Battery and method for manufacturing a battery

Abstract

This battery (1) is provided with: an electric power generating element (10) that comprises a plurality of battery cells (100), each of which comprises an electrode layer (110), a counter electrode layer (120) and a solid electrolyte layer (130) that is positioned between the electrode layer (110) and the counter electrode layer (120), wherein the plurality of battery cells (100) are stacked, while being electrically connected in parallel with each other; an electrode insulating layer (21) which covers the electrode layer (110) on a lateral surface (11) of the electric power generating element (10); and a counter electrode terminal (31) which covers the lateral surface (11) and the electrode insulating layer (21), while being electrically connected to the counter electrode layer (120). The electric power generating element (10) comprises: a parallel unit (10A) which comprises a plurality of first battery cells among the plurality of battery cells (100), while having the counter electrode layer (120) on both ends in the stacking direction; and a parallel unit (10B) which is superposed on the parallel unit (10A) and comprises a plurality of second battery cells among the plurality of battery cells (100), while having the electrode layer (110) on both ends in the stacking direction.

Description

Technical Field

[0001] The present disclosure relates to a battery and a method for manufacturing the battery.

Background Art

[0002] Conventionally, a battery in which a plurality of serially connected battery cells are connected in parallel is known (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] For conventional batteries, further improvement in battery characteristics is required.

[0005] Therefore, the present disclosure provides a high-performance battery and a method for manufacturing the same.

Means for Solving the Problems

[0006] A battery according to one aspect of the present disclosure comprises a power generation element having a plurality of battery cells, each containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer, wherein the plurality of battery cells are electrically connected in parallel and stacked; and a first insulating member covering the electrode layer on a first side surface of the power generation element, and a first terminal electrode covering the first side surface and the first insulating member and electrically connected to the counter electrode layer. The power generation element comprises a first parallel unit including a plurality of first battery cells from the plurality of battery cells, with the counter electrode layer located at both ends in the stacking direction; and a second parallel unit including a plurality of second battery cells from the plurality of battery cells, with the electrode layer located at both ends in the stacking direction, and stacked on the first parallel unit.

[0007] A method for manufacturing a battery according to one aspect of the present disclosure includes: a first step of preparing a plurality of battery cells, each containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer; a second step of forming a laminate by sequentially stacking the plurality of battery cells such that the order of the electrode layer, the counter electrode layer, and the solid electrolyte layer alternates; a third step of covering the electrode layer with an insulating member on one side of the laminate; and a fourth step of covering the one side and the insulating member with terminal electrodes electrically connected to the counter electrode layer. In the second step, a first parallel unit is formed, which includes a plurality of first battery cells from the plurality of battery cells, with the counter electrode layers located at both ends in the stacking direction; and a second parallel unit is formed, which includes a plurality of second battery cells from the plurality of battery cells, with the electrode layers located at both ends in the stacking direction, and is stacked on the first parallel unit. [Effects of the Invention]

[0008] This disclosure provides a high-performance battery and a method for manufacturing the same. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view showing the cross-sectional configuration of a battery according to Embodiment 1. [Figure 2]Figure 2 is a top view of the power generation element of the battery according to Embodiment 1. [Figure 3A] Figure 3A is a cross-sectional view of an example of a battery cell included in the power generation element according to Embodiment 1. [Figure 3B] Figure 3B is a cross-sectional view of another example of a battery cell included in the power generation element according to Embodiment 1. [Figure 3C] Figure 3C is a cross-sectional view of another example of a battery cell included in the power generation element according to Embodiment 1. [Figure 4] Figure 4 is a cross-sectional view of the power generation element and insulating layer according to Embodiment 1. [Figure 5] Figure 5 is a top view of the battery according to Embodiment 1. [Figure 6] Figure 6 is a plan view of the bottom surface of the battery according to Embodiment 1, seen through from above. [Figure 7] Figure 7 is a cross-sectional view showing the cross-sectional configuration of the battery along lines VIIa-VIIa and VIIb-VIIb in Figures 2, 5, or 6. [Figure 8] Figure 8 is a cross-sectional view showing the cross-sectional configuration of the battery along line VIII-VIII in Figure 2, Figure 5, or Figure 6. [Figure 9] Figure 9 is a side view showing the positional relationship between the first side surface of the power generation element according to Embodiment 1, the electrode insulating layer provided on the first side surface, and the counter electrode terminal. [Figure 10] Figure 10 is a side view showing the positional relationship between the second side surface of the power generation element according to Embodiment 1 and the counter electrode insulating layer and electrode terminals provided on the second side surface. [Figure 11] Figure 11 is a top view of the battery according to Embodiment 2. [Figure 12] Figure 12 is a plan view of the bottom surface of the battery according to Embodiment 2, seen through from above. [Figure 13] Figure 13 is a cross-sectional view showing the cross-sectional configuration of the battery according to Embodiment 2. [Figure 14] Figure 14 is a cross-sectional view showing the cross-sectional configuration of the battery according to Embodiment 3. [Figure 15]FIG. 15 is a cross-sectional view showing a cross-sectional configuration of a battery according to a modified example. [Figure 16] FIG. 16 is a flowchart showing an example of a method for manufacturing a battery according to an embodiment or a modified example.

Embodiments for Carrying Out the Invention

[0010] (Summary of the Present Disclosure) A battery according to one aspect of the present disclosure has 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, and a power generation element in which the plurality of battery cells are electrically connected in parallel and stacked, a first insulating member that covers the electrode layer on a first side surface of the power generation element, and a first terminal electrode that covers the first side surface and the first insulating member and is electrically connected to the counter electrode layer. The power generation element includes a first parallel unit including a plurality of first battery cells among the plurality of battery cells, with the counter electrode layer located at both ends in the stacking direction, and a second parallel unit including a plurality of second battery cells among the plurality of battery cells, with the electrode layer located at both ends in the stacking direction and stacked on the first parallel unit.

[0011] Thereby, a high-performance battery can be realized. For example, since the first insulating member covers the electrode layer on the first side surface, the occurrence of a short circuit between the counter electrode layer and the electrode layer via the first terminal electrode can be suppressed. Also, for example, by electrically connecting all the battery cells in parallel, it is possible to suppress a specific battery cell from being overcharged or overdischarged due to variations in the capacity of each battery cell. Thus, since the reliability of the battery can be enhanced, a high-performance battery can be realized.

[0012] In addition, since the same layer is located at both ends in the stacking direction in each of the first parallel unit and the second parallel unit, warping is unlikely to occur. Therefore, a large number of parallel units can be stacked stably, and the capacity energy density can be increased.

[0013] Furthermore, for example, the first parallel unit may be located at one end in the stacking direction of the power generation elements, and the second parallel unit may be located at the other end in the stacking direction of the power generation elements.

[0014] As a result, the top and bottom layers of the power generation element have electrode layers of different polarities, allowing these layers to be used as electrode outlets for external use. For example, it becomes possible to connect large external terminals, increasing the contact area and reducing connection resistance. This improves the high-current characteristics of the battery.

[0015] Furthermore, for example, the power generation element may include an insulating layer located between the first parallel unit and the second parallel unit.

[0016] This makes it possible to suppress short circuits between parallel units.

[0017] Furthermore, for example, when the first side surface is viewed from the front, the first terminal electrode does not cover at least one end of the counter electrode layer in a direction perpendicular to the lamination direction, and the first insulating member may further cover at least one end.

[0018] As a result, the first insulating member covers the electrically unstable end, which is prone to short circuits, thus suppressing the occurrence of short circuits.

[0019] Furthermore, for example, the first insulating member may cover at least a portion of the solid electrolyte layer on its first side surface.

[0020] This allows the first insulating member to be formed so as to cover a portion of the solid electrolyte layer, thereby preventing the electrode layer from being exposed even if there are variations in the size of the first insulating member. Furthermore, since the solid electrolyte layer is generally made of powdered material, its edge surface has very fine irregularities. This improves the adhesion strength of the first insulating member and enhances insulation reliability. In this way, the reliability of the battery can be further enhanced.

[0021] Furthermore, for example, the first insulating member may, on its first side surface, cover from the electrode layer to a portion of the counter electrode layer along the stacking direction of the power generation element.

[0022] This effectively prevents the electrode layer from being exposed without being covered by the first insulating material, by covering even a portion of the counter electrode layer. Furthermore, since the counter electrode active material layer is generally made of powdered material, its edge surface has very fine irregularities. Therefore, the adhesion strength of the first insulating material is further improved, enhancing insulation reliability. This, in turn, further increases the reliability of the battery.

[0023] Furthermore, for example, the first insulating member may cover the electrode layer of each of the plurality of battery cells on its first side surface, and the first terminal electrode may be electrically connected to the counter electrode layer of each of the plurality of battery cells.

[0024] This allows the first terminal electrode to be used for parallel connection of multiple battery cells. Since the first terminal electrode can be brought into close contact with the first side surface and the first insulating member, the volume of the part involved in the parallel connection can be reduced. As a result, the energy density of the battery can be increased.

[0025] Furthermore, for example, the first insulating member may have a striped shape in a plan view of the first side surface.

[0026] This allows the end face of the electrode layer exposed in a stripe pattern on the first side surface to be covered by a stripe-shaped first insulating member.

[0027] Furthermore, for example, a battery according to one aspect of the present disclosure may further include, on the second side surface of the power generation element, a second insulating member covering the counter electrode layer, and a second terminal electrode covering the second side surface and the second insulating member, and electrically connected to the electrode layer.

[0028] This makes it possible to realize a higher-performance battery. Specifically, since the second insulating material covers the counter electrode layer on the second side surface, it is possible to suppress the occurrence of short circuits between the electrode layer and the counter electrode layer via the second terminal electrode. In this way, the reliability of the battery can be improved, and a high-performance battery can be realized.

[0029] Furthermore, for example, the power generation element may be a rectangular parallelepiped, and the second side may be the side opposite to the first side. Note that "rectangular parallelepiped" refers to any shape that can be substantially considered a rectangular parallelepiped; for example, each face and edge may have irregularities or inclines. For example, there may be differences of a few percent in length, area, angle, etc.

[0030] This allows the electrode terminal and the counter terminal to be separated, further suppressing the occurrence of short circuits.

[0031] Furthermore, for example, the third side surface of the power generation element may further include a third insulating member covering the electrode layer, and a third terminal electrode covering the third side surface and the third insulating member, and electrically connected to the counter electrode layer.

[0032] This design allows for connection to the counter electrode layer on two sides, the first and third sides, thereby increasing the contact area between the counter electrode layer and the terminal electrodes and reducing connection resistance. This improves the high-current characteristics of the battery.

[0033] Furthermore, for example, the power generation element may be a rectangular parallelepiped, and the third side may be a side adjacent to the first side.

[0034] This allows for electrode extraction from two adjacent sides. Since the electrode layer, as well as the counter electrode layer, can have the same configuration, it becomes easier to balance the positive and negative polarities, thereby improving the reliability of the battery.

[0035] Furthermore, for example, the electrode layer or the counter electrode layer may have a current collector, and the thickness of the current collector may be 20 μm or less.

[0036] This makes it possible to improve energy density, increase power density, and reduce material costs.

[0037] Furthermore, for example, the first insulating member may contain resin.

[0038] This improves the shock resistance of the battery. It also reduces the stress on the battery caused by temperature changes or expansion and contraction during charging and discharging.

[0039] Furthermore, for example, a battery according to one aspect of the present disclosure may further include a sealing member that exposes at least a portion of the main surface of the power generation element and seals the power generation element.

[0040] This protects the power generation elements from the outside air and water, thereby further enhancing the reliability of the battery.

[0041] Furthermore, a method for manufacturing a battery according to one aspect of the present disclosure includes: a first step of preparing a plurality of battery cells, each containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer; a second step of forming a laminate by sequentially stacking the plurality of battery cells such that the order of the electrode layer, the counter electrode layer, and the solid electrolyte layer alternates; a third step of covering the electrode layer with an insulating member on one side of the laminate; and a fourth step of covering the one side and the insulating member with terminal electrodes electrically connected to the counter electrode layer. In the second step, a first parallel unit may be formed, which includes a plurality of first battery cells from the plurality of battery cells, with the counter electrode layers located at both ends in the stacking direction; and a second parallel unit may be formed, which includes a plurality of second battery cells from the plurality of battery cells, with the electrode layers located at both ends in the stacking direction, and is stacked on the first parallel unit.

[0042] This makes it possible to manufacture the high-performance batteries mentioned above.

[0043] The embodiments will be described in detail below with reference to the drawings.

[0044] 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.

[0045] 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.

[0046] Furthermore, in this specification, terms indicating relationships between elements such as parallel or orthogonal, terms indicating the shape of elements such as rectangles or cuboids, and numerical ranges do not represent only strict meanings, but also include substantially equivalent ranges, such as differences of a few percent.

[0047] Furthermore, in this specification and the drawings, the x, y, and z axes represent the three axes of a three-dimensional Cartesian coordinate system. The x and y axes correspond to the first side and the second side perpendicular to the first side of a rectangle, respectively, when the plan view shape of the power generation element of the battery is rectangular. The z axis corresponds to the stacking direction of the multiple battery cells included in the power generation element.

[0048] Furthermore, in this specification, the "stacking direction" coincides with the direction normal to the main surface of the current collector and the active material layer. Also, in this specification, "plan view" refers to the view from a direction perpendicular to the main surface of the power generation element, unless otherwise specified, such as when used alone. When it is written as "plan view of a certain surface," such as "plan view of the first side," it refers to the view of that "certain surface" from the front.

[0049] 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."

[0050] Furthermore, in this specification, ordinal numbers such as "first" and "second" do not mean the number or order of components unless otherwise specified, but are used to avoid confusion between similar components and to distinguish them.

[0051] (Embodiment 1) The configuration of the battery according to Embodiment 1 will be described below.

[0052] Figure 1 is a cross-sectional view showing the cross-sectional configuration of a battery 1 according to this embodiment. As shown in Figure 1, the battery 1 comprises a power generation element 10, an electrode insulating layer 21, a counter electrode insulating layer 22, a counter electrode terminal 31, an electrode terminal 32, and an insulating layer 40. The battery 1 is, for example, an all-solid-state battery.

[0053] [1. Power generation elements] First, the specific configuration of the power generation element 10 will be explained using Figures 1 and 2. Figure 2 is a top view of the power generation element 10 of the battery 1 according to this embodiment. Figure 1 shows a cross-section along line II in Figure 2.

[0054] The plan view shape of the power generation element 10 is rectangular, for example, as shown in Figure 2. In other words, the shape of the power generation element 10 is a flattened rectangular parallelepiped. Here, flattened means that the thickness (i.e., the length in the z-axis direction) is shorter than the length of each side of the main face (i.e., the respective lengths in the x-axis and y-axis directions) or the maximum width. The plan view shape of the power generation element 10 may also be a square, hexagon, or octagon, or it may be a circle or an ellipse, etc.

[0055] In addition, in cross-sectional views such as Figure 1, the thickness of each layer is exaggerated to make the layered structure of the power generation element 10 easier to understand. Furthermore, Figure 1 also includes a small perspective view of the approximate shape of the battery 1, schematically representing the location of the cross-section. Similarly, in other drawings described later, the perspective view of the power generation element and the location of the cross-section or side view shown in each drawing are sometimes schematically represented.

[0056] The power generation element 10 includes four side surfaces 11, 12, 13, and 14 and two main surfaces 15 and 16, as shown in Figures 1 and 2. In this embodiment, the side surfaces 11, 12, 13, and 14, as well as the main surfaces 15 and 16, are all flat surfaces.

[0057] Side 11 is an example of a first side. Side 12 is an example of a second side. Sides 11 and 12 are opposite each other and parallel to each other. Sides 11 and 12 are sides that include the short side of the main surface 15.

[0058] Side 13 is an example of a third side. Side 14 is an example of a fourth side. Sides 13 and 14 are opposite each other and parallel to each other. Sides 13 and 14 are sides that include the long side of the main surface 15.

[0059] The main surfaces 15 and 16 are opposite each other and parallel to each other. Main surface 15 is the uppermost surface of the power generation element 10. Main surface 16 is the lowermost surface of the power generation element 10.

[0060] As shown in Figure 1, the power generation element 10 has a plurality of battery cells 100. A battery cell 100 is the smallest battery 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 of the power generation element 10 are electrically connected in parallel. In the example shown in Figure 1, the power generation element 10 has eight battery cells 100, but it is not limited to this. For example, the number of battery cells 100 of the power generation element 10 may be an even number, such as two or four.

[0061] 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.

[0062] The electrode layer 110 is one of the positive and negative electrode layers of the battery cell 100. The counter electrode layer 120 is the other of the positive and negative electrode layers of the battery cell 100. In the following explanation, we will describe the case where the electrode layer 110 is the negative electrode layer and the counter electrode layer 120 is the positive electrode layer as an example.

[0063] The configurations of the multiple battery cells 100 are substantially identical to each other. 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 along the z-axis, with the order of the layers constituting the battery cell 100 alternating. In this embodiment, since the number of battery cells 100 is even, the bottom and top layers of the power generation element 10 become current collectors of the same polarity.

[0064] Multiple battery cells 100 are grouped together in predetermined numbers to form units. Specifically, an even number of battery cells 100 are connected in parallel to each other to form a single parallel unit. Layers of the same polarity are located at both ends of the stacking direction of the parallel unit.

[0065] In this embodiment, the power generation element 10 includes parallel units 10A and 10B. Parallel units 10A and 10B are stacked with an insulating layer 40 in between.

[0066] The parallel unit 10A is an example of a first parallel unit, with counter electrode layers 120 located at both ends in the stacking direction. Specifically, the uppermost and lowermost layers of the parallel unit 10A are counter electrode current collectors 121 of the counter electrode layer 120.

[0067] The parallel unit 10A is a stack consisting of four battery cells 100. The battery cells 100 included in the parallel unit 10A are an example of first battery cells. Since the number of battery cells 100 included in the parallel unit 10A is even, when the order of each layer constituting the battery cells 100 is alternately rearranged during stacking, counter electrode layers 120 can be easily placed at both the top and bottom ends.

[0068] The parallel unit 10A is located at one end of the stacking direction of the power generation element 10 (specifically, the negative end of the z-axis). Specifically, the parallel unit 10A is located at the bottom layer of the power generation element 10. The main surface 16, which is the bottom surface of the power generation element 10, is the main surface of the counter electrode current collector 121 located at the bottom layer within the parallel unit 10A.

[0069] The parallel unit 10B is an example of a second parallel unit, with electrode layers 110 located at both ends in the stacking direction. Specifically, the uppermost and lowermost layers of the parallel unit 10B are electrode current collectors 111 of the electrode layer 110.

[0070] The parallel unit 10B is a stack consisting of four battery cells 100. The battery cells 100 included in the parallel unit 10B are an example of a second battery cell. Since the number of battery cells 100 included in the parallel unit 10B is even, when the order of each layer constituting the battery cells 100 is alternately rearranged during stacking, electrode layers 110 can be easily placed at both the top and bottom ends.

[0071] The parallel unit 10B is located at the other end of the power generation element 10 in the stacking direction (specifically, the end on the positive side of the z-axis). Specifically, the parallel unit 10B is located at the top layer of the power generation element 10. The main surface 15, which is the top surface of the power generation element 10, is the main surface of the electrode current collector 111 located at the top layer within the parallel unit 10B.

[0072] Generally, because the positive electrode current collector and the negative electrode current collector are often made of different materials, the battery cell 100 is prone to warping due to differences in the strength of the current collectors. In contrast, the parallel unit 10A has counter electrode current collectors, i.e., current collectors of the same polarity, at both ends in the stacking direction. Therefore, the parallel unit 10A is less prone to warping. The same applies to the parallel unit 10B. As a result, a large number of parallel units 10A and 10B can be stacked stably, and the capacity energy density can be increased. Note that the number of battery cells 100 contained in each of the parallel units 10A and 10B may be different from each other.

[0073] In the following section, Figure 3A will be used to describe each layer of the battery cell 100. Figure 3A is a cross-sectional view of the battery cell 100 included in the power generation element 10 according to this embodiment.

[0074] The electrode current collector 111 and the counter electrode current collector 121 are each conductive foil-shaped, plate-shaped, or mesh-shaped members. The electrode current collector 111 and the counter electrode current collector 121 may each be, for example, conductive thin films. As materials for constituting the electrode current collector 111 and the counter electrode current collector 121, metals such as stainless steel (SUS), aluminum (Al), copper (Cu), and nickel (Ni) can be used. The electrode current collector 111 and the counter electrode current collector 121 may be formed using different materials.

[0075] The thickness of the electrode current collector 111 and the counter electrode current collector 121 is, for example, 5 μm to 100 μm, but is not limited to this. The thickness of the electrode current collector 111 and the counter electrode current collector 121 may be 20 μm or less. By reducing the thickness of the current collector to 20 μm or less, improvements in energy density, power density, and material costs can be achieved. In this embodiment, since a single battery cell 100 is connected in parallel and stacked, the thickness of the power generation element 10 can be kept small even if the number of parallel connections is increased, contributing to an improvement in 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 in suppressing the increase in the thickness of the power generation element 10.

[0076] The electrode active material layer 112 is in contact with the main surface of the electrode current collector 111. The electrode current collector 111 may also include a current collector layer containing a conductive material in the portion that is in contact with the electrode active material layer 112. The counter electrode current collector 121 is in contact with the counter electrode active material layer 122. The counter electrode current collector 121 may also include a current collector layer containing a conductive material in the portion that is in contact with the counter electrode active material layer 122.

[0077] The electrode active material layer 112 is located on the main surface of the electrode current collector 111, on the side facing the counter electrode layer 120. The electrode active material layer 112 includes, for example, a negative electrode active material as the electrode material. The electrode active material layer 112 is located opposite the counter electrode active material layer 122.

[0078] As the negative electrode active material contained in the electrode active material layer 112, for example, negative electrode active materials such as graphite and metallic lithium can be used. As the material for the negative electrode active material, various materials that can release and insert ions such as lithium (Li) or magnesium (Mg) can be used.

[0079] Furthermore, as the material containing the electrode active material layer 112, a solid electrolyte such as an inorganic solid electrolyte may be used. As an inorganic solid electrolyte, for example, a sulfide solid electrolyte or an oxide solid electrolyte may be used. As a sulfide solid electrolyte, for example, a mixture of lithium sulfide (Li2S) and phosphorus pentasulfide (P2S5) may be used. In addition, as the material containing the electrode active material layer 112, a conductive material such as acetylene black, or a binding binder such as polyvinylidene fluoride may be used.

[0080] The electrode active material layer 112 is produced by applying a paste-like coating, which is made by kneading the materials containing the electrode active material layer 112 together with a solvent, onto the main surface of the electrode current collector 111 and drying it. In order to increase the density of the electrode active material layer 112, the electrode layer 110 (also called an electrode plate), which includes 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 to 300 μm, but is not limited to this.

[0081] The counter electrode active material layer 122 is located on the main surface of the counter electrode current collector 121 on the electrode layer 110 side. 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 the material that constitutes the counter electrode of the negative electrode material. The counter electrode active material layer 122 contains, for example, a positive electrode active material.

[0082] As the positive electrode active material contained in the counter electrode active material layer 122, for example, positive electrode active materials such as 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), and lithium-nickel-manganese-cobalt oxide composite oxide (LNMCO) can be used. As the material for the positive electrode active material, various materials that can release and insert ions such as Li or Mg can be used.

[0083] Furthermore, as the material containing the counter electrode active material layer 122, a solid electrolyte such as an inorganic solid electrolyte may be used. As the inorganic solid electrolyte, sulfide solid electrolytes or oxide solid electrolytes may be used. As the sulfide solid electrolyte, for example, a mixture of Li2S and P2S5 may be used. The surface of the positive electrode active material may be coated with a solid electrolyte. Furthermore, as the material containing the counter electrode active material layer 122, a conductive material such as acetylene black, or a binding binder such as polyvinylidene fluoride may be used.

[0084] The counter electrode active material layer 122 is manufactured by applying a paste-like coating, in which the materials containing 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 it. In order to increase the density of the counter electrode active material layer 122, the counter electrode layer 120 (also called the counter electrode plate), which includes 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, 5 μm to 300 μm, but is not limited to this.

[0085] The solid electrolyte layer 130 is placed 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. As the electrolyte material, generally known electrolytes for batteries can be used. 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.

[0086] The solid electrolyte layer 130 contains a solid electrolyte. As the solid electrolyte, for example, an inorganic solid electrolyte may be used. As an inorganic solid electrolyte, sulfide solid electrolytes or oxide solid electrolytes may be used. As a sulfide solid electrolyte, for example, a mixture of Li2S and P2S5 may be used. In addition to the electrolyte material, the solid electrolyte layer 130 may also contain a binding binder, such as polyvinylidene fluoride.

[0087] 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 a parallel plate shape. This suppresses the occurrence of cracks 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.

[0088] Furthermore, in this embodiment, the end face of the counter electrode current collector 121 on the side surface 11 and the end face of the electrode layer 110 on the side surface 11 coincide when viewed from the z-axis direction. Specifically, the end face of the counter electrode current collector 121 on the side surface 11 and the end face of the electrode current collector 111 on the side surface 11 coincide when viewed from the z-axis direction. The same applies to the end faces of the respective side surfaces 12 of the counter electrode current collector 121 and the electrode current collector 111.

[0089] More specifically, in the battery cell 100, the 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 are all the same in shape and size, and their contours match. In other words, the shape of the battery cell 100 is a flat, rectangular parallelepiped.

[0090] As shown in Figure 1, in this embodiment, two adjacent battery cells 100 share a current collector. For example, the bottommost battery cell 100 and the battery cell 100 above it share an electrode current collector 111.

[0091] Specifically, as shown in Figure 1, in multiple battery cells 100, two adjacent electrode layers 110 share each other's electrode current collectors 111. Electrode active material layers 112 are provided on both sides of the main surface of the shared electrode current collector 111. Similarly, two adjacent counter electrode layers 120 share each other's counter electrode current collectors 121. Counter electrode active material layers 122 are provided on both sides of the main surface of the shared counter electrode current collector 121.

[0092] Such a battery 1 is formed by stacking not only the battery cell 100 shown in Figure 3A, but also battery cells 100B and 100C shown in Figures 3B and 3C. Here, the battery cell 100 shown in Figure 3A will be referred to as battery cell 100A.

[0093] The battery cell 100B shown in Figure 3B has the same configuration as the battery cell 100A shown in Figure 3A, but without the electrode current collector 111. In other words, the electrode layer 110B of the battery cell 100B consists only of the electrode active material layer 112.

[0094] The battery cell 100C shown in Figure 3C has the same configuration as the battery cell 100A shown in Figure 3A, but without the counter electrode current collector 121. In other words, the counter electrode layer 120C of the battery cell 100C consists only of the counter electrode active material layer 122.

[0095] Figure 4 is a cross-sectional view showing the power generation element 10 according to this embodiment. Figure 4 is a view showing only the power generation element 10 from Figure 1. As shown in Figure 4, a battery cell 100A is placed in the bottom layer, and battery cells 100B and 100C are stacked alternately upwards. At this time, the battery cells 100B are stacked in the opposite orientation to that shown in Figure 3B. This forms a parallel unit 10A.

[0096] The same applies to parallel unit 10B. In parallel unit 10B, battery cells 100C and 100B are stacked alternately, and then battery cell 100A is stacked on top. Note that the method of forming each parallel unit is not limited to this. For example, two units of battery cells 100 sharing a current collector may be formed by coating both sides of a single current collector, and the formed units may be stacked.

[0097] As described above, in the power generation element 10 according to this embodiment, all battery cells 100 are connected in parallel, and no battery cells are connected in series. Therefore, when charging and discharging the battery 1, it is less likely that unevenness in the charge and discharge state will occur due to variations in the capacity of the battery cells 100. As a result, the risk of some of the multiple battery cells 100 becoming overcharged or over-discharged can be greatly reduced, and the reliability of the battery 1 can be improved.

[0098] [2. Insulating layer] Next, the electrode insulating layer 21 and the counter electrode insulating layer 22 will be explained using Figures 5 to 10.

[0099] Figure 5 is a top view of the battery 1 according to this embodiment. Figure 6 is a plan view of the bottom surface of the battery 1 according to this embodiment, viewed from above.

[0100] Figure 7 is a cross-sectional view showing the cross-sectional configuration of battery 1 along the VIIa-VIIa and VIIb-VIIb lines in Figures 2, 5, or 6. The cross-section along the VIIa-VIIa line is the same as the cross-section along the VIIb-VIIb line. Figure 8 is a cross-sectional view showing the cross-sectional configuration of battery along the VIII-VIII line in Figures 2, 5, or 6.

[0101] Figure 9 is a side view showing the positional relationship between the side surface 11 of the power generation element 10 according to this embodiment, the electrode insulating layer 21 provided on the side surface 11, and the counter electrode terminal 31. Figure 10 is a side view showing the positional relationship between the side surface 12 of the power generation element 10 according to this embodiment, the counter electrode insulating layer 22 provided on the side surface 12, and the electrode terminal 32. In Figures 9 and 10, the end faces of each layer appearing on the side surface 11 or 12 are given the same shading as the shading of each layer shown in the cross-section of Figure 1.

[0102] The electrode insulating layer 21 is an example of a first insulating member, and as shown in Figure 1, it 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.

[0103] Figure 9(a) is a side view of the power generation element 10, and a plan view of the side 11 as seen from the front. Figure 9(b) shows the side 11 of Figure 9(a) and the electrode insulating layer 21 provided on the side 11. In other words, Figure 9(b) is a side view of the battery 1 in Figure 1 as seen from the negative side of the x-axis, with the counter electrode terminal 31 visible through it. Figure 9(c) is a side view of the battery 1 on the side 11 side.

[0104] As shown in Figure 9(b), the electrode insulating layer 21 covers each electrode layer 110 of the multiple battery cells 100 on the side surface 11. The electrode insulating layer 21 does not cover at least a portion of each counter electrode layer 120 of the multiple battery cells 100. Therefore, the electrode insulating layer 21 has a striped shape in a plan view of the side surface 11.

[0105] In this configuration, the electrode insulating layer 21 continuously covers the electrode layers 110 of two adjacent battery cells 100. Specifically, the electrode insulating layer 21 continuously covers at least a portion of the solid electrolyte layer 130 of one of the two adjacent battery cells 100, and at least a portion of the solid electrolyte layer 130 of the other of the two adjacent battery cells 100.

[0106] Thus, the electrode insulating layer 21 covers at least a portion of 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 with the solid electrolyte layer 130. 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 fluctuates due to manufacturing variations. Therefore, it is possible to suppress short circuits 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. In addition, the end face of the solid electrolyte layer 130, which is made of powdered material, has very fine irregularities. Therefore, the electrode insulating layer 21 penetrates these irregularities, improving the adhesion strength of the electrode insulating layer 21 and enhancing its insulation reliability.

[0107] In this embodiment, the electrode insulating layer 21 may cover the entire solid electrolyte layer 130 on its side surface 11. Specifically, the contour of the electrode insulating layer 21 may overlap with the boundary between the solid electrolyte layer 130 and the counter electrode active material layer 122. It is not essential that the electrode insulating layer 21 covers only a portion of the solid electrolyte layer 130. For example, the contour of the electrode insulating layer 21 may overlap with the boundary between the solid electrolyte layer 130 and the electrode active material layer 112.

[0108] The electrode insulating layer 21 covers a portion of the insulating layer 40 on the side surface 11, but is not limited to this. For example, the electrode insulating layer 21 may cover the entire insulating layer 40 on the side surface 11, as long as the uppermost counter electrode current collector 121 of the parallel unit 10A is exposed. Alternatively, the electrode insulating layer 21 may leave the entire insulating layer 40 exposed on the side surface 11, as long as the lowermost electrode current collector 111 of the parallel unit 10B is completely covered.

[0109] In this embodiment, the electrode insulating layer 21 is provided not only in the stripe-shaped portion but also along the z-axis direction at the y-axis end of the side surface 11. In other words, the shape of the electrode insulating layer 21 may be ladder-shaped in a plan view of the side surface 11. Thus, the electrode insulating layer 21 may cover a part of the counter electrode current collector 121. For example, as shown in Figure 7, at the y-axis end of the side surface 11, the electrode insulating layer 21 covers from the bottom layer to the top layer. This allows the electrode insulating layer 21 to cover the end, which is electrically unstable and prone to short circuits, thereby suppressing the occurrence of short circuits.

[0110] Furthermore, in this embodiment, the electrode insulating layer 21 is provided not only on the side surface 11 but also on the side surface 13, as shown in Figures 5 and 6. As shown in Figure 8, the electrode insulating layer 21 provided on the side surface 13 covers not only the electrode layer 110 but also the solid electrolyte layer 130, the counter electrode layer 120, and the insulating layer 40. Specifically, the electrode insulating layer 21 covers the entire side surface 13. The portion of the electrode insulating layer 21 provided on the side surface 13 is an example of a third insulating member.

[0111] Furthermore, since the uppermost layer of the power generation element 10 is the electrode current collector 111, as shown in Figure 5, the electrode insulating layer 21 covers a portion of the main surface of the electrode current collector 111 located in the uppermost layer, near the upper end of the side surface 11. The same applies near the upper end of the side surface 13. As a result, the electrode insulating layer 21 is resistant to external forces from the z-axis direction, and detachment is suppressed. Also, even if the counter electrode terminal 31 wraps around to the main surface 15 of the power generation element 10, it can contact the electrode current collector 111, preventing a short circuit. In this way, the reliability of the battery 1 can be improved.

[0112] On the other hand, the lowest layer of the power generation element 10 is the counter electrode current collector 121. Therefore, as shown in Figure 6, the electrode insulating layer 21 does not cover the counter electrode current collector 121 near the lower end of the side surface 11, except for both ends in the y-axis direction. This ensures connection between the counter electrode terminal 31 and the main surface of the counter electrode current collector 121. In addition, the electrode insulating layer 21 covers the counter electrode current collector 121 near the lower end of the side surface 13. This makes the electrode insulating layer 21 resistant to external forces from the z-axis direction, and prevents detachment.

[0113] The counter electrode insulating layer 22 is an example of a second insulating member, and as shown in Figure 1, it 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.

[0114] Figure 10(a) is a side view of the power generation element 10, and a plan view of the side 12 as seen from the front. Figure 10(b) shows the side 12 of Figure 10(a) and the counter electrode insulating layer 22 provided on the side 12. In other words, Figure 10(b) is a side view of the battery 1 in Figure 1 as seen from the positive side of the x-axis, with the electrode terminal 32 visible through it. Figure 10(c) is a side view of the battery 1 on the side 12 side.

[0115] As shown in Figure 10(b), the counter electrode insulating layer 22 covers each of the counter electrode layers 120 of the multiple battery cells 100 on the side surface 12. The counter electrode insulating layer 22 does not cover at least a portion of each of the electrode layers 110 of the multiple battery cells 100. Therefore, the counter electrode insulating layer 22 has a striped shape in a plan view of the side surface 12.

[0116] In this configuration, the counter electrode insulating layer 22 continuously covers the counter electrode layers 120 of two adjacent battery cells 100. Specifically, the counter electrode insulating layer 22 continuously covers at least a portion of the solid electrolyte layer 130 of one of the two adjacent battery cells 100, and at least a portion of the solid electrolyte layer 130 of the other of the two adjacent battery cells 100.

[0117] Thus, the counter electrode insulating layer 22 covers at least a portion of the solid electrolyte layer 130 on the side surface 12. Specifically, when the side surface 12 is viewed from above, the contour of the counter electrode insulating layer 22 overlaps with the solid electrolyte layer 130. This reduces the risk of exposing the counter electrode layer 120 even if the width (length in the z-axis direction) of the counter electrode insulating layer 22 fluctuates due to manufacturing variations. Therefore, it is possible to suppress short circuits 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. In addition, the adhesion strength of the counter electrode insulating layer 22 is improved as the counter electrode insulating layer 22 fits into the irregularities of the end face of the solid electrolyte layer 130, thereby improving insulation reliability.

[0118] In this embodiment, the counter electrode insulating layer 22 may cover the entire solid electrolyte layer 130 on its side surface 12. Specifically, the contour of the counter electrode insulating layer 22 may overlap the boundary between the solid electrolyte layer 130 and the electrode active material layer 112. It is not essential that the counter electrode insulating layer 22 covers only a portion of the solid electrolyte layer 130. For example, the contour of the counter electrode insulating layer 22 may overlap the boundary between the solid electrolyte layer 130 and the counter electrode active material layer 122.

[0119] The counter electrode insulating layer 22 covers a portion of the insulating layer 40 on the side surface 12, but is not limited to this. For example, the counter electrode insulating layer 22 may expose the entire insulating layer 40 as long as it covers the uppermost counter electrode current collector 121 of the parallel unit 10A on the side surface 12. Alternatively, the counter electrode insulating layer 22 may cover the entire insulating layer 40 as long as it exposes the lowermost electrode current collector 111 of the parallel unit 10B on the side surface 12.

[0120] In this embodiment, the counter electrode insulating layer 22 is provided not only in the stripe-shaped portion but also along the z-axis at the end of the side surface 12 in the y-axis direction. In other words, the shape of the counter electrode insulating layer 22 may be ladder-shaped in a plan view of the side surface 12. Thus, the counter electrode insulating layer 22 may cover a part of the electrode current collector 111. Specifically, as shown in Figure 7, at the end of the side surface 12 in the y-axis direction, the counter electrode insulating layer 22 covers from the bottom layer to the top layer. As a result, the counter electrode insulating layer 22 covers the end that is electrically unstable and at risk of short circuits, thereby suppressing the occurrence of short circuits.

[0121] In this embodiment, the counter electrode insulating layer 22 is provided not only on the side surface 12 but also on the side surface 14, as shown in Figures 5 and 6. As shown in Figure 8, the counter electrode insulating layer 22 provided on the side surface 14 covers not only the counter electrode layer 120 but also the solid electrolyte layer 130, the electrode layer 110, and the insulating layer 40. Specifically, the counter electrode insulating layer 22 covers the entire side surface 14. The portion of the counter electrode insulating layer 22 provided on the side surface 14 is an example of a fourth insulating member.

[0122] Furthermore, since the lowest layer of the power generation element 10 is the counter electrode current collector 121, as shown in Figure 6, the counter electrode insulating layer 22 covers a portion of the main surface of the counter electrode current collector 121 located in the lowest layer, near the lower end of the side surface 12. The same applies near the lower end of the side surface 14. As a result, the counter electrode insulating layer 22 is resistant to external forces from the z-axis direction and detachment is suppressed. Also, even if the electrode terminal 32 wraps around to the main surface 16 of the power generation element 10, it can contact the counter electrode current collector 121 and prevent a short circuit. In this way, the reliability of the battery 1 can be improved.

[0123] Furthermore, the uppermost layer of the power generation element 10 is the electrode current collector 111. Therefore, as shown in Figure 5, the counter electrode insulating layer 22 does not cover the electrode current collector 111 except at both ends in the y-axis direction near the upper end of the side surface 12. This ensures connection between the electrode terminals 32 and the main surface of the electrode current collector 111.

[0124] Although the example shown illustrates the electrode insulating layer 21 and the counter electrode insulating layer 22 each covering two sides of the power generation element 10, the example is not limited to this. For example, one of the electrode insulating layer 21 or the counter electrode insulating layer 22 may cover three sides. Alternatively, at least one of sides 13 and 14 may be covered by both the electrode insulating layer 21 and the counter electrode insulating layer 22.

[0125] The electrode insulating layer 21 and the counter electrode insulating layer 22 are each formed using an electrically insulating material. 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 resin, but is not limited to this. Inorganic materials may also be used as the insulating material. The usable insulating material is 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, but they may also be formed using different materials.

[0126] Furthermore, the electrode insulating layer 21 and the counter electrode insulating layer 22 may be integrally formed from the same material. In other words, the boundary between the electrode insulating layer 21 and the counter electrode insulating layer 22 does not need to be clearly distinguishable. Also, the electrode insulating layer 21 may cover only the side surface 11 and not be provided on the side surface 13. Similarly, the counter electrode insulating layer 22 may cover only the side surface 12 and not be provided on the side surface 14. Moreover, the insulating layer provided on the side surface 13 may be formed using a material different from that of either the electrode insulating layer 21 or the counter electrode insulating layer 22. The same applies to the insulating layer provided on the side surface 14.

[0127] [3. Terminals] Next, the counter terminal 31 and the electrode terminal 32 will be described.

[0128] The counter electrode terminal 31 is an example of a first terminal electrode, and as shown in Figure 1, it 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 the portion of the side surface 11 that is not covered by the electrode insulating layer 21.

[0129] As shown in Figure 9(b), the end faces of the counter electrode current collector 121 and the counter electrode active material layer 122 are exposed in the portion of the side surface 11 that is not covered by 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. Since the counter electrode active material layer 122 is made of a powdery material, it has very fine irregularities, similar to the solid electrolyte layer 130. The contact strength of the counter electrode terminal 31 is improved as it fits into the irregularities of the end face of the counter electrode active material layer 122, thereby improving the reliability of the electrical connection.

[0130] The counter electrode terminal 31 is electrically connected to the counter electrode layer 120 of each of the multiple battery cells 100. In other words, the counter electrode terminal 31 plays a part in electrically connecting each battery cell 100 in parallel. As shown in Figures 1 and 9(c), the counter electrode terminal 31 covers almost the entire side surface 11 as a whole. In this embodiment, since the counter electrode layer 120 is the positive electrode, the counter electrode terminal 31 functions as the positive electrode extraction electrode of the battery 1.

[0131] As shown in Figure 1, near the lower end of the side surface 11, the counter electrode terminal 31 covers a portion of the main surface of the counter electrode current collector 121 located at the lowest layer. This makes the counter electrode terminal 31 resistant to external forces from the z-axis direction, suppressing detachment. Furthermore, since the contact area between the counter electrode terminal 31 and the counter electrode current collector 121 is increased, the connection resistance between the counter electrode terminal 31 and the counter electrode current collector 121 is reduced, improving the high-current characteristics. For example, rapid charging of the battery 1 becomes possible.

[0132] The electrode terminal 32 is an example of a second terminal electrode, and as shown in Figure 1, it 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 the portion of the side surface 12 that is not covered by the counter electrode insulating layer 22.

[0133] As shown in Figure 10(b), the end faces of the electrode current collector 111 and the electrode active material layer 112 are exposed in the portion of the side surface 12 that is not covered by the counter electrode insulating layer 22. Therefore, the electrode terminal 32 contacts 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. Since the electrode active material layer 112 is made of a powdery material, it has very fine irregularities, similar to the solid electrolyte layer 130. The electrode terminal 32 fits into the irregularities of the end face of the electrode active material layer 112, improving the adhesion strength of the electrode terminal 32 and improving the reliability of the electrical connection.

[0134] The electrode terminals 32 are electrically connected to the respective electrode layers 110 of the multiple battery cells 100. In other words, the electrode terminals 32 play a part in electrically connecting each battery cell 100 in parallel. As shown in Figures 1 and 10(c), the electrode terminals 32 cover almost the entire side surface 12. In this embodiment, since the electrode layer 110 is the negative electrode, the electrode terminals 32 function as negative electrode extraction electrodes for the battery 1.

[0135] As shown in Figure 1, near the upper end of the side surface 12, the electrode terminal 32 covers a portion of the main surface of the electrode current collector 111 located in the uppermost layer. This makes the electrode terminal 32 resistant to external forces from the z-axis direction, suppressing detachment. Furthermore, since the contact area between the electrode terminal 32 and the electrode current collector 111 is increased, the connection resistance between the electrode terminal 32 and the electrode current collector 111 is reduced, improving the high-current characteristics.

[0136] 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 metallic material such as solder. The usable conductive material is 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 they may also be formed using different materials.

[0137] As described above, the counter electrode terminal 31 and the electrode terminal 32 not only function as the positive electrode extraction electrode or the negative electrode extraction electrode of the battery 1, respectively, but also serve the function of parallel connection of multiple battery cells 100. As shown in Figure 1, the counter electrode terminal 31 and the electrode terminal 32 are formed to closely cover the sides 11 and 12 of the power generation element 10, respectively, so that 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, so that the energy density per unit volume of the battery 1 can be improved.

[0138] [4. Insulating layer] Next, the insulating layer 40 will be described.

[0139] The insulating layer 40 is located between the parallel unit 10A and the parallel unit 10B. The insulating layer 40 is provided to prevent the parallel unit 10A and the parallel unit 10B from being electrically connected in series. Specifically, the insulating layer 40 prevents contact between the counter electrode current collector 121 located at the top of the parallel unit 10A and the electrode current collector 111 located at the bottom of the parallel unit 10B, thereby preventing them from being electrically connected.

[0140] The size and shape of the insulating layer 40 in plan view are the same as those of the current collector in contact with the insulating layer 40. As a result, the end face of the insulating layer 40 and the end faces of the parallel units 10A and 10B are flush with each of the sides 11, 12, 13, and 14. In other words, each of the sides 11, 12, 13, and 14 is a flat surface.

[0141] Furthermore, the end face of the insulating layer 40 may be set back from the end faces of the parallel units 10A and 10B. In this case, a gap is formed between the parallel unit 10A and the parallel unit 10B. The electrode insulating layer 21 and the counter electrode insulating layer 22 fit into this gap. This allows the electrode insulating layer 21 and the counter electrode insulating layer 22 to be fixed more firmly.

[0142] The insulating layer 40 is formed using, for example, an insulating resin material. For example, the insulating layer 40, the electrode insulating layer 21, and the counter electrode insulating layer 22 may all be formed using the same material. The insulating layer 40 may also be formed using an inorganic material such as an insulating metal oxide film. The insulating layer 40 only needs to have its upper and lower surfaces insulated, so for example, it may be a metal plate with an insulating film formed on one or both sides.

[0143] The placement of the insulating layer 40 allows two parallel units 10A and 10B, each with layers of different polarities exposed on their upper and lower surfaces, to be stacked without being connected in series. As a result, the top and bottom layers of the power generation element 10 will have layers of different polarities. This means that the top and bottom layers of the power generation element 10 can be used for electrode extraction, respectively. For example, it becomes possible to connect large external terminals, increasing the contact area and reducing connection resistance. This improves the high-current characteristics of the battery 1. An example of an external terminal will be explained later using Figure 14.

[0144] (Embodiment 2) Next, Embodiment 2 will be described.

[0145] The battery according to Embodiment 2 differs from the battery according to Embodiment 1 in that the electrode terminals and counter electrode terminals are provided on two sides of the power generation element 10. Below, we will focus on explaining the differences from Embodiment 1, and omit or simplify the explanation of the common points.

[0146] Figure 11 is a top view of the battery 201 according to this embodiment. Figure 12 is a plan view of the bottom surface of the battery 201 according to this embodiment, viewed from above. Figure 13 is a cross-sectional view showing the cross-sectional configuration of the battery 201 according to this embodiment. Figure 13 shows the cross-section along line XIII-XIII in Figure 11 or Figure 12.

[0147] Compared to the battery 1 shown in Figures 5 and 6, the battery 201 according to this embodiment includes a counter electrode terminal 231 and an electrode terminal 232 in addition to the counter electrode terminal 31 and electrode terminal 32.

[0148] The counter electrode terminal 231 is an example of a third terminal electrode, covering the side surface 13 and the electrode insulating layer 21, and connected to the counter electrode layer 120. The counter electrode terminal 231 has the same configuration as the counter electrode terminal 31, as shown in Figure 13, except that it is provided on the side surface 13 instead of the side surface 11. Note that the counter electrode terminal 231 and the counter electrode terminal 31 are connected and may be integrated.

[0149] Electrode terminal 232 is an example of a fourth terminal electrode, covering the side surface 14 and the counter electrode insulating layer 22, and connected to the electrode layer 110. Except for being located on side surface 14 instead of side surface 12, electrode terminal 232 has the same configuration as electrode terminal 32, as shown in Figure 13. Note that electrode terminal 232 and electrode terminal 32 may be connected and integrated.

[0150] This allows electrodes to be extracted from two adjacent sides. Since the contact area between each layer and the terminals is increased, the connection resistance is reduced, thereby improving the high-current characteristics of the battery 201. Furthermore, since the electrode layer 110 can have the same configuration as the counter electrode layer 120, it becomes easier to balance the positive and negative polarities, improving the reliability of the battery.

[0151] Furthermore, instead of two adjacent sides, terminals of the same polarity may be provided on two opposing sides. For example, counter terminals 31 and 231 may be provided on sides 11 and 12, respectively, and electrode terminals 32 and 232 may be provided on sides 13 and 14, respectively.

[0152] (Embodiment 3) Next, Embodiment 3 will be described.

[0153] The battery according to Embodiment 3 differs from the battery according to Embodiment 1 in that it further includes a sealing member and a contact portion. Below, we will mainly explain the differences from Embodiment 1, and the explanation of the common points will be omitted or simplified.

[0154] Figure 14 is a cross-sectional view showing the cross-sectional configuration of the battery 301 according to this embodiment. As shown in Figure 14, the battery 301 includes, in addition to the configuration of the battery 1 according to Embodiment 1, a sealing member 350, an electrode contact 361, and a counter electrode contact 362.

[0155] The sealing member 350 exposes at least a portion of the main surface of the power generation element 10 and seals the power generation element 10. Specifically, the sealing member 350 exposes a portion of the bottom surface of the parallel unit 10A and a portion of the top surface of the parallel unit 10B, while covering the rest.

[0156] The sealing member 350 is formed using, for example, an electrically insulating insulating material. As the insulating material, generally known materials for sealing members of batteries, such as encapsulants, may be used. As the insulating material, for example, a resin material may be used. The insulating material may be an insulating material that does not have ionic conductivity. For example, the insulating material may be at least one of epoxy resin, acrylic resin, polyimide resin, and silsesquioxane.

[0157] The sealing member 350 may include multiple different insulating materials. For example, the sealing member 350 may have a multilayer structure. Each layer of the multilayer structure may be formed using a different material and have different properties.

[0158] The sealing member 350 may contain particulate metal oxide material. Examples of metal oxide material include silicon oxide, aluminum oxide, titanium oxide, zinc oxide, cerium oxide, iron oxide, tungsten oxide, zirconium oxide, calcium oxide, zeolite, and glass. For example, the sealing member 350 may be formed using a resin material in which multiple particles made of metal oxide material are dispersed.

[0159] The particle size of the metal oxide material should be less than or equal to the distance between the electrode current collector 111 and the counter electrode current collector 121. The particle shape of the metal oxide material may be, for example, spherical, ellipsoidal, or rod-shaped, but is not limited to these.

[0160] The provision of the sealing member 350 improves the reliability of the battery 301 in various aspects, including mechanical strength, short-circuit prevention, and moisture resistance.

[0161] An electrode contact 361 is connected to the portion of the main surface 15 of the power generation element 10 that is not covered by the sealing member 350. A counter electrode contact 362 is connected to the portion of the main surface 16 of the power generation element 10 that is not covered by the sealing member 350.

[0162] The electrode contact 361 is electrically connected by contacting the electrode current collector 111 located at the top layer of the parallel unit 10B. The electrode contact 361 is an example of an extraction electrode for one polarity of the power generation element 10.

[0163] The counter electrode contact 362 is electrically connected to the counter electrode current collector 121 located at the bottom layer of the parallel unit 10A by contacting it. The counter electrode contact 362 is an example of an extraction electrode for the other polarity of the power generation element 10.

[0164] In each cross-sectional view, the power generation element 10 is depicted as being elongated in the thickness direction, but in reality, the shape of the power generation element 10 is flat. That is, the area of ​​the main surfaces 15 and 16 of the power generation element 10 is larger than the area of ​​each side surface of the power generation element 10. Therefore, by connecting contacts to the main surfaces 15 and 16, a strong and stable connection and low connection resistance are achieved.

[0165] (modified version) Next, we will describe some variations of the embodiments described above.

[0166] In each modified example, the extent of the insulating layer covering the sides differs compared to the respective embodiments. Below, we will focus on explaining the differences from each embodiment, omitting or simplifying the explanation of the commonalities.

[0167] Figure 15 is a cross-sectional view showing the cross-sectional configuration of a modified battery 401. As shown in Figure 15, compared to the battery 1 according to Embodiment 1, the battery 401 includes an electrode insulating layer 421 and a counter electrode insulating layer 422 instead of the electrode insulating layer 21 and the counter electrode insulating layer 22.

[0168] As shown in Figure 15, the electrode insulating layer 421 covers not only the electrode layer 110 but also a portion of the solid electrolyte layer 130 and the counter electrode layer 120 on the side surface 11. In other words, the electrode insulating layer 421 covers from the electrode layer 110 to a portion of the counter electrode layer 120. Specifically, the electrode insulating layer 421 covers a portion of the counter electrode active material layer 122. In this modified example, the electrode insulating layer 421 continuously covers at least a portion of the counter electrode active material layer 122 of one of two adjacent battery cells 100 to at least a portion of the counter electrode active material layer 122 of the other of the two adjacent battery cells 100. For example, the electrode insulating layer 421 completely covers one electrode current collector 111, the electrode active material layers 112 located on both sides of one electrode current collector 111, and the two solid electrolyte layers 130. For example, when the side surface 11 is viewed from above, the contour of the electrode insulating layer 421 overlaps with the counter electrode active material layer 122.

[0169] As a result, even if the width (length in the z-axis direction) of the electrode insulating layer 421 fluctuates due to manufacturing variations, the risk of exposing the electrode layer 110 is extremely low. Therefore, it is possible to suppress short circuits between the electrode layer 110 and the counter electrode layer 120 via the counter electrode terminal 31. In addition, as the electrode insulating layer 421 fits into the irregularities on the end face of the counter electrode active material layer 122, the adhesion strength of the electrode insulating layer 421 is improved, and the insulation reliability is enhanced.

[0170] Furthermore, the electrode insulating layer 421 may completely cover the counter electrode active material layer 122 on the side surface 11. Specifically, the contour of the electrode insulating layer 421 may overlap the boundary between the counter electrode active material layer 122 and the counter electrode current collector 121.

[0171] In this modified example, the counter electrode insulating layer 422 has a similar configuration on side 12. Specifically, on side 12, the counter electrode insulating layer 422 covers not only the counter electrode layer 120 but also a portion of the solid electrolyte layer 130 and the electrode layer 110. In other words, the counter electrode insulating layer 422 covers from the counter electrode layer 120 to a portion of the electrode layer 110. Specifically, the counter electrode insulating layer 422 covers a portion of the electrode active material layer 112. In this modified example, the counter electrode insulating layer 422 continuously covers from at least a portion of the electrode active material layer 112 of one of two adjacent battery cells 100 to at least a portion of the electrode active material layer 112 of the other of the two adjacent battery cells 100. For example, the counter electrode insulating layer 422 completely covers one counter electrode current collector 121, the counter electrode active material layers 122 located on both sides of one counter electrode current collector 121, and the two solid electrolyte layers 130.

[0172] For example, when the side surface 12 is viewed from above, the contour of the counter electrode insulating layer 422 overlaps with the electrode active material layer 112. As a result, even if the width (length in the z-axis direction) of the counter electrode insulating layer 422 fluctuates due to manufacturing variations, the risk of exposing the counter electrode layer 120 is extremely low. Therefore, it is possible to suppress short circuits between the counter electrode layer 120 and the electrode layer 110 via the electrode terminal 32. In addition, as the counter electrode insulating layer 422 fits into the irregularities of the end face of the electrode active material layer 112, the adhesion strength of the counter electrode insulating layer 422 is improved, and the insulation reliability is enhanced.

[0173] Furthermore, the counter electrode insulating layer 422 may completely cover the electrode active material layer 112 on its side surface 12. Specifically, the contour of the counter electrode insulating layer 422 may overlap the boundary between the electrode active material layer 112 and the electrode current collector 111.

[0174] Figure 15 shows a modified example of the battery 1 according to Embodiment 1, but the electrode insulating layer 421 and the counter electrode insulating layer 422 may also be applied to the batteries according to each of the embodiments described above. In any case, as with battery 401, the possibility of a short circuit between the electrode layer 110 and the counter electrode layer 120 can be sufficiently reduced, thereby improving the reliability of the battery.

[0175] (Manufacturing method) Next, a method for manufacturing batteries according to each of the embodiments and variations described above will be explained.

[0176] Figure 16 is a flowchart showing an example of a battery manufacturing method according to each embodiment or modification. Below, an example of battery 1 will be described.

[0177] As shown in Figure 16, first, several battery cells are prepared (S10, first step). The battery cells to be prepared are, for example, battery cells 100A, 100B, and 100C shown in Figures 3A to 3C.

[0178] Next, two types of parallel units are formed by stacking multiple battery cells 100 (S20). Specifically, multiple battery cells 100 are stacked in order so that the order of the electrode layer 110, counter electrode layer 120, and solid electrolyte layer 130 alternates. At this time, a parallel unit 10A is formed by stacking an even number of battery cells 100 such that the counter electrode layer 120 is located at both ends in the stacking direction. Also, a parallel unit 10B is formed by stacking an even number of battery cells 100 such that the electrode layer 110 is located at both ends in the stacking direction. Parallel units 10A and 10B are formed by stacking battery cells 100A, 100B, and 100C in appropriate combinations.

[0179] Next, an insulating layer 40 is placed on the main surface of at least one of the parallel units 10A and 10B (S30). For example, the insulating layer 40 is placed on the main surface of the counter electrode current collector 121 of the parallel unit 10A. The insulating layer 40 to be placed is, for example, an insulating adhesive before curing. The insulating layer 40 is placed by an inkjet method, spray method, screen printing method or gravure printing method, etc.

[0180] Next, the parallel units 10A and 10B are stacked with an insulating layer 40 in between (S40). After stacking, the insulating layer 40 is cured as needed. Steps S20 to S40 described above are an example of the second step. This forms the power generation element 10, which is a stack of the parallel units 10A and 10B.

[0181] Furthermore, the sides of the power generation element 10 may be flattened after stacking multiple battery cells 100. For example, by cutting the stack of multiple battery cells 100 all at once, a power generation element 10 with flat sides can be formed. The flattening of the sides may be performed for each parallel unit. The cutting process can be performed, for example, by a blade, laser, or jet.

[0182] Next, an insulating layer is formed on the side surface of the power generation element 10 (S50, third step). Specifically, an electrode insulating layer 21 is formed on the side surface 11 to cover the electrode layer 110. Also, a counter electrode insulating layer 22 is formed on the side surface 12 to cover the counter electrode layer 120.

[0183] The electrode insulating layer 21 and the counter electrode insulating layer 22 are formed, for example, by coating and curing a fluid resin material. Coating is carried out by methods such as inkjet printing, spray printing, screen printing, or gravure printing. Curing is carried out by drying, heating, light irradiation, etc., depending on the resin material used.

[0184] Furthermore, when forming the electrode insulating layer 21 and the counter electrode insulating layer 22, a protective member may be formed in areas where the insulating layer should not be formed, such as by masking with tape or by resist treatment, so that the end faces of the counter electrode current collector 121 and the end faces of the electrode current collector 111 are not insulated. After the formation of the electrode insulating layer 21 and the counter electrode insulating layer 22, the conductivity of each current collector can be ensured by removing the protective member.

[0185] Next, extraction terminals are formed on the side surface of the power generation element 10 (S60, fourth step). Specifically, on side surface 11, a counter electrode terminal 31 is formed to electrically connect multiple counter electrode layers 120. On side surface 12, an electrode terminal 32 is formed to electrically connect multiple electrode layers 110.

[0186] For example, the counter electrode terminal 31 is formed by coating and curing a conductive resin so as to cover the electrode insulating layer 21 and the portion of the side surface 11 not covered by the electrode insulating layer 21. Similarly, the electrode terminal 32 is positioned by coating and curing a conductive resin so as to cover the counter electrode insulating layer 22 and the portion of the side surface 12 not covered by the counter electrode insulating layer 22. The counter electrode terminal 31 and electrode terminal 32 may also be formed by methods such as printing, plating, vapor deposition, sputtering, welding, soldering, joining, or other methods.

[0187] Through the above process, the battery 1 shown in Figure 1 can be manufactured.

[0188] In addition, the process of pressing the multiple battery cells 100 prepared in step S10 individually, or after stacking the multiple battery cells, in the stacking direction may be performed.

[0189] Furthermore, after forming the extraction terminals (S60), the sealing member 350 shown in Figure 10 may be formed. The sealing member 350 is formed, for example, by coating and curing a fluid resin material. Coating is carried out by methods such as inkjet printing, spray printing, screen printing, or gravure printing. Curing is carried out by drying, heating, light irradiation, etc., depending on the resin material used.

[0190] (Other embodiments) Although one or more embodiments of batteries and methods for manufacturing batteries have been described above based on embodiments, this disclosure is not limited to these embodiments. Within the scope of this disclosure, various modifications to these embodiments that a person skilled in the art could conceive, as well as forms constructed by combining components from different embodiments, are also included.

[0191] For example, in the above embodiment, an example was described in which terminal electrodes are provided on each of the sides 11 and 12, but terminal electrodes may also be provided on each of the sides 13 and 14. In other words, side 13 may be an example of a first side, and side 14 may be an example of a second side. Also, terminal electrodes may be provided on one of the sides 11 and 12 and on one of the sides 13 and 14. In other words, terminal electrodes may be provided along two adjacent sides of the main surface 15.

[0192] Furthermore, for example, the power generation element 10 may comprise three or more parallel units. In this case, current collectors of the same polarity may be located at the top and bottom layers of the power generation element 10.

[0193] The number of battery cells 100 included in parallel units 10A and 10B may be different from each other. Furthermore, the power generation element 10 may include three or more parallel units.

[0194] Furthermore, for example, a battery cell 100 may be placed between the parallel unit 10A and the parallel unit 10B instead of the insulating layer 40.

[0195] Furthermore, for example, the electrode insulating layer 21 has a portion that covers the side surface 11 from the bottom layer to the top layer in the stacking direction, but is not limited to this. The electrode insulating layer 21 may have only a stripe-shaped portion when the side surface 11 is viewed from above. Specifically, the electrode insulating layer 21 does not have to cover the counter electrode layer 120 or the counter electrode current collector 121 at all on the side surface 11. The same applies to the counter electrode insulating layer 22.

[0196] Furthermore, external electrodes may be formed on the outermost surface of each of the electrode terminals and counter electrode terminals by methods such as plating, printing, or soldering. By providing external electrodes, the battery's mountability can be further improved.

[0197] Furthermore, although the above embodiment shows an example in which each battery has both a counter electrode terminal 31 and an electrode terminal 32, it may also have only one of them. In other words, the extraction of one of the positive or negative electrodes of the battery may be performed by a tab electrode.

[0198] Furthermore, each of the above embodiments may be modified, replaced, added, or omitted in various ways within the scope of the claims or their equivalents. [Industrial applicability]

[0199] This disclosure can be used, for example, as a battery for electronic devices, electrical appliances, and electric vehicles. [Explanation of Symbols]

[0200] 1, 201, 301, 401 batteries 10 Power generation elements 10A, 10B Parallel Unit 11, 12, 13, 14 Side view 15, 16 Main surface 21, 421 Electrode insulating layer 22, 422 Counter electrode insulating layer 31, 231 Counter terminals 32, 232 electrode terminal 40 Insulating layer 100, 100A, 100B, 100C battery cells 110, 110B electrode layer 111 Electrode current collector 112 Electrode active material layer 120°C, 120°C counter polarity layer 121 Counter electrode current collector 122 Counter electrode active material layer 130 Solid electrolyte layer 350 Sealing member 361 Electrode Contact 362 Counter-electrode contact

Claims

1. A power generation element having a plurality of battery cells, each containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer, wherein the plurality of battery cells are electrically connected in parallel and stacked, On the first side surface of the power generation element, a first insulating member covering the electrode layer and The first side surface and the first insulating member are covered, and the first terminal electrode is electrically connected to the counter electrode layer, Equipped with, The aforementioned power generation element is A first parallel unit comprising a plurality of first battery cells among the plurality of battery cells, with the counter electrode layers located at both ends in the stacking direction, The second parallel unit includes a plurality of second battery cells among the plurality of battery cells, the electrode layers are located at both ends in the stacking direction, and the second parallel unit is stacked on the first parallel unit, When the first terminal electrode is viewed from the front, it does not cover at least one end of the counter electrode layer in a direction perpendicular to the stacking direction. The first insulating member further covers at least one end. battery.

2. The first parallel unit is located at one end in the stacking direction of the power generation elements, The second parallel unit is located at the other end in the stacking direction of the power generation element, The battery according to claim 1.

3. The power generation element includes an insulating layer located between the first parallel unit and the second parallel unit, The battery according to claim 1 or 2.

4. A power generation element having a plurality of battery cells, each containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer, wherein the plurality of battery cells are electrically connected in parallel and stacked, On the first side surface of the power generation element, a first insulating member covering the electrode layer and The first side surface and the first insulating member are covered, and the first terminal electrode is electrically connected to the counter electrode layer, Equipped with, The aforementioned power generation element is A first parallel unit comprising a plurality of first battery cells among the plurality of battery cells, with the counter electrode layers located at both ends in the stacking direction, The second parallel unit includes a plurality of second battery cells among the plurality of battery cells, the electrode layers are located at both ends in the stacking direction, and the second parallel unit is stacked on the first parallel unit, The first insulating member covers at least a portion of the solid electrolyte layer on the first side surface. battery.

5. The first insulating member, on its first side surface, covers from the electrode layer to a portion of the counter electrode layer along the stacking direction of the power generation element, The battery according to claim 4.

6. The first insulating member covers the electrode layer of each of the plurality of battery cells on its first side surface. The first terminal electrode is electrically connected to the counter electrode layer of each of the plurality of battery cells. The battery according to any one of claims 1 to 5.

7. The first insulating member has a stripe shape in a plan view of the first side surface. The battery according to claim 6.

8. On the second side of the power generation element, a second insulating member covering the counter electrode layer, The system further comprises a second terminal electrode that covers the second side surface and the second insulating member and is electrically connected to the electrode layer, The battery according to any one of claims 1 to 7.

9. The aforementioned power generation element is a rectangular parallelepiped, The second side is the side opposite to the first side. The battery according to claim 8.

10. A power generation element having a plurality of battery cells, each containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer, wherein the plurality of battery cells are electrically connected in parallel and stacked, On the first side surface of the power generation element, a first insulating member covering the electrode layer and The first side surface and the first insulating member are covered, and the first terminal electrode is electrically connected to the counter electrode layer, On the third side of the power generation element, a third insulating member covering the electrode layer, The third terminal electrode covers the third side surface and the third insulating member and is electrically connected to the counter electrode layer, The aforementioned power generation element is A first parallel unit comprising a plurality of first battery cells among the plurality of battery cells, with the counter electrode layers located at both ends in the stacking direction, The second parallel unit includes a plurality of second battery cells among the plurality of battery cells, the electrode layers are located at both ends in the stacking direction, and the second parallel unit is stacked on the first parallel unit, battery.

11. The aforementioned power generation element is a rectangular parallelepiped, The third side is the side adjacent to the first side. The battery according to claim 10.

12. The electrode layer or the counter electrode layer has a current collector, The thickness of the current collector is 20 μm or less. The battery according to any one of claims 1 to 11.

13. The first insulating member includes resin, The battery according to any one of claims 1 to 12.

14. The system further includes a sealing member that exposes at least a portion of the main surface of the power generation element and seals the power generation element. The battery according to any one of claims 1 to 13.

15. A first step is to prepare a plurality of battery cells, each containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer. A second step is to form a laminate by sequentially stacking the plurality of battery cells such that the order of the electrode layer, the counter electrode layer, and the solid electrolyte layer alternates, A third step involves covering one side of the laminate with an insulating material, The fourth step includes covering the aforementioned side surface and the insulating member with terminal electrodes electrically connected to the counter electrode layer, In the second step mentioned above, A first parallel unit is formed which includes a plurality of first battery cells from the plurality of battery cells, with the counter electrode layer located at both ends in the stacking direction, and a second parallel unit is formed which includes a plurality of second battery cells from the plurality of battery cells, with the electrode layer located at both ends in the stacking direction, and which is stacked on the first parallel unit. When the terminal electrode is viewed from the front on one side, it does not cover at least one end of the counter electrode layer in a direction perpendicular to the stacking direction. The insulating member further covers at least one end. Battery manufacturing method.

16. A first step is to prepare a plurality of battery cells, each containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer. A second step is to form a laminate by sequentially stacking the plurality of battery cells such that the order of the electrode layer, the counter electrode layer, and the solid electrolyte layer alternates, A third step involves covering one side of the laminate with an insulating material, The fourth step includes covering the aforementioned side surface and the insulating member with terminal electrodes electrically connected to the counter electrode layer, In the second step mentioned above, A first parallel unit is formed which includes a plurality of first battery cells from the plurality of battery cells, with the counter electrode layers located at both ends in the stacking direction, and a second parallel unit is formed which includes a plurality of second battery cells from the plurality of battery cells, with the electrode layers located at both ends in the stacking direction, and which is stacked on the first parallel unit. The insulating member covers at least a portion of the solid electrolyte layer on one side. Battery manufacturing method.

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