Battery

Abstract

A battery (1) comprises: a power generation element (10) having a plurality of battery cells (100) which are laminated therein, and which each include an electrode layer (110), a counter-electrode layer (120), and a solid electrolyte layer (130) located between the electrode layer (110) and the counter-electrode layer (120); an electrode insulating layer (21) that covers the electrode layer (110) at a side surface (11) of the power generation element (10); and a counter-electrode terminal (31) that covers the side surface (11) and the electrode insulating layer (21) and that is electrically connected to the counter-electrode layer (120). At least a portion of the plurality of battery cells (100) are connected in parallel. The electrode insulating layer (21) covers, at the side surface (11), a portion from the electrode layer (110) to a part of the counter-electrode layer (120) along the lamination direction of the power generation element (10).

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, batteries in which a plurality of battery cells are connected in parallel are known (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 020699 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-120717 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for further improvements in battery characteristics compared to conventional batteries.

[0005] Therefore, the present disclosure provides a high-performance battery. [Means for solving the problem]

[0006] A battery according to one aspect of the present disclosure includes a power generating element in which the plurality of battery cells are stacked, each battery cell including an electrode layer, a counter electrode layer, and a solid electrolyte layer between the electrode layer and the counter electrode layer, a first insulating member covering the electrode layer on a first side surface of the power generating element, and a first terminal electrode covering the first side surface and the first insulating member and electrically connected to the counter electrode layer. At least some of the plurality of battery cells are connected in parallel. The first insulating member covers from the electrode layer to a portion of the counter electrode layer on the first side surface along the stacking direction of the power generating element. [Effects of the Invention]

[0007] According to the present disclosure, a high-performance battery can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing the cross-sectional structure of a battery according to an embodiment. [Figure 2] FIG. 2 is a top view of the battery according to the embodiment. [Figure 3A] FIG. 3A is a cross-sectional view of an example of a battery cell included in a power generating element according to an embodiment. [Figure 3B] FIG. 3B is a cross-sectional view of another example of a battery cell included in the power generating element according to the embodiment. [Figure 3C] FIG. 3C is a cross-sectional view of another example of a battery cell included in a power generating element according to an embodiment. [Figure 4] FIG. 4 is a cross-sectional view of a power generating element according to an embodiment. [Figure 5] FIG. 5 is a side view showing the positional relationship between a first side surface of a power generating element according to an embodiment, and an electrode insulating layer and a counter electrode terminal provided on the first side surface. [Figure 6] FIG. 6 is a side view showing the positional relationship between the second side surface of the power generating element according to the embodiment and the counter electrode insulating layer and electrode terminal provided on the second side surface. [Figure 7] FIG. 7 is a cross-sectional view of a coin battery including a battery according to the embodiment. [Figure 8] FIG. 8 is a cross-sectional view of a laminated battery including a battery according to an embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing the cross-sectional structure of a battery according to the first modification. [Figure 10] FIG. 10 is a cross-sectional view showing the cross-sectional structure of a battery according to the second modification. [Figure 11A] FIG. 11A is a cross-sectional view showing a step of a method for manufacturing a battery according to the embodiment or the modification. [Figure 11B] FIG. 11B is a cross-sectional view showing one step of the method for manufacturing a battery according to the embodiment or the modification. [Figure 11C] FIG. 11C is a cross-sectional view showing a step of the method for manufacturing a battery according to the embodiment or the modification. [Figure 11D] FIG. 11D is a cross-sectional view showing a step of the method for manufacturing a battery according to the embodiment or the modification. [Figure 11E] FIG. 11E is a cross-sectional view showing a step of the method for manufacturing a battery according to the embodiment or the modification. [Figure 11F] FIG. 11F is a cross-sectional view showing a step of the method for manufacturing a battery according to the embodiment or the modification. [Figure 11G] FIG. 11G is a cross-sectional view showing a step of the method for manufacturing a battery according to the embodiment or the modification. [Figure 11H] FIG. 11H is a cross-sectional view showing a step of the method for manufacturing a battery according to the embodiment or the modification. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Summary of the Disclosure) A battery according to one aspect of the present disclosure includes a power generating element in which the plurality of battery cells are stacked, each battery cell including an electrode layer, a counter electrode layer, and a solid electrolyte layer between the electrode layer and the counter electrode layer, a first insulating member covering the electrode layer on a first side surface of the power generating element, and a first terminal electrode covering the first side surface and the first insulating member and electrically connected to the counter electrode layer. At least some of the plurality of battery cells are connected in parallel. The first insulating member covers from the electrode layer to a portion of the counter electrode layer on the first side surface along the stacking direction of the power generating element.

[0010] This makes it possible to realize a high-performance battery. For example, because the first insulating member covers the electrode layer on the first side surface, it is possible to suppress the occurrence of a short circuit between the counter electrode layer and the electrode layer via the first terminal electrode. Furthermore, because the first insulating member covers even a portion of the counter electrode layer, it is possible to sufficiently suppress the electrode layer from being exposed without being covered by the first insulating member. Furthermore, because the adhesion of the first insulating member to the power generating element is increased, detachment of the first insulating member is suppressed, and the reliability of the battery can be improved. In this way, the reliability of the battery can be improved, and therefore a high-performance battery can be realized.

[0011] Furthermore, for example, the counter electrode layer may include a counter electrode current collector and a counter electrode active material layer located between the counter electrode current collector and the solid electrolyte layer. The first insulating member may cover the electrode layer to at least a portion of the counter electrode active material layer, but may not cover the counter electrode current collector.

[0012] Since the counter electrode active material layer is generally formed of a powder material, its end surface has very fine irregularities. This improves the adhesion strength of the first insulating member and improves insulation reliability. Furthermore, since the counter electrode current collector is exposed, electrical connection between the first terminal electrode and the counter electrode current collector can be sufficiently ensured.

[0013] Furthermore, for example, the thickness of the counter electrode current collector may be 20 μm or less.

[0014] This makes it possible to achieve improvements in energy density, power density, and reductions in material costs.

[0015] Furthermore, for example, the battery according to one aspect of the present disclosure may further include an outer counter electrode current collector disposed on a first main surface of the power generating element, the outer counter electrode current collector having a first extension portion extending outward from the first main surface, and the first extension portion being connected to the first terminal electrode.

[0016] As a result, the outer counter electrode current collector is provided, and can be used as an electrode for external extraction. For example, a large main surface of the outer counter electrode current collector can be secured, allowing a large external terminal to be connected, and the contact area can be increased, thereby reducing connection resistance. This improves the large-current characteristics of the battery.

[0017] Furthermore, for example, the battery according to one aspect of the present disclosure may further include an insulating layer located between the outer counter electrode current collector and the first main surface.

[0018] This can suppress contact between the outer counter electrode current collector and the electrode layer when a part of the electrode layer constitutes the first main surface, which means that occurrence of a short circuit between the counter electrode layer and the electrode layer via the outer counter electrode current collector can be suppressed, thereby improving the reliability of the battery.

[0019] Furthermore, for example, the electrode layer, the counter electrode layer, and the solid electrolyte layer may have the same outline in a plan view.

[0020] This prevents the occurrence of short circuits due to the formation of lithium dendrites, since none of the layers protrude in plan view. Also, since each layer has the same area in plan view, the effective area of ​​the battery cell can be increased, thereby increasing the battery capacity.

[0021] Furthermore, for example, the battery according to one aspect of the present disclosure may further include a second insulating member that covers the counter electrode layer on the second side surface of the power generating element, and a second terminal electrode that covers the second side surface and the second insulating member and is electrically connected to the electrode layer. The second insulating member may cover from the counter electrode layer to a portion of the electrode layer on the second side surface along the stacking direction of the power generating element.

[0022] This allows for the realization of a battery with higher performance. For example, because the second insulating member covers the counter electrode layer on the second side surface, it is possible to suppress the occurrence of a short circuit between the counter electrode layer and the electrode layer via the second terminal electrode. Furthermore, because the second insulating member covers even a portion of the electrode layer, it is possible to sufficiently suppress the counter electrode layer from being exposed without being covered by the second insulating member. Furthermore, because the adhesion of the second insulating member to the power generating element is increased, detachment of the second insulating member is suppressed, thereby further improving the reliability of the battery.

[0023] Furthermore, for example, the electrode layer may include an electrode current collector and an electrode active material layer located between the electrode current collector and the solid electrolyte layer. The second insulating member may cover from the counter electrode layer to at least a portion of the electrode active material layer, but may not cover the electrode current collector.

[0024] Since the electrode active material layer is generally formed of a powder material, the end surface thereof has extremely fine irregularities. This improves the adhesion strength of the second insulating member and improves insulation reliability. Furthermore, since the electrode current collector is exposed, electrical connection between the second terminal electrode and the electrode current collector can be sufficiently ensured.

[0025] Furthermore, for example, the thickness of the electrode current collector may be 20 μm or less.

[0026] This makes it possible to achieve improvements in energy density, power density, and reductions in material costs.

[0027] Furthermore, for example, the battery according to one aspect of the present disclosure may further include an outer electrode current collector disposed on a second main surface of the power generating element, the outer electrode current collector having a second extension portion extending outward from the second main surface, and the second extension portion connected to the second terminal electrode.

[0028] As a result, the outer electrode current collector can be used as an external extraction electrode. For example, a large main surface of the outer electrode current collector can be secured, allowing a large external terminal to be connected, increasing the contact area and reducing connection resistance. This improves the large-current characteristics of the battery.

[0029] Furthermore, for example, all of the plurality of battery cells may be connected in parallel.

[0030] By electrically connecting all the battery cells in parallel, it is possible to prevent a specific battery cell from being overcharged or overdischarged due to variations in capacity among the battery cells, thereby further improving the reliability of the battery.

[0031] Also, for example, some of the plurality of battery cells may be connected in series.

[0032] This makes it possible to realize a battery suitable for the required capacity and voltage.

[0033] Furthermore, for example, the solid electrolyte layer may include a solid electrolyte having lithium ion conductivity.

[0034] For example, the shape of the power generating element may be cylindrical, and the first side surface and the second side surface may be different portions of the cylindrical side surface. For example, the battery may be a coin battery.

[0035] This allows a plurality of battery cells to be connected in parallel in a coin-type battery, thereby realizing a coin-type battery with a large capacity.

[0036] Furthermore, for example, the battery may be sealed with a laminate film.

[0037] This makes it possible to realize a high-performance laminated battery.

[0038] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0039] 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.

[0040] 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.

[0041] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel or orthogonal, terms indicating the shape of elements, such as rectangular or rectangular parallelepiped, 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.

[0042] In this specification and drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional Cartesian coordinate system. The x-axis and y-axis are parallel to the main surfaces of the power generating element. The z-axis is the stacking direction of the multiple battery cells included in the power generating element.

[0043] In this specification, the "stacking direction" corresponds to the direction normal to the main surfaces of the current collector and the active material layer. In this specification, the term "plan view" refers to a view perpendicular to the main surface of the power generating element unless otherwise specified, such as when used alone. When the term "plan view of a certain surface" is used, such as "plan view of a first side surface," it refers to a view of the "certain surface" from the front.

[0044] 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."

[0045] Furthermore, in this specification, unless otherwise specified, ordinal numbers such as "first" and "second" do not refer to the number or order of components, but are used to avoid confusion between similar components and to distinguish between components.

[0046] (Embodiment) The configuration of the battery according to the embodiment will be described below.

[0047] Fig. 1 is a cross-sectional view showing the cross-sectional configuration of a battery 1 according to the present embodiment. Fig. 2 is a top view of the battery 1 according to the present embodiment. Fig. 1 shows a cross section taken along line II in Fig. 2. In Fig. 2, the layers are shaded in the same manner as the shaded sections shown in the cross section of Fig. 1 to make it easier to understand the correspondence between the components.

[0048] As shown in FIG. 2, the shape of the battery 1 in a plan view is approximately circular. In other words, the shape of the battery 1 is a flat, approximately cylindrical body. Here, "flat" means that the thickness (i.e., the length in the z-axis direction) is shorter than the maximum width of the main surface. As will be described in detail later, the battery 1 is used as a coin battery. The shape of the battery 1 in a plan view may be a polygon such as a rectangle, square, hexagon, or octagon, or may be an ellipse. In cross-sectional views such as FIG. 1, the thickness of each layer is exaggerated to make the layer structure of the power generating element 10 easier to understand.

[0049] 1, the battery 1 includes a power generating element 10, an electrode insulating layer 21, a counter electrode insulating layer 22, a counter electrode terminal 31, an electrode terminal 32, an outer counter electrode current collector 41, an outer electrode current collector 42, and an insulating layer 50. The battery 1 is, for example, an all-solid-state battery.

[0050] [1. Power generation elements] First, the specific configuration of the power generating element 10 will be described.

[0051] 1, the power generating element 10 includes side surfaces 11 and 12 and main surfaces 15 and 16. In this embodiment, both main surfaces 15 and 16 are flat surfaces.

[0052] Side surface 11 is an example of a first side surface. Side surface 12 is an example of a second side surface. In this embodiment, the shape of power generating element 10 is a flat cylinder. Therefore, side surfaces 11 and 12 are different parts of the cylindrical side surface and are back-to-back facing parts. For example, in a plan view, side surface 12 is located on a straight line connecting an arbitrary point on side surface 11 and the center of main surface 15.

[0053] Principal surface 15 is an example of a first principal surface. Principal surface 16 is an example of a second principal surface. Principal surfaces 15 and 16 are back-to-back and parallel to each other. Principal surface 15 is the top surface of power-generating element 10. Principal surface 16 is the bottom surface of power-generating element 10.

[0054] As shown in FIG. 1, the power generating element 10 has a plurality of battery cells 100. The battery cell 100 is a battery with a minimum configuration and is also called a unit cell. The plurality of battery cells 100 are electrically connected in parallel and stacked. In this embodiment, all of the battery cells 100 included in the power generating element 10 are electrically connected in parallel. In the example shown in FIG. 1, the number of battery cells 100 included in the power generating element 10 is six, but this is not limited to this. For example, the number of battery cells 100 included in the power generating element 10 may be an even number, such as two or four, or an odd number, such as three or five.

[0055] Each of the multiple battery cells 100 includes an electrode layer 110, a counter electrode layer 120, and a solid electrolyte layer 130. The electrode layer 110 has an electrode current collector 111 and an electrode active material layer 112. The counter electrode layer 120 has a counter electrode current collector 121 and a counter electrode active material layer 122. In each of the multiple battery cells 100, the electrode current collector 111, the electrode active material layer 112, the solid electrolyte layer 130, the counter electrode active material layer 122, and the counter electrode current collector 121 are stacked in this order along the z-axis.

[0056] The electrode layer 110 is one of the positive electrode layer and the negative electrode layer of the battery cell 100. The counter electrode layer 120 is the other of the positive electrode layer and the negative electrode layer of the battery cell 100. In the following, a case where the electrode layer 110 is the negative electrode layer and the counter electrode layer 120 is the positive electrode layer will be described as an example.

[0057] The multiple battery cells 100 have substantially the same configuration. In two adjacent battery cells 100, the order of the layers constituting the battery cell 100 is reversed. In other words, the multiple battery cells 100 are stacked side by side along the z-axis with the order of the layers constituting the battery cell 100 alternating. In this embodiment, since there is an even number of battery cells 100, the bottom and top layers of the power generating element 10 each serve as current collectors of the same polarity.

[0058] Below, each layer of the battery cell 100 will be described with reference to Fig. 3A. Fig. 3A is a cross-sectional view of the battery cell 100 included in the power generating element 10 according to this embodiment.

[0059] The electrode current collector 111 and the counter electrode current collector 121 are each a conductive foil-like, plate-like, or mesh-like member. The electrode current collector 111 and the counter electrode current collector 121 may each be, for example, a conductive thin film. The electrode current collector 111 and the counter electrode current collector 121 may be made of a material such as stainless steel (SUS), aluminum (Al), copper (Cu), or nickel (Ni). The electrode current collector 111 and the counter electrode current collector 121 may be made of different materials.

[0060] The thickness of each of the electrode current collector 111 and the counter electrode current collector 121 is, for example, 5 μm or more and 100 μm or less, but is not limited to this. The thickness of each of the electrode current collector 111 and the counter electrode current collector 121 may be 20 μm or less. A current collector thickness of 20 μm or less can achieve improved energy density, improved output density, and reduced material costs. In this embodiment, single battery cells 100 are connected in parallel and stacked, so the thickness of the power generating element 10 can be kept small even when the number of parallel connections is increased, contributing to improved energy density. As the number of parallel connections increases, the number of current collectors also increases, so reducing the thickness of the current collectors is useful for suppressing an increase in the thickness of the power generating element 10.

[0061] An electrode active material layer 112 is in contact with a main surface of the electrode current collector 111. The electrode current collector 111 may include a current collector layer that is a layer containing a conductive material and is provided in a portion that contacts the electrode active material layer 112. A counter electrode active material layer 122 is in contact with a main surface of the counter electrode current collector 121. The counter electrode current collector 121 may include a current collector layer that is a layer containing a conductive material and is provided in a portion that contacts the counter electrode active material layer 122.

[0062] The electrode active material layer 112 is disposed on the main surface of the electrode current collector 111 facing the counter electrode layer 120. The electrode active material layer 112 contains, for example, a negative electrode active material as an electrode material. The electrode active material layer 112 is disposed opposite the counter electrode active material layer 122.

[0063] The negative electrode active material contained in the electrode active material layer 112 may be, for example, graphite, metallic lithium, or the like. As the material for the negative electrode active material, various materials capable of extracting and inserting ions such as lithium (Li) or magnesium (Mg) may be used.

[0064] The material contained in the electrode active material layer 112 may be, for example, a solid electrolyte such as an inorganic solid electrolyte. Examples of inorganic solid electrolytes that can be used include sulfide solid electrolytes and oxide solid electrolytes. Examples of sulfide solid electrolytes that can be used include a mixture of lithium sulfide (LiS) and diphosphorus pentasulfide (P2S5). Examples of materials that can be used in the electrode active material layer 112 include a conductive material such as acetylene black, or a binder for bonding such as polyvinylidene fluoride.

[0065] The electrode active material layer 112 is produced by applying a paste-like paint, in which the materials contained in the electrode active material layer 112 are kneaded together with a solvent, onto the main surface of the electrode current collector 111 and drying the paint. In order to increase the density of the electrode active material layer 112, the electrode layer 110 (also referred to as an electrode plate) including the electrode active material layer 112 and the electrode current collector 111 may be pressed after drying. The thickness of the electrode active material layer 112 is, for example, 5 μm or more and 300 μm or less, but is not limited to this.

[0066] The counter electrode active material layer 122 is disposed on the main surface of the counter electrode current collector 121 facing the electrode layer 110. The counter electrode active material layer 122 is a layer containing a positive electrode material such as an active material. The positive electrode material is a material that constitutes a counter electrode for the negative electrode material. The counter electrode active material layer 122 contains, for example, a positive electrode active material.

[0067] Possible positive electrode active materials that can be used in the counter electrode active material layer 122 include, 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), and lithium-nickel-manganese-cobalt composite oxide (LNMCO).Various materials that can extract and insert ions such as Li or Mg can be used as the positive electrode active material.

[0068] The counter electrode active material layer 122 may contain, for example, a solid electrolyte such as an inorganic solid electrolyte. Examples of inorganic solid electrolytes include sulfide solid electrolytes and oxide solid electrolytes. Examples of sulfide solid electrolytes include a mixture of Li2S and P2S5. The surface of the positive electrode active material may be coated with a solid electrolyte. Examples of materials that may be used in the counter electrode active material layer 122 include a conductive material such as acetylene black, or a binder such as polyvinylidene fluoride.

[0069] The counter electrode active material layer 122 is produced by applying a paste-like paint, in which the materials contained in the counter electrode active material layer 122 are kneaded together with a solvent, onto the main surface of the counter electrode current collector 121 and drying the paint. In order to increase the density of the counter electrode active material layer 122, the counter electrode layer 120 (also referred to as a counter electrode plate) including the counter electrode active material layer 122 and the counter electrode current collector 121 may be pressed after drying. The thickness of the counter electrode active material layer 122 is, for example, not less than 5 μm and not more than 300 μm, but is not limited to this.

[0070] The solid electrolyte layer 130 is disposed between the electrode active material layer 112 and the counter electrode active material layer 122. The solid electrolyte layer 130 is in contact with both the electrode active material layer 112 and the counter electrode active material layer 122. The solid electrolyte layer 130 is a layer containing an electrolyte material. A commonly known electrolyte for batteries can be used as the electrolyte material. The thickness of the solid electrolyte layer 130 may be 5 μm or more and 300 μm or less, or 5 μm or more and 100 μm or less.

[0071] The solid electrolyte layer 130 includes a solid electrolyte. For example, an inorganic solid electrolyte or other solid electrolyte may be used as the solid electrolyte. For example, a sulfide solid electrolyte or an oxide solid electrolyte may be used as the inorganic solid electrolyte. For example, a mixture of Li2S and P2S5 may be used as the sulfide solid electrolyte. In addition to the electrolyte material, the solid electrolyte layer 130 may contain a binder such as polyvinylidene fluoride.

[0072] In this embodiment, the electrode active material layer 112, the counter electrode active material layer 122, and the solid electrolyte layer 130 are maintained in the shape of parallel plates. This makes it possible to prevent cracking or collapse due to bending. Alternatively, the electrode active material layer 112, the counter electrode active material layer 122, and the solid electrolyte layer 130 may be smoothly curved together.

[0073] In the present embodiment, the end face of the counter electrode current collector 121 on the side surface 11 side and the end face of the electrode layer 110 on the side surface 11 side coincide with each other when viewed from the z-axis direction. Specifically, the end face of the counter electrode current collector 121 on the side surface 11 side and the end face of the electrode current collector 111 on the side surface 11 side coincide with each other when viewed from the z-axis direction. The same is true for the end faces of the counter electrode current collector 121 and the electrode current collector 111 on the side surface 12 side.

[0074] More specifically, in the battery cell 100, the electrode current collector 111, the electrode active material layer 112, the solid electrolyte layer 130, the counter electrode active material layer 122, and the counter electrode current collector 121 all have the same shape and size, and their outlines match. In other words, the shape of the battery cell 100 is a flat, cylindrical plate.

[0075] 1, in this embodiment, a current collector is shared between two adjacent battery cells 100. For example, the battery cell 100 in the bottom layer and the battery cell 100 immediately above it share an electrode current collector 111.

[0076] 1, in a plurality of battery cells 100, two adjacent electrode layers 110 share a mutual electrode current collector 111. An electrode active material layer 112 is provided on both main surfaces of the shared electrode current collector 111. Furthermore, two adjacent counter electrode layers 120 share a mutual counter electrode current collector 121. A counter electrode active material layer 122 is provided on both main surfaces of the shared counter electrode current collector 121.

[0077] Such a battery 1 is formed by combining and stacking not only the battery cell 100 shown in Fig. 3A but also the battery cells 100B and 100C shown in Fig. 3B and 3C. Note that the battery cell 100 shown in Fig. 3A will be described as battery cell 100A here.

[0078] The battery cell 100B shown in Fig. 3B has a configuration similar to that of the battery cell 100A shown in Fig. 3A, except that the counter electrode current collector 121 is removed. In other words, the counter electrode layer 120B of the battery cell 100B is composed of only the counter electrode active material layer 122.

[0079] The battery cell 100C shown in Fig. 3C has a configuration similar to that of the battery cell 100A shown in Fig. 3A, except that the electrode current collector 111 is removed. In other words, the electrode layer 110C of the battery cell 100C is composed of only the electrode active material layer 112.

[0080] FIG. 4 is a cross-sectional view showing the power generating element 10 according to this embodiment. FIG. 4 is a view of only the power generating element 10 of FIG. 1. As shown in FIG. 4, the battery cell 100A is placed in the lowest layer, and the battery cells 100B and 100C are alternately stacked upward. At this time, the battery cell 100B is stacked upside down relative to the orientation shown in FIG. 3B. In this way, the power generating element 10 is formed.

[0081] The method for forming the power generating element 10 is not limited to this. For example, the battery cell 100A may be arranged in the uppermost layer. Alternatively, the battery cell 100A may be arranged in a position different from either the uppermost or lowermost layer. A plurality of battery cells 100A may also be used. Furthermore, a unit of two battery cells 100 that share a current collector may be formed by coating both sides of a single current collector. Specific examples of manufacturing methods will be described later.

[0082] As described above, in the power generating element 10 according to this embodiment, all battery cells 100 are connected in parallel, and no battery cells are connected in series. This makes it less likely that unevenness in the charge / discharge state due to variations in capacity among the battery cells 100 will occur when the battery 1 is charged or discharged. This significantly reduces the risk of some of the multiple battery cells 100 being overcharged or overdischarged, thereby improving the reliability of the battery 1.

[0083] [2. Insulation layer] Next, the electrode insulating layer 21 and the counter electrode insulating layer 22 will be described.

[0084] 1, the electrode insulating layer 21 covers the electrode layer 110 on the side surface 11. Specifically, the electrode insulating layer 21 completely covers the electrode current collector 111 and the electrode active material layer 112 on the side surface 11.

[0085] FIG. 5 is a side view showing the positional relationship between the side surface 11 of the power generating element 10 according to this embodiment and the electrode insulating layer 21 and counter electrode terminal 31 provided on the side surface 11. FIG. 5 schematically shows the negative half of the x-axis of the cylindrical side surface of the power generating element 10. In FIG. 5, the end faces of each layer appearing on the side surface 11 are shaded in the same manner as the shaded areas of each layer shown in the cross section of FIG. 1. This also applies to FIG. 6, which will be described later.

[0086] 5(a) is a side view of the power-generating element 10, and is a plan view of the side surface 11 as viewed from the front. FIG. 5(b) shows the side surface 11 of FIG. 5(a) and the electrode insulating layer 21 provided on the side surface 11. That is, FIG. 5(b) is a side view of the battery 1 of FIG. 1 as viewed from the negative side of the x-axis, with the counter electrode terminal 31 seen through. FIG. 5(c) is a side view of the battery 1 as viewed from the negative side of the x-axis, and the outer counter electrode current collector 41, outer electrode current collector 42, and insulating layer 50 are not shown.

[0087] 5(b), the electrode insulating layer 21 covers the electrode layer 110 of each of the multiple battery cells 100 on the side surface 11. The electrode insulating layer 21 does not cover at least a portion of the counter electrode layer 120 of each of the multiple battery cells 100. Therefore, the electrode insulating layer 21 has a striped shape when viewed from above on the side surface 11.

[0088] At this time, the electrode insulating layer 21 continuously covers the electrode layers 110 of the two adjacent battery cells 100. Specifically, the electrode insulating layer 21 continuously covers from a portion of the counter electrode layer 120 of one of the two adjacent battery cells 100 to a portion of the counter electrode layer 120 of the other of the two adjacent battery cells 100.

[0089] In this manner, the electrode insulating layer 21 covers a portion of the counter electrode layer 120 and the solid electrolyte layer 130 on the side surface 11. Specifically, when the side surface 11 is viewed from above, the contour of the electrode insulating layer 21 overlaps the counter electrode active material layer 122 of the counter electrode layer 120. This reduces the risk of exposing the electrode layer 110 even if the width (length in the z-axis direction) of the electrode insulating layer 21 varies due to manufacturing variations. This makes it possible to prevent a short circuit between the electrode layer 110 and the counter electrode layer 120 via the counter electrode terminal 31 formed to cover the electrode insulating layer 21. Furthermore, the end surface of the counter electrode active material layer 122 formed of a powder-like material has very fine irregularities. Therefore, the electrode insulating layer 21 penetrates into these irregularities, thereby improving the adhesion strength of the electrode insulating layer 21 and improving insulation reliability. The electrode insulating layer 21 may cover the entire counter electrode active material layer 122. In other words, the outline of the electrode insulating layer 21 may overlap the boundary between the counter electrode active material layer 122 and the counter electrode current collector 121 .

[0090] 5(b), the electrode insulating layer 21 is provided so as to extend along the z-axis direction at both ends of the stripe-shaped portion in the y-axis direction. That is, the shape of the electrode insulating layer 21 is a ladder shape when viewed from the side surface 11 in a plan view.

[0091] 1 , the counter electrode insulating layer 22 covers the counter electrode layer 120 on the side surface 12. Specifically, the counter electrode insulating layer 22 completely covers the counter electrode current collector 121 and the counter electrode active material layer 122 on the side surface 12.

[0092] FIG. 6 is a side view showing the positional relationship between the side surface 12 of the power-generating element 10 according to this embodiment and the counter electrode insulating layer 22 provided on the side surface 12. FIG. 6 schematically shows the x-axis positive half of the cylindrical side surface of the power-generating element 10. FIG. 6(a) is a side view of the power-generating element 10 and a plan view of the side surface 12 as viewed from the front. FIG. 6(b) shows the side surface 12 of FIG. 6(a) and the counter electrode insulating layer 22 provided on the side surface 12. That is, FIG. 6(b) is a side view of the battery 1 in FIG. 1 as viewed from the x-axis positive side, with the electrode terminal 32 seen through. FIG. 6(c) is a side view of the battery 1 on the x-axis positive side, with the outer counter electrode current collector 41, outer electrode current collector 42, and insulating layer 50 not shown.

[0093] 6(b), the counter electrode insulating layer 22 covers the counter electrode layer 120 of each of the plurality of battery cells 100 on the side surface 12. The counter electrode insulating layer 22 does not cover at least a portion of the electrode layer 110 of each of the plurality of battery cells 100. Therefore, the counter electrode insulating layer 22 has a striped shape in a plan view of the side surface 12.

[0094] At this time, the counter electrode insulating layer 22 continuously covers the counter electrode layers 120 of the two adjacent battery cells 100. Specifically, the counter electrode insulating layer 22 continuously covers from a portion of the electrode layer 110 of one of the two adjacent battery cells 100 to a portion of the electrode layer 110 of the other of the two adjacent battery cells 100.

[0095] In this manner, the counter electrode insulating layer 22 covers a portion of the electrode layer 110 and the solid electrolyte layer 130 on the side surface 12. Specifically, when the side surface 12 is viewed from above, the outline of the counter electrode insulating layer 22 overlaps the electrode active material layer 112 of the electrode layer 110. This reduces the risk of the counter electrode layer 120 being exposed even if the width (length in the z-axis direction) of the counter electrode insulating layer 22 varies due to manufacturing variations. This makes it possible to prevent a short circuit between the counter electrode layer 120 and the electrode layer 110 via the electrode terminal 32 formed to cover the counter electrode insulating layer 22. Furthermore, the end surface of the electrode active material layer 112 formed of a powder-like material has very fine irregularities. Therefore, the counter electrode insulating layer 22 penetrates into these irregularities, thereby improving the adhesion strength of the counter electrode insulating layer 22 and improving insulation reliability. The counter electrode insulating layer 22 may cover the entire electrode active material layer 112. In other words, the outline of the counter electrode insulating layer 22 may overlap the boundary between the electrode active material layer 112 and the electrode current collector 111 .

[0096] 6(b), counter electrode insulating layer 22 is provided so as to extend along the z-axis direction at both ends in the y-axis direction of the striped portion. That is, counter electrode insulating layer 22 has a ladder shape in the plan view of side surface 12.

[0097] The electrode insulating layer 21 and the counter electrode insulating layer 22 are each formed using an insulating material that is electrically insulating. For example, the electrode insulating layer 21 and the counter electrode insulating layer 22 each contain a resin. The resin is, for example, an epoxy-based resin, but is not limited to this. Note that an inorganic material may also be used as the insulating material. Usable insulating materials are selected based on various properties such as flexibility, gas barrier properties, impact resistance, and heat resistance. The electrode insulating layer 21 and the counter electrode insulating layer 22 are formed using the same material. In other words, the electrode insulating layer 21 and the counter electrode insulating layer 22 may be formed integrally and indistinguishable. Note that the electrode insulating layer 21 and the counter electrode insulating layer 22 may also be formed using different materials.

[0098] [3. Terminals] Next, the counter electrode terminal 31 and the electrode terminal 32 will be described.

[0099] 1 , the counter electrode terminal 31 covers the side surface 11 and the electrode insulating layer 21, and is electrically connected to the counter electrode layer 120. Specifically, the counter electrode terminal 31 covers the electrode insulating layer 21 and a portion of the side surface 11 that is not covered by the electrode insulating layer 21.

[0100] 5(b), the end face of the counter electrode current collector 121 and part of the end face of the counter electrode active material layer 122 are exposed in the portion of the side surface 11 that is not covered with the electrode insulating layer 21. Therefore, the counter electrode terminal 31 contacts the end faces of the counter electrode current collector 121 and the counter electrode active material layer 122, and is electrically connected to the counter electrode layer 120. The counter electrode terminal 31 fits into the irregularities on the end face of the counter electrode active material layer 122, thereby improving the adhesion strength of the counter electrode terminal 31 and the reliability of the electrical connection.

[0101] The counter electrode terminal 31 is electrically connected to each counter electrode layer 120 of the plurality of battery cells 100. In other words, the counter electrode terminal 31 performs part of the function of electrically connecting the battery cells 100 in parallel. As shown in FIG. 1 , the counter electrode terminal 31 covers almost the entire side surface 11 in the stacking direction. As shown in FIG. 2 , in a plan view, the counter electrode terminal 31 covers about one-fourth of the cylindrical side surface of the power generating element 10. The size of the counter electrode terminal 31 is not particularly limited as long as it does not come into contact with the electrode terminal 32. In this embodiment, since the counter electrode layer 120 is the positive electrode, the counter electrode terminal 31 functions as a positive electrode lead-out electrode of the battery 1.

[0102] 1 , the electrode terminal 32 covers the side surface 12 and the counter electrode insulating layer 22, and is electrically connected to the electrode layer 110. Specifically, the electrode terminal 32 covers the counter electrode insulating layer 22 and a portion of the side surface 12 that is not covered by the counter electrode insulating layer 22.

[0103] 6(b), the end face of the electrode current collector 111 and a part of the end face of the electrode active material layer 112 are exposed in the portion of the side surface 12 that is not covered with the counter electrode insulating layer 22. Therefore, the electrode terminal 32 comes into contact with the end faces of the electrode current collector 111 and the electrode active material layer 112, and is electrically connected to the electrode layer 110. The electrode terminal 32 fits into the irregularities on the end face of the electrode active material layer 112, thereby improving the adhesion strength of the electrode terminal 32 and the reliability of the electrical connection.

[0104] The electrode terminal 32 is electrically connected to each electrode layer 110 of the multiple battery cells 100. In other words, the electrode terminal 32 plays a part of the function of electrically connecting the battery cells 100 in parallel. As shown in FIG. 1 , the electrode terminal 32 collectively covers almost the entire side surface 12 in the stacking direction. Also, as shown in FIG. 2 , in a plan view, the electrode terminal 32 covers about one-fourth of the cylindrical side surface of the power generating element 10. The size of the electrode terminal 32 is not particularly limited as long as it does not come into contact with the counter electrode terminal 31. In this embodiment, since the electrode layer 110 is the negative electrode, the electrode terminal 32 functions as a negative electrode lead-out electrode of the battery 1.

[0105] The counter electrode terminal 31 and the electrode terminal 32 are formed using a conductive resin material or the like. Alternatively, the counter electrode terminal 31 and the electrode terminal 32 may be formed using a metal material such as solder. Usable conductive materials are selected based on various properties such as flexibility, gas barrier properties, impact resistance, heat resistance, and solder wettability. The counter electrode terminal 31 and the electrode terminal 32 are formed using the same material, but may also be formed using different materials.

[0106] As described above, the counter electrode terminal 31 and the electrode terminal 32 not only function as the positive and negative electrode lead electrodes of the battery 1, respectively, but also function to connect multiple battery cells 100 in parallel. As shown in Fig. 1, the counter electrode terminal 31 and the electrode terminal 32 are formed so as to closely cover the side surfaces 11 and 12 of the power generating element 10, respectively, and therefore their volumes can be reduced. In other words, the volume of the terminal electrodes is smaller than that of conventionally used tab electrodes for current collection, and therefore the energy density per volume of the battery 1 can be improved.

[0107] [4.Outer current collector] Next, the outer counter electrode current collector 41 and the outer electrode current collector 42 will be described.

[0108] The outer counter electrode current collector 41 is disposed on the main surface 15 of the power generating element 10. As shown in Fig. 1 , the outer counter electrode current collector 41 has a flat plate portion 41a disposed above the main surface 15 and an extension portion 41b extending outward from the main surface 15. Note that "outward" refers to a direction away from the center of the power generating element 10 in a plan view.

[0109] The flat plate portion 41a is a portion that overlaps with the main surface 15 in a plan view of the main surface 15. The extension portion 41b is an example of a first extension portion, and is a portion that does not overlap with the main surface 15 in a plan view. The extension portion 41b is configured integrally with the flat plate portion 41a.

[0110] The extension portion 41b is bent relative to the flat plate portion 41a and is in contact with the counter electrode terminal 31. This electrically connects the counter electrode terminal 31 and the outer counter electrode current collector 41. In other words, the outer counter electrode current collector 41 is electrically connected to the counter electrode layer 120 of each of the plurality of battery cells 100 via the counter electrode terminal 31.

[0111] In this embodiment, the main surface 15 of the power generating element 10 is the main surface of the electrode current collector 111. Therefore, an insulating layer 50 is provided between the flat plate portion 41a of the outer counter electrode current collector 41 and the main surface 15. This makes it possible to suppress the occurrence of a short circuit between the outer counter electrode current collector 41 and the electrode layer 110.

[0112] 2, the flat plate portion 41a has a circular shape in a plan view and covers substantially the entire power generating element 10. The extension portion 41b is a tongue-shaped portion that protrudes from part of the outer periphery of the flat plate portion 41a, and is bent toward the counter electrode terminal 31 to come into contact with the counter electrode terminal 31.

[0113] The outer electrode current collector 42 has a configuration similar to that of the outer counter electrode current collector 41. Specifically, the outer electrode current collector 42 is disposed on the main surface 16 of the power generating element 10. As shown in FIG. 1 , the outer electrode current collector 42 has a flat portion 42a disposed below the main surface 16 and an extension portion 42b extending outward from the main surface 16.

[0114] The flat plate portion 42a is a portion that overlaps with the main surface 16 in a plan view of the main surface 16. The extension portion 42b is an example of a second extension portion, and is a portion that does not overlap with the main surface 16 in a plan view. The extension portion 42b is configured integrally with the flat plate portion 42a.

[0115] The extension portion 42b is bent relative to the flat plate portion 42a and is in contact with the electrode terminal 32. This electrically connects the electrode terminal 32 and the outer electrode current collector 42. In other words, the outer electrode current collector 42 is electrically connected to the electrode layer 110 of each of the multiple battery cells 100 via the electrode terminal 32.

[0116] In this embodiment, the main surface 16 of the power generating element 10 is the main surface of the electrode current collector 111. Therefore, the flat plate portion 42a of the outer electrode current collector 42 and the main surface 16 are in direct contact with each other. This increases the contact area, which reduces the connection resistance and improves the large current characteristics of the battery 1.

[0117] The flat plate portion 42a has a circular shape in a plan view and covers substantially the entire power generating element 10. The extension portion 42b is a tongue-shaped portion that protrudes from part of the outer periphery of the flat plate portion 42a and is bent toward the electrode terminal 32 to contact the electrode terminal 32. As shown in FIG. 2, the extension portion 42b is arranged in a plan view such that the center of the power generating element 10 is located on the line connecting the extension portion 41b and the extension portion 42b. This allows the extension portion 41b and the extension portion 42b to be spaced apart, thereby preventing the occurrence of a short circuit.

[0118] The outer counter electrode current collector 41 and the outer electrode current collector 42 are each a plate-shaped or foil-shaped metal member. Examples of metals contained in the metal members include Al, Fe, SUS, Ni, and Cu. The outer counter electrode current collector 41 and the outer electrode current collector 42 may be formed using the same material or different materials.

[0119] [5. Insulation layer] Next, the insulating layer 50 will be described.

[0120] The insulating layer 50 is located between the outer counter electrode current collector 41 and the main surface 15 of the power generating element 10. The insulating layer 50 is provided to ensure electrical insulation between the outer counter electrode current collector 41 and the electrode current collector 111 that forms the main surface 15 of the power generating element 10. For example, the insulating layer 50 covers the entire main surface 15.

[0121] The insulating layer 50 is a known insulating material such as a resin film. For example, the insulating layer 50 is a PET (polyethylene terephthalate) film, a PEN (polyethylene naphthalate) film, a polyimide film, or the like. The insulating layer 50 may contain a metal oxide. An adhesive layer may be provided on the surface of the insulating layer 50 to improve adhesion to the power generating element 10 or the outer counter electrode current collector 41. The adhesive layer is formed using, for example, an acrylic resin.

[0122] [6. Application Examples] Next, an application example of the battery 1 according to this embodiment will be described. The battery 1 is applied to, for example, a coin-type battery or a laminated battery.

[0123] [6-1. Coin cell battery] 7 is a cross-sectional view of a coin-type battery 201 including the battery 1 according to the present embodiment. The coin-type battery 201 is also called a button battery. As shown in FIG. 7, the coin-type battery 201 includes the battery 1, a sealing plate 211, an outer can 212, and a gasket 220.

[0124] The battery 1 is housed inside an outer can 212 and is covered with a sealing plate 211. The sealing plate 211 and the outer can 212 are each made of a conductive material such as metal. The sealing plate 211 is in contact with the outer counter electrode current collector 41 of the battery 1. The outer can 212 is in contact with the outer electrode current collector 42 of the battery 1. In other words, the sealing plate 211 and the outer can 212 function as the positive electrode and negative electrode of the battery 1, respectively. The gasket 220 is a member that insulates electrical contact between the outer can 212 and the sealing plate 211 and seals the battery 1 within the outer can 212.

[0125] As described above, according to this embodiment, a coin-type battery 201 is realized that includes a battery 1 that includes a plurality of battery cells 100. High capacity and long-term reliability are achieved while reducing the risk of short-circuiting of the coin-type battery 201.

[0126] [6-2. Laminated battery] 8 is a cross-sectional view of a laminated battery 301 including the battery 1 according to the present embodiment. As shown in FIG. 8, the laminated battery 301 includes the battery 1, a counter electrode external terminal 311, an electrode external terminal 312, and an exterior body 320.

[0127] A counter electrode external terminal 311 and an electrode external terminal 312 are connected to the battery 1. The battery 1 is sealed in an exterior body 320.

[0128] The counter electrode external terminal 311 and the electrode external terminal 312 are respectively lead-out electrodes for the positive and negative electrodes of the battery 1. A portion of each of the counter electrode external terminal 311 and the electrode external terminal 312 is drawn out to the outside of the exterior body 320.

[0129] The counter electrode external terminal 311 is in contact with the outer counter electrode current collector 41. As a result, the counter electrode external terminal 311 is electrically connected to the counter electrode layers 120 of the multiple battery cells 100 of the power generating element 10 via the outer counter electrode current collector 41 and the counter electrode terminal 31.

[0130] The electrode external terminal 312 is in contact with the outer electrode current collector 42. As a result, the electrode external terminal 312 is electrically connected to the electrode layers 110 of the multiple battery cells 100 of the power generating element 10 via the outer electrode current collector 42 and the electrode terminal 32.

[0131] The counter electrode external terminal 311 and the electrode external terminal 312 are each a plate-shaped or foil-shaped metal member. Examples of metals contained in the metal members include Al, Fe, SUS, Ni, and Cu. The counter electrode external terminal 311 and the electrode external terminal 312 may be made of the same material or different materials.

[0132] The exterior body 320 includes two laminate films 321 and 322. The two laminate films 321 and 322 sandwich and seal the battery 1 between them. Known laminate film materials can be used for the two laminate films 321 and 322. The exterior body 320 may also be formed by folding a single laminate film.

[0133] As described above, according to this embodiment, a laminated battery 301 is realized that includes a battery 1 that includes a plurality of battery cells 100. High capacity and long-term reliability are achieved while reducing the risk of short circuiting in the laminated battery 301.

[0134] Furthermore, the exterior body 320 may be a metal can or a box made of a resin material. In this case, the counter electrode external terminal 311 and the electrode external terminal 312 may each be made of a rod-shaped metal material.

[0135] In the laminated battery 301, the shape of the power generating element 10 in a plan view does not have to be circular. For example, the shape of the power generating element 10 in a plan view may be a polygon such as a rectangle, square, hexagon, or octagon, or may be an ellipse.

[0136] [7. Variations] Next, a modification of the embodiment will be described.

[0137] In the embodiment, an example was shown in which all of the multiple battery cells 100 were electrically connected in parallel, but in this modified example, some of the multiple battery cells 100 are electrically connected in series.

[0138] [7-1. Variation 1] First, the battery according to the first modification will be described.

[0139] FIG. 9 is a cross-sectional view showing the cross-sectional configuration of a battery 401 according to Modification 1. The battery 401 shown in FIG. 9 includes a power generating element 410 including six battery cells 100 connected in a 3-series, 2-parallel configuration. Here, "A series, B parallel" means that B stacks, each consisting of A series-connected battery cells, are connected in parallel. That is, in the "3 series, 2 parallel" power generating element 410, three battery cells 100 are electrically connected in series to form two series stacks 411 and 412. The two series stacks 411 and 412 are connected in parallel to each other. The power generating element 10 shown in FIG. 1 can be considered a "1 series, 6 parallel" power generating element.

[0140] The three battery cells 100 included in the series stack 411 have the same arrangement order of the constituent layers. That is, in all three battery cells 100 included in the series stack 411, the layers are arranged in the following order from upward (positive direction of the z-axis): counter electrode current collector 121, counter electrode active material layer 122, solid electrolyte layer 130, electrode active material layer 112, and electrode current collector 111. The electrode current collector 111 and counter electrode current collector 121 of two adjacent battery cells 100 are in direct contact with each other.

[0141] The three battery cells 100 included in the series stack 412 have the same arrangement order of the layers constituting each. This arrangement order is reverse to the arrangement order of the layers in the battery cells 100 included in the series stack 411. That is, in each of the three battery cells 100 included in the series stack 412, the layers are arranged in the following order from upward (positive direction of the z-axis): electrode current collector 111, electrode active material layer 112, solid electrolyte layer 130, counter electrode active material layer 122, and counter electrode current collector 121. The electrode current collector 111 and counter electrode current collector 121 of two adjacent battery cells 100 are in direct contact with each other. Note that in the series stacks 411 and 412, the electrode current collector 111 and counter electrode current collector 121 that are in contact with each other may be a single current collector.

[0142] Counter electrode current collector 121 in the bottom layer of series stack 411 and counter electrode current collector 121 in the top layer of series stack 412 are shared by each other, thereby electrically connecting the counter electrodes of the two series stacks 411 and 412.

[0143] In this modification, the battery 401 includes an electrode insulating layer 421 , a counter electrode insulating layer 422 , a counter electrode terminal 431 , and an electrode terminal 432 .

[0144] The electrode insulating layer 421 covers the electrode layer 110 on the side surface 11. Specifically, the electrode insulating layer 421 covers the central counter electrode current collector 121 shared by the two series laminates 411 and 412, and the other portions except for portions of the counter electrode active material layer 122 located on both sides of the central counter electrode current collector 121. Specifically, the electrode insulating layer 421 continuously covers from the uppermost layer of the series laminate 411 to a portion of the counter electrode active material layer 122 on the upper surface side of the central counter electrode current collector 121. Furthermore, the electrode insulating layer 421 continuously covers from the lowermost layer of the series laminate 412 to a portion of the counter electrode active material layer 122 on the lower surface side of the central counter electrode current collector 121.

[0145] In this modification, the counter electrode terminal 431 covers the electrode insulating layer 421 and a portion of the side surface 11 that is not covered by the electrode insulating layer 421. Specifically, the counter electrode terminal 431 contacts and is electrically connected to the central counter electrode current collector 121. This makes it possible to ensure electrical connection to the counter electrode current collector 121 while preventing a short circuit between the counter electrode terminal 431 and the electrode layer 110.

[0146] The counter electrode insulating layer 422 covers the counter electrode layer 120 on the side surface 12. Specifically, the counter electrode insulating layer 422 covers at least a portion of the electrode layer 110 located in the uppermost layer of the series laminate 411 and a portion of the electrode layer 110 located in the lowermost layer of the series laminate 412, excluding at least a portion of the electrode layer 110. Specifically, the counter electrode insulating layer 422 continuously covers from a portion of the electrode active material layer 112 of the electrode layer 110 located in the uppermost layer of the series laminate 411 to a portion of the electrode active material layer 112 of the electrode layer 110 located in the lowermost layer of the series laminate 412. The counter electrode insulating layer 422 does not cover the uppermost or lowermost electrode current collectors 111.

[0147] In this modification, the electrode terminal 432 covers the counter electrode insulating layer 422 and a portion of the side surface 12 that is not covered by the counter electrode insulating layer 422. Specifically, the electrode terminal 432 contacts and is electrically connected to each of the uppermost and lowermost electrode current collectors 111. This makes it possible to ensure electrical connection to the electrode current collectors 111 while preventing a short circuit between the electrode terminal 432 and the counter electrode layer 120.

[0148] As described above, even in the battery 401 including the battery cells 100 connected in series, it is possible to take out electrodes and make electrical connections using the side surfaces of the power generating element 410. As with the battery 1 according to the embodiment, it is possible to increase the adhesion strength of the insulating layer, and therefore the reliability of the battery 401.

[0149] [7-2. Variation 2] First, the battery according to the second modification will be described.

[0150] Fig. 10 is a cross-sectional view showing the cross-sectional configuration of a battery 501 according to Modification 2. The battery 501 shown in Fig. 10 includes a power generating element 510 including six battery cells 100 connected in a two-parallel, three-series configuration. Here, "A parallel, B series" means that B stacks, each made up of A parallel-connected battery cells, are connected in series. That is, in the "two parallel, three series" power generating element 510, two battery cells 100 are electrically connected in parallel to form three parallel stacks 511, 512, and 513. The three parallel stacks 511, 512, and 513 are connected in series to each other.

[0151] The two battery cells 100 included in the parallel stack 511 have their constituent layers arranged in reverse order. The two battery cells 100 share a counter electrode current collector 121 in the center in the stacking direction. The parallel stacks 512 and 513 have the same configuration as the parallel stack 511.

[0152] In this modification, the battery 501 includes an electrode insulating layer 521, a counter electrode insulating layer 522, counter electrode terminals 531a and 531b, electrode terminals 532a and 532b, and insulating layers 551 and 552.

[0153] The electrode insulating layer 521 covers the electrode layer 110 on the side surface 11. Like the electrode insulating layer 21 according to the embodiment, the electrode insulating layer 521 covers all of the electrode layers 110 and all of the solid electrolyte layers 130 on the side surface 11. The electrode insulating layer 521 exposes the counter electrode current collector 121 and a portion of the counter electrode active material layer 122 of each of the counter electrode layers 120. The electrode insulating layer 521 also covers portions of the insulating layers 551 and 552 on the side surface 11, but is not limited to this.

[0154] The counter electrode insulating layer 522 covers the counter electrode layer 120 on the side surface 12. Similar to the counter electrode insulating layer 522 according to the embodiment, the counter electrode insulating layer 522 covers all of the plurality of counter electrode layers 120 and all of the plurality of solid electrolyte layers 130. The counter electrode insulating layer 522 exposes the electrode current collector 111 and a portion of the electrode active material layer 112 of each of the plurality of electrode layers 110. Note that the counter electrode insulating layer 522 also covers portions of the insulating layers 551 and 552 on the side surface 12, but is not limited to this.

[0155] The counter electrode terminals 531a and 531b each cover the electrode insulating layer 521 and a portion of the side surface 11 that is not covered by the electrode insulating layer 521. Specifically, the counter electrode terminal 531a contacts and is electrically connected to the counter electrode current collector 121 of the parallel stack 511. The counter electrode terminal 531b contacts and is electrically connected to the counter electrode current collectors 121 of the parallel stacks 512 and 513. The counter electrode terminals 531a and 531b do not contact and are electrically insulated from each other. The outer counter electrode current collector 41 is connected to the counter electrode terminal 531a but not to the counter electrode terminal 531b. This allows the parallel stacks to be connected in series while preventing short-circuiting between the counter electrode terminals 531a and 531b and the electrode layer 110.

[0156] The electrode terminals 532a and 532b each cover the counter electrode insulating layer 522 and a portion of the side surface 12 that is not covered by the counter electrode insulating layer 522. Specifically, the electrode terminal 532a contacts and is electrically connected to the electrode current collectors 111 of the parallel stack bodies 511 and 512. The electrode terminal 532b contacts and is electrically connected to the electrode current collector 111 of the parallel stack body 513. The electrode terminals 532a and 532b do not contact and are electrically insulated from each other. The outer electrode current collector 42 is connected to the electrode terminal 532b but not to the electrode terminal 532a. This allows the parallel stack bodies to be connected in series while preventing short-circuiting between the electrode terminals 532a and 532b and the counter electrode layer 120.

[0157] The insulating layers 551 and 552 are each disposed between two adjacent parallel laminates. The insulating layers 551 and 552 are provided so that the parallel laminates do not come into contact with each other, so that electrical connection between the parallel laminates is made via the electrode terminal and the counter electrode terminal. The insulating layers 551 and 552 are formed, for example, using the same material as the insulating layer 50. Alternatively, the insulating layers 551 and 552 may be formed using an adhesive resin material such as an acrylic resin.

[0158] As described above, even in the battery 501 including the battery cells 100 connected in series, it is possible to take out electrodes and make electrical connections using the side surfaces of the power generating element 510. As with the battery 1 according to the embodiment, it is possible to increase the adhesion strength of the insulating layer, and thus improve the reliability of the battery 501.

[0159] [8. Manufacturing method] Next, a method for manufacturing a battery according to the embodiment and the modified example will be described with reference to Figures 11A to 11H, each of which is a cross-sectional view showing one step in the method for manufacturing a battery according to the embodiment or the modified example.

[0160] First, a paste-like paint is prepared by kneading a counter electrode material with a solvent. This paint is applied to both sides of a counter electrode current collector 121. The counter electrode material is a material that constitutes a counter electrode active material layer 122. As a result, as shown in FIG. 11A, two counter electrode layers 120 that share the counter electrode current collector 121 are formed. Note that in the case of a configuration in which the electrode current collector 111 is shared, this can be formed by a similar method using the electrode current collector 111 and the electrode material. Here, the electrode material is a material that constitutes the electrode active material layer 112.

[0161] Next, a solid electrolyte material is applied to the main surface of the counter electrode active material layer 122 so as to cover the applied paint, and is then dried. The solid electrolyte material is a material that constitutes the solid electrolyte layer 130. As a result, the solid electrolyte layer 130 is formed as shown in FIG. 11B.

[0162] Next, a paste-like paint is prepared by kneading the electrode material with a solvent. This paint is applied to the main surface of the solid electrolyte layer 130. As a result, the electrode active material layer 112 is formed, as shown in FIG. 11C. Note that the counter electrode material, electrode material, and solid electrolyte material may each be prepared using a material that does not contain a solvent.

[0163] Examples of coating methods used to form the electrode active material layer 112, the counter electrode active material layer 122, and the solid electrolyte layer 130 include, but are not limited to, screen printing, die coating, spraying, and gravure printing.

[0164] Next, the electrode current collector 111 is laminated onto one of the electrode active material layers 112. In this way, a laminate unit 610 is obtained as shown in Fig. 11D.

[0165] Next, three laminate units 610 are laminated so that the electrode active material layer 112 contacts the electrode current collector 111. Furthermore, the electrode current collector 111 is laminated so that it contacts the electrode active material layer 112. As a result, an intermediate laminate 620 is obtained, as shown in Fig. 11E.

[0166] Next, the edges of the intermediate laminate 620 are cut to the desired battery size. This results in a power generating element 10, which is a laminate of multiple battery cells 100, as shown in FIG. 11F. By performing the edge cutting process, the electrode active material layer 112, counter electrode active material layer 122, solid electrolyte layer 130, electrode current collector 111, and counter electrode current collector 121 can have the same area in a plan view without any protrusions. This reduces the risk of short circuits, improves reliability, and maximizes battery capacity. The edge cutting process is performed using, for example, a blade, laser, or jet.

[0167] Next, as shown in FIG. 11G, an electrode insulating layer 21 and a counter electrode insulating layer 22 are formed on the side surfaces 11 and 12 of the power generating element 10. The insulating layers are formed, for example, by applying an insulating material and curing it. Specific examples of the formation method include, but are not limited to, screen printing, gravure printing, spraying, and dispenser methods.

[0168] At this time, it is important that the coated end of the electrode insulating layer 21 is located on the end face of the counter electrode active material layer 122. The end face of the counter electrode active material layer 122, which is made of a powder material, has very fine irregularities. This improves the adhesive strength of the electrode insulating layer 21 and improves the insulation reliability.

[0169] Similarly, it is important that the coated end of counter electrode insulating layer 22 is located on the end face of electrode active material layer 112. The end face of electrode active material layer 112, which is made of a powder material, has very fine irregularities. This improves the adhesion strength of counter electrode insulating layer 22 and improves insulation reliability.

[0170] Next, as shown in Fig. 11H, a counter electrode terminal 31 and an electrode terminal 32 are formed on the side surface of the power generating element 10 so as to cover the electrode insulating layer 21 or the counter electrode insulating layer 22, respectively. The terminals are formed, for example, by applying a conductive material and then curing it. Specific examples of the formation method include, but are not limited to, screen printing, gravure printing, spraying, and dispenser methods.

[0171] At this time, it is important that the coated end of the contact surface of the electrode terminal 32 with the power generating element 10 is located at the end face of the electrode active material layer 112. The end face of the electrode active material layer 112, which is made of a powder material, has very fine irregularities. This improves the adhesive strength of the electrode terminal 32 and improves the long-term reliability of its characteristics.

[0172] Similarly, it is important that the coated end of the surface of the counter electrode terminal 31 that comes into contact with the power generating element 10 is located at the end face of the counter electrode active material layer 122. The end face of the counter electrode active material layer 122, which is made of a powder material, has very fine irregularities. This improves the adhesion strength of the counter electrode terminal 31 and improves the long-term reliability of its characteristics.

[0173] Next, an insulating layer 50, an outer counter electrode current collector 41, and an outer electrode current collector 42 are laminated together to obtain the battery 1 shown in FIG.

[0174] By the above manufacturing method, for example, the above-mentioned battery 1 can be manufactured.

[0175] The manufacturing method is not limited to the above example. Coating may be performed on only one side of the current collector. Furthermore, by appropriately adjusting the stacking order of the battery cells 100, it is possible to manufacture the battery 401 or 501 shown in FIG. 9 or FIG. 10.

[0176] (Other embodiments) While the batteries according to one or more aspects 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 present embodiments and configurations constructed by combining components of different embodiments are also included within the scope of the present disclosure.

[0177] For example, there is no particular limitation on the number of battery cells 100 included in the power generating element 10. Furthermore, as long as at least two battery cells 100 are connected in parallel, there is no particular limitation on the number of series and parallel connections of the battery cells 100.

[0178] In the above embodiment, an example has been described in which two adjacent electrode cells share a current collector, but the current collector does not have to be shared. Specifically, a plurality of battery cells 100A shown in FIG. 3A may be stacked adjacent to each other. In this case, two current collectors of the same polarity are stacked. In this case, the two current collectors may be stacked in direct contact with each other, or may be stacked via a conductive material or an adhesive material.

[0179] Furthermore, for example, external electrodes may be formed on the outermost surfaces of the electrode terminal and the counter electrode terminal by plating, printing, soldering, etc. Providing external electrodes in a battery can further improve the mountability of the battery.

[0180] In the above embodiment, each battery is provided with both the counter electrode terminal 31 and the electrode terminal 32, but it may be provided with only one of them. In other words, the electrode lead-out of one of the positive and negative electrodes of the battery may be provided by a tab electrode.

[0181] Furthermore, for example, extension portions 41b and 42b are provided at positions 180 degrees apart from each other with respect to the center of circular main surface 15 in a plan view, but are not limited to this. The angle formed between extension portions 41b and 42b and the center of main surface 15 may be 90 degrees or less. Furthermore, at least one of extension portions 41b and 42b may be provided in plurality.

[0182] Furthermore, various modifications, substitutions, additions, omissions, etc. can be made to each of the above-described embodiments within the scope of the claims or their equivalents. [Industrial Applicability]

[0183] The present disclosure can be used, for example, as batteries for electronic devices, electrical appliances, electric vehicles, and the like. [Explanation of symbols]

[0184] 1, 401, 501 batteries 10, 410, 510 power generation elements 11, 12 Side 15, 16 main surfaces 21, 421, 521 Electrode insulating layer 22, 422, 522 Counter electrode insulating layer 31, 431, 531a, 531b Counter electrode terminal 32, 432, 532a, 532b electrode terminal 41 Outer counter electrode current collector 41a, 42a flat plate part 41b, 42b extension part 42 Outer electrode current collector 50, 551, 552 Insulation layer 100, 100A, 100B, 100C battery cells 110, 110C electrode layer 111 Electrode current collector 112 Electrode active material layer 120, 120B counter electrode layer 121 Counter electrode current collector 122 Counter electrode active material layer 130 Solid electrolyte layer 201 Coin cell battery 211 Sealing plate 212 outer can 220 Gasket 301 Laminated battery 311 Counter electrode external terminal 312 Electrode external terminal 320 Exterior body 321, 322 Laminate film 411, 412 Series stack 511, 512, 513 parallel stacks 610 Stacking Unit 620 Intermediate laminate

Claims

1. a power generating element including a plurality of battery cells each including an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer, the plurality of battery cells being stacked; a first insulating member covering the electrode layer on a first side surface of the power generating element; a first terminal electrode covering the first side surface and the first insulating member and electrically connected to the counter electrode layer; Equipped with At least some of the plurality of battery cells are connected in parallel, the first insulating member covers from the electrode layer to a part of the counter electrode layer along the stacking direction of the power generating element on the first side surface; battery.

2. The counter electrode layer is a counter electrode current collector; a counter electrode active material layer located between the counter electrode current collector and the solid electrolyte layer, the first insulating member covers from the electrode layer to at least a portion of the counter electrode active material layer, and does not cover the counter electrode current collector; The battery of claim 1 .

3. The thickness of the counter electrode current collector is 20 μm or less. The battery of claim 2.

4. further comprising an outer counter electrode current collector disposed on the first main surface of the power generating element; the outer counter electrode current collector has a first extension portion extending outward from the first main surface, the first extension portion is connected to the first terminal electrode; The battery according to any one of claims 1 to 3.

5. further comprising an insulating layer located between the outer counter electrode current collector and the first main surface, The battery of claim 4.

6. The electrode layer, the counter electrode layer, and the solid electrolyte layer have the same outline in a plan view. The battery of any one of claims 1 to 5.

7. a second insulating member covering the counter electrode layer on a second side surface of the power generating element; a second terminal electrode covering the second side surface and the second insulating member and electrically connected to the electrode layer; Furthermore, the second insulating member covers, on the second side surface, from the counter electrode layer to a part of the electrode layer along the stacking direction of the power generating element; The battery of any one of claims 1 to 6.

8. The electrode layer is an electrode current collector; an electrode active material layer located between the electrode current collector and the solid electrolyte layer, the second insulating member covers from the counter electrode layer to at least a portion of the electrode active material layer, and does not cover the electrode current collector; The battery of claim 7.

9. The thickness of the electrode current collector is 20 μm or less. The battery of claim 8.

10. further comprising an outer electrode current collector disposed on the second main surface of the power generating element, the outer electrode current collector has a second extension portion extending outward from the second main surface, the second extension portion is connected to the second terminal electrode; The battery of any one of claims 7 to 9.

11. The shape of the power generating element is cylindrical, the first side surface and the second side surface are different portions of a cylindrical side surface, The battery of any one of claims 7 to 10.

12. All of the plurality of battery cells are connected in parallel.

12. The battery of claim 1.

13. Some of the plurality of battery cells are connected in series.

12. The battery of claim 1.

14. The solid electrolyte layer contains a solid electrolyte having lithium ion conductivity.

14. The battery of any one of claims 1 to 13.

15. The battery constitutes a coin battery.

15. The battery of any one of claims 1 to 14.

16. The battery is sealed with a laminate film.

15. The battery of any one of claims 1 to 14.

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