electrode current collector 22 Counter electrode active material layer 30 Solid electrolyte layer 40, 40A, 41 Insulating layer 40c, 41d Outer surface 51a, 51b, 53a, 53b Region (first region) 52a, 52b, 54a, 54b Area (second area) 101 Stacked battery

Claims

1. An electrode current collector; Two electrode active material layers disposed on both main surfaces of the electrode current collector; Two solid electrolyte layers are arranged on the opposite side of each of the two electrode active material layers from the electrode current collector; Two counter electrode active material layers disposed on the opposite side of each of the two solid electrolyte layers from the electrode active material layer; Two counter electrode current collectors arranged on the opposite side of the two counter electrode active material layers from the solid electrolyte layer; a first insulating layer covering each side surface of the two solid electrolyte layers and the two electrode active material layers; Equipped with a first region that is not covered by either of the two electrode active material layers is provided at end portions of both main surfaces of the electrode current collector; a second region that is not covered by either of the two counter electrode current collectors is provided at an end portion of a main surface of each of the two counter electrode active material layers facing the counter electrode current collector; The electrode current collector protrudes from the outer surface of the first insulating layer. battery.

2. In a plan view, the length of the second region on a straight line connecting a point on the outer edge of the battery and the center of the battery and intersecting the second region is 100 μm or more.

10. The battery of claim 1.

3. In a plan view, a length of the first region on a straight line that connects a point on an outer edge of the battery and a center of the battery and intersects with the first region is 1 mm or more.

10. The battery of claim 1.

4. a thickness of the portion of the first insulating layer covering the second region is greater than a thickness of the counter electrode current collector; The battery according to any one of claims 1 to 3.

5. The electrode active material layer contains a negative electrode active material, The counter electrode active material layer contains a positive electrode active material. The battery according to any one of claims 1 to 3.

6. The battery has a rectangular shape in a plan view, The first insulating layer is provided on at least one side of the battery in a plan view. The battery according to any one of claims 1 to 3.

7. the electrode current collector, the two electrode active material layers, the two solid electrolyte layers, the two counter electrode active material layers, and the two counter electrode current collectors constitute a unit cell, A plurality of the unit cells are stacked. The battery according to any one of claims 1 to 3.

8. a second insulating layer covering each side surface of the two counter electrode current collectors, the two counter electrode active material layers, the two solid electrolyte layers, and the two electrode active material layers that is not covered by the first insulating layer; At least one of the plurality of counter electrode current collectors protrudes from an outer surface of the second insulating layer.

8. The battery of claim 7.

9. The first insulating layer further covers side surfaces of the two counter electrode active material layers.

10. The battery of claim 1.

10. The first insulating layer further covers side surfaces of the two counter electrode collectors.

10. The battery of claim 9.

11. The first insulating layer covers the second region.

10. The battery of claim 1.