Battery and method for manufacturing a battery

Abstract

This battery comprises: a power generation element that 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, said plurality of battery cells being electrically connected in parallel and layered; an electrode insulation member that covers the respective electrode layers of the plurality of battery cells at a first side surface of the power generation element; a counter electrode extraction layer that covers the first side surface and the electrode insulation member, and is electrically connected to the respective counter electrode layers of the plurality of battery cells; and a counter electrode collector terminal that is provided to a first main surface of the power generation element and is connected to the counter electrode extraction layer, wherein the resistance of a first section in the counter electrode extraction layer is smaller than the resistance of a second section in the counter electrode extraction layer, said first section being connected to the counter electrode layer of the battery cell that is closest to the first main surface among the plurality of battery cells, and said second section being connected to the counter electrode layer of the battery cell that is farthest from the first main surface among the plurality of battery cells.

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 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 as a power generation element; an electrode insulating member covering the electrode layer of each of the plurality of battery cells on a first side surface of the power generation element; a counter electrode extraction layer covering the first side surface and the electrode insulating member and electrically connected to the counter electrode layer of each of the plurality of battery cells; and a counter electrode current collector terminal provided on a first main surface of the power generation element and connected to the counter electrode extraction layer, wherein the resistance of a first portion of the counter electrode extraction layer connected to the counter electrode layer of the battery cell closest to the first main surface among the plurality of battery cells is smaller than the resistance of a second portion of the counter electrode extraction layer connected to the counter electrode layer of the battery cell furthest from the first main surface among the plurality of battery cells.

[0007] A method for manufacturing a battery according to one aspect of the present disclosure includes the steps 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; 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 for each battery cell; covering the electrode layer of each of the plurality of battery cells with an electrode insulating member on the first side surface of the laminate; and covering the first side surface and the electrode insulating member with the electrode insulating member of each of the plurality of battery cells The process includes the steps of covering the laminate with a counter electrode extraction layer electrically connected to the counter electrode layer, and providing a counter electrode current collector terminal connected to the counter electrode extraction layer on the first main surface of the laminate, wherein in the step of covering with the counter electrode extraction layer, the counter electrode extraction layer is formed such that the resistance of the first portion of the counter electrode extraction layer connected to the counter electrode layer of the battery cell closest to the first main surface among the plurality of battery cells is smaller than the resistance of the second portion of the counter electrode extraction layer connected to the counter electrode layer of the battery cell furthest from the first main surface among the plurality of battery cells. [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 of a battery according to Embodiment 1. [Figure 2A] Figure 2A is a top view of the battery according to Embodiment 1. [Figure 2B] Figure 2B is a bottom view 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 according to Embodiment 1. [Figure 5] Figure 5 is a side view showing the positional relationship between the first side surface of the power generation element according to Embodiment 1 and the electrode insulating layer provided on the first side surface. [Figure 6] Figure 6 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 provided on the second side surface. [Figure 7] Figure 7 is a cross-sectional view of the battery according to Embodiment 2. [Figure 8] Figure 8 is a cross-sectional view of the battery according to Embodiment 3. [Figure 9] Figure 9 is a cross-sectional view of the battery according to Embodiment 4. [Figure 10] Figure 10 is a cross-sectional view of the battery according to Embodiment 5. [Figure 11] Figure 11 is a cross-sectional view of a battery according to Embodiment 6. [Figure 12] Figure 12 is a cross-sectional view of the battery according to Embodiment 7. [Figure 13A]FIG. 13A is a top view of the battery according to Embodiment 7. [Figure 13B] FIG. 13B is a bottom view of the battery according to Embodiment 7. [Figure 14] FIG. 14 is a cross-sectional view of the battery according to Embodiment 8. [Figure 15] FIG. 15 is a cross-sectional view of the battery according to Embodiment 9. [Figure 16] FIG. 16 is a cross-sectional view of the battery according to Embodiment 10. [Figure 17] FIG. 17 is a flowchart showing a method for manufacturing the battery according to the embodiment.

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, an electrode insulating member that covers the electrode layer of each of the plurality of battery cells on a first side surface of the power generation element, a counter electrode extraction layer that covers the first side surface and the electrode insulating member and is electrically connected to the counter electrode layer of each of the plurality of battery cells, and a counter electrode current collecting terminal provided on a first main surface of the power generation element and connected to the counter electrode extraction layer. A resistance of a first portion connected to the counter electrode layer of the battery cell closest to the first main surface among the plurality of battery cells in the counter electrode extraction layer is smaller than a resistance of a second portion connected to the counter electrode layer of the battery cell farthest from the first main surface among the plurality of battery cells in the counter electrode extraction layer.

[0011] Thereby, a high-performance battery can be realized. For example, a battery with high uniformity of current flowing in the battery and excellent reliability can be realized.

[0012] Specifically, since the electrode insulating material covers the electrode layer on the first side surface of the power generation element, the occurrence of short circuits between the electrode layer and the counter electrode layer can be suppressed. Furthermore, by electrically connecting all battery cells in parallel, it is possible to suppress overcharging and over-discharging of specific battery cells due to variations in the capacity of each battery cell. In this way, the reliability of the battery can be improved.

[0013] Furthermore, the counter electrode extraction layer serves the function of parallel connection of multiple battery cells. Since the counter electrode extraction layer can be closely attached to the first side surface and the electrode insulating material, the volume of the part involved in parallel connection can be reduced. As a result, the energy density of the battery can be increased.

[0014] Furthermore, in the counter electrode extraction layer, the first portion connected to the counter electrode layer closest to the counter electrode current collector terminal carries current corresponding to all the counter electrode layers of multiple battery cells. On the other hand, the second portion connected to the counter electrode layer furthest from the counter electrode current collector terminal carries current corresponding to one counter electrode layer. In the counter electrode extraction layer, the resistance of the first portion is smaller than the resistance of the second portion. Therefore, the current flowing in the electrical connection path between the counter electrode layer and the counter electrode current collector terminal flows more easily in the first portion, where current corresponding to all counter electrode layers flows, than in the second portion, where current corresponding to one counter electrode layer flows. Thus, the uniformity of the current flowing between each counter electrode layer and the counter electrode current collector terminal can be improved. As a result, each counter electrode layer can be charged and discharged more uniformly, preventing overcharging and over-discharging of specific battery cells, and improving the reliability of the battery.

[0015] In this specification, "resistance" refers to the electrical resistance per unit length in the direction of current flow. Furthermore, "low resistance" of a part does not mean that the inherent electrical resistivity of the materials constituting the part is low, but rather that the value obtained by dividing the electrical resistivity by the cross-sectional area perpendicular to the direction of current flow is low. For example, if a part is composed of multiple materials, the resistance of that part can be determined by summing the values ​​obtained by dividing the corresponding electrical resistivity by the cross-sectional area of ​​each of these materials.

[0016] Furthermore, for example, the thickness of the counter electrode extraction layer in the first portion may be greater than the thickness of the counter electrode extraction layer in the second portion.

[0017] This allows for easier battery manufacturing by simply adjusting the thickness of the counter electrode extraction layer to reduce the resistance of the first part and improve current uniformity.

[0018] Furthermore, for example, the first side surface may be inclined with respect to the stacking direction of the power generation element such that the interior angle formed by the first side surface and the first main surface is an obtuse angle.

[0019] As a result, the first side surface is inclined to extend outward from the power generation element as it moves away from the first main surface along the stacking direction. Consequently, even if the counter electrode extraction layer is thicker in the first portion closer to the counter electrode current collector terminal than in the second portion, the angle of the outer surface of the counter electrode extraction layer with respect to the first main surface can be made closer to a right angle. Therefore, when mounting a battery on a substrate with the counter electrode current collector terminal facing the substrate, unnecessary space is less likely to be formed, improving the mountability of the battery on the substrate.

[0020] Furthermore, for example, the height of the counter electrode extraction layer from the first side surface may increase as it approaches the counter electrode current collector terminal along the stacking direction of the power generation element.

[0021] As a result, in the counter electrode extraction layer, the thickness of the counter electrode extraction layer increases and the resistance decreases as it is connected to the counter electrode layer closer to the counter electrode current collector terminal. Therefore, the uniformity of the current flowing between each counter electrode layer and the counter electrode current collector terminal can be further improved.

[0022] Furthermore, for example, the counter electrode extraction layer may cover the first main surface.

[0023] This allows the counter electrode extraction layer to wrap around from the first side to the first main surface, thus increasing the reliability of the connection of the counter electrode extraction layer. For example, the portion of the counter electrode extraction layer covering the first main surface catches on the power generation element, making it less likely for the counter electrode extraction layer to detach even when external force is applied.

[0024] Furthermore, for example, the counter electrode current collector terminal is a current collector that constitutes the first main surface, and the thickness of the counter electrode current collector terminal may be greater than the thickness of the current collector included in one of the plurality of battery cells.

[0025] This allows for a reduction in the number of components by using a counter current collector as a counter current collector terminal. Furthermore, by making the counter current collector used as a counter current collector thicker than other current collectors, it is easy to achieve low resistance for the counter current collector terminal. Thus, in this specification, "a current collector terminal is provided on the main surface" means not only when a component different from the components constituting the main surface is arranged on the main surface as a current collector terminal, but also when the component constituting the main surface itself is a current collector terminal.

[0026] Furthermore, for example, the counter electrode extraction layer may have a first conductive member that contacts the counter electrode layer and a second conductive member that covers the first conductive member.

[0027] This allows the counter electrode extraction layer to be formed using multiple materials with different properties. For example, the material used for the first conductive member in contact with the counter electrode layer can be selected based on its high conductivity and alloying with the metal contained in the current collector. The material used for the second conductive member can be selected based on its flexibility, impact resistance, chemical stability, cost, and ease of spreading during installation. In this way, suitable materials can be selected for each component, improving battery performance and ease of manufacturing.

[0028] Furthermore, for example, the conductivity of the material constituting the first part may be higher than the conductivity of the material constituting the second part.

[0029] This allows for a reduction in the resistance of the first portion of the counter electrode extraction layer, even without making the first portion thicker than the second portion, thus enabling a smaller battery.

[0030] Furthermore, if a material is composed of multiple materials, the conductivity is the average conductivity of these multiple materials on a volume basis.

[0031] Furthermore, for example, the battery further comprises, on the second side surface of the power generation element, a counter electrode insulating member covering the counter electrode layer of each of the plurality of battery cells; an electrode extraction layer covering the second side surface and the counter electrode insulating member and electrically connected to the electrode layer of each of the plurality of battery cells; and an electrode current collector terminal provided on the first main surface of the power generation element and connected to the electrode extraction layer, wherein the resistance of the third portion of the electrode extraction layer connected to the electrode layer of the battery cell closest to the first main surface among the plurality of battery cells may be smaller than the resistance of the fourth portion of the counter electrode extraction layer connected to the electrode layer of the battery cell furthest from the first main surface among the plurality of battery cells.

[0032] This makes it possible to create batteries with higher performance.

[0033] Specifically, on the second side of the power generation element, the counter electrode insulating member covers the counter electrode layer, and the electrode extraction layer functions as a parallel connection for multiple battery cells. Therefore, similar to the electrode insulating member and the counter electrode extraction layer, the reliability and energy density of the battery can be increased.

[0034] Furthermore, in the electrode extraction layer, the third portion, which is connected to the electrode layer closest to the electrode current collector terminal, carries current corresponding to all electrode layers of multiple battery cells. On the other hand, the fourth portion, which is connected to the electrode layer furthest from the electrode current collector terminal, carries current corresponding to one electrode layer. In the electrode extraction layer, the resistance of the third portion is smaller than that of the fourth portion. Therefore, the current flowing in the electrical connection path between the electrode layer and the electrode current collector terminal flows more easily in the third portion, where current corresponding to all electrode layers flows, than in the fourth portion, where current corresponding to one electrode layer flows. Thus, the uniformity of the current flowing between each electrode layer and the electrode current collector terminal can be improved. As a result, each electrode layer can be charged and discharged more uniformly, preventing overcharging or over-discharging of specific battery cells, and improving the reliability of the battery.

[0035] Furthermore, since the counter electrode current collector terminal and the electrode current collector terminal are provided on different main surfaces, they can be formed as large current collector terminals that cover a large portion of each main surface, for example. This allows for lower resistance of the current collector terminals, thereby improving high-current characteristics.

[0036] Furthermore, for example, the thickness of the electrode extraction layer in the third portion may be greater than the thickness of the electrode extraction layer in the fourth portion.

[0037] This allows for easier battery manufacturing by simply adjusting the thickness of the electrode extraction layer to reduce the resistance of the third section and improve current uniformity.

[0038] Furthermore, for example, the first side surface and the second side surface face away from each other, and when the power generation element is cut along the stacking direction at a position passing through the first side surface and the second side surface, the cross-sectional shape of the power generation element is trapezoidal, and the interior angle formed by the first side surface and the first main surface and the interior angle formed by the second side surface and the first main surface may each be obtuse angles.

[0039] As a result, even if the counter electrode extraction layer is thicker in the first portion closer to the counter electrode current collector terminal than in the second portion, and the electrode extraction layer is thicker in the third portion closer to the electrode current collector terminal than in the fourth portion, the overall shape of the battery can be made closer to a rectangular parallelepiped. Therefore, when mounting the battery on a substrate, unnecessary space is less likely to be formed, improving the mountability of the battery on the substrate.

[0040] Furthermore, for example, the battery further comprises, on the second side surface of the power generation element, a counter electrode insulating member covering the counter electrode layer of each of the plurality of battery cells; an electrode extraction layer covering the second side surface and the counter electrode insulating member and electrically connected to the electrode layer of each of the plurality of battery cells; and an electrode current collector terminal provided on the second main surface of the power generation element opposite to the first main surface and connected to the electrode extraction layer, wherein the resistance of the third portion of the electrode extraction layer connected to the electrode layer of the battery cell closest to the second main surface among the plurality of battery cells may be smaller than the resistance of the fourth portion of the counter electrode extraction layer connected to the electrode layer of the battery cell furthest from the second main surface among the plurality of battery cells.

[0041] This makes it possible to create batteries with higher performance.

[0042] Specifically, on the second side of the power generation element, the counter electrode insulating member covers the counter electrode layer, and the electrode extraction layer functions as a parallel connection for multiple battery cells. Therefore, similar to the electrode insulating member and the counter electrode extraction layer, the reliability and energy density of the battery can be increased.

[0043] Furthermore, in the electrode extraction layer, the third portion, which is connected to the electrode layer closest to the electrode current collector terminal, carries current corresponding to all electrode layers of multiple battery cells. On the other hand, the fourth portion, which is connected to the electrode layer furthest from the electrode current collector terminal, carries current corresponding to one electrode layer. In the electrode extraction layer, the resistance of the third portion is smaller than that of the fourth portion. Therefore, the current flowing in the electrical connection path between the electrode layer and the electrode current collector terminal flows more easily in the third portion, where current corresponding to all electrode layers flows, than in the fourth portion, where current corresponding to one electrode layer flows. Thus, the uniformity of the current flowing between each electrode layer and the electrode current collector terminal can be improved. As a result, each electrode layer can be charged and discharged more uniformly, preventing overcharging and over-discharging of specific battery cells, and improving the reliability of the battery.

[0044] Furthermore, since the counter electrode current collector terminal and the electrode current collector terminal are located on the same main surface, battery mounting becomes easier. In addition, the shape and arrangement of the current collector terminals can be adjusted according to the wiring layout of the mounting board, for example, thus increasing the flexibility of connections.

[0045] Furthermore, since both the positive and negative terminals are located on the same main surface, the battery can be mounted compactly. For example, the pattern of connection terminals (also called the footprint) formed on the mounting substrate can be reduced. In addition, mounting becomes possible with the main surface of the power generation element and the mounting substrate arranged parallel to each other, enabling low-profile mounting on the substrate.

[0046] Furthermore, for example, the thickness of the electrode extraction layer in the third portion may be greater than the thickness of the electrode extraction layer in the fourth portion.

[0047] This allows for easier battery manufacturing by simply adjusting the thickness of the electrode extraction layer to reduce the resistance of the third section and improve current uniformity.

[0048] Furthermore, for example, the first side surface and the second side surface face away from each other, and when the power generation element is cut along the stacking direction at a position passing through the first side surface and the second side surface, the cross-sectional shape of the power generation element is a parallelogram, and the interior angle formed by the first side surface and the first main surface and the interior angle formed by the second side surface and the second main surface may each be obtuse angles.

[0049] As a result, even if the counter electrode extraction layer is thicker in the first portion closer to the counter electrode current collector terminal than in the second portion, and the electrode extraction layer is thicker in the third portion closer to the electrode current collector terminal than in the fourth portion, the overall shape of the battery can be made closer to a rectangular parallelepiped. Therefore, when mounting the battery on a substrate, unnecessary space is less likely to be formed, improving the mountability of the battery on the substrate.

[0050] Furthermore, for example, the electrode current collector terminal is a current collector that constitutes the second main surface, and the thickness of the electrode current collector terminal may be greater than the thickness of the current collector included in one of the plurality of battery cells.

[0051] This allows for a reduction in the number of components by using electrode current collectors as electrode current collector terminals. Furthermore, by making the electrode current collectors used as electrode current collector terminals thicker than other current collectors, it is easy to achieve low resistance in the electrode current collector terminals.

[0052] Furthermore, for example, the height of the electrode extraction layer from the second side surface may increase as it approaches the electrode current collection terminal along the stacking direction of the power generation element.

[0053] As a result, in the electrode extraction layer, the thickness of the electrode extraction layer increases and the resistance decreases in the portion of the electrode extraction layer that is connected to the electrode current collection terminal. Therefore, the uniformity of the current flowing between each electrode layer and the electrode current collection terminal can be further improved.

[0054] Furthermore, for example, the electrode insulating member may contain resin.

[0055] 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.

[0056] Furthermore, for example, the battery may further include a sealing member that exposes at least a portion of the counter electrode current collector terminal and seals the power generation element and the counter electrode extraction layer.

[0057] This protects the power generation elements from the outside air and water, further enhancing the reliability of the battery.

[0058] Furthermore, a method for manufacturing a battery according to one aspect of the present disclosure includes the steps 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; 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 for each battery cell; covering each of the electrode layers of the plurality of battery cells with an electrode insulating member on the first side surface of the laminate; and covering the first side surface and the electrode insulating member with each of the plurality of battery cells. The steps include covering the counter electrode layer with a counter electrode extraction layer electrically connected to the counter electrode layer, and providing a counter electrode current collector terminal connected to the counter electrode extraction layer on the first main surface of the laminate, wherein in the step of covering with the counter electrode extraction layer, the counter electrode extraction layer is formed such that the resistance of the first portion of the counter electrode extraction layer connected to the counter electrode layer of the battery cell closest to the first main surface among the plurality of battery cells is smaller than the resistance of the second portion of the counter electrode extraction layer connected to the counter electrode layer of the battery cell furthest from the first main surface among the plurality of battery cells.

[0059] This makes it possible to manufacture the high-performance batteries mentioned above.

[0060] Furthermore, for example, in the step of covering with the counter electrode extraction layer, the counter electrode extraction layer may be formed such that the thickness of the counter electrode extraction layer in the first portion is greater than the thickness of the counter electrode extraction layer in the second portion.

[0061] This allows for easy battery manufacturing because the resistance of the first part can be reduced simply by adjusting the thickness of the counter electrode extraction layer.

[0062] The embodiments will be described in detail below with reference to the drawings.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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."

[0069] Furthermore, in this specification, the expression "cover A" means to cover at least a part of "A". In other words, "cover A" includes not only the case of "covering all of A" but also the case of "covering only a part of A". "A" is, for example, the side and main surface of a predetermined member such as a layer or terminal.

[0070] 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.

[0071] (Embodiment 1) The configuration of the battery according to Embodiment 1 will be described below.

[0072] Figure 1 is a cross-sectional view 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 extraction layer 31, an electrode extraction layer 32, a counter electrode current collector terminal 41, an electrode current collector terminal 42, a counter electrode intermediate layer 51, and an electrode intermediate layer 52. The battery 1 is, for example, an all-solid-state battery.

[0073] [1. Power generation elements] First, the specific configuration of the power generation element 10 will be explained using Figures 1, 2A, and 2B. Figure 2A is a top view of the battery 1 according to this embodiment. Figure 2B is a bottom view of the battery 1 according to this embodiment. Note that Figure 1 shows a cross-section along line II in Figures 2A and 2B.

[0074] The plan view shape of the power generation element 10 is rectangular, as shown in Figures 2A and 2B, for example. 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 other polygons such as a square, hexagon, or octagon, or it may be circular or elliptical. As mentioned above, the power generation element 10 is actually flattened, but 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.

[0075] 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, 2A, and 2B. In this embodiment, the side surfaces 11, 12, 13, and 14, as well as the main surfaces 15 and 16, are all flat surfaces.

[0076] Side 11 is an example of a first side. Side 12 is an example of a second side. Sides 11 and 12 are facing away from each other and are parallel to each other. Sides 13 and 14 are facing away from each other and are parallel to each other. Sides 11, 12, 13 and 14 are, for example, cut surfaces formed by cutting a stack of multiple battery cells 100 all at once. Also, sides 11, 12, 13 and 14 are erected perpendicular to the main surfaces 15 and 16 from each side of the main surfaces 15 and 16. Sides 11, 12, 13 and 14 are parallel to the stacking direction. Sides 11, 12, 13 and 14 are formed by cutting along the stacking direction when cutting a stack of multiple battery cells 100 all at once. Therefore, the cutting process can be simplified. Also, since the area of ​​each layer of the battery cell 100 is precisely determined by cutting, the variation in the capacity of the battery 1 can be reduced and the accuracy of the battery capacity can be improved.

[0077] Main surface 15 is an example of a first main surface. Main surface 16 is an example of a second main surface. 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. Main surfaces 15 and 16 have a larger area than sides 11, 12, 13, and 14, respectively.

[0078] Furthermore, as shown in Figure 1, the cross-sectional shape of the power generation element 10 when cut along the stacking direction at a position passing through sides 11 and 12 is rectangular.

[0079] As shown in Figure 1, the power generation element 10 has a plurality of battery cells 100. A battery cell 100 is, for example, a minimal battery 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 7 battery cells 100, but 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 2 or 4, or an odd number such as 3 or 5.

[0080] 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.

[0081] 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.

[0082] 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 odd, the bottom layer and top layer of the power generation element 10 become current collectors of opposite polarity, respectively.

[0083] 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.

[0084] 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.

[0085] 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 main surface of the electrode current collector 111 is in contact with the electrode active material layer 112. The electrode current collector 111 may also include a current collector layer containing a conductive material, provided in the portion that is in contact with the electrode active material layer 112. The main surface of 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, provided in the portion that is in contact with the counter electrode active material layer 122.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] Furthermore, in this embodiment, the end face of the counter electrode layer 120 on the side surface 11 and the end face of the electrode layer 110 on the side surface 11 coincide when viewed along the direction in which the layers of the battery cell 100 are aligned and the direction in which the side surface 11 extends, that is, when viewed from the z-axis direction in this embodiment. 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 along the direction in which the layers of the battery cell 100 are aligned and the direction in which the side surface 11 extends. The same applies to the end faces of the side surfaces 12 of the counter electrode current collector 121 and the electrode current collector 111, respectively.

[0098] 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 each have the same shape and size, and their contours match. In other words, the shape of the battery cell 100 is a flat, rectangular parallelepiped-like plate shape. Note that the counter electrode current collector 121 may protrude beyond the end faces of the electrode active material layer 112, solid electrolyte layer 130, and counter electrode active material layer 122 on its side surface 11. Also, the counter electrode active material layer 122 may be recessed from the counter electrode current collector 121 on its side surface 11. Similarly, the electrode current collector 111 may protrude beyond the end faces of the electrode active material layer 112, solid electrolyte layer 130, and counter electrode active material layer 122 on its side surface 12. Also, the electrode active material layer 112 may be recessed from the electrode current collector 111 on its side surface 12. This structure, in which the main surface of the current collector is exposed, increases the contact area between the current collector and the extraction layer. Such a structure is formed, for example, by processing the ends of the battery cell 100 by partial cutting, polishing, sandblasting, brushing, etching, or plasma irradiation.

[0099] 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 one electrode current collector 111.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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 at the bottom, and battery cells 100B and 100C are stacked alternately upwards. At this time, battery cells 100A and 100B are stacked upside down compared to the orientation shown in Figure 3A or Figure 3B. This forms the power generation element 10.

[0105] The method for forming the power generation element 10 is not limited to this. For example, a battery cell 100A may be placed on the top layer. Alternatively, a battery cell 100A may be placed at a position different from both the top and bottom layers. Multiple battery cells 100A may also be used. Furthermore, by applying double-sided coating to a single current collector, two units of battery cells 100 sharing a current collector may be formed, and these formed units may be stacked.

[0106] 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.

[0107] [2. Insulating layer] Next, the electrode insulating layer 21 and the counter electrode insulating layer 22 will be described.

[0108] The electrode insulating layer 21 is an example of an electrode 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.

[0109] Figure 5 is a side view showing the positional relationship between the side surface 11 of the power generation element 10 according to this embodiment and the electrode insulating layer 21 provided on the side surface 11. In Figure 5, the end faces of each layer visible on the side surface 11 are shaded in the same way as the shading shown for each layer in the cross-section of Figure 1. The same applies to Figure 6, which will be described later.

[0110] Figure 5(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 5(b) shows the side 11 of Figure 5(a) and the electrode insulating layer 21 provided on the side 11. In other words, Figure 5(b) is a side view of the battery 1 of Figure 1 as seen from the negative side of the x-axis, with the counter electrode extraction layer 31 visible through it.

[0111] As shown in Figure 5(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. For example, the electrode insulating layer 21 does not cover the counter electrode current collector 121. Therefore, the electrode insulating layer 21 has a striped shape in a plan view of the side surface 11.

[0112] 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.

[0113] 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 extraction layer 31 which is 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 improving insulation reliability.

[0114] 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. Furthermore, the electrode insulating layer 21 may cover not only the electrode layer 110, but also the entire solid electrolyte layer 130 and a portion of the counter electrode layer 120 on its side surface 11. In other words, the electrode insulating layer 21 may cover from the electrode layer 110 to a portion of the counter electrode layer 120, for example, at least a portion of the counter electrode active material layer 122.

[0115] In Figure 5(b), the electrode insulating layer 21 is provided separately for each electrode layer 110, but this is not limited to this. For example, the electrode insulating layer 21 may be provided not only in the stripe-shaped portion but also along the z-axis direction at the end of the side surface 11 in the y-axis direction. 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.

[0116] Furthermore, in the power generation element 10 according to this embodiment, the lowest layer is the electrode current collector 111. As shown in Figures 1 and 5(b), near the lower end of the side surface 11, the electrode insulating layer 21 covers a portion of the main surface (i.e., the main surface 16) of the electrode current collector 111 where the lowest layer is located. 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 extraction layer 31 wraps around to the main surface 16 of the power generation element 10, it can contact the electrode current collector 111 and prevent a short circuit from occurring. In this way, the reliability of the battery 1 can be improved.

[0117] The counter electrode insulating layer 22 is an example of a counter electrode 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.

[0118] Figure 6 is a side view showing the positional relationship between the side surface 12 of the power generation element 10 according to this embodiment and the counter electrode insulating layer 22 provided on the side surface 12. Figure 6(a) is a side view of the power generation element 10, and is a plan view of the side surface 12 as seen from the front. Figure 6(b) shows the side surface 12 of Figure 6(a) and the counter electrode insulating layer 22 provided on the side surface 12. In other words, Figure 6(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 extraction layer 32 visible through it.

[0119] As shown in Figure 6(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. For example, the counter electrode insulating layer 22 does not cover the electrode current collector 111. Therefore, the counter electrode insulating layer 22 has a striped shape in a plan view of the side surface 12.

[0120] 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.

[0121] 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 extraction layer 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.

[0122] 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 with 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 with the boundary between the solid electrolyte layer 130 and the counter electrode active material layer 122. Furthermore, the counter electrode insulating layer 22 may cover not only the counter electrode layer 120, but also the entire solid electrolyte layer 130 and a portion of the electrode layer 110 on its side surface 12. In other words, the counter electrode insulating layer 22 may cover from the counter electrode layer 120 to a portion of the electrode layer 110, for example, at least a portion of the electrode active material layer 112.

[0123] In Figure 6(b), the counter electrode insulating layer 22 is provided separately for each counter electrode layer 120, but this is not limited to this. For example, in addition to the stripe-shaped portion, the counter electrode insulating layer 22 may be provided along the z-axis direction 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.

[0124] Furthermore, in the power generation element 10 according to this embodiment, the uppermost layer is the counter electrode current collector 121. As shown in Figures 1 and 6(b), near the upper end of the side surface 12, the counter electrode insulating layer 22 covers a portion of the main surface (i.e., the main surface 15) of the counter electrode current collector 121 located in the uppermost layer. 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 extraction layer 32 wraps around to the main surface 15 of the power generation element 10, it can contact the counter electrode current collector 121 and prevent a short circuit from occurring. In this way, the reliability of the battery 1 can be improved.

[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] [3. Removal layer] Next, the counter electrode extraction layer 31 and the electrode extraction layer 32 will be described.

[0127] As shown in Figure 1, the counter electrode extraction layer 31 is a conductive portion that 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 extraction layer 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.

[0128] As shown in Figure 5(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 extraction layer 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 powdered material, it has very fine irregularities, similar to the solid electrolyte layer 130. The adhesion strength of the counter electrode extraction layer 31 is improved as the counter electrode extraction layer 31 fits into the irregularities of the end face of the counter electrode active material layer 122, thereby improving the reliability of the electrical connection.

[0129] The counter electrode extraction layer 31 is electrically connected to each of the counter electrode layers 120 of the multiple battery cells 100. In other words, the counter electrode extraction layer 31 is responsible for electrically connecting each battery cell 100 in parallel. As shown in Figure 1, the counter electrode extraction layer 31 covers almost the entire surface from the bottom end to the top end of the side surface 11.

[0130] In the power generation element 10 according to this embodiment, the uppermost layer is the counter electrode current collector 121. As shown in Figure 1, at the upper end of the side surface 11, the counter electrode extraction layer 31 covers a part of the main surface of the counter electrode current collector 121 located in the uppermost layer, that is, the main surface 15 of the power generation element 10. As a result, the counter electrode extraction layer 31 is resistant to external forces from the z-axis direction and detachment is suppressed. In addition, since the contact area between the counter electrode extraction layer 31 and the counter electrode current collector 121 is increased, the connection resistance between the counter electrode extraction layer 31 and the counter electrode current collector 121 is reduced, and the high-current characteristics can be improved. For example, rapid charging of the battery 1 becomes possible. Note that if the uppermost layer is the electrode current collector 111, the counter electrode extraction layer 31 may cover the main surface 15 via an insulating layer that covers the electrode current collector 111.

[0131] Furthermore, the counter electrode extraction layer 31 includes a first portion P1 connected to the counter electrode layer 120 of the battery cell 100 closest to the main surface 15 among the multiple battery cells 100, and a second portion P2 connected to the counter electrode layer 120 of the battery cell 100 furthest from the main surface 15 among the multiple battery cells 100. Specifically, the first portion P1 is the part of the counter electrode extraction layer 31 that is at the same distance in the stacking direction from the main surface 15 as the counter electrode layer 120 of the battery cell 100 closest to the main surface 15 among the multiple battery cells 100. Specifically, the second portion P2 is the part of the counter electrode extraction layer 31 that is at the same distance in the stacking direction from the main surface 15 as the counter electrode layer 120 of the battery cell 100 furthest from the main surface 15 among the multiple battery cells 100. Furthermore, in this embodiment, since the counter electrode current collector terminal 41 is located on the main surface 15, the battery cells 100 that are close to or far from the main surface 15 can be rephrased as the battery cells 100 that are close to or far from the counter electrode current collector terminal 41. For example, the first part P1 and the second part P2 are each in contact with the corresponding counter electrode layer 120.

[0132] In the counter electrode extraction layer 31, the resistance of the first portion P1 is smaller than the resistance of the second portion P2. Specifically, this resistance is the electrical resistance to the current flowing in the electrical connection path between the counter electrode layer 120 and the counter electrode current collector terminal 41. In battery 1, the connection between battery 1 and the wiring circuit (load) is made via the counter electrode current collector terminal 41 and the electrode current collector terminal 42. Because the resistance of the first portion P1 is smaller than the resistance of the second portion P2, the current flowing in the electrical connection path between the counter electrode layer 120 and the counter electrode current collector terminal 41 flows more easily in the first portion P1, through which the current corresponding to all the counter electrode layers 120 of the multiple battery cells 100 flows, than in the second portion P2, through which the current corresponding to one counter electrode layer 120 flows. Therefore, the uniformity of the current flowing between each counter electrode layer 120 and the counter electrode current collector terminal 41 can be improved. As a result, each counter electrode layer 120 can be charged and discharged more uniformly, and overcharging and over-discharging of a particular battery cell 100 can be suppressed. This effect is particularly noticeable when charging and discharging with high currents.

[0133] In this embodiment, the thickness of the counter electrode extraction layer 31 in the first portion P1 is greater than the thickness of the counter electrode extraction layer 31 in the second portion P2. In other words, the height of the first portion P1 from the side surface 11 is greater than the height of the second portion P2 from the side surface 11. As a result, when the counter electrode extraction layer 31 is cut along the thickness direction, the cross-sectional area of ​​the first portion P1 is larger than that of the second portion P2, and the resistance of the first portion P1 is smaller than that of the second portion P2. Thus, the effect of improving the uniformity of the current as described above can be obtained simply by adjusting the thickness of the counter electrode extraction layer 31, making it easy to form the battery 1.

[0134] Furthermore, the height of the counter electrode extraction layer 31 from the side surface 11 increases along the stacking direction as it approaches the counter electrode current collector terminal 41 (i.e., as it approaches the main surface 15). As a result, the thickness of the counter electrode extraction layer 31 increases and the resistance decreases in the portion of the counter electrode extraction layer 31 that is connected to the counter electrode layer 120 that is closer to the counter electrode current collector terminal 41. Therefore, the uniformity of the current flowing between each counter electrode layer 120 and the counter electrode current collector terminal 41 can be further improved. The height of the counter electrode extraction layer 31 from the side surface 11 is, in other words, the distance between the side surface 11 and the side surface 11 of the counter electrode extraction layer 31. In the example shown in Figure 1, the height of the counter electrode extraction layer 31 increases in a gentle curve, but it is not limited to this, and it may increase in a straight line or in a stepped manner.

[0135] As shown in Figure 1, the electrode extraction layer 32 is a conductive portion that covers the side surface 12 and the counter electrode insulating layer 22 and is electrically connected to the electrode layer 110. Specifically, the electrode extraction layer 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.

[0136] As shown in Figure 6(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 extraction layer 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 powdered material, it has very fine irregularities, similar to the solid electrolyte layer 130. The electrode extraction layer 32 fits into the irregularities of the end face of the electrode active material layer 112, improving the adhesion strength of the electrode extraction layer 32 and improving the reliability of the electrical connection.

[0137] The electrode extraction layer 32 is electrically connected to each electrode layer 110 of the multiple battery cells 100. In other words, the electrode extraction layer 32 is responsible for electrically connecting each battery cell 100 in parallel. As shown in Figure 1, the electrode extraction layer 32 covers almost the entire surface from the bottom to the top of the side surface 12.

[0138] In the power generation element 10 according to this embodiment, the bottom layer is the electrode current collector 111. As shown in Figure 1, at the lower end of the side surface 12, the electrode extraction layer 32 covers a part of the main surface of the electrode current collector 111 located in the bottom layer, that is, the main surface 16 of the power generation element 10. As a result, the electrode extraction layer 32 is resistant to external forces from the z-axis direction and detachment is suppressed. In addition, since the contact area between the electrode extraction layer 32 and the electrode current collector 111 is increased, the connection resistance between the electrode extraction layer 32 and the electrode current collector 111 is reduced, and the high-current characteristics can be improved. For example, rapid charging of the battery 1 becomes possible. If the top layer is the counter electrode current collector 121, the counter electrode extraction layer 31 may cover the main surface 16 via an insulating layer that covers the counter electrode current collector 121.

[0139] Furthermore, the electrode extraction layer 32 includes a third portion P3 connected to the electrode layer 110 of the battery cell 100 closest to the main surface 16 among the multiple battery cells 100, and a fourth portion P4 connected to the electrode layer 110 of the battery cell 100 furthest from the main surface 16 among the multiple battery cells 100. Specifically, the third portion P3 is the part of the electrode extraction layer 32 that is at the same distance in the stacking direction from the main surface 16 as the electrode layer 110 of the battery cell 100 closest to the main surface 16 among the multiple battery cells 100. Furthermore, the fourth portion P4 is the part of the electrode extraction layer 32 that is at the same distance in the stacking direction from the main surface 16 as the electrode layer 110 of the battery cell 100 furthest from the main surface 16 among the multiple battery cells 100. Furthermore, in this embodiment, since the electrode current collector terminal 42 is located on the main surface 16, the battery cells 100 that are close to or far from the main surface 16 can be rephrased as the battery cells 100 that are close to or far from the electrode current collector terminal 42. For example, the third portion P3 and the fourth portion P4 are in contact with the corresponding electrode layer 110, respectively.

[0140] In the electrode extraction layer 32, the resistance of the third portion P3 is smaller than the resistance of the fourth portion P4. Specifically, this resistance is the electrical resistance to the current flowing in the electrical connection path between the electrode layer 110 and the electrode current collector terminal 42. In the battery 1, the connection between the battery 1 and the wiring circuit (load) is made via the counter electrode current collector terminal 41 and the electrode current collector terminal 42. Because the resistance of the third portion P3 is smaller than the resistance of the fourth portion P4, the current flowing in the electrical connection path between the electrode layer 110 and the electrode current collector terminal 42 flows more easily in the third portion P3, through which the current corresponding to all electrode layers 110 of the multiple battery cells 100 flows, than in the fourth portion P4, through which the current corresponding to one electrode layer 110 flows. Therefore, the uniformity of the current flowing between each electrode layer 110 and the electrode current collector terminal 42 can be improved. As a result, each electrode layer 110 can be charged and discharged more uniformly, and overcharging and over-discharging of a particular battery cell 100 can be suppressed. This effect is particularly noticeable when charging and discharging with high currents.

[0141] In this embodiment, the thickness of the electrode extraction layer 32 in the third portion P3 is greater than the thickness of the electrode extraction layer 32 in the fourth portion P4. In other words, the height of the third portion P3 from the side surface 12 is greater than the height of the fourth portion P4 from the side surface 12. As a result, when the electrode extraction layer 32 is cut along the thickness direction, the cross-sectional area of ​​the third portion P3 is larger than that of the fourth portion P4, and the resistance of the third portion P3 is smaller than that of the fourth portion P4. In this way, the effect of improving the uniformity of the current as described above can be obtained simply by adjusting the thickness of the electrode extraction layer 32, and the battery 1 can be easily formed.

[0142] Furthermore, the height of the electrode extraction layer 32 from the side surface 12 increases along the stacking direction as it approaches the electrode current collection terminal 42 (i.e., as it approaches the main surface 16). As a result, the electrode extraction layer 32 becomes thicker and has lower resistance in the portion of the electrode extraction layer 32 that is connected to the electrode layer 110 that is closer to the electrode current collection terminal 42. Therefore, the uniformity of the current flowing between each electrode layer 110 and the electrode current collection terminal 42 can be further improved. The height of the electrode extraction layer 32 from the side surface 12 is, in other words, the distance between the side surface 12 and the side surface 12 of the electrode extraction layer 32. In the example shown in Figure 1, the height of the electrode extraction layer 32 increases in a gentle curve, but it is not limited to this, and it may increase in a straight line or in a stepped manner.

[0143] The counter electrode extraction layer 31 and the electrode extraction layer 32 are formed using a conductive resin material or the like. The conductive resin material includes, for example, a resin and a conductive material composed of metal particles or the like that is filled into the resin. Alternatively, the counter electrode extraction layer 31 and the electrode extraction layer 32 may be formed using a metal 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 extraction layer 31 and the electrode extraction layer 32 are formed using the same material, but they may be formed using different materials.

[0144] [4. Current collector terminal] Next, the counter electrode current collector terminal 41 and the electrode current collector terminal 42 will be described.

[0145] The counter electrode current collector terminal 41 is a conductive terminal connected to the counter electrode extraction layer 31. The counter electrode current collector terminal 41 is one of the external connection terminals of the battery 1, and in this embodiment, it is the positive electrode extraction terminal. As shown in Figure 1, the counter electrode current collector terminal 41 is arranged on the main surface 15 of the power generation element 10 via the counter electrode intermediate layer 51.

[0146] As shown in Figure 2A, the counter electrode current collector terminal 41 is positioned away from the side surface 11 in a plan view of the main surface 15. In other words, the counter electrode extraction layer 31 is provided so as to cover the area of ​​the main surface 15 between the side surface 11 and the counter electrode current collector terminal 41. The counter electrode extraction layer 31 continuously covers from the side surface 11 to the main surface 15 and is connected to the counter electrode current collector terminal 41. At this time, the height of the counter electrode extraction layer 31 from the main surface 15 is less than or equal to the height of the counter electrode current collector terminal 41 from the main surface 15. In other words, the counter electrode extraction layer 31 is in contact with the end face of the counter electrode current collector terminal 41 without covering its upper surface. Since the upper surface of the counter electrode current collector terminal 41 is the uppermost surface of the battery 1, connection to the counter electrode current collector terminal 41 can be easily made when mounting the battery 1. Furthermore, as shown in the positional relationship between the electrode extraction layer 32 and the electrode current collector terminal 42 below, the counter electrode extraction layer 31 may cover the upper surface of the counter electrode current collector terminal 41.

[0147] The electrode current collector terminal 42 is a conductive terminal connected to the electrode extraction layer 32. The electrode current collector terminal 42 is one of the external connection terminals of the battery 1, and in this embodiment, it is the negative electrode extraction terminal. As shown in Figure 1, the electrode current collector terminal 42 is arranged on the main surface 16 of the power generation element 10 via the electrode intermediate layer 52.

[0148] As shown in Figure 2B, the electrode current collector terminal 42 is positioned away from the side surface 12 in a plan view of the main surface 16. In other words, the electrode extraction layer 32 is provided so as to cover the area of ​​the main surface 16 between the side surface 12 and the electrode current collector terminal 42. The electrode extraction layer 32 continuously covers from the side surface 12 to the main surface 16 and is connected to the electrode current collector terminal 42. At this time, the height of the electrode extraction layer 32 from the main surface 16 is greater than or equal to the height of the electrode current collector terminal 42 from the main surface 16. In other words, the electrode extraction layer 32 covers the lower surface of the electrode current collector terminal 42 and is in contact with the end face of the electrode current collector terminal 42. By covering the lower surface of the electrode current collector terminal 42 with the electrode extraction layer 32, detachment of the electrode current collector terminal 42 can be suppressed. Note that, as with the positional relationship between the counter electrode extraction layer 31 and the counter electrode current collector terminal 41 described above, the electrode extraction layer 32 does not necessarily have to cover the lower surface of the electrode current collector terminal 42.

[0149] As described above, in this embodiment, the counter electrode current collector terminal 41 and the electrode current collector terminal 42 are provided on the main surfaces 15 and 16 of the power generation element 10, respectively, which are different from each other. Since the two terminals with different polarities are arranged far apart, the occurrence of short circuits can be suppressed. In addition, since the battery 1 can be used by sandwiching it between the wiring terminals, it can be easily attached and detached.

[0150] In this embodiment, the counter current collector terminal 41 has higher conductivity than, for example, the counter current collector body 121. For example, the thickness (length in the z-axis direction) of the counter current collector terminal 41 is greater than the thickness of the counter current collector body 121. Also, as shown in Figure 2A, the counter current collector terminal 41 is provided so as to occupy more than half of the main surface 15. For example, the length of the counter current collector terminal 41 (i.e., the length in the x-axis direction) is more than half the length of the sides 13 and 14 (i.e., the length in the x-axis direction). For example, the width of the counter current collector terminal 41 (i.e., the length in the y-axis direction) is more than half the width of the side 11 (i.e., the length in the y-axis direction). The width of the counter current collector terminal 41 can be made equal to the width of the counter extraction layer 31 (i.e., the length in the y-axis direction). This makes it possible to widen the width in the direction in which current flows from the counter extraction layer 31 to the counter current collector terminal 41, thereby reducing resistance and being effective for extracting large currents. Furthermore, since the area of ​​the counter electrode current collector terminal 41 can be made large, when mounted on a mounting board (not shown), the contact area with the conductive part of the mounting board can be increased, and the contact resistance can be reduced. From this point of view as well, it is effective for extracting large currents. In this specification, "high conductivity" of a component does not mean that the electrical resistivity inherent to the material constituting the component is low, but rather that the value obtained by dividing the cross-sectional area perpendicular to the direction of current flow by the electrical resistivity is large.

[0151] The electrode current collector terminal 42 has higher conductivity than, for example, the electrode current collector body 111. For example, the thickness (length in the z-axis direction) of the electrode current collector terminal 42 is greater than the thickness of the electrode current collector body 111. Also, as shown in Figure 2B, the electrode current collector terminal 42 is provided so as to occupy more than half of the main surface 16. For example, the length of the electrode current collector terminal 42 (i.e., the length in the x-axis direction) is more than half the length of the sides 13 and 14 (i.e., the length in the x-axis direction). For example, the width of the electrode current collector terminal 42 (i.e., the length in the y-axis direction) is more than half the width of the side 12 (i.e., the length in the y-axis direction). The width of the electrode current collector terminal 42 can be made equal to the width of the electrode extraction layer 32 (i.e., the length in the y-axis direction). This makes it possible to widen the width in the direction in which current flows from the electrode extraction layer 32 to the electrode current collector terminal 42, thereby lowering the resistance and being effective for extracting large currents. Furthermore, since the area of ​​the electrode current collection terminal 42 can be made larger, when mounted on a mounting board (not shown), the contact area with the conductive part of the mounting board can be increased, and the contact resistance can be reduced. From this point of view as well, it is effective for extracting large currents.

[0152] The counter current collector terminal 41 and the electrode current collector terminal 42 are each formed using a conductive material. For example, the counter current collector terminal 41 and the electrode current collector terminal 42 are metal foils or metal plates made of metals such as copper, aluminum, or stainless steel. Alternatively, the counter current collector terminal 41 and the electrode current collector terminal 42 may be hardened solder.

[0153] [5. Middle Class] Next, the counter electrode intermediate layer 51 and the electrode intermediate layer 52 will be described.

[0154] The counter electrode intermediate layer 51 is positioned between the counter electrode current collector terminal 41 and the main surface 15. In this embodiment, since the main surface 15 is the main surface of the counter electrode current collector 121, it is not necessary to ensure insulation between the counter electrode current collector terminal 41 and the main surface 15. For this reason, the counter electrode intermediate layer 51 may be a conductive layer. Furthermore, the counter electrode intermediate layer 51 may not be provided at all.

[0155] The electrode intermediate layer 52 is positioned between the electrode current collector terminal 42 and the main surface 16. In this embodiment, since the main surface 16 is the main surface of the electrode current collector 111, it is not necessary to ensure insulation between the electrode current collector terminal 42 and the main surface 16. For this reason, the electrode intermediate layer 52 may be a conductive layer. Furthermore, the electrode intermediate layer 52 may not be provided at all.

[0156] The shape and size of the counter electrode intermediate layer 51 in plan view are the same as, but not limited to, the counter electrode current collector terminal 41. For example, the counter electrode intermediate layer 51 may be larger or smaller than the counter electrode current collector terminal 41 in plan view. For example, the counter electrode intermediate layer 51 may cover the entire surface of the main surface 15.

[0157] The shape and size of the electrode intermediate layer 52 in plan view are the same as, but not limited to, the electrode current collector terminal 42. For example, the electrode intermediate layer 52 may be larger or smaller than the electrode current collector terminal 42 in plan view. For example, the electrode intermediate layer 52 may cover the entire area of ​​the main surface 16.

[0158] The counter electrode intermediate layer 51 and the electrode intermediate layer 52 are formed using, for example, an electrically insulating material. For example, the counter electrode intermediate layer 51 and the electrode intermediate layer 52 each contain a resin. The resin is, for example, an epoxy resin, but is not limited thereto. Inorganic materials may also be used as the insulating material. The counter electrode intermediate layer 51 and the electrode intermediate layer 52 are formed using the same material, but they may also be formed using different materials. If the counter electrode intermediate layer 51 and the electrode intermediate layer 52 are conductive layers, they can be formed using metal or a conductive resin, etc.

[0159] Furthermore, by providing the counter electrode intermediate layer 51 and the electrode intermediate layer 52, the heights of the counter electrode current collector terminal 41 and the electrode current collector terminal 42 from their respective main surfaces 15 and 16 can be adjusted.

[0160] In this embodiment, the arrangement of the counter electrode current collector terminal 41 and the electrode current collector terminal 42 may be reversed. That is, the counter electrode current collector terminal 41 may be located on the main surface 16, and the electrode current collector terminal 42 may be located on the main surface 15. In this case, since the main surface 16 is the main surface of the electrode current collector 111, an insulating layer, which is the counter electrode intermediate layer 51, is placed between the main surface 16 and the counter electrode current collector terminal 41 in order to ensure insulation between the main surface 16 and the counter electrode current collector terminal 41. Similarly, since the main surface 15 is the main surface of the counter electrode current collector 121, an insulating layer, which is the electrode intermediate layer 52, is placed between the main surface 15 and the electrode current collector terminal 42 in order to ensure insulation between the main surface 15 and the electrode current collector terminal 42.

[0161] The counter electrode intermediate layer 51 and the electrode intermediate layer 52 may have additional functions such as impact resistance, corrosion resistance, and waterproofing, in addition to ensuring insulation. Materials suitable for these functions can be used for the counter electrode intermediate layer 51 and the electrode intermediate layer 52. The counter electrode intermediate layer 51 and the electrode intermediate layer 52 may each have a laminated structure of multiple different materials.

[0162] [6. Summary] As described above, in the battery 1 according to this embodiment, the counter electrode extraction layer 31 and the electrode extraction layer 32 each serve the function of parallel connection of multiple battery cells 100. As shown in Figure 1, the counter electrode extraction layer 31 and the electrode extraction layer 32 are formed to closely cover the sides 11 and 12 of the power generation element 10, respectively, so their volumes can be reduced. In other words, the volume of the terminal electrodes is smaller compared to the tab electrodes used for current collection in the past, so the energy density per unit volume of the battery 1 can be improved.

[0163] Furthermore, since the counter electrode current collector terminal 41, which is a different component from the counter electrode current collector 121 located at the top layer, is provided via the counter electrode intermediate layer 51, which is an insulating layer, current concentration on the uppermost counter electrode current collector 121 can be suppressed. According to this embodiment, the counter electrode extraction layer 31 and the counter electrode current collector terminal 41, as well as the electrode extraction layer 32 and the electrode current collector terminal 42, are used as current paths from each battery cell 100. Therefore, current concentration on the uppermost counter electrode current collector 121 can be suppressed, and the reliability of the battery 1 can be improved. The same can be said for the electrode current collector terminal 42 and the electrode intermediate layer 52 at the bottom layer.

[0164] Furthermore, in the counter electrode extraction layer 31, the first portion P1, which is connected to the counter electrode layer 120 closest to the counter electrode current collector terminal 41, carries current corresponding to all the counter electrode layers 120 of the multiple battery cells 100. On the other hand, the second portion P2, which is connected to the counter electrode layer 120 furthest from the counter electrode current collector terminal 41, carries current corresponding to one counter electrode layer 120. In the counter electrode extraction layer 31, the resistance of the first portion P1 is smaller than the resistance of the second portion P2, so the current flowing in the electrical connection path between the counter electrode layer 120 and the counter electrode current collector terminal 41 flows more easily in the first portion P1, where current corresponding to all counter electrode layers 120 flows, than in the second portion P2, where current corresponding to one counter electrode layer 120 flows. Therefore, the uniformity of the current flowing between each counter electrode layer 120 and the counter electrode current collector terminal 41 can be improved. As a result, each counter electrode layer 120 can be charged and discharged uniformly, preventing overcharging and over-discharging of specific battery cells 100, thereby improving the reliability of the battery 1. The same applies to the electrode extraction layer 32.

[0165] (Embodiment 2) Next, Embodiment 2 will be described.

[0166] The battery according to Embodiment 2 differs from the battery according to Embodiment 1 in that the side surface of the power generation element is inclined with respect to the stacking direction. Below, we will mainly explain the differences from Embodiment 1, and the explanation of the common points will be omitted or simplified.

[0167] Figure 7 is a cross-sectional view of the battery 201 according to this embodiment. As shown in Figure 7, the battery 201 differs from the battery 1 according to Embodiment 1 in that it includes a power generation element 20 instead of a power generation element 10. The power generation element 20 includes side surfaces 211 and 212 that are inclined with respect to the stacking direction, instead of the side surfaces 11 and 12 of the power generation element 10. Although not shown, the power generation element 20 also includes side surfaces 13 and 14 that are parallel to the stacking direction, similar to the power generation element 10, as side surfaces other than side surfaces 211 and 212.

[0168] Side 211 is an example of a first side. Side 212 is an example of a second side. Sides 211 and 212 face away from each other and are parallel to each other. Also, side 211 and 212 are erected from two opposing sides of the main surfaces 15 and 16, respectively.

[0169] Side surface 211 is inclined with respect to the stacking direction such that the interior angle between side surface 211 and the main surface 15 is obtuse. Therefore, side surface 211 is inclined so that the side facing the main surface 16 is more outward than the side facing the main surface 15. Similarly, side surface 212 is inclined with respect to the stacking direction such that the interior angle between side surface 212 and the main surface 16 is obtuse. Therefore, side surface 212 is inclined so that the side facing the main surface 15 is more outward than the side facing the main surface 16. Furthermore, as shown in Figure 7, the cross-sectional shape of the power generation element 20 when cut along the stacking direction at a point passing through sides 211 and 212 is a parallelogram. As a result, even if the counter electrode extraction layer 31 is thicker in the first portion P1 closer to the counter electrode current collector terminal 41 than in the second portion P2, and the electrode extraction layer 32 is thicker in the third portion P3 closer to the electrode current collector terminal 42 than in the fourth portion P4, the angle of the outer surface of the counter electrode extraction layer 31 with respect to the main surface 15 and the angle of the outer surface of the electrode extraction layer 32 with respect to the main surface 16 can be made closer to a right angle. In particular, because the cross-sectional shape of the power generation element 20 is a parallelogram, the overall shape of the battery 201 can be made closer to a rectangular parallelepiped. Therefore, when mounting the battery 201 on a substrate, it is less likely that unnecessary space will be formed, and the mountability of the battery 201 on the substrate is improved.

[0170] Sides 211 and 212 are, for example, cut surfaces formed by cutting a stack of multiple battery cells 100 together. Sides 211 and 212 are formed by cutting along a direction inclined with respect to the stacking direction when cutting a stack of multiple battery cells 100 together. Note that sides of the power generation element 20 other than sides 211 and 212 may be inclined with respect to the stacking direction in the same way as sides 211 and 212.

[0171] In addition, in battery 201, as with battery 1, the thickness of the counter electrode extraction layer 31 in the first part P1 is greater than the thickness of the counter electrode extraction layer 31 in the second part P2. In other words, the height from the side 211 of the first part P1 is greater than the height from the side 211 of the second part P2. Also, the thickness of the electrode extraction layer 32 in the third part P3 is greater than the thickness of the electrode extraction layer 32 in the fourth part P4. In other words, the height from the side 212 of the third part P3 is greater than the height from the side 212 of the fourth part P4.

[0172] Furthermore, the height of the counter electrode extraction layer 31 from the side surface 211 increases along the stacking direction as it approaches the counter electrode current collector terminal 41 (i.e., as it approaches the main surface 15). Similarly, the height of the electrode extraction layer 32 from the side surface 212 increases along the stacking direction as it approaches the electrode current collector terminal 42 (i.e., as it approaches the main surface 16).

[0173] Furthermore, in the battery 201, in a plan view of the main surface 15, the end of the main surface 15 on the side surface 211 side and the end of the counter electrode current collector terminal 41 are positioned to overlap. The counter electrode current collector terminal 41 may be positioned away from the side surface 211 in a plan view of the main surface 15. Also, in a plan view of the main surface 16, the end of the main surface 16 on the side surface 212 side and the end of the electrode current collector terminal 42 are positioned to overlap. The electrode current collector terminal 42 may be positioned away from the side surface 212 in a plan view of the main surface 16.

[0174] (Embodiment 3) Next, Embodiment 3 will be described.

[0175] The battery according to Embodiment 3 differs from the battery according to Embodiment 2 in that it uses the uppermost counter electrode current collector as the counter electrode current collector terminal and the lowermost electrode current collector as the electrode current collector terminal. Below, we will mainly explain the differences from Embodiments 1 and 2, and omit or simplify the explanation of the common points.

[0176] Figure 8 is a cross-sectional view of the battery 301 according to this embodiment. As shown in Figure 8, the battery 301 differs from the battery 201 according to Embodiment 2 in that it has a counter electrode current collector terminal 341 and an electrode current collector terminal 342 instead of a counter electrode current collector terminal 41, an electrode current collector terminal 42, a counter electrode intermediate layer 51 and an electrode intermediate layer 52, and a power generation element 30 instead of a power generation element 20. The power generation element 30 of the battery 301 includes battery cells 302 and 303 instead of the two battery cells 100 located at the top and bottom of the power generation element 20. The power generation element 30, like the power generation element 20, includes side surfaces 211 and 212 inclined with respect to the stacking direction, and main surfaces 15 and 16 which are the top and bottom surfaces.

[0177] The battery cell 302 is located at the top of the power generation element 30. Compared to the other battery cells 100, the battery cell 302 has a counter electrode layer 320 instead of a counter electrode layer 120. The counter electrode layer 320 includes a counter electrode current collector 321 that is thicker than the counter electrode current collector 121. The counter electrode current collector 321 is the top layer of the power generation element 30. In other words, the top surface of the counter electrode current collector 321 is the main surface 15 of the power generation element 30.

[0178] The battery cell 303 is located at the bottom of the power generation element 30. Compared to the other battery cells 100, the battery cell 303 has an electrode layer 310 instead of an electrode layer 110. The electrode layer 310 includes an electrode current collector 311 which is thicker than the electrode current collector 111. The electrode current collector 311 is the bottom layer of the power generation element 30. In other words, the bottom surface of the electrode current collector 311 is the main surface 16 of the power generation element 30.

[0179] In the battery 301 according to this embodiment, the uppermost counter electrode current collector 321 functions as the counter electrode current collector terminal 341. In other words, the counter electrode current collector terminal 341 is a component that constitutes the main surface 15, i.e., the uppermost counter electrode current collector 321. Also, the lowermost electrode current collector 311 functions as the electrode current collector terminal 342. In other words, the electrode current collector terminal 342 is a component that constitutes the main surface 16, i.e., the lowermost electrode current collector 311.

[0180] Both the uppermost counter electrode current collector 321 and the lowermost electrode current collector 311 are thicker than the other counter electrode current collectors 121 and the other electrode current collectors 111. As a result, the counter electrode current collector 321 and the electrode current collector 311 allow current to flow more easily than the other counter electrode current collectors 121 and the other electrode current collectors 111.

[0181] In this way, by using the current-conducting counter electrode current collector 321 as the counter electrode current collector terminal 341 and the current-conducting electrode current collector 311 as the electrode current collector terminal 342, the number of components can be reduced. Because current flows easily through the counter electrode current collector 321 and the electrode current collector 311, heat generation due to current concentration can be suppressed.

[0182] In this embodiment, an example is shown in which current collectors are used for both the counter current collector terminal 341 and the electrode current collector terminal 342, but only one of them may be used. For example, the battery 301 may be equipped with the above-mentioned counter current collector terminal 41 and counter current collector 121 instead of the counter current collector terminal 341. Alternatively, the battery 301 may be equipped with the above-mentioned electrode current collector terminal 42 and electrode current collector 111 instead of the electrode current collector terminal 342. Furthermore, although the counter current collector 321 and electrode current collector 311 were constructed to be thicker than the other counter current collector 121 and the other electrode current collector 111, this is not limited to this. For example, at least one of the counter current collector 321 and the electrode current collector 311 may be the same thickness as the other counter current collector 121 and the other electrode current collector 111. Furthermore, at least one of the counter electrode current collector 321 and the electrode current collector 311 may be made of a material with higher conductivity than the other counter electrode current collector 121 and the other electrode current collector 111.

[0183] (Embodiment 4) Next, Embodiment 4 will be described.

[0184] The battery according to Embodiment 4 differs from the battery according to Embodiment 2 in that the extraction layer is formed using multiple different materials. Below, we will mainly explain the differences from Embodiments 1 to 3, and omit or simplify the explanation of the common points.

[0185] Figure 9 is a cross-sectional view of the battery 401 according to this embodiment. As shown in Figure 9, the battery 401 differs from the battery 1 according to Embodiment 1 in that it has a counter electrode extraction layer 431 and an electrode extraction layer 432 instead of the counter electrode extraction layer 31 and the electrode extraction layer 32.

[0186] The counter electrode extraction layer 431 includes a first conductive member 431a and a second conductive member 431b. The second conductive member 431b is the same as the counter electrode extraction layer 31 according to Embodiment 1, except that it covers the first conductive member 431a. In this embodiment, the second conductive member 431b is connected to the counter electrode current collector terminal 41.

[0187] The first conductive member 431a is a conductive member that covers at least a portion of the counter electrode layer 120 on the side surface 211. Specifically, the first conductive member 431a covers the end face of the counter electrode current collector 121 and a portion of the end face of the counter electrode active material layer 122 in contact with each other. For example, the first conductive member 431a is provided for each counter electrode current collector 121 and covers the entire end face of the counter electrode current collector 121. In a plan view of the side surface 211, the first conductive member 431a and the electrode insulating layer 21 are arranged alternately one by one along the z-axis.

[0188] Each of the multiple first conductive members 431a is covered by and electrically connected to the second conductive member 431b. In other words, each counter electrode layer 120 of the multiple battery cells 100 is electrically connected to the second conductive member 431b via each first conductive member 431a, and electrically connected in parallel via the second conductive member 431b.

[0189] The first conductive member 431a has different properties from the second conductive member 431b. For example, the first conductive member 431a and the second conductive member 431b are formed using different materials. Specifically, the first conductive member 431a is formed using a material selected primarily for its high conductivity and alloying with the counter electrode current collector 121. The second conductive member 431b is formed using a material selected primarily for its flexibility, impact resistance, chemical stability, cost, and ease of spreading during installation.

[0190] In the counter electrode extraction layer 431, similar to the counter electrode extraction layer 31, the resistance of the first portion P1 is smaller than the resistance of the second portion P2. Also, the thickness of the counter electrode extraction layer 431 in the first portion P1 is greater than the thickness of the counter electrode extraction layer 431 in the second portion P2.

[0191] The electrode extraction layer 432 includes a first conductive member 432a and a second conductive member 432b. The second conductive member 432b is the same as the electrode extraction layer 32 according to Embodiment 1, except that it covers the first conductive member 432a. In this embodiment, the second conductive member 432b is connected to the electrode current collector terminal 42.

[0192] The first conductive member 432a is a conductive member that covers at least a portion of the electrode layer 110 on the side surface 212. Specifically, the first conductive member 432a covers the end face of the electrode current collector 111 and a portion of the end face of the electrode active material layer 112 in contact with each other. For example, the first conductive member 432a is provided for each electrode current collector 111 and covers the entire end face of the electrode current collector 111. In a plan view of the side surface 212, the first conductive member 432a and the counter electrode insulating layer 22 are arranged alternately one by one along the z-axis.

[0193] Each of the multiple first conductive members 432a is covered by and electrically connected to the second conductive member 432b. In other words, each electrode layer 110 of the multiple battery cells 100 is electrically connected to the second conductive member 432b via each first conductive member 432a, and electrically connected in parallel via the second conductive member 432b.

[0194] The first conductive member 432a has different properties from the second conductive member 432b. For example, the first conductive member 432a and the second conductive member 432b are formed using different materials. Specifically, the first conductive member 432a is formed using a material selected primarily for its high conductivity and alloying with the electrode current collector 111. The second conductive member 432b is formed using a material selected primarily for its flexibility, impact resistance, chemical stability, cost, and ease of spreading during installation.

[0195] Furthermore, in the electrode extraction layer 432, similar to the electrode extraction layer 32, the resistance of the third portion P3 is smaller than the resistance of the fourth portion P4. Also, the thickness of the electrode extraction layer 432 in the third portion P3 is greater than the thickness of the electrode extraction layer 432 in the fourth portion P4.

[0196] As described above, an appropriate material can be used for the extraction layer of battery 401, thereby improving battery performance and ease of manufacturing.

[0197] In Figure 9, an example is shown in which the first conductive member 431a is connected to all counter electrode current collectors 121. However, there may be counter electrode current collectors 121 to which the first conductive member 431a is not connected. The same applies to the electrode current collectors 111. Furthermore, one of the first conductive members 431a and 432a may be omitted.

[0198] (Embodiment 5) Next, Embodiment 5 will be described.

[0199] In the battery according to Embodiment 5, the direction in which the sides of the power generation element are inclined with respect to the stacking direction is different from that of the battery according to Embodiment 2. Below, we will mainly explain the differences from Embodiments 1 to 4, and will omit or simplify the explanation of the common points.

[0200] Figure 10 is a cross-sectional view of the battery 501 according to this embodiment. As shown in Figure 10, the battery 501 differs from the battery 201 according to Embodiment 2 in that it has a power generation element 50 instead of a power generation element 20, and the electrode current collector terminals 42 and the electrode intermediate layer 52 are arranged on the main surface 15. The power generation element 50 includes a side surface 512 instead of the side surface 212 of the power generation element 20. Although not shown, the power generation element 50 also includes side surfaces 13 and 14 parallel to the stacking direction, similar to the power generation element 10, as side surfaces other than sides 211 and 512.

[0201] Side 512 is an example of a second side. Sides 211 and 512 face away from each other. Also, side 211 and 512 are erected from two opposing sides of the main surfaces 15 and 16, respectively.

[0202] Side surface 512 is inclined with respect to the stacking direction such that the interior angle formed by side surface 512 and the main surface 15 is obtuse. Therefore, side surface 512 is inclined such that the side facing the main surface 16 is more outward than the side facing the main surface 15. The interior angle formed by side surface 211 and the main surface 15 is equal to, for example, the interior angle formed by side surface 512 and the main surface 15. Also, as shown in Figure 10, the cross-sectional shape of the power generation element 50 when cut along the stacking direction at a position passing through sides 211 and 512 is trapezoidal, more specifically isosceles trapezoidal. As a result, even if the counter electrode extraction layer 31 is thicker in the first portion P1 closer to the counter electrode current collector terminal 41 than in the second portion P2, and the electrode extraction layer 32 is thicker in the third portion P3 closer to the electrode current collector terminal 42 than in the fourth portion P4, the angle of the outer surface of the counter electrode extraction layer 31 with respect to the main surface 15 and the angle of the outer surface of the electrode extraction layer 32 with respect to the main surface 15 can be made closer to a right angle. In particular, because the cross-sectional shape of the power generation element 50 is trapezoidal, the overall shape of the battery 501 can be made closer to a rectangular parallelepiped. Therefore, when mounting the battery 501 on a substrate, it is less likely that unnecessary space will be formed, and the substrate can be made smaller.

[0203] In the battery 501, the electrode extraction layer 32 includes a third portion P3 connected to the electrode layer 110 of the battery cell 100 closest to the main surface 15 among the multiple battery cells 100, and a fourth portion P4 connected to the electrode layer 110 of the battery cell 100 furthest from the main surface 15 among the multiple battery cells 100. Specifically, the third portion P3 is the part of the electrode extraction layer 32 that is at the same distance in the stacking direction from the main surface 15 as the electrode layer 110 of the battery cell 100 closest to the main surface 15 among the multiple battery cells 100. Specifically, the fourth portion P4 is the part of the electrode extraction layer 32 that is at the same distance in the stacking direction from the main surface 15 as the electrode layer 110 of the battery cell 100 furthest from the main surface 15 among the multiple battery cells 100. Furthermore, in this embodiment, since the electrode current collection terminal 42 is located on the main surface 15, the battery cells 100 that are close to or far from the main surface 15 may be rephrased as the battery cells 100 that are close to or far from the electrode current collection terminal 42.

[0204] In this embodiment as well, the resistance of the third portion P3 is smaller than the resistance of the fourth portion P4. Furthermore, the thickness of the electrode extraction layer 32 in the third portion P3 is greater than the thickness of the electrode extraction layer 32 in the fourth portion P4.

[0205] Furthermore, in the battery 501, the height of the electrode extraction layer 32 from the side surface 512 increases along the stacking direction as it approaches the electrode current collection terminal 42 (i.e., as it approaches the main surface 15).

[0206] In the battery 501, the electrode current collector terminal 42 is located on the main surface 15 of the power generation element 50 via an electrode intermediate layer 52. The electrode current collector terminal 42 is in contact with the upper end of the electrode extraction layer 32.

[0207] Thus, in this embodiment, the counter electrode current collector terminal 41 and the electrode current collector terminal 42 are provided on the same main surface 15 of the power generation element 50.

[0208] The counter electrode current collector terminal 41 and the electrode current collector terminal 42 are arranged in this order along the direction from side surface 211 to side surface 512 (i.e., the positive x-axis direction). Specifically, when the main surface 15 is virtually divided into two regions by an imaginary line parallel to the y-axis, the counter electrode current collector terminal 41 is provided in the negative x-axis region, and the electrode current collector terminal 42 is provided on the positive x-axis side.

[0209] For example, the width (i.e., the length in the y-axis direction) of the counter electrode current collector terminal 41 is more than half the width (i.e., the length in the y-axis direction) of the side surface 211. The width of the counter electrode current collector terminal 41 can be made equal to the width (i.e., the length in the y-axis direction) of the counter electrode extraction layer 31. This allows for a wider width in the direction in which current flows from the counter electrode extraction layer 31 to the counter electrode current collector terminal 41, thereby lowering resistance and being effective for extracting large currents. The same applies to the electrode current collector terminal 42.

[0210] As described above, in the battery 501, a counter electrode current collector terminal 41 and an electrode current collector terminal 42 are provided on the main surface 15 of the power generation element 50. That is, both the positive and negative electrode terminals necessary for extracting current from the power generation element 50 are provided on the same main surface 15. For example, the main surface 15 has a larger area than the sides 211, 512, 13, and 14. Since the terminals are provided on a larger surface, the battery 501 can be mounted over a large area, thereby improving connection reliability. In addition, the shape and arrangement of the terminals can be adjusted according to the wiring layout of the circuit board to be mounted, thus increasing the flexibility of connections.

[0211] Furthermore, since both the positive and negative terminals are located on the same main surface, the battery 501 can be compactly mounted. For example, the pattern of connection terminals (also called the footprint) formed on the mounting board can be reduced. In addition, mounting is possible with the main surface 15 of the battery 501 and the mounting board positioned parallel to each other, enabling low-profile mounting on the mounting board. Reflow soldering connections can be used for mounting. In this way, a battery 501 with excellent mountability can be realized.

[0212] (Embodiment 6) Next, Embodiment 6 will be described.

[0213] The battery according to Embodiment 6 differs from the battery according to Embodiment 5 in that it uses the uppermost counter electrode current collector as the counter electrode current collector terminal. Below, we will mainly explain the differences from Embodiments 1 to 5, and will omit or simplify the explanation of the common points.

[0214] Figure 11 is a cross-sectional view of the battery 601 according to this embodiment. As shown in Figure 11, the battery 601 differs from the battery 501 according to Embodiment 5 in that it does not have a counter electrode current collector terminal 41 and a counter electrode intermediate layer 51, and has a power generation element 60 instead of a power generation element 50. The power generation element 60 of the battery 601 includes a battery cell 602 instead of the battery cell 100 located at the top of the power generation element 50. The power generation element 60, like the power generation element 50, includes side surfaces 211 and 512 inclined with respect to the stacking direction, and main surfaces 15 and 16 which are the top and bottom surfaces.

[0215] The battery cell 602 is located at the top of the power generation element 60. Compared to the other battery cells 100, the battery cell 602 has a counter electrode layer 620 instead of a counter electrode layer 120. The counter electrode layer 620 includes a counter electrode current collector 621 that is thicker than the counter electrode current collector 121. The counter electrode current collector 621 is the top layer of the power generation element 60. In other words, the top surface of the counter electrode current collector 621 is the main surface 15 of the power generation element 60.

[0216] In the battery 601 according to this embodiment, a portion of the uppermost counter electrode current collector 621 functions as a counter electrode current collector terminal 641. In other words, the counter electrode current collector terminal 641 is a component that constitutes the main surface 15, i.e., the uppermost counter electrode current collector 621. On the other hand, the electrode current collector terminal 42 is a component different from the uppermost counter electrode current collector 621 that constitutes the main surface 15, similar to Embodiment 5.

[0217] The uppermost counter electrode current collector 621 is similar to the counter electrode current collector terminal 341 and electrode current collector terminal 342 described above, and is thicker than, for example, the other counter electrode current collectors 121 and electrode current collectors 111. As a result, current flows more easily through the counter electrode current collector 621 than through the other counter electrode current collectors 121 and electrode current collectors 111.

[0218] In this way, by using the current-conducting counter electrode current collector 621 as the counter electrode current collector terminal 641, the number of components can be reduced. Because current flows easily through the counter electrode current collector 621, heat generation due to current concentration can be suppressed.

[0219] (Embodiment 7) Next, Embodiment 7 will be described.

[0220] The battery according to Embodiment 7 differs from the battery according to Embodiment 2 in that it includes a sealing member. Below, we will mainly explain the differences from Embodiments 1 to 6, and omit or simplify the explanation of the common points.

[0221] Figure 12 is a cross-sectional view of the battery 701 according to this embodiment. Figure 13A is a top view of the battery 701 according to this embodiment. Figure 13B is a bottom view of the battery 701 according to this embodiment. Note that Figure 12 represents a cross-section along the line XII-XII in Figures 13A and 13B. As shown in Figures 12, 13A, and 13B, the battery 701 differs from the battery 201 according to Embodiment 2 in that it includes a sealing member 760.

[0222] The sealing member 760 exposes at least a portion of each of the counter electrode current collector terminal 41 and the electrode current collector terminal 42, and seals the power generation element 20. The sealing member 760 is provided such that, for example, the power generation element 20, the electrode insulating layer 21, the counter electrode insulating layer 22, the counter electrode extraction layer 31, and the electrode extraction layer 32 are not exposed.

[0223] The sealing member 760 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.

[0224] The sealing member 760 may include multiple different insulating materials. For example, the sealing member 760 may have a multilayer structure. Each layer of the multilayer structure may be formed using a different material and have different properties.

[0225] The sealing member 760 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 760 may be formed using a resin material in which multiple particles made of metal oxide material are dispersed.

[0226] 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.

[0227] The provision of the sealing member 760 improves the reliability of the battery 701 in various aspects, including mechanical strength, short-circuit prevention, and moisture resistance.

[0228] (Embodiment 8) Next, Embodiment 8 will be described.

[0229] The battery according to Embodiment 8 differs from the battery according to Embodiment 1 in that it includes a sealing member. Below, we will mainly explain the differences from Embodiments 1 to 7, and omit or simplify the explanation of the common points.

[0230] Figure 14 is a cross-sectional view of the battery 801 according to this embodiment. As shown in Figure 14, the battery 801 differs from the battery 1 according to Embodiment 1 in that it includes a sealing member 760.

[0231] Similar to the battery 701, the sealing member 760 in the battery 801 also exposes at least a portion of each of the counter electrode current collector terminal 41 and the electrode current collector terminal 42, and seals the power generation element 10. The sealing member 760 is provided such that, for example, the power generation element 10, the electrode insulating layer 21, the counter electrode insulating layer 22, the counter electrode extraction layer 31, and the electrode extraction layer 32 are not exposed.

[0232] Furthermore, in the battery 801, the side of the counter electrode extraction layer 31 opposite to the side surface 11 and the side of the electrode extraction layer 32 opposite to the side surface 12 are inclined with respect to the stacking direction, but because they are sealed by the sealing member 760, the shape of the battery 801 is that of a rectangular parallelepiped.

[0233] The provision of the sealing member 760 improves the reliability of the battery 801 in various aspects, including mechanical strength, short-circuit prevention, and moisture resistance.

[0234] (Embodiment 9) Next, Embodiment 9 will be described.

[0235] The battery according to Embodiment 9 differs from the battery according to Embodiment 3 in that the thickness of the current collector used as the current collection terminal is thinner, and that it is equipped with a sealing member. Below, we will mainly explain the differences from Embodiments 1 to 8, and will omit or simplify the explanation of the common points.

[0236] Figure 15 is a cross-sectional view of the battery 901 according to this embodiment. As shown in Figure 15, the battery 901 differs from the battery 301 according to Embodiment 3 in that it has a power generation element 20 instead of a power generation element 30, and also has a sealing member 760.

[0237] In battery 901, the uppermost counter electrode current collector 121 functions as the counter electrode current collector terminal 941. In other words, the counter electrode current collector terminal 941 is a component that makes up the main surface 15, i.e., the uppermost counter electrode current collector 121. Also, the lowermost electrode current collector 111 functions as the electrode current collector terminal 942. In other words, the electrode current collector terminal 942 is a component that makes up the main surface 16, i.e., the lowermost electrode current collector 111.

[0238] In this way, by having the uppermost counter electrode current collector 121 function as the counter electrode current collector terminal 941 and the lowermost electrode current collector 111 function as the electrode current collector terminal 942, the number of parts can be reduced.

[0239] Furthermore, in the battery 901, the sealing member 760 exposes at least a portion of each of the uppermost counter electrode current collector 121, which functions as the counter electrode current collector terminal 941, and the lowermost electrode current collector 111, which functions as the electrode current collector terminal 942, and seals the power generation element 20. The sealing member 760 has openings on the main surface 15 and the main surface 16, respectively, which expose a portion of each of the uppermost counter electrode current collector 121 and the lowermost electrode current collector 111.

[0240] The provision of the sealing member 760 improves the reliability of the battery 901 in various aspects, including mechanical strength, short-circuit prevention, and moisture resistance.

[0241] (Embodiment 10) Next, Embodiment 10 will be described.

[0242] The battery according to Embodiment 10 differs from the battery according to Embodiment 1 in that, rather than the thickness of the extraction layer, the conductivity of the extraction layer differs depending on the part of the extraction section. Below, we will mainly explain the differences from Embodiments 1 to 9, and the explanation of common points will be omitted or simplified.

[0243] Figure 16 is a cross-sectional view of the battery 1001 according to this embodiment. As shown in Figure 16, the battery 1001 differs from the battery 1 according to Embodiment 1 in that it has a counter electrode extraction layer 1031 and an electrode extraction layer 1032 instead of the counter electrode extraction layer 31 and the electrode extraction layer 32.

[0244] The counter electrode extraction layer 1031 includes a first portion P11 connected to the counter electrode layer 120 of the battery cell 100 closest to the main surface 15 among the multiple battery cells 100, and a second portion P12 connected to the counter electrode layer 120 of the battery cell 100 furthest from the main surface 15 among the multiple battery cells 100.

[0245] In the counter electrode extraction layer 1031, the conductivity of the material constituting the first portion P11 is higher than that of the material constituting the second portion P12. In the counter electrode extraction layer 1031, the thickness of the first portion P11 and the thickness of the second portion P12 are the same, and therefore, due to the above conductivity relationship, the resistance of the first portion P11 is smaller than the resistance of the second portion P12. In this way, the resistance of the first portion P11 can be reduced without making the thickness of the first portion P11 greater than that of the second portion P12, thus enabling miniaturization of the battery 1001.

[0246] The electrode extraction layer 1032 includes a third portion P13 connected to the electrode layer 110 of the battery cell 100 closest to the main surface 16 among the multiple battery cells 100, and a fourth portion P14 connected to the electrode layer 110 of the battery cell 100 furthest from the main surface 16 among the multiple battery cells 100.

[0247] In the electrode extraction layer 1032, the conductivity of the material constituting the third portion P13 is higher than that of the material constituting the fourth portion P14. In the electrode extraction layer 1032, the thickness of the third portion P13 and the thickness of the fourth portion P14 are the same, and therefore, due to the above conductivity relationship, the resistance of the third portion P13 is smaller than the resistance of the fourth portion P14. In this way, the resistance of the third portion P13 can be reduced without making the thickness of the third portion P13 greater than that of the fourth portion P14, thus enabling miniaturization of the battery 1001.

[0248] The counter electrode extraction layer 1031 and the electrode extraction layer 1032 are formed using a conductive resin material or the like. The conductive resin material includes, for example, a resin and a conductive material composed of metal particles or the like that is filled into the resin.

[0249] In the counter electrode extraction layer 1031, for example, the packing density of the conductive material in the first portion P11 is higher than that of the conductive material in the second portion P12, so that the conductivity of the first portion P11 is higher than that of the second portion P12. Alternatively, the conductivity of the first portion P11 may be made higher than that of the second portion P12 by using a conductive material with higher conductivity in the first portion P11 than that in the second portion P12.

[0250] For example, when forming the counter electrode extraction layer 1031 using a conductive resin material, the resin material is applied to the side surface 11 so that the area where high conductivity is desired is thicker, and the applied resin material is compressed to make the thickness uniform, thereby increasing the conductivity of the thickly applied area. Alternatively, the counter electrode extraction layer 1031 may be formed by applying resin materials with different conductivity in different areas.

[0251] Similarly to the electrode extraction layer 1031, the conductivity of the third portion P13 can be made higher than that of the fourth portion P14 in the electrode extraction layer 1032.

[0252] (Manufacturing method) Next, a description of the battery manufacturing method according to each of the embodiments described above will be provided.

[0253] Figure 17 is a flowchart showing an example of a battery manufacturing method according to each embodiment. Below, an example of battery 201 according to Embodiment 2 will be described.

[0254] As shown in Figure 17, first, several battery cells are prepared (step S10). The battery cells to be prepared are, for example, battery cells 100A, 100B, and 100C shown in Figures 3A to 3C.

[0255] Next, multiple battery cells 100 are stacked (step S20). Specifically, a laminate is formed by stacking multiple battery cells 100 in order such that the order of the electrode layer 110, counter electrode layer 120, and solid electrolyte layer 130 alternates. In this embodiment, a power generation element 10, as shown in Figure 4, is formed by stacking battery cells 100A, 100B, and 100C in appropriate combinations. The power generation element 10 is an example of a laminate.

[0256] Next, the laminate is cut (step S30). Specifically, by cutting the laminate of multiple battery cells 100 all at once, a power generation element 20 can be formed, with each side surface being composed of the cut surfaces. As a result, each formed side surface becomes flat. The power generation element 20 is an example of a laminate. When forming the cut surfaces corresponding to sides 211 and 212, the cut is made along a direction inclined with respect to the lamination direction. The cutting process is performed, for example, by a blade, laser, or jet. Note that when manufacturing a battery that includes a power generation element 10, such as battery 1, step S30 may be omitted. Alternatively, all cut surfaces may be formed by cutting along the lamination direction. Furthermore, even when forming a power generation element 20, step S30 may be omitted by forming the power generation element 20 by laminating multiple battery cells with inclined end faces.

[0257] Next, an insulating layer is formed on the side surface of the power generation element 20 (step S40). Specifically, an electrode insulating layer 21 is formed on the side surface 211 to cover the electrode layer 110. Also, a counter electrode insulating layer 22 is formed on the side surface 212 to cover the counter electrode layer 120.

[0258] 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.

[0259] 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.

[0260] Next, extraction layers are formed on the side surfaces of the power generation element 20 (step S50). Specifically, a counter electrode extraction layer 31 is formed that is electrically connected to multiple counter electrode layers 120 so as to cover the main surface 15, side surface 211 and electrode insulating layer 21 of the power generation element 20. An electrode extraction layer 32 is formed that is electrically connected to multiple electrode layers 110 so as to cover the main surface 16, side surface 212 and counter electrode insulating layer 22 of the power generation element 20.

[0261] For example, a counter electrode extraction layer 31 is formed by applying and curing a conductive paste, such as a conductive resin, to cover the end portion along the side surface 211 of the main surface 15, the electrode insulating layer 21, and the portion of the side surface 211 not covered by the electrode insulating layer 21. Similarly, an electrode extraction layer 32 is formed by applying and curing a conductive resin to cover the portion along the side surface 212 of the main surface 16, the counter electrode insulating layer 22, and the portion of the side surface 212 not covered by the counter electrode insulating layer 22. The counter electrode extraction layer 31 and the electrode extraction layer 32 may be formed by methods such as printing, plating, vapor deposition, sputtering, welding, soldering, joining, or other methods.

[0262] Furthermore, in step S50, the counter electrode extraction layer 31 is formed such that the resistance of the first portion P1 of the counter electrode extraction layer 31 is smaller than the resistance of the second portion P2 of the counter electrode extraction layer 31. Specifically, the counter electrode extraction layer 31 is formed such that the thickness of the first portion P1 of the counter electrode extraction layer 31 in the first portion P1 is greater than the thickness of the counter electrode extraction layer 31 in the second portion P2. For example, the conductive resin is coated with a coating pattern such that the first portion P1 is thicker than the second portion P2. Alternatively, the conductive resin may be coated multiple times to laminate multiple conductive films, so that the number of laminated conductive films is greater in the first portion P1 than in the second portion P2. Alternatively, the second portion P2 of the counter electrode extraction layer 31, which has been coated with a uniform thickness, may be scraped off.

[0263] Furthermore, the electrode extraction layer 32 is formed in the same manner as the counter electrode extraction layer 31, such that the resistance of the third portion P3 in the electrode extraction layer 32 is smaller than the resistance of the fourth portion P4 in the electrode extraction layer 32. Specifically, the electrode extraction layer 32 is formed such that the thickness of the electrode extraction layer 32 in the third portion P3 is greater than the thickness of the electrode extraction layer 32 in the fourth portion P4.

[0264] Next, current collector terminals are formed on the main surfaces 15 and 16 of the power generation element 20 (step S60). Specifically, a counter electrode current collector terminal 41 is formed on the main surface 15 via a counter electrode intermediate layer 51. At this time, the counter electrode current collector terminal 41 is formed to connect with the counter electrode extraction layer 31. Also, an electrode current collector terminal 42 is formed on the main surface 16 via an electrode intermediate layer 52. At this time, the electrode current collector terminal 42 is formed to connect with the electrode extraction layer 32. The counter electrode current collector terminal 41 and the electrode current collector terminal 42 are formed by placing a conductive material such as a metal material in a desired area by plating, printing, or soldering. Alternatively, the counter electrode current collector terminal 41 and the electrode current collector terminal 42 may be formed by welding or joining metal plates or the like.

[0265] The counter electrode intermediate layer 51 and the electrode intermediate layer 52 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.

[0266] Through the above process, the battery 201 shown in Figure 7 can be manufactured.

[0267] 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.

[0268] Furthermore, the counter electrode intermediate layer 51 and the electrode intermediate layer 52 may be formed in step S40 following the formation of the electrode insulating layer 21 and the counter electrode insulating layer 22, or simultaneously with the formation of the electrode insulating layer 21 and the counter electrode insulating layer 22. Alternatively, the counter electrode intermediate layer 51 and the electrode intermediate layer 52 may be formed after the formation of the laminate (step S20) and before the cutting of the laminate (step S30), or after the cutting of the laminate (step S30) and before the formation of the insulating layer (step S40).

[0269] Furthermore, the formation of the current collection terminals (step S60) may be performed at any point after the preparation of the multiple battery cells (step S10).

[0270] Furthermore, when manufacturing the battery 401, the first conductive members 431a and 432a shown in Figure 9 may be formed after cutting the laminate (step S30) and before forming the extraction layer (step S40). The first conductive members 431a and 432a may be formed by, for example, printing, plating, vapor deposition, sputtering, welding, soldering, joining, or other methods.

[0271] Also, when manufacturing the battery 701, after forming the extraction layer (step S50) or forming the current collector terminal (step S60), a sealing member 760 shown in FIGS. 12, 13A, and 13B may be formed. The sealing member 760 is formed, for example, by applying a resin material having fluidity and curing it. The application is performed by an inkjet method, a spray method, a screen printing method, a gravure printing method, or the like. The curing is performed by drying, heating, light irradiation, or the like depending on the resin material used.

[0272] Also, for example, the thick counter electrode current collector terminal 341 and the electrode current collector terminal 342 shown in FIG. 8 can be formed by laminating a metal layer on a current collector having the same thickness as the other counter electrode current collector 121 or electrode current collector 111 by methods such as adhesion, coating, welding, or joining. Alternatively, thick metal foils or metal plates may be used as current collectors that function as current collector terminals to form the battery cells 302 and 303.

[0273] (Other embodiments) As described above, the battery and the method for manufacturing the battery according to one or more aspects have been described based on the embodiments. However, the present disclosure is not limited to these embodiments. As long as the gist of the present disclosure is not deviated from, various modifications conceived by those skilled in the art applied to each embodiment, and forms constructed by combining components in different embodiments are also included in the scope of the present disclosure.

[0274] For example, in the above embodiment, an example in which one current collector is shared between adjacent battery cells is shown, but the current collectors may not be shared. Two counter electrode current collectors may be stacked, or two electrode current collectors may be stacked.

[0275] Also, for example, in the above embodiment, an example in which the first side surface provided with the counter electrode extraction layer and the second side surface provided with the electrode extraction layer are side surfaces facing each other is shown, but the present disclosure is not limited thereto. For example, the first side surface and the second side surface may be adjacent side surfaces.

[0276] Furthermore, for example, the first side may be the same side as the second side. For example, if the power generation element is a rectangular parallelepiped, the power generation element has four sides. A portion of one of the four sides may be the first side, and the other regions may be the second side.

[0277] Furthermore, while the above embodiment included a set of electrode layers, a counter electrode layer, and a solid electrolyte layer, the battery cell is not limited to this. A battery cell may also be a battery cell in which multiple sets of electrode layers, counter electrode layers, and solid electrolyte layers are electrically connected in series. In this case, for example, the electrode layers other than those located at both ends of the battery cell in the stacking direction, and the end faces of the counter electrode layers, are covered with an insulating layer.

[0278] Furthermore, each of the above embodiments can be modified, replaced, added, or omitted in various ways within the scope of the claims or their equivalents. [Industrial applicability]

[0279] This disclosure can be used, for example, as a battery for electronic devices, electrical appliances, and electric vehicles. [Explanation of symbols]

[0280] 1, 201, 301, 401, 501, 601, 701, 801, 901, 1001 batteries 10, 20, 30, 50, 60 power generation elements 11, 12, 13, 14, 211, 212, 512 Side view 15, 16 Main surface 21 Electrode insulating layer 22 Counter electrode insulating layer 31, 431, 1031 Counter electrode extraction layer 32, 432, 1032 electrode extraction layer 41, 341, 641, 941 Counter-pole current collector terminals 42, 342, 942 electrode current collector terminals 51 Opposite Intermediate Layer 52 Electrode intermediate layer 100, 100A, 100B, 100C, 302, 303, 602 battery cells 110, 110B, 310 electrode layer 111, 311 Electrode current collector 112 Electrode active material layer 120, 120C, 320, 620 Counter pole layers 121, 321, 621 Counter-pole current collector 122 Counter electrode active material layer 130 Solid electrolyte layer 431a, 432a First conductive member 431b, 432b Second conductive member 760 Sealing member P1, P11 First part P2, P12 second part P3, P13 Third part P4, P14 Fourth part

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, an electrode insulating member covers the electrode layer of each of the plurality of battery cells, A counter electrode extraction layer that covers the first side surface and the electrode insulating member and is electrically connected to the counter electrode layer of each of the plurality of battery cells, The power generation element is provided on the first main surface and includes a counter electrode current collector terminal connected to the counter electrode extraction layer, In the counter electrode extraction layer, the resistance of the first portion connected to the counter electrode layer of the battery cell closest to the first main surface among the plurality of battery cells is smaller than the resistance of the second portion connected to the counter electrode layer of the battery cell furthest from the first main surface among the plurality of battery cells. battery.

2. The thickness of the counter electrode extraction layer in the first portion is greater than the thickness of the counter electrode extraction layer in the second portion. The battery according to claim 1.

3. The first surface is inclined with respect to the stacking direction of the power generation element such that the interior angle formed by the first surface and the first main surface is an obtuse angle. The battery according to claim 2.

4. The height of the counter electrode extraction layer from the first side surface increases as it approaches the counter electrode current collector terminal along the stacking direction of the power generation element. The battery according to claim 2.

5. The counter electrode extraction layer covers the first main surface, The battery according to claim 1.

6. The aforementioned counter-current collector terminal is a current collector that constitutes the first main surface, The thickness of the counter electrode current collector terminal is greater than the thickness of the current collector included in one of the plurality of battery cells. The battery according to claim 1.

7. The aforementioned counter electrode extraction layer is, A first conductive member in contact with the counter electrode layer, A second conductive member covering the first conductive member is provided. The battery according to claim 1.

8. The conductivity of the material constituting the first part is higher than that of the material constituting the second part. The battery according to claim 1.

9. On the second side of the power generation element, a counter electrode insulating member covers the counter electrode layer of each of the plurality of battery cells, An electrode extraction layer covering the second side surface and the counter electrode insulating member, which is electrically connected to the electrode layer of each of the plurality of battery cells, The power generation element further comprises an electrode current collector terminal provided on the first main surface and connected to the electrode extraction layer, The resistance of the third portion of the electrode extraction layer connected to the electrode layer of the battery cell closest to the first main surface among the plurality of battery cells is smaller than the resistance of the fourth portion of the counter electrode extraction layer connected to the electrode layer of the battery cell furthest from the first main surface among the plurality of battery cells. The battery according to claim 1.

10. The thickness of the electrode extraction layer in the third portion is greater than the thickness of the electrode extraction layer in the fourth portion. The battery according to claim 9.

11. The first side and the second side face away from each other, When the power generation element is cut along the stacking direction at a position passing through the first and second sides, the cross-sectional shape of the power generation element is trapezoidal. The interior angle formed by the first side surface and the first principal surface, and the interior angle formed by the second side surface and the first principal surface, are both obtuse angles. The battery according to claim 10.

12. On the second side of the power generation element, a counter electrode insulating member covers the counter electrode layer of each of the plurality of battery cells, An electrode extraction layer covering the second side surface and the counter electrode insulating member, which is electrically connected to the electrode layer of each of the plurality of battery cells, The power generation element further comprises an electrode current collector terminal provided on a second main surface opposite to the first main surface and connected to the electrode extraction layer, The resistance of the third portion of the electrode extraction layer connected to the electrode layer of the battery cell closest to the second main surface among the plurality of battery cells is smaller than the resistance of the fourth portion of the counter electrode extraction layer connected to the electrode layer of the battery cell furthest from the second main surface among the plurality of battery cells. The battery according to claim 1.

13. The thickness of the electrode extraction layer in the third portion is greater than the thickness of the electrode extraction layer in the fourth portion. The battery according to claim 12.

14. The first side and the second side face away from each other, When the power generation element is cut along the stacking direction at a position passing through the first and second sides, the cross-sectional shape of the power generation element is a parallelogram. The interior angle formed by the first surface and the first principal surface, and the interior angle formed by the second surface and the second principal surface, are both obtuse angles. The battery according to claim 13.

15. The electrode current collection terminal is a current collector that constitutes the second main surface, The thickness of the electrode current collector terminal is greater than the thickness of the current collector included in one of the plurality of battery cells. The battery according to claim 12.

16. The height of the electrode extraction layer from the second side surface increases as it approaches the electrode current collection terminal along the stacking direction of the power generation element. The battery according to any one of claims 9 to 15.

17. The electrode insulating member includes resin, The battery according to any one of claims 1 to 15.

18. The system further includes a sealing member that exposes at least a portion of the counter electrode current collector terminal and seals the power generation element and the counter electrode extraction layer. The battery according to any one of claims 1 to 15.

19. The steps include 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, The steps include forming a laminate by sequentially stacking a plurality of battery cells such that the order of the electrode layer, the counter electrode layer, and the solid electrolyte layer alternates for each battery cell, The first side surface of the laminate is covered with an electrode insulating member, and The steps include covering the first side surface and the electrode insulating member with a counter electrode extraction layer electrically connected to the counter electrode layer of each of the plurality of battery cells, The step of providing a counter electrode current collector terminal connected to the counter electrode extraction layer on the first main surface of the laminate is included, In the step of covering with the counter electrode extraction layer, the counter electrode extraction layer is formed such that the resistance of the first portion of the counter electrode extraction layer connected to the counter electrode layer of the battery cell closest to the first main surface among the plurality of battery cells is less than the resistance of the second portion of the counter electrode extraction layer connected to the counter electrode layer of the battery cell furthest from the first main surface among the plurality of battery cells. Battery manufacturing method.

20. In the step of covering with the counter electrode extraction layer, the counter electrode extraction layer is formed such that the thickness of the counter electrode extraction layer in the first portion is greater than the thickness of the counter electrode extraction layer in the second portion. A method for manufacturing a battery according to claim 19.

Images