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

Technical Field

[0001] The present disclosure relates to a battery.

Background Art

[0002] Patent Document 1 and Patent Document 2 disclose a battery provided with an insulating member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art, improvement in the reliability of a battery has been demanded. Therefore, an object of the present disclosure is to provide a highly reliable battery.

Means for Solving the Problems

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

[0006] According to this disclosure, a highly reliable battery can be provided. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic top view showing an example of a battery according to Embodiment 1. [Figure 2] Figure 2 is a schematic cross-sectional view of the battery according to Embodiment 1 at the position indicated by the line II-II in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view of a battery according to a modified example 1 of Embodiment 1. [Figure 4] Figure 4 is a schematic top view of a battery according to a modified example 2 of Embodiment 1. [Figure 5] Figure 5 is a schematic cross-sectional view of a battery according to a modified example 2 of Embodiment 1 at the position indicated by the VV line in Figure 4. [Figure 6] Figure 6 is a flowchart showing the method for manufacturing a battery according to Embodiment 1. [Figure 7]Figure 7 is a schematic cross-sectional view showing an example of a battery according to Embodiment 2. [Figure 8A] Figure 8A is a flowchart showing an example of a battery manufacturing method according to Embodiment 2. [Figure 8B] Figure 8B is a flowchart showing another example of a battery manufacturing method according to Embodiment 2. [Modes for carrying out the invention]

[0008] (Summary of this disclosure) The inventors of the present invention have investigated forming terminals at the ends of batteries, such as all-solid-state batteries, which have 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, they attempted to form terminals in the region at 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, a problem arises in which end-face short circuits are likely to occur due to contact with the electrode current collector. Furthermore, when multiple unit cells are stacked, a problem arises in which the possibility of end-face short circuits increases due to misalignment of the stacked cells. In addition, if the edges of the active material layer are exposed, a problem arises in which short circuits are likely to occur due to the detachment of the active material. As a result of these problems, the reliability of the battery decreases.

[0010] Therefore, this 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 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 disposed on the opposite side of each of the two counter electrode active material layers from the solid electrolyte layer, and a first insulating layer covering the side surfaces of each 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. At the ends of both main surfaces of the electrode current collector, a first region not covered by any of the two electrode active material layers is provided. At the ends of the main surfaces of each of the two counter electrode active material layers on the counter electrode current collector side, a second region not covered by any of the two counter electrode current collectors is provided. 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, since the counter electrode current collector is recessed from the counter electrode active material layer, it is less likely to cause an end face short circuit due to contact between the counter electrode current collector and the electrode active material layer or the electrode current collector. In addition, due to the formation of the first insulating layer, the exposure of the electrode active material layer and the counter electrode active material layer is suppressed. Therefore, damage or short circuit caused by contact between the electrode active material layer and the counter electrode active material layer and other members is less likely to occur. Thus, the reliability of the battery can be improved.

[0013] Also, for example, in 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 may be 100 μm or more.

[0014] As a result, even when the counter electrode current collector is damaged, it is less likely to protrude from the counter electrode active material layer in plan view, so that an end face short circuit due to contact with the electrode active material layer or the electrode current collector is less likely to occur. Thus, the reliability of the battery can be improved.

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

[0016] Thereby, it is possible to easily form a terminal in a region not covered by the electrode active material layer at the end of the electrode current collector. The connection between the terminal and the electrode current collector can be improved, and the connection resistance can be reduced. By reducing the connection resistance, the high-current characteristics of the battery are improved, and for example, rapid charging becomes possible.

[0017] Also, for example, the thickness of the portion of the first insulating layer covering the second region may be larger than the thickness of the counter electrode current collector.

[0018] Thereby, even when the counter electrode current collector is damaged, it becomes difficult to protrude from the counter electrode active material layer in a plan view, so that an end face short circuit due to contact with the electrode active material layer or the electrode current collector is less likely to occur. Therefore, the reliability of the battery can be enhanced.

[0019] Also, 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] Thereby, in the positive electrode active material layer, the region covered by the positive electrode current collector and functioning as a positive electrode becomes smaller than the negative electrode active material layer. Therefore, it becomes easier for the capacity of the negative electrode active material layer to be larger than the capacity of the positive electrode active material layer. For this reason, the precipitation of the metal derived from the metal ions not incorporated into the negative electrode active material layer is suppressed, and the reliability of the battery can be further enhanced.

[0021] Also, for example, the first insulating layer may contain a resin.

[0022] As a result, the resin contained in the first insulating layer has an anchoring effect, embedding itself into 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 delamination between the first insulating layer and the current collector and active material layer.

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

[0024] As a result, the first insulating layer becomes harder, so even if the first insulating layer is formed thinly during battery manufacturing, the first insulating layer is less likely to deform, and a thin first insulating layer with a 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 lithium-ion batteries that include 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 allows for efficient battery manufacturing by ensuring reliability at the edges that form terminals, while enabling the edges that do not form terminals to be cut in a single process, for example.

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

[0030] As a result, the sides of the battery are cut surfaces, making it easy to align the sides of the electrode layer, the counter electrode layer, and the solid electrolyte layer flush.

[0031] Furthermore, for example, the shape of the cross-section may be rectangular or trapezoidal.

[0032] This results in straight edges on the cross-section. Therefore, there is no space that does not contribute to the battery's charge and discharge performance, which would otherwise be formed if the edges were not straight, thus suppressing the effective decrease in the battery's energy density. Consequently, the battery's energy density can be increased.

[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 multiple such unit cells may be stacked.

[0034] This allows for the creation of highly reliable stacked batteries, as the unit cells are stacked.

[0035] Furthermore, for example, the device may include a second insulating layer that covers each of the sides 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 multiple counter electrode current collectors may protrude from the outer surface of the second insulating layer.

[0036] This makes it easier to form counter electrode terminals for extracting current from the counter electrode layer in a stacked battery arranged for parallel connection, in the region of the counter electrode current collector that is not covered by the second insulating layer, excluding the outermost shell of the stacked battery. Furthermore, exposure of the electrode active material layer and the counter electrode active material layer is suppressed on the side where the counter electrode current collector protrudes. As a result, damage or short circuits caused by contact between the electrode active material layer and the counter electrode active material layer and other components are less likely to occur. Thus, the reliability of the battery can be improved.

[0037] The embodiments will be described in detail below with reference to the drawings.

[0038] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit this disclosure. Furthermore, any components in the following embodiments that are not described in an independent claim will be described as optional components.

[0039] Furthermore, each figure is a schematic diagram and not necessarily a strictly accurate representation. Therefore, for example, the scale may not necessarily match in each figure. Also, in each figure, substantially identical components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0040] Furthermore, in this specification, terms indicating relationships between elements such as parallel or orthogonal, terms indicating the shape of elements such as rectangles or circles, and numerical ranges are not expressions that represent only strict meanings, but also expressions that include substantially equivalent ranges, such as differences of a few percent.

[0041] In this specification and in the drawings, the x, y, and z axes represent the three axes of a three-dimensional Cartesian coordinate system. The x and y axes are the directions parallel to the first side and the second side perpendicular to the first side of the rectangle, respectively, when the plan view shape of the power generation element of the battery is rectangular. The z axis is the stacking direction of the multiple unit cells contained in the power generation element. In this specification, the "stacking direction" coincides with the direction normal to the main surface of the current collector and the active material layer. In this specification, "plan view" means a view from a direction perpendicular to the main surface, unless otherwise specified.

[0042] Furthermore, in this specification, the terms "upper" and "lower" do not refer to the upward (vertically upward) and downward (vertically downward) directions in absolute spatial perception, but rather to terms defined by the relative positional relationship based on the stacking order in a stacked configuration. In addition, the terms "upper" and "lower" apply not only when two components are spaced apart and another component exists between them, but also when two components are placed in close proximity and touching each other. In the following description, the negative side of the z-axis is referred to as "lower" or "bottom," and the positive side of the z-axis is referred to as "upper" or "top."

[0043] Furthermore, unless otherwise specified in this specification, "projecting" means projecting outward from the center of the unit cell in a cross-sectional view perpendicular to the main surface of the unit cell. "Element A projecting from element B" means that in the projection direction, the tip of element A projects further than the tip of element B, that is, the tip of element A is further from the center of the unit cell than the tip of element B. "Projection direction" is considered to be the direction parallel to the main surface of the unit cell. Also, "projection of element A" means a part of element A that projects further than the tip of element B in the projection direction. Elements include, for example, electrode layers, active material layers, solid electrolyte layers, and current collectors.

[0044] Furthermore, in this specification, ordinal numbers such as "first," "second," etc., do not mean the number or order of components unless otherwise specified, but are used to avoid confusion and to distinguish similar components.

[0045] (Embodiment 1) [1. Overview] First, an overview of the battery according to Embodiment 1 will be explained using Figures 1 and 2.

[0046] Figure 1 is a schematic top view showing an example of a battery 1 according to this embodiment. In Figure 1, the plan view shapes of each component of the battery 1 are shown by solid and dashed lines. Figure 2 is a schematic cross-sectional view of the battery 1 according to this embodiment at the position indicated by the line II-II in Figure 1.

[0047] As shown in Figures 1 and 2, the battery 1 according to this embodiment comprises an electrode layer 10, a counter electrode layer 20 positioned 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 comprises two counter electrode layers 20 and two solid electrolyte layers 30. One counter electrode layer 20 and one solid electrolyte layer 30 are positioned on each of the two main surfaces 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 comprises 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 arranged on both main surfaces of the electrode current collector 11. At the end of the main surface 11a of the electrode current collector 11, there is a region 51a that is not covered by the upper electrode active material layer 12. At the end of the main surface 11b of the electrode current collector 11, there is a region 51b that is not covered by the lower electrode active material layer 12. Regions 51a and 51b are examples of first regions that are not covered by either of the two electrode active material layers 12.

[0049] The counter electrode layer 20 includes 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. The end of the main surface 22a of the upper counter electrode active material layer 22 is provided with a region 52a that is not covered by the upper counter electrode current collector 21. The end of the main surface 22b of the lower counter electrode active material layer 22 is provided with a region 52b that is not covered by the lower counter electrode current collector 21. Regions 52a and 52b are examples of second regions that are not covered by either of the two counter electrode current collectors 21.

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

[0051] The electrode current collector 11 has both a region covered by the insulating layer 40 and an uncovered region. 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 extends outward from the outer surface 40c. In the region of the electrode current collector 11 that is not covered by the insulating layer 40, it is easy to form electrode terminals for extracting current from the electrode layer 10.

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

[0053] As shown in Figure 1, the battery 1 has two sides 1c and 1d facing away from each other, and two sides 1e and 1f facing away from each other. Sides 1c and 1d constitute the short sides of the rectangular battery 1 in a plan view. Sides 1e and 1f constitute the long sides of the rectangular battery 1 in a plan view. As shown in Figure 1, side 1c of the battery 1 is composed of the side 11c of the electrode current collector 11 and the outer side 40c of the insulating layer 40.

[0054] In Figure 1, the electrode current collector 11 has a structure in which a protrusion 13 protrudes from the outer surface 40c of the insulating layer 40 on the side surface 1c. However, this protrusion 13 may also be on the side surface 1d, the side surface 1e, or the side surface 1f.

[0055] Battery 1 is, for example, an all-solid-state battery. Furthermore, the sides 1d, 1e, and 1f of the electrode current collector 11 of battery 1 that do not have the protruding portion 13 are each flat planes. On each of these flat sides, the sides of the electrode layer 10, the counter electrode layer 20, and the solid electrolyte layer 30 are flush, meaning there are no steps or unevenness, and they are located on the same flat plane. As a result, on the sides of the electrode current collector 11 that do not have the protruding portion 13, there are no steps or irregularities on the sides of each layer. Therefore, spaces that do not function as a battery due to irregularities are not formed, and the effective volumetric energy density of battery 1 is improved. Also, since the sides of each layer can be made flush by cutting each layer together, the manufacturing of battery 1 becomes easier.

[0056] The sides 1d, 1e, and 1f of the electrode current collector 11 of the battery 1 that do not have a protruding portion 13 are, for example, cut surfaces. Specifically, the sides 1d, 1e, and 1f are surfaces formed by cutting with a blade such as a cutter. The sides 1d, 1e, and 1f each have cut marks such as fine grooves. Because each side is a cut surface, the sides of the electrode layer 10, the counter electrode layer 20, and the solid electrolyte layer 30 can be easily made flush. The cut marks 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 at both main surfaces 11a and 11b. As described above, at least one end of the electrode current collector 11 in plan view is provided with regions 51a and 51b that are not covered by the electrode active material layer 12. Region 51a also has both a region covered by the insulating layer 40 and a region that is not covered. In plan view, the region not covered by the insulating layer 40 corresponds to the protruding portion 13.

[0058] The following description will focus on the upper region 51a, but the lower region 51b has a similar configuration.

[0059] To facilitate the formation of terminals in the region 51a 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. Alternatively, the length of the region 51a is, for example, 20 mm or less. This prevents the terminal portion from becoming too large, reduces the portion that does not function as a battery, and improves the volumetric energy density of the battery 1.

[0060] The length of region 51a is the length of the straight line that intersects region 51a, connecting a point on the outer edge of battery 1 to the center of battery 1, in a plan 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 plan view. The center of battery 1 is the geometric center of battery 1 in a plan view. For example, if the plan view shape of battery 1 is rectangular, the center of battery 1 is the intersection of the diagonals in a plan view. The straight line that intersects region 51a, connecting a point on the outer edge of battery 1 to the center of battery 1, is, for example, the line II-II shown in Figure 1. In other words, the length of region 51a is the length along the x-axis. In this embodiment, region 51a is a rectangular region that is elongated in the y-axis direction, but it is not limited to this.

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

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

[0063] Any known material can be used as the material for the electrode current collector 11. For example, the electrode current collector 11 may be made of copper, aluminum, nickel, iron, stainless steel, platinum or gold, or an alloy of two or more of these materials, in the form of a foil, plate, or mesh.

[0064] The upper counter electrode current collector 21 is in contact with the main surface 22a of the counter electrode active material layer 22. At least one end of the counter electrode current collector 21 in a plan view is provided with a region 52a that does not cover the main surface 22a of the counter electrode active material layer 22. In other words, the side surface of the counter electrode current collector 21 is recessed relative to the counter electrode active material layer 22. To put it another way, in a plan view, 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.

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

[0066] By preventing protrusion from the counter electrode active material layer 22 in a plan view when a part of the counter electrode current collector 21 is damaged, the occurrence of a short circuit on the side surface 1c of the battery 1 can be suppressed. For this purpose, the length of region 52a is, for example, 100 μm or more. Alternatively, the length of region 52a is, for example, 2 mm or less. This prevents the area of ​​the counter electrode current collector 21 from becoming too small, ensuring that a sufficient portion functions as a battery, and thereby improving the volumetric energy density of the battery 1.

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

[0068] Note that the length of region 52a is equal to, but not limited to, the length of region 52b. The lengths of region 52a and 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 region 52a. In this embodiment, the upper surface of the upper counter electrode current collector 21 and the upper surface of the insulating layer 40 are flush. Also, the lower surface of the lower counter electrode current collector 21 and the lower surface of the insulating layer 40 are flush. This makes it easy to stack unit cells 2 and form a stacked battery. A specific example of the stacked battery will be described later in Embodiment 2.

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

[0071] Known materials can be used as the material for the counter electrode current collector 21. For example, the counter electrode current collector 21 may be made of copper, aluminum, nickel, iron, stainless steel, platinum or gold, or an alloy of two or more of these materials, in the form of a foil, plate or mesh.

[0072] The electrode active material layer 12 is arranged on both sides of the main surfaces 11a and 11b of the electrode current collector 11. The side of the electrode active material layer 12 opposite to 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 in between. The side surface 12c of the electrode active material layer 12 is in contact with the insulating layer 40. In a plan view, the electrode active material layer 12 and the counter electrode active material layer 22 have the same shape and position. The thickness of the electrode active material layer 12 is, for example, between 5 μm and 300 μm. The material used for the electrode active material layer 12 will be described later.

[0073] The counter electrode active material layer 22 is laminated on the solid electrolyte layer 30 and positioned opposite the electrode active material layer 12. The side 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, at least one end of the counter electrode active material layer 22 in 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 to 300 μm. The material 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 to 150 μm, but is not limited to this range.

[0075] The solid electrolyte layer 30 includes at least a solid electrolyte and may optionally include a binder material. The solid electrolyte layer 30 may also 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 may be used. For example, solid electrolyte materials such as sulfide solid electrolytes, halogen-based solid electrolytes, or oxide solid electrolytes can be used. As a sulfide solid electrolyte, if the material can conduct lithium ions, for example, a compound consisting of lithium sulfide (Li2S) and phosphorus pentasulfide (P2S5) can be used. Furthermore, as the sulfide solid electrolyte, sulfides such as Li2S-SiS2, Li2S-B2S3, or Li2S-GeS2 may be used, or sulfides to which at least one of Li3N, LiCl, LiBr, Li3PO4, and Li4SiO4 is added as an additive may be used.

[0077] As an oxide solid electrolyte, if the material can conduct lithium ions, for example, Li7La3Zr2O 12 (LLZ), Li 1.3 Al 0.3 Ti 1.7 (PO4)3(LATP) or (La,Li)TiO3(LLTO) are used.

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

[0079] In the examples shown in Figures 1 and 2, the insulating layer 40 is in contact with 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 on the side surface in the direction in which the protrusion 13 exists when viewed from above. It also covers a portion of the main surfaces 11a and 11b 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, or polyimide resin. The resin may be a thermosetting resin or an ultraviolet curing resin. By including a resin in the insulating layer 40, the bonding of the insulating layer 40 to each layer and each current collector can be improved by an anchoring effect in which the resin bites 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. Examples of the metal oxide include silicon oxide, titanium oxide, or aluminum oxide. By including a metal oxide in the insulating layer 40, the insulating layer 40 becomes harder. Therefore, even if the insulating layer 40 is formed thinly during the manufacture 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 this embodiment, 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, one is a positive electrode layer comprising a positive electrode active material layer and the other is a negative electrode layer comprising a negative electrode active material layer. For example, electrode layer 10 is the negative electrode layer and counter electrode layer 20 is the positive electrode layer. That is, electrode current collector 11 is the negative electrode current collector and electrode active material layer 12 is the negative electrode active material layer. Counter electrode current collector 21 is the positive electrode current collector and counter electrode active material layer 22 is the positive electrode active material layer.

[0082] The positive electrode active material layer comprises at least a positive electrode active material and may optionally include at least one of a solid electrolyte, a conductive additive, and a binder material.

[0083] As the positive electrode active material, known materials capable of intercalating and releasing (e.g., insertion and deintercalation, or dissolution and deposition) lithium ions, sodium ions, or magnesium ions may be used. Examples of positive electrode active materials capable of releasing and inserting lithium ions include lithium cobalt oxide composite oxide (LCO), lithium nickel oxide composite oxide (LNO), lithium manganese oxide composite oxide (LMO), lithium-manganese-nickel oxide composite oxide (LMNO), lithium-manganese-cobalt oxide composite oxide (LMCO), lithium-nickel-cobalt oxide composite oxide (LNCO), or lithium-nickel-manganese-cobalt oxide composite oxide (LNMCO).

[0084] As the solid electrolyte, the solid electrolyte material described above may be used. As the conductive additive, conductive materials such as acetylene black, carbon black, graphite, or carbon fiber may be used. As the binder material, the binder material described above may be used.

[0085] The negative electrode active material layer comprises at least a negative electrode active material and may optionally contain at least one of the same solid electrolyte, conductive additive, and binder material as the positive electrode active material layer.

[0086] As the negative electrode active material, known materials capable of intercalating and releasing (e.g., insertion and deintercalation, or dissolution and deposition) lithium ions, sodium ions, or magnesium ions may be used. In the case of materials capable of detaching and inserting lithium ions, examples of negative electrode active materials include natural graphite, artificial graphite, carbon materials such as graphite carbon fiber or resin-fired carbon, metallic lithium, lithium alloys, or oxides of lithium and transition metal elements.

[0087] Thus, in battery 1, the ends of the main surfaces 11a and 11b of the electrode current collector 11 are provided with regions 51a and 51b that are not covered by the electrode active material layer 12. Also, the end of the main surface 22a of the upper counter electrode active material layer 22 is provided with a region 52a that is not covered by the upper counter electrode current collector 21. The end of the main surface 22b of the lower counter electrode active material layer 22 is provided with a region 52b that is not covered by the lower counter electrode current collector 21. Furthermore, 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 set back from the counter electrode active material layer 22, making it less likely for end-face short circuits to occur due to contact between the counter electrode current collector 21 and the electrode active material layer 12 or the electrode current collector 11. In addition, the presence of the insulating layer 40 suppresses exposure of the electrode active material layer 12 and the counter electrode active material layer 22. Therefore, damage or short circuits caused by contact between the electrode active material layer 12 and the counter electrode active material layer 22 and other components are less likely to occur. Thus, the reliability of the battery 1 can be improved.

[0089] Furthermore, if 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 will be less likely to protrude from the counter electrode active material layer 22 in a plan view. As a result, end face short circuits due to contact with the electrode active material layer 12 or the electrode current collector 11 will be less likely to occur. Thus, the reliability of the battery can be improved.

[0090] Furthermore, if the length of the region 51a at the end of the electrode current collector 11 that is not covered by the electrode active material layer 12 is set to 1 mm or more, terminals can be easily formed using this region 51a.

[0091] Furthermore, when the electrode layer 10 is used as the negative electrode layer and the counter electrode layer 20 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 the positive electrode becomes smaller than that of the negative electrode active material layer. As a result, the capacity of the negative electrode active material layer tends to be larger than that of the positive electrode active material layer. Therefore, the deposition of metals derived from metal ions that were not incorporated into the negative electrode active material layer is suppressed, and the reliability of the battery 1 can be further improved.

[0092] [2. Variant] The following describes modified versions of the battery 1 according to this embodiment. In the following description of the modified versions, the differences from Embodiment 1 will be the main focus, and the similarities will be omitted or simplified.

[0093] [2-1. Variation 1] First, the battery relating to Modification 1 will be explained using Figure 3. Figure 3 is a schematic cross-sectional view of battery 1A relating to this modification.

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

[0095] Thus, by making the thickness t2 of the portion of the insulating layer 40A that covers region 52a greater than the thickness t1 of the counter electrode current collector 21, even if the counter electrode current collector 21 is damaged, it becomes less likely to protrude from the counter electrode active material layer 22 in a plan view. Therefore, end-face short circuits due to contact between the counter electrode current collector 21 and the electrode active material layer 12 or electrode current collector 11 become less likely. Thus, the reliability of the 1A battery can be improved.

[0096] In this modified example, the same applies to the lower counter electrode current collector 21 and the portion of the insulating layer 40A that covers region 52b. As a result, in a plan view, the lower counter electrode current collector 21 is less likely to protrude from the counter electrode active material layer 22, thus reducing the likelihood of end-face short circuits due to contact with the electrode active material layer 12 or the electrode current collector 11. Therefore, the reliability of the 1A battery can be improved.

[0097] Furthermore, the thickness t2 of the insulating layer 40A does not need to be large on either the upper or lower side. 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, as in Embodiment 1.

[0098] [2-2. Variation 2] Next, the battery relating to the second modified example will be explained using Figures 4 and 5.

[0099] Figure 4 is a schematic top view of the battery 1B according to this modified example. In Figure 4, the plan view shapes of each component of the battery 1B are shown by solid and dashed lines. Figure 5 is a schematic cross-sectional view of the battery 1B according to this modified example at the position indicated by the VV line in Figure 4.

[0100] As shown in Figures 4 and 5, battery 1B differs from battery 1 of Embodiment 1 in that it has electrode layer 10B and counter electrode layer 20B instead of electrode layer 10 and counter electrode layer 20. In addition, battery 1B further includes an insulating layer 41.

[0101] The electrode layer 10B includes an electrode current collector 11B instead of an 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. In other words, the electrode current collector 11B has a protrusion 13 on the side 1c and a protrusion 14 on the side 1d. The specific configuration of the protrusion 14 is the same as that of the protrusion 13.

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

[0103] The counter electrode layer 20B includes a counter electrode current collector 21B instead of a counter electrode current collector 21. The counter electrode current collector 21B is recessed from the sides 22c and 22d of the counter electrode active material layer 22 on two sides of the battery 1B. Specifically, on the side 21d side of the counter electrode current collector 21B, the end of the main surface 22a of the upper counter electrode active material layer 22 has a region 54a that is not covered by the upper counter electrode current collector 21B. On the side 21d side, the end of the main surface 22b of the lower counter electrode active material layer 22 has a region 54b that is not covered by the lower counter electrode current collector 21B. Regions 54a and 54b are examples of second regions that are not covered by either of the two counter electrode current collectors 21B. The lengths of regions 54a and 54b are, for example, the same as the lengths of 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 each side 21d of the two counter electrode current collectors 21B, each side 22d of the two counter electrode active material layers 22, each side 30d of the two solid electrolyte layers 30, and each side 12d of the two electrode active material layers 12. For example, sides 21d, 22d, 30d, and 12d are completely covered by the insulating layer 41 and are not exposed. Sides 21d, 22d, 30d, and 12d are, for example, flat planes. Sides 22d, 30d, and 12d are, for example, flush, i.e., they 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 is provided that covers the sides 1e and 1f of the battery 1, and may be connected to and integrally formed with the insulating layers 40 and 41.

[0106] Thus, the battery 1B according to this modified example includes not only the insulating layer 40, but also an insulating layer 41 that covers the side surface 21d of the counter electrode current collector 21B, the side surface 22d of the counter electrode active material layer 22, the side surface 30d of the solid electrolyte layer 30, and the side surface 12d of the electrode active material layer 12. Furthermore, on two sides of the battery 1B in a plan view, 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, respectively.

[0107] As a result, battery 1B achieves the effect of suppressing end-face short circuits by forming an insulating layer on two sides. Furthermore, terminals can be easily formed in the areas 51a, 51b, 53a, and 53b at the ends of the electrode current collector 11B that are not covered by the electrode active material layer 12.

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

[0109] [3. Manufacturing method] Next, the manufacturing methods for batteries 1, 1A, and 1B according to this embodiment and its various modifications will be explained using the flowchart shown in Figure 6. Figure 6 is a flowchart showing the manufacturing method for battery 1 according to this embodiment. Note that the manufacturing method for battery 1 described below is just one example, and the manufacturing method for battery 1 is not limited to the following example.

[0110] The manufacturing method for battery 1 includes (1) a power generation 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 formation step (step S19). Each step will be described in detail below.

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

[0112] At this time, at the respective ends of the main surfaces 11a and 11b of the electrode current collector 11, regions 51a and 51b that are not covered by the electrode active material layer 12 are formed. In other words, the electrode active material layer 12 is not formed over the entire surface 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 easy to form the protruding portion 13 of the electrode current collector 11 in a subsequent process.

[0113] In addition, during the power generation element lamination process, the electrode active material layer 12 may be formed to cover the entire surface of the main surfaces 11a and 11b. In this case, a step to expose the ends of the main surfaces 11a and 11b may be performed during the counter electrode current collector lamination or cutting process described later.

[0114] The electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22 that constitute the power generation element are each formed sequentially, for example, using a wet coating method. By using a wet coating method, the power generation element can be easily laminated onto the electrode current collector 11. Wet coating methods include, but are not limited to, die coating, doctor blade coating, roll coating, screen printing, or inkjet coating.

[0115] When using a wet coating method, a coating process is performed in which the materials and solvents that form the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22 are appropriately mixed to obtain a slurry.

[0116] The solvent used in the paint formulation process may be a known solvent used in the manufacture of known solid-state batteries, such as lithium-ion solid-state batteries.

[0117] The slurry of each layer obtained in the coating process is applied to the electrode current collector 11 in the order of electrode active material layer 12, solid electrolyte layer 30, and counter electrode active material layer 22. In this case, the next layer may be applied after the application of the previously applied layer is completed. Alternatively, the application of the next layer may be started while the application of the previously applied layer is still in progress. In other words, steps S12, S13, and S14 may be performed simultaneously. After the slurry of each layer is applied sequentially and all layers have been applied, for example, a heat treatment to remove the solvent and binder material, and a high-pressure press treatment to promote the filling of the material in each layer are performed.

[0118] Furthermore, heat treatment and high-pressure pressing may be performed after each coating layer. The heat treatment and high-pressure pressing may be performed after each coating layer in the coating lamination of the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22, or they may be performed separately after the coating lamination of any two layers and after the coating lamination of one layer, or they may be performed all at once after the coating lamination of all three layers. For the high-pressure pressing, for example, a roll press or a flat plate press may be used. Furthermore, at least one of the heat treatment and high-pressure pressing may be omitted.

[0119] By performing this lamination coating method, the bonding properties and interfacial resistance of the interfaces between the electrode current collector 11, the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22 can be improved. Furthermore, the bonding properties and grain boundary resistance of the powder materials used in the electrode active material layer 12, the solid electrolyte layer 30, and the counter electrode active material layer 22 can be improved. In other words, good interfaces are formed between each layer of the power generation element and between the powder materials within each layer.

[0120] The power generation element stacking process may be carried out in a series of continuous processes, such as a roll-to-roll method.

[0121] (2) Counter electrode current collector lamination process Next, the counter electrode current collector lamination process will be described. In the counter electrode current collector lamination process, counter electrode current collectors 21 are laminated on both sides of a laminated electrode plate in which power generation elements are laminated on both sides of the electrode current collector 11 (step S15). Specifically, the counter electrode current collector 21 is laminated on the main surface 22a of the upper counter electrode active material layer 22 and on the main surface 22b of the lower counter electrode active material layer 22. At this time, the materials are joined by high-pressure pressing or the like (step S16).

[0122] Next, the end of the counter electrode current collector 21 is removed so that the counter electrode active material layer 22 is exposed at the end of the side where the electrode current collector 11 is to protrude (step S17). This forms the unit cell 2 shown in Figure 2.

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

[0124] Furthermore, in the power generation element stacking process, 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 methods such as near-cutting or polishing. This exposes the ends of the main surfaces 11a and 11b of the electrode current collector 11, allowing regions 51a and 51b to be formed.

[0125] In the counter electrode current collector lamination process, a counter electrode current collector 21, which has been molded in advance to the desired dimensions, may be prepared and laminated on both sides of a laminated electrode plate in which power generation elements are laminated on both sides of the electrode current collector 11, and then joined by high-pressure pressing or the like. In this case, the step of removing a part of the counter electrode current collector (step S17) can be omitted.

[0126] (3) Cutting process Next, the cutting process will be described. In the cutting process, 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 is cut with a blade, laser, jet, etc.

[0127] At the edge to be cut, 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, but these are cut all at once. This eliminates the need to stack each layer of the power generation element in the shape after cutting, making it easy to manufacture the battery 1. At the cut edge, the sides 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 are exposed. After cutting, a sealing member or the like may be placed to cover the exposed sides in order to protect them. That is, if the sides are covered with a sealing member or the like, the exposed sides may also be covered by the other member.

[0128] (4) Insulating layer formation process Next, the insulating layer formation process will be described. In the insulating layer formation process, an insulating layer 40 is formed at the end of the side where the electrode current collector 11 is to 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 coating and curing a fluid resin material. Coating is performed by inkjet or screen printing, or by dipping the end face of the unit cell into the resin material. Curing is performed by drying, heating, light irradiation, etc., depending on the resin material used.

[0129] Furthermore, when forming the insulating layer 40, the protruding portion 13 of the electrode current collector 11 may be protected by masking with tape or other means, or by a resist treatment, so that the protruding portion 13 is not insulated. After the insulating layer 40 is placed, the conductivity of the protruding portion 13 can be ensured by removing the protective material for the protruding portion 13.

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

[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 on the electrode current collector 11 in the shape shown in Figures 1 and 2 by lamination coating to obtain an electrode plate.

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

[0133] Next, the obtained electrode plates and counter plates are stacked so that their respective solid electrolyte layers 30 are in contact. The stacked laminate, i.e., the unit cell 2, is subjected to high-pressure pressing from both sides in the stacking direction using a flat plate press. After that, a battery 1 is obtained by removing a portion of the counter electrode current collector 21 (step S17), cutting a portion of the unit cell 2 (step S18), and forming an insulating layer 40 (step S19).

[0134] Furthermore, in step S19, by applying a thick insulating material to cover the end of the counter electrode current collector 21, the battery 1A shown in Figure 3 can be formed.

[0135] Furthermore, in step S12, regions 53a and 53b that are not covered by the electrode active material layer 12 are formed not only on the side 11c side of the electrode current collector 11, but also on the end of the side 11d side. In step S17, the end of the side 21d side of the counter electrode current collector 21 is removed not only on the side 21c side. This makes it possible to form the battery 1B shown in Figures 4 and 5.

[0136] (Embodiment 2) Next, Embodiment 2 will be described. Embodiment 2 describes a stacked battery in which the unit cells of the battery according to Embodiment 1 are stacked. In the following description, the differences from Embodiment 1 described above will be the main focus, and the explanation of the common points will be omitted or simplified as appropriate.

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

[0138] As shown in Figure 7, the stacked battery 101 comprises a plurality of unit cells 3. The plurality of unit cells 3 are stacked along the stacking direction of the layers that make up each unit cell. The plurality of unit cells 3 are electrically connected in parallel.

[0139] Multiple unit cells 3 have the same configuration as each other. Unit cells 3 differ from unit cells 2 according to Embodiment 1 in that they have counter electrode layers 20B and 120 instead of two counter electrode layers 20. Counter electrode layer 20B is the same as the counter electrode layer 20B of battery 1B according to Modification 2 of Embodiment 1. Unit cells 3 also have 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. The end of the counter electrode current collector 121 has a region that is not covered by 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 protrusion 123 that protrudes outward from the outer surface 41d. In a plan view, the region not covered by the insulating layer 41 corresponds to the protrusion 123.

[0141] Furthermore, since the counter electrode current collector 121 protrudes from the outer surface 41d of the insulating layer 41, it becomes easy to form counter electrode terminals for extracting current from the counter electrode layers 20B and 120 in the region of the counter electrode current collector 121 that is not covered by the insulating layer 41. In addition, because the insulating layer 41 is provided, exposure of the electrode active material layer 12 and the counter electrode active material layer 22 is suppressed, making it less likely for damage or short circuits to occur due to contact between the electrode active material layer 12 and the counter electrode active material layer 22 and other components. Thus, the reliability of the stacked battery 101 can be improved.

[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 sides of the stacked battery 101. For example, if the plan view shape of the stacked battery 101 is rectangular, the side on which the protrusion 13 is provided and the side on which the protrusion 123 is provided are opposite sides. This allows the protrusion 13 and the protrusion 123 to be separated, thereby suppressing the occurrence of short circuits 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. Therefore, end-face short circuits due to contact between each of the counter electrode current collectors 21B and 121 and the electrode active material layer 12 or electrode current collector 11 are less likely to occur. In addition, because the insulating layer 40 is provided, exposure of the electrode active material layer 12 and the counter electrode active material layer 22 is suppressed, so damage or short circuits caused by contact between the electrode active material layer 12 and the counter electrode active material layer 22 and other components are less likely to occur. Thus, the reliability of the stacked battery 101 can be improved.

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

[0145] The current collectors are not shared between two adjacent unit cells 3. That is, two counter-polarity current collectors 21B and 121 of the same polarity are arranged in overlapping positions. In this case, an adhesive layer may be provided between the current collectors. It is preferable that the adhesive layer has high conductivity.

[0146] Furthermore, the unit cell 3 may be equipped with a counter-pole current collector 121 instead of the counter-pole current collector 21B. In other words, two counter-pole current collectors 121 may be arranged on top of each other.

[0147] [2. Manufacturing method] Next, the manufacturing method of the stacked battery according to this embodiment will be explained using the flowcharts shown in Figures 8A and 8B. Note that the manufacturing method of the stacked battery 101 described below is just one example, and the manufacturing method of the stacked battery 101 is not limited to the example below.

[0148] The manufacturing method for the stacked battery 101 includes (1) a power generation 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 formation step (step S29), and (5) a unit cell stacking step (step S30). In Figures 8A and 8B, steps S21 to S28 represent the manufacturing process for the unit cell. Steps S21, S22, S3, and S24, the power generation element stacking steps, are the same as steps S11, S12, S13, and S14 of the manufacturing method in Embodiment 1, so their explanation is omitted. The counter electrode current collector stacking step and subsequent steps will be described in detail below.

[0149] (2) Counter electrode current collector lamination process In the counter electrode current collector lamination process, counter electrode current collectors 21B and 121 are laminated on both sides of a laminated electrode plate in which power generation elements are laminated on both sides of the electrode current collector 11 (step S25). Specifically, the counter electrode current collector 21B is laminated on the main surface 22a of the upper counter electrode active material layer 22. The counter electrode current collector 121 is laminated on the main surface 22b of the lower counter electrode active material layer 22. At this time, the materials are joined by high-pressure pressing or the like (step S26).

[0150] Next, the ends of the counter electrode current collectors 21B and 121 are removed so that the counter electrode active material layer 22 is exposed at the ends of the sides where the electrode current collector 11 should protrude (step S27). This forms the unit cell 3 shown in Figure 7.

[0151] At least part of the removal is carried out by cutting with a blade, laser, or jet. In this case, the counter electrode active material layer 22, the solid electrolyte layer 30, and a portion of the electrode active material layer 12 may be removed simultaneously. However, the cutting is done just short of the point where the electrode current collector 11 that should be protruding is not cut off. Alternatively, the removal may be carried out by polishing, laser trimming, plasma etching, or chemical etching instead of cutting. Alternatively, the removal may be carried out by a combination of these methods. The method of removal 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 Figure 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 part of the removal is performed by cutting with a blade, laser, or jet. In this case, the counter electrode active material layer 22, the solid electrolyte layer 30, the electrode active material layer 12, and a portion of the electrode current collector 11 may be removed simultaneously, but the cutting is performed just short of the point where the counter electrode current collector 121 that is to protrude is not cut off. 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 method of removal is not limited to these methods.

[0153] In the counter electrode current collector lamination process, counter electrode current collectors 21B and 121, which have been pre-formed to the desired dimensions, may be prepared and laminated on both sides of a laminated electrode plate in which power generation elements are laminated on both sides of the electrode current collector 11, and then joined by high-pressure pressing or the like. In this case, the step of removing a part of the counter electrode current collector 21B or 121 (step S27) can be omitted.

[0154] (3) Cutting process Next, the cutting process will be described. In the cutting process, the ends of the unit cell 3 are cut so as to leave the protrusion 13 of the electrode current collector 11 and the protrusion 123 of the counter electrode current collector 121 (step S28). Specifically, part or all of the sides other than the side with the protrusion 13 and the side with the protrusion 123 are cut with a blade, laser, jet, etc.

[0155] At the edge to be cut, 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, but these are cut all at once. This eliminates the need to stack each layer of the power generation element in the shape after cutting, making it easy to manufacture the unit cell 3. At the cut edge, the sides 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 are exposed. After cutting, a sealing member or the like may be placed to cover the exposed side in order to protect it. That is, if the side is covered with another member such as a sealing member, the exposed side may also be covered by the other member.

[0156] (4) Insulating layer formation process Next, the insulating layer formation process will be described. In the insulating layer formation process, an insulating layer 40 is formed at the end of the edge where the electrode current collector 11 is to 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 surfaces 21c of the counter electrode current collectors 21B and 121 (step S29). In addition, an insulating layer 41 is formed at the end of the edge where the counter electrode current collector 121 is to protrude, so as to cover the side surface 21d of the counter electrode current collector 21B, the side surface 22d of the counter electrode active material layer 22, the side surface 30d of the solid electrolyte layer 30, the side surface 12d of the electrode active material layer 12, and the side surface 11d of the electrode current collector 11. The insulating layers 40 and 41 are arranged, for example, by coating and curing a fluid resin material. Coating is performed by inkjet or screen printing, or by dipping the end face of a unit cell into the resin material. Curing is carried out by drying, heating, or light irradiation, depending on the resin material used.

[0157] Furthermore, when forming the insulating layers 40 and 41, the protrusions 13 of the electrode current collector 11 and the protrusions 123 of the counter electrode current collector 121 may be protected by masking with tape or other means, or by resist treatment, so that these protrusions are not insulated. After the insulating layers 40 and 41 are placed, the conductivity of the protrusions 13 and 123 can be ensured by removing the protective material.

[0158] (5) Unit cell stacking process Next, the unit cell lamination process will be described. In the unit cell lamination process, multiple unit cells 3 are laminated in the same orientation (step S30). Specifically, the units are laminated so that the side with the counter electrode active material layer 22 exposed and the side without the counter electrode active material layer 22 exposed are adjacent to each other. At this time, it is preferable that each unit cell 3 is laminated so that its shape and position in a plan view are the same. The unit cells 3 are laminated by coating with an adhesive or laminating with an adhesive film, but the lamination method is not limited to these methods. In addition, heat treatment or pressing may be performed after lamination.

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

[0160] (Other embodiments) The battery and its manufacturing method described above have been explained based on embodiments, but the disclosure is not limited to these embodiments. Within the scope of the disclosure, various modifications to the embodiments that a person skilled in the art could conceive, as long as they do not depart from the spirit of the disclosure, and other forms constructed by combining some components from different embodiments, are also included.

[0161] In the above embodiment, the battery consisted 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, a bonding layer or the like may be provided between each layer of the battery to reduce electrical resistance and improve bonding strength, within a range that is acceptable for the battery characteristics.

[0162] Furthermore, for example, in the above embodiment, if the battery is enclosed by a housing or substrate, and a part of the housing or substrate functions as a current collector, then a current collector on the counter electrode active material layer side of the battery does not need to be provided. In other words, the counter electrode layer may be composed of a counter electrode active material layer.

[0163] Furthermore, although the electrode active material layer, solid electrolyte layer, and counter electrode active material layer had the same shape and position in a plan view in the above embodiment, the embodiment is not limited to this. At least one of the electrode active material layer, solid electrolyte layer, and counter electrode active material layer may have different shapes or positions in a plan view.

[0164] Furthermore, in the above embodiment, the power generation element was formed by sequentially laminating an electrode active material layer, a solid electrolyte layer, and a counter electrode active material layer onto a current collector in the power generation element lamination process, but this is not limited to this. For example, in the power generation element lamination process, the power generation element may be formed by sequentially laminating an electrode active material layer, a solid electrolyte layer, and a counter electrode active material layer onto a sheet-like substrate, and the formed power generation element may be removed from the substrate and laminated onto an electrode current collector.

[0165] Furthermore, each of the above embodiments can be modified, replaced, added, or omitted in various ways within the scope of the claims or their equivalents. [Industrial applicability]

[0166] The battery relating to this disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices, electrical appliances, or automobiles. [Explanation of Symbols]

[0167] 1, 1A, 1B battery 1c, 1d, 1e, 1f, 11c, 11d, 12c, 12d, 21c, 21d, 22c, 22d, 30c, 30d side 2, 3 unit cells 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 Counterpolar Layers 21, 21B, 121 Counter-pole current collector 22 Counter electrode active material layer 30 Solid electrolyte layer 40, 40A, 41 Insulation layer 40c, 41d outer surface 51a, 51b, 53a, 53b area (first area) 52a, 52b, 54a, 54b area (second area) 101 Stacked Cell

Claims

1. Electrode current collector and Two electrode active material layers are arranged on both main surfaces of the electrode current collector, Each of the two electrode active material layers comprises two solid electrolyte layers positioned on the opposite side from the electrode current collector, Two counter electrode active material layers are arranged on the opposite side of each of the two solid electrolyte layers from the electrode active material layer, Two counter electrode current collectors are arranged on the opposite side of each of the two counter electrode active material layers from the solid electrolyte layer, The two counter electrode current collectors, the two counter electrode active material layers, the two solid electrolyte layers, and the first insulating layer covering each side surface of the two electrode active material layers, Equipped with, At the ends of both main surfaces of the electrode current collector, a first region is provided which is not covered by either of the two electrode active material layers. A second region is provided at the end of the main surface of each of the two counter electrode active material layers that is on the side of the counter electrode current collector, and this region is not covered by either of the two counter electrode current collectors. The first insulating layer covers the second region, The electrode current collector protrudes from the outer surface of the first insulating layer, The thickness of the portion of the first insulating layer that covers the second region is greater than the thickness of the counter electrode current collector. 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. The battery according to claim 1.

3. In a plan view, the length of the first region on a straight line connecting a point on the outer edge of the battery and the center of the battery, and intersecting the first region, is 1 mm or more. The battery according to claim 1.

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

5. The planar shape of the aforementioned battery is rectangular. 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.

6. 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. Multiple of the aforementioned unit cells are stacked, The battery according to any one of claims 1 to 3.

7. The system comprises the two counter electrode current collectors, the two counter electrode active material layers, the two solid electrolyte layers, and a second insulating layer that covers each of the sides of the two electrode active material layers that are not covered by the first insulating layer. At least one of the multiple counter electrode current collectors protrudes from the outer surface of the second insulating layer. The battery according to claim 6.

Images