Battery and method for manufacturing a battery

Abstract

A battery according to the present disclosure is provided with a power generation element having a structure in which a plurality of power generation layers and a plurality of current collectors are stacked. Each of the plurality of power generation layers has an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer. The plurality of current collectors includes counter electrode current collectors electrically connected to the counter electrode layers, and electrode current collectors electrically connected to the electrode layers. A side surface of the power generation element includes a first region in which each of the power generation layers have not receded further than a current collector, from among the plurality of current collectors, that is adjacent to each of the power generation layers, and a second region in which each of the power generation layers recedes further than the current collector, from among the plurality of current collectors, that is adjacent to each of the power generation layers, thus forming a recess. Provided in the second region are an insulation member for covering the electrode layers and the electrode current collectors, and an electroconductive member that covers the second region and the insulation member and that is electrically connected to at least one principal surface of the counter electrode current collectors.

Description

Technical Field

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

Background Art

[0002] Conventionally, laminated batteries such as all-solid-state batteries in which an electrode and a solid electrolyte layer are laminated are known.

[0003] Patent Document 1 discloses electrically connecting in parallel at the end faces a plurality of unit cells laminated so as to be electrically connected in series.

[0004] Patent Document 2 discloses protruding a current collector in order to electrically connect in parallel at the end faces a plurality of unit cells laminated so as to be electrically connected in series.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the prior art, further improvement in the energy density, high-current characteristics, and reliability of the battery is desired.

[0007] In a battery in which a plurality of unit cells are laminated, it is important to make a connection with high convenience and reliability for each of the laminated unit cells while realizing a high energy density.

[0008] On the other hand, since the unit cell is thin, it is difficult to secure a connection area at the end face of the unit cell.

[0009] Therefore, this disclosure provides a battery with improved energy density, high current characteristics, and reliability, as well as a method for manufacturing the battery. [Means for solving the problem]

[0010] A battery according to one aspect of this disclosure comprises a power generation element having a structure in which a plurality of power generation layers and a plurality of current collectors are stacked, Each of the plurality of power generation layers has an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer. The plurality of current collectors include a counter electrode current collector electrically connected to the counter electrode layer and an electrode current collector electrically connected to the electrode layer. The plurality of power generation layers are stacked so as to be electrically connected in parallel, adjacent power generation layers are stacked via at least one current collector from the plurality of current collectors, and each power generation layer of the power generation element is sandwiched between two adjacent current collectors from the plurality of current collectors. The side of the aforementioned power generation element is, Each of the aforementioned power generation layers has a first region in which it is not recessed compared to the current collectors adjacent to each of the plurality of current collectors, Each of the aforementioned power generation layers includes a second region in which a recess is formed by the current collector being set back from the current collector adjacent to each of the plurality of current collectors, The second region includes an insulating member that covers the electrode layer and the electrode current collector, and a conductive member that covers the second region and the insulating member and is electrically connected to at least one main surface of the counter electrode current collector.

[0011] A method for manufacturing a battery according to one aspect of the present disclosure includes a first step of preparing a plurality of unit cells, each having a structure in which an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer are stacked, and a current collector; and a second step of forming a power generation element by stacking the plurality of unit cells, wherein the second step is a step of connecting the plurality of unit cells in parallel, and includes forming a first region on the side surface of the power generation element in which each power generation layer of the plurality of unit cells is not recessed compared to the current collector adjacent to each power generation layer among the current collectors of the plurality of unit cells, and a second region in which a recess is formed by each power generation layer being recessed compared to the current collector adjacent to each power generation layer among the current collectors of the plurality of unit cells, wherein in the second region, an insulating member covers the electrode layer and the electrode current collector electrically connected to the electrode layer, and a conductive member is electrically connected to at least one main surface of the counter electrode current collector that covers the second region and the insulating member and is electrically connected to the counter electrode layer. [Effects of the Invention]

[0012] According to this disclosure, the energy density, high current characteristics, and reliability of the battery can be improved. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a side view of a battery according to Embodiment 1. [Figure 2A] Figure 2A is a cross-sectional view of the battery according to Embodiment 1. [Figure 2B] Figure 2B is another cross-sectional view of the battery according to Embodiment 1. [Figure 3] Figure 3 is a top view of the battery according to Embodiment 1. [Figure 4] Figure 4 is a side view of a battery according to a modified example 1 of Embodiment 1. [Figure 5A] Figure 5A is a cross-sectional view of a battery according to a modified example 1 of Embodiment 1. [Figure 5B] Figure 5B is another cross-sectional view of the battery according to Modification 1 of Embodiment 1. [Figure 6A]FIG. 6A is a cross-sectional view of a battery according to Modification Example 2 of Embodiment 1. [Figure 6B] FIG. 6B is another cross-sectional view of a battery according to Modification Example 2 of Embodiment 1. [Figure 7A] FIG. 7A is a cross-sectional view of a battery according to Modification Example 3 of Embodiment 1. [Figure 7B] FIG. 7B is another cross-sectional view of a battery according to Modification Example 3 of Embodiment 1. [Figure 8A] FIG. 8A is a cross-sectional view of a battery according to Modification Example 4 of Embodiment 1. [Figure 8B] FIG. 8B is another cross-sectional view of a battery according to Modification Example 4 of Embodiment 1. [Figure 9A] FIG. 9A is a cross-sectional view of a battery according to Modification Example 5 of Embodiment 1. [Figure 9B] FIG. 9B is another cross-sectional view of a battery according to Modification Example 5 of Embodiment 1. [Figure 10] FIG. 10 is a side view of a battery according to Modification Example 6 of Embodiment 1. [Figure 11] FIG. 11 is a side view of a battery according to Modification Example 7 of Embodiment 1. [Figure 12] FIG. 12 is a side view of a battery according to Modification Example 8 of Embodiment 1. [Figure 13] FIG. 13 is a side view of a battery according to Modification Example 9 of Embodiment 1. [Figure 14A] FIG. 14A is a cross-sectional view of a battery according to Modification Example 10 of Embodiment 1. [Figure 14B] FIG. 14B is another cross-sectional view of a battery according to Modification Example 10 of Embodiment 1. [Figure 15] FIG. 15 is a side view of a battery according to Modification Example 11 of Embodiment 1. [Figure 16A] FIG. 16A is a cross-sectional view of a battery according to Modification Example 12 of Embodiment 1. [Figure 16B] FIG. 16B is another cross-sectional view of a battery according to Modification Example 12 of Embodiment 1. [Figure 17A] FIG. 17A is a cross-sectional view of a battery according to Modification Example 13 of Embodiment 1. [Figure 17B] Figure 17B is another cross-sectional view of the battery according to modification 13 of Embodiment 1. [Figure 18A] Figure 18A is a cross-sectional view of a battery according to a modified example 14 of Embodiment 1. [Figure 18B] Figure 18B is another cross-sectional view of the battery according to modification 14 of Embodiment 1. [Figure 19A] Figure 19A is a cross-sectional view of the battery according to Embodiment 2. [Figure 19B] Figure 19B is another cross-sectional view of the battery according to Embodiment 2. [Figure 20A] Figure 20A is a cross-sectional view of a battery according to a modified example 1 of Embodiment 2. [Figure 20B] Figure 20B is another cross-sectional view of the battery according to Modification 1 of Embodiment 2. [Figure 21] Figure 21 is a side view of a battery according to a modified example 2 of Embodiment 2. [Figure 22A] Figure 22A is a cross-sectional view of a battery according to a modified example 2 of Embodiment 2. [Figure 22B] Figure 22B is another cross-sectional view of the battery according to a modified example 2 of Embodiment 2. [Figure 23] Figure 23 is a side view of a battery according to a modified example 3 of Embodiment 2. [Figure 24A] Figure 24A is a cross-sectional view of a battery according to a modified example 4 of Embodiment 2. [Figure 24B] Figure 24B is another cross-sectional view of the battery according to Modification 4 of Embodiment 2. [Figure 25] Figure 25 is a flowchart showing an example of a battery manufacturing method according to an embodiment or modification. [Figure 26A] Figure 26A is a cross-sectional view of an example of a unit cell according to an embodiment or modification. [Figure 26B] Figure 26B is a cross-sectional view of another example of a unit cell according to an embodiment or modification. [Figure 26C] Figure 26C is a cross-sectional view of another example of a unit cell according to an embodiment or modification. [Modes for carrying out the invention]

[0014] (Summary of this disclosure) A battery according to one aspect of the present disclosure comprises a power generation element having a structure in which a plurality of power generation layers and a plurality of current collectors are stacked, each of the plurality of power generation layers having an electrode layer, a counter electrode layer and a solid electrolyte layer located between the electrode layer and the counter electrode layer, the plurality of current collectors including a counter electrode current collector electrically connected to the counter electrode layer and an electrode current collector electrically connected to the electrode layer, the plurality of power generation layers are stacked so as to be electrically connected in parallel, adjacent power generation layers are stacked via at least one current collector from the plurality of current collectors, and each power generation layer of the power generation element is The power generation element is sandwiched between two adjacent current collectors among the plurality of current collectors, and the side surface of the power generation element includes a first region in which each power generation layer is not recessed compared to the current collector adjacent to each power generation layer among the plurality of current collectors, and a second region in which a recess is formed by each power generation layer being recessed compared to the current collector adjacent to each power generation layer among the plurality of current collectors, wherein the second region includes an insulating member covering the electrode layer and the electrode current collector, and a conductive member covering the second region and the insulating member and electrically connected to at least one main surface of the counter electrode current collector.

[0015] As a result, in the second region, conductive members such as terminals for extracting current can be connected within the recess on the main surface of the recessed side of the current collector. Therefore, compared to connecting terminals to the side of the current collector, the connection area between the terminal and the current collector can be increased, and the resistance of the connection part can be reduced, thereby improving the high-current characteristics of the battery. In addition, the increased connection area between the terminal and the current collector increases the mechanical connection strength between the terminal and the current collector, thereby improving the reliability of the battery.

[0016] As a result, in the second region, conductive members such as terminals for extracting current can be connected within the recess on the main surface of the recessed side of the current collector. Therefore, compared to connecting terminals to the side of the current collector, the connection area between the terminal and the current collector can be increased, and the resistance of the connection part can be reduced, thereby improving the high-current characteristics of the battery. In addition, the increased connection area between the terminal and the current collector increases the mechanical connection strength between the terminal and the current collector, thereby improving the reliability of the battery.

[0017] Furthermore, in the second region, the current collector protrudes beyond the side surface of the power generation layer. On the other hand, in the first region, since the power generation layer has not receded, the current collector and the power generation layer are stacked at the position of the tip of the current collector that protrudes in the second region. Normally, when a current collector protrudes, the protruding portion of the current collector is prone to deformation due to movement in the stacking direction. However, the current collector that protrudes in the second region is supported by the power generation layer in the adjacent first region, making it less likely to move, and thus the spacing between current collectors is more easily maintained. Therefore, during the battery manufacturing process and use, contact between current collectors and short circuits, as well as discharge short circuits due to proximity, are suppressed, thereby improving the reliability of the battery.

[0018] Furthermore, in terms of the power generation element, since the power generation layer recedes only in the second region of the two regions (the first and second regions), the area where the power generation layer recedes can be reduced, thereby increasing the energy density of the battery.

[0019] Furthermore, this allows the insulating material to cover the electrode layer in the second region, thereby suppressing the occurrence of short circuits between the counter electrode layer and the electrode layer via the conductive material.

[0020] Furthermore, a high-capacity battery can be realized by stacking the multiple power generation layers so that they are electrically connected in parallel. In this case, for example, the same poles of each layer are electrically connected by terminals connected to the current collector.

[0021] Furthermore, for example, on the side surface, the first region may be positioned so as to sandwich the second region from both sides in a direction perpendicular to the stacking direction of the power generation elements.

[0022] As a result, the protruding current collectors in the second region are supported by the generating layers in the first region on both sides, making it easier for the current collectors to remain taut and for the spacing between current collectors in the second region to be maintained more easily.

[0023] Furthermore, for example, in the second region, the recesses formed by the recession of each power generation layer may be aligned along the stacking direction of the power generation elements.

[0024] This makes it easier to form the second region because the recesses in the second region can be formed by processing them all at once.

[0025] Furthermore, for example, the maximum depth of the recess may be greater than the width of the recess in the stacking direction of the power generation elements.

[0026] This increases the contact area between the terminal and the current collector when the terminal is connected to the current collector within a recess, thereby improving the high-current characteristics of the battery.

[0027] Furthermore, for example, the second region may be separated by the first region.

[0028] As a result, the individual widths of the separated second region become smaller, making it more difficult for the current collectors protruding in the second region to move, and making it easier to maintain a more constant spacing between the current collectors.

[0029] Furthermore, for example, on the side surface, the length of the second region in a direction perpendicular to the stacking direction of the power generation elements may be greater than the length of the first region in a direction perpendicular to the stacking direction of the power generation elements.

[0030] This allows for an increase in the connection area between the current collector and the terminal when the terminal is connected to the current collector within the recess in the second region, thereby improving the high-current characteristics of the battery.

[0031] Furthermore, for example, the conductive member may cover the main surfaces on both sides of the current collector adjacent to the recess.

[0032] This increases the contact area between the conductive material and the current collector, thereby improving the high-current characteristics of the battery and enhancing the mechanical connection strength between the terminals and the current collector, thus improving the reliability of the battery.

[0033] Furthermore, for example, the second region may further include insulating members that cover each of the power generation layers.

[0034] As a result, the sides of the power generation layer in the second region are covered with an insulating material, which suppresses material collapse and short circuits on the sides of each layer of the power generation layer.

[0035] Furthermore, for example, in the second region, the counter electrode layer may be recessed compared to the electrode layer.

[0036] This allows, for example, the counter electrode layer to be recessed while the electrode layer is protected by an insulating material, thereby simplifying the manufacturing process.

[0037] Furthermore, for example, the insulating member may further cover at least a portion of the solid electrolyte layer in the second region.

[0038] This allows the insulating material to be formed to cover a portion of the solid electrolyte layer, thus preventing the electrode layer from being exposed even if there are variations in the size of the insulating material. Furthermore, since the solid electrolyte layer is generally made of powdered material, its sides have very fine irregularities. This improves the adhesion strength of the insulating material and enhances the insulation reliability.

[0039] Furthermore, for example, the insulating member may further cover the first region.

[0040] As a result, the first region is also covered with an insulating material, which suppresses material collapse and short circuits on the sides of each layer of the power generation layer in the first region as well.

[0041] Furthermore, a method for manufacturing a battery according to one aspect of the present disclosure includes a first step of preparing a plurality of unit cells, each having a structure in which an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer are stacked, and a current collector; and a second step of forming a power generation element by stacking the plurality of unit cells, wherein the second step is a step of connecting the plurality of unit cells in parallel, and includes forming a first region on the side surface of the power generation element in which each power generation layer of the plurality of unit cells is not recessed compared to the current collector adjacent to each power generation layer among the current collectors of the plurality of unit cells, and a second region in which a recess is formed by each power generation layer being recessed compared to the current collector adjacent to each power generation layer among the current collectors of the plurality of unit cells, wherein an insulating member covers the electrode layer and the electrode current collector electrically connected to the electrode layer, and a conductive member is electrically connected to at least one main surface of the counter electrode current collector that covers the second region and the insulating member and is electrically connected to the counter electrode layer.

[0042] As a result, in the second region formed, conductive members such as terminals for extracting current can be connected within the recess to the main surface on the recessed side of the current collector. Therefore, compared to connecting terminals to the side of the current collector, the connection area between the terminals and the current collector can be increased, and the resistance of the connection part can be reduced, thereby improving the high-current characteristics of the manufactured battery. In addition, the increased connection area between the terminals and the current collector increases the mechanical connection strength between the terminals and the current collector, thereby improving the reliability of the manufactured battery.

[0043] Furthermore, in the formed second region, the current collector protrudes beyond the side surface of the power generation layer. On the other hand, in the formed first region, since the power generation layer has not receded, the current collector and the power generation layer are stacked and arranged at the position of the tip of the current collector that protrudes in the second region. Normally, when a current collector protrudes, the protruding portion of the current collector is prone to movement and deformation in the stacking direction, but the current collector that protrudes in the second region is supported by the power generation layer in the adjacent first region, making it difficult to move and making it easier to maintain a constant spacing between the current collectors. Therefore, during the battery manufacturing process and during the use of the manufactured batteries, contact between current collectors and short circuits, as well as discharge short circuits due to proximity, are suppressed, thereby improving the reliability of the manufactured batteries.

[0044] Furthermore, in terms of the power generation element, since the power generation layer recedes only in the second region of the two regions (the first and second regions), the area where the power generation layer recedes can be reduced, thereby increasing the energy density of the manufactured battery.

[0045] Furthermore, this allows the insulating material to cover the electrode layer in the second region, thereby suppressing the occurrence of short circuits between the counter electrode layer and the electrode layer via the conductive material.

[0046] Furthermore, a high-capacity battery can be realized by stacking the multiple power generation layers so that they are electrically connected in parallel. In this case, for example, the same poles of each layer are electrically connected by terminals connected to the current collector.

[0047] Furthermore, for example, in the second step, the recess may be formed such that the first region sandwiches the second region from both sides in a direction perpendicular to the stacking direction of the power generation elements.

[0048] As a result, the protruding current collectors in the formed second region are supported by the generating layers in the first region on both sides, making it easier for the current collectors to remain taut and for the spacing between current collectors in the second region to be more easily maintained.

[0049] Furthermore, for example, in the second step, the recesses may be formed by partial cutting, polishing, sandblasting, brushing, etching, laser irradiation, or plasma irradiation of each power generation layer.

[0050] This makes it easy to form recesses.

[0051] Furthermore, a battery according to another aspect of the present disclosure comprises a power generation element having a structure in which a plurality of power generation layers and a plurality of current collectors are stacked, each of the plurality of power generation layers having an electrode layer, a counter electrode layer and a solid electrolyte layer located between the electrode layer and the counter electrode layer, adjacent power generation layers among the plurality of power generation layers are stacked via at least one current collector among the plurality of current collectors, and each power generation layer of the power generation element is sandwiched between adjacent current collectors among the plurality of current collectors, and the side surface of the power generation element includes a first region in which each power generation layer is not recessed compared to the current collector adjacent to each power generation layer among the plurality of current collectors, and a second region in which a recess is formed by each power generation layer being recessed compared to the current collector adjacent to each power generation layer among the plurality of current collectors.

[0052] As a result, in the second region, conductive members such as terminals for extracting current can be connected within the recess on the main surface of the recessed side of the current collector. Therefore, compared to connecting terminals to the side of the current collector, the connection area between the terminal and the current collector can be increased, and the resistance of the connection part can be reduced, thereby improving the high-current characteristics of the battery. In addition, the increased connection area between the terminal and the current collector increases the mechanical connection strength between the terminal and the current collector, thereby improving the reliability of the battery.

[0053] Furthermore, in the second region, the current collector protrudes beyond the side surface of the power generation layer. On the other hand, in the first region, since the power generation layer has not receded, the current collector and the power generation layer are stacked at the position of the tip of the current collector that protrudes in the second region. Normally, when a current collector protrudes, the protruding portion of the current collector is prone to deformation due to movement in the stacking direction. However, the current collector that protrudes in the second region is supported by the power generation layer in the adjacent first region, making it less likely to move, and thus the spacing between current collectors is more easily maintained. Therefore, during the battery manufacturing process and use, contact between current collectors and short circuits, as well as discharge short circuits due to proximity, are suppressed, thereby improving the reliability of the battery.

[0054] Furthermore, in terms of the power generation element, since the power generation layer recedes only in the second region of the two regions (the first and second regions), the area where the power generation layer recedes can be reduced, thereby increasing the energy density of the battery.

[0055] Furthermore, for example, on the side surface, the first region may be positioned so as to sandwich the second region from both sides in a direction perpendicular to the stacking direction of the power generation elements.

[0056] As a result, the protruding current collectors in the second region are supported by the generating layers in the first region on both sides, making it easier for the current collectors to remain taut and for the spacing between current collectors in the second region to be maintained more easily.

[0057] Furthermore, for example, in the second region, the recesses formed by the recession of each power generation layer may be aligned along the stacking direction of the power generation elements.

[0058] This makes it easier to form the second region because the recesses in the second region can be formed by processing them all at once.

[0059] Furthermore, for example, the maximum depth of the recess may be greater than the width of the recess in the stacking direction of the power generation elements.

[0060] This increases the contact area between the terminal and the current collector when the terminal is connected to the current collector within a recess, thereby improving the high-current characteristics of the battery.

[0061] Furthermore, for example, the second region may be separated by the first region.

[0062] As a result, the individual widths of the separated second region become smaller, making it more difficult for the current collectors protruding in the second region to move, and making it easier to maintain a more constant spacing between the current collectors.

[0063] Furthermore, for example, on the side surface, the length of the second region in a direction perpendicular to the stacking direction of the power generation elements may be greater than the length of the first region in a direction perpendicular to the stacking direction of the power generation elements.

[0064] This allows for an increase in the connection area between the current collector and the terminal when the terminal is connected to the current collector within the recess in the second region, thereby improving the high-current characteristics of the battery.

[0065] Furthermore, for example, the multiple power generation layers may be stacked so as to be electrically connected in parallel.

[0066] This makes it possible to create a high-capacity battery. In this case, for example, the same poles in each layer are electrically connected by terminals connected to the current collector.

[0067] Furthermore, for example, the multiple power generation layers may be stacked so as to be electrically connected in series.

[0068] This makes it possible to create a high-voltage battery. In this case, for example, the voltage of each generating layer can be individually monitored by terminals connected to the current collector.

[0069] Furthermore, for example, the battery may further include a conductive member electrically connected to the main surface of at least one of the current collectors adjacent to the recess among the plurality of current collectors in the second region.

[0070] This allows conductive members, which are electrically connected to the main surface of the current collector, to be used as terminals or the like, with an increased contact area with the current collector.

[0071] Furthermore, for example, the conductive member may cover the main surfaces on both sides of the current collector adjacent to the recess.

[0072] This increases the contact area between the conductive material and the current collector, thereby improving the high-current characteristics of the battery and enhancing the mechanical connection strength between the terminals and the current collector, thus improving the reliability of the battery.

[0073] Furthermore, for example, the battery may further include an insulating member covering each of the power generation layers in the second region.

[0074] As a result, the sides of the power generation layer in the second region are covered with an insulating material, which suppresses material collapse and short circuits on the sides of each layer of the power generation layer.

[0075] Furthermore, for example, the plurality of current collectors may include a counter electrode current collector electrically connected to the counter electrode layer and an electrode current collector electrically connected to the electrode layer, and the battery may further include, in the second region, an insulating member covering the electrode layer and the electrode current collector, and a conductive member covering the second region and the insulating member and electrically connected to at least one main surface of the counter electrode current collector.

[0076] As a result, the insulating material covers the electrode layer in the second region, which suppresses the occurrence of short circuits between the counter electrode layer and the electrode layer via the conductive material.

[0077] Furthermore, for example, in the second region, the counter electrode layer may be recessed compared to the electrode layer.

[0078] This allows, for example, the counter electrode layer to be recessed while the electrode layer is protected by an insulating material, thereby simplifying the manufacturing process.

[0079] Furthermore, for example, the insulating member may further cover at least a portion of the solid electrolyte layer in the second region.

[0080] This allows the insulating material to be formed to cover a portion of the solid electrolyte layer, thus preventing the electrode layer from being exposed even if there are variations in the size of the insulating material. Furthermore, since the solid electrolyte layer is generally made of powdered material, its sides have very fine irregularities. This improves the adhesion strength of the insulating material and enhances the insulation reliability.

[0081] Furthermore, for example, the insulating member may cover the electrode layer of each power generation layer and the counter electrode current collector electrically connected to the electrode layer of each power generation layer in the second region, and the conductive member may be electrically connected to the counter electrode current collector electrically connected to the counter electrode layer of each power generation layer.

[0082] This allows for the use of conductive materials in the parallel connection of multiple power generation layers. Since the conductive materials can be brought into close contact with the second region and the insulating material, the volume of the parts involved in the parallel connection can be reduced. As a result, the energy density of the battery can be increased.

[0083] Furthermore, for example, the insulating member may further cover the first region.

[0084] As a result, the first region is also covered with an insulating material, which suppresses material collapse and short circuits on the sides of each layer of the power generation layer in the first region as well.

[0085] Furthermore, a method for manufacturing a battery according to another aspect of the present disclosure includes a first step of preparing a plurality of unit cells, each having a structure in which an electrode layer having an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer is stacked with a current collector, and a second step of forming a power generation element by stacking the plurality of unit cells, wherein the second step includes forming a first region on the side surface of the power generation element in which each power generation layer of the plurality of unit cells is not recessed compared to the current collector of the plurality of unit cells adjacent to each power generation layer, and a second region in which each power generation layer is recessed compared to the current collector of the plurality of unit cells, thereby forming a recess.

[0086] As a result, in the second region formed, conductive members such as terminals for extracting current can be connected within the recess to the main surface on the recessed side of the current collector. Therefore, compared to connecting terminals to the side of the current collector, the connection area between the terminals and the current collector can be increased, and the resistance of the connection part can be reduced, thereby improving the high-current characteristics of the manufactured battery. In addition, the increased connection area between the terminals and the current collector increases the mechanical connection strength between the terminals and the current collector, thereby improving the reliability of the manufactured battery.

[0087] Furthermore, in the formed second region, the current collector protrudes beyond the side surface of the power generation layer. On the other hand, in the formed first region, since the power generation layer has not receded, the current collector and the power generation layer are stacked and arranged at the position of the tip of the current collector that protrudes in the second region. Normally, when a current collector protrudes, the protruding portion of the current collector is prone to movement and deformation in the stacking direction, but the current collector that protrudes in the second region is supported by the power generation layer in the adjacent first region, making it difficult to move and making it easier to maintain a constant spacing between the current collectors. Therefore, during the battery manufacturing process and during the use of the manufactured batteries, contact between current collectors and short circuits, as well as discharge short circuits due to proximity, are suppressed, thereby improving the reliability of the manufactured batteries.

[0088] Furthermore, in terms of the power generation element, since the power generation layer recedes only in the second region of the two regions (the first and second regions), the area where the power generation layer recedes can be reduced, thereby increasing the energy density of the manufactured battery.

[0089] Furthermore, for example, in the second step, the recess may be formed such that the first region sandwiches the second region from both sides in a direction perpendicular to the stacking direction of the power generation elements.

[0090] As a result, the protruding current collectors in the formed second region are supported by the generating layers in the first region on both sides, making it easier for the current collectors to remain taut and for the spacing between current collectors in the second region to be more easily maintained.

[0091] Furthermore, for example, in the second step, the recesses may be formed by partial cutting, polishing, sandblasting, brushing, etching, laser irradiation, or plasma irradiation of each power generation layer.

[0092] This makes it easy to form recesses.

[0093] Furthermore, for example, the manufacturing method may further include a third step of forming a conductive member in the second region that is electrically connected to the main surface of at least one of the current collectors among the plurality of unit cells that is adjacent to the recess.

[0094] This allows for the formation of a conductive member that can be electrically connected to the main surface of the current collector, thereby increasing the connection area with the current collector, and enabling the conductive member to be used as a terminal or the like.

[0095] The embodiments will be described in detail below with reference to the drawings.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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 directions parallel 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 power generation layers contained in the power generation element.

[0100] Furthermore, in this specification, the "stacking direction" of the power generation elements coincides with the direction normal to the main surface of the current collector and the power generation layer. Also, in this specification, "plan view" means a view from a direction perpendicular to the main surface of the power generation element or power generation layer, 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 side," it means a view of that "certain surface" from the front.

[0101] 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."

[0102] Furthermore, in this specification, ordinal numbers such as "first," "second," etc., do not mean the number or order of components unless otherwise specified, but are used to avoid confusion between similar components and to distinguish them.

[0103] (Embodiment 1) First, the configuration of the battery according to Embodiment 1 will be described.

[0104] Figure 1 is a side view of the battery according to Embodiment 1. Figure 1 is a plan view of the side surface 11, which will be described later, when viewed from the front, that is, a plan view of the side surface 11. Figures 2A and 2B are cross-sectional views of the battery according to Embodiment 1. Figure 2A is a cross-sectional view at the position where the recessed region 92, which will be described later, is cut. Figure 2A shows the cross-section along the line IIA-IIA in Figure 3. Figure 2B is a cross-sectional view at the position where the continuous region 91, which will be described later, is cut. Figure 2B shows the cross-section along the line IIB-IIB in Figure 3. Figure 3 is a top view of the battery according to Embodiment 1. Note that in Figure 1, the side surfaces (end faces) of each layer appearing on the side surface 11 are shaded in the same way as the shading of each layer shown in the cross-sections of Figures 2A and 2B. This is also the case for each side view described later.

[0105] As shown in Figures 1 to 3, the battery 1 according to this embodiment comprises a power generation element 10, a counter electrode terminal 31, and an electrode terminal 32. The counter electrode terminal 31 and the electrode terminal 32 are examples of conductive materials. The battery 1 is, for example, an all-solid-state battery.

[0106] The power generation element 10 has a structure in which multiple power generation layers 100 and multiple current collectors 200 are stacked along the thickness direction of the multiple power generation layers 100.

[0107] As shown in Figure 3, the plan view shape of the power generation element 10 is, for example, a rectangle. In other words, the shape of the power generation element 10 is a flattened rectangular parallelepiped. Here, flattening means that the thickness (i.e., the length in the z-axis direction) is shorter than the length of each side of the main face (i.e., the respective lengths in the x-axis and y-axis directions) or the maximum width. The plan view shape of the power generation element 10 may also be a square, hexagon, or octagon, or it may be a circle or an ellipse. In the drawings relating to this specification, the thickness of each layer is exaggerated in the side view such as Figure 1 and the cross-sectional view such as Figures 2A and 2B to make the layered structure of the power generation element 10 easier to understand.

[0108] As shown in Figure 3, the power generation element 10 includes four sides 11, 12, 13 and 14 and two main surfaces 15 and 16.

[0109] Sides 11 and 12 are opposite each other and parallel to each other. Sides 11 and 12 are sides that include the long side of the main surface 15.

[0110] Sides 13 and 14 are opposite each other and parallel to each other. Sides 13 and 14 are sides that include the short side of the main surface 15.

[0111] 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. Both main surfaces 15 and 16 are flat surfaces.

[0112] As shown in Figures 1 to 2B, the power generation element 10 has multiple power generation layers 100 and multiple current collectors 200. The power generation layer 100 is the minimum configuration of the power generation section of the battery and is also called a unit cell. In some cases, the power generation layer 100 and the current collectors 200 connected to the power generation layer 100 are collectively referred to as a unit cell. The multiple power generation layers 100 are stacked so as to be electrically connected in parallel. In this embodiment, the multiple power generation layers 100 are stacked so as to be electrically connected in parallel to all of the power generation layers 100 of the power generation element 10. In the illustrated example, the power generation element 10 has 8 power generation layers 100, but is not limited to this. For example, the number of power generation layers 100 in the power generation element 10 may be an even number such as 2 or 4, or an odd number such as 3 or 5.

[0113] Each of the multiple power generation layers 100 includes an electrode layer 110, a counter electrode layer 120, and a solid electrolyte layer 130. The electrode layer 110 and the counter electrode layer 120 each contain an active material and are also referred to as the electrode active material layer and the counter electrode active material layer. In each of the multiple power generation layers 100, the electrode layer 110, the solid electrolyte layer 130, and the counter electrode layer 120 are stacked in this order along the z-axis.

[0114] The electrode layer 110 is one of the positive and negative electrode layers of the power generation layer 100. The counter electrode layer 120 is the other of the positive and negative electrode layers of the power generation layer 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.

[0115] The configurations of the multiple power generation layers 100 are substantially identical to each other. In two adjacent power generation layers 100, the order of the layers constituting the power generation layer 100 is reversed. In other words, the multiple power generation layers 100 are stacked along the z-axis with the order of the layers constituting the power generation layer 100 alternating. As a result, the multiple power generation layers 100 are stacked so as to be electrically connected in parallel. In this embodiment, since the number of power generation layers 100 is even, the bottom and top layers of the power generation element 10 are layers of the same polarity.

[0116] Two adjacent power generation layers 100 from a plurality of power generation layers 100 are stacked via at least one current collector 200 from a plurality of current collectors 200, and each power generation layer 100 of the power generation element 10 is sandwiched between two adjacent current collectors 200 from the plurality of current collectors 200. In the illustrated example, all adjacent pairs of power generation layers 100 from the plurality of power generation layers 100 are stacked via one current collector 200, but they may be stacked via two or three or more current collectors 200. When adjacent power generation layers 100 are stacked via two current collectors 200, the two current collectors 200 are joined using, for example, a conductive adhesive, solder, or direct welding.

[0117] The multiple current collectors 200 include an electrode current collector 210 electrically connected to the electrode layer 110 and a counter electrode current collector 220 electrically connected to the counter electrode layer 120. The electrode layer 110 is laminated on at least one main surface of the electrode current collector 210 without an intervening solid electrolyte layer 130. The counter electrode layer 120 is laminated on at least one main surface of the counter electrode current collector 220 without an intervening solid electrolyte layer 130.

[0118] The details of each component included in the power generation element 10 will be explained.

[0119] The current collector 200 is a conductive foil, plate, or mesh-like member. The current collector 200 may be, for example, a conductive thin film. As the material constituting the current collector 200, metals such as stainless steel (SUS), aluminum (Al), copper (Cu), and nickel (Ni) may be used. The electrode current collectors 210 and counter electrode current collectors 220 in multiple current collectors 200 may be formed using different materials.

[0120] The thickness of the current collector 200 is, for example, 5 μm to 100 μm, but is not limited to this.

[0121] The electrode layer 110 is in contact with the main surface of the electrode current collector 210. The electrode current collector 210 may also include a current collector layer containing a conductive material in the portion that contacts the electrode layer 110. The counter electrode layer 120 is in contact with the main surface of the counter electrode current collector 220. The counter electrode current collector 220 may also include a current collector layer containing a conductive material in the portion that contacts the counter electrode layer 120.

[0122] The electrode layer 110 is located on the main surface of the electrode current collector 210, on the side facing the counter electrode layer 120. The electrode layer 110 includes, for example, a negative electrode active material as the electrode material. The electrode layer 110 is located opposite the counter electrode layer 120.

[0123] As the negative electrode active material contained in the electrode layer 110, for example, graphite, metallic lithium, and other negative electrode active materials 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.

[0124] Furthermore, as the material containing the electrode layer 110, 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. Furthermore, as the material containing the electrode layer 110, a conductive agent such as acetylene black, or a binding binder such as polyvinylidene fluoride may be used.

[0125] The electrode layer 110 is manufactured by applying a paste-like coating, in which the materials for the electrode layer 110 are kneaded together with a solvent, onto the main surface of the electrode current collector 210 and drying it. To increase the density of the electrode layer 110, the electrode current collector 210 (also called an electrode plate) coated with the electrode layer 110 may be pressed after drying. The thickness of the electrode layer 110 is, for example, 5 μm to 300 μm, but is not limited to this.

[0126] The counter electrode layer 120 is located on the main surface of the counter electrode current collector 220, on the side facing the electrode layer 110. The counter electrode layer 120 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 layer 120 contains, for example, a positive electrode active material.

[0127] As the positive electrode active material contained in the counter electrode layer 120, 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.

[0128] Furthermore, as the material containing the counter electrode layer 120, 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 layer 120, a conductive agent such as acetylene black, or a binding binder such as polyvinylidene fluoride may be used.

[0129] The counter electrode layer 120 is manufactured by applying a paste-like coating, in which the materials for the counter electrode layer 120 are kneaded together with a solvent, onto the main surface of the counter electrode current collector 220 and allowing it to dry. To increase the density of the counter electrode layer 120, the counter electrode current collector 220 (also called the counter electrode plate) coated with the counter electrode layer 120 may be pressed after drying. The thickness of the counter electrode layer 120 is, for example, 5 μm to 300 μm, but is not limited to this.

[0130] The solid electrolyte layer 130 is placed between the electrode layer 110 and the counter electrode layer 120. The solid electrolyte layer 130 is in contact with both the electrode layer 110 and the counter electrode layer 120. 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.

[0131] 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.

[0132] In this embodiment, the electrode layer 110, the counter electrode layer 120, 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 layer 110, the counter electrode layer 120, and the solid electrolyte layer 130 may be smoothly curved together.

[0133] Furthermore, in the power generation layer 100, for example, the electrode layer 110, the solid electrolyte layer 130, and the counter electrode layer 120 each have the same shape and size, and their contours coincide.

[0134] Furthermore, in this embodiment, in the power generation element 10, the end face on the side surface 11 of the counter electrode current collector 220 and the end face on the side surface 11 of the electrode current collector 210 coincide when viewed from the z-axis direction. The same applies to the end faces on the side surfaces 12 of each of the counter electrode current collector 220 and the electrode current collector 210. In the power generation element 10, the shape and size of each of the multiple current collectors 200 are the same, and their contours coincide.

[0135] Sides 11 and 12 each include a continuous region 91 and a recessed region 92. The continuous region 91 is an example of a first region. The recessed region 92 is an example of a second region.

[0136] The continuous region 91 is the region on sides 11 and 12 in which each power generation layer 100 is not recessed compared to the current collectors 200 adjacent to each power generation layer 100 among the multiple current collectors 200. In other words, in the continuous region 91, when focusing on a single power generation layer 100, that single power generation layer 100 is not recessed compared to the current collectors 200 adjacent to that single power generation layer 100. In the continuous region 91, for example, when viewed from the z-axis direction, the sides of each of the multiple power generation layers 100, specifically the sides of the electrode layer 110, solid electrolyte layer 130, and counter electrode layer 120 of each of the multiple power generation layers 100, coincide with the sides of each of the multiple current collectors 200. In the continuous region 91, for example, the sides of each of the multiple power generation layers 100 and the sides of each of the multiple current collectors 200 form a flat surface, are continuous, and are flush.

[0137] Furthermore, the continuous region 91 is, for example, a region that includes the ends of the side surfaces 11 and 12 of the power generation elements 10 in a direction perpendicular to the stacking direction. This ensures that the power generation layer 100 is positioned on adjacent current collectors 200 at the ridges of the power generation elements 10, thereby suppressing contact between the current collectors 200 at the ridges of the power generation elements 10, where external forces are highly influential.

[0138] The recessed region 92 is a region on the side surfaces 11 and 12 where each power generation layer 100 is recessed compared to the current collector 200 adjacent to it among the multiple current collectors 200, thereby forming a recess 20. In other words, in the recessed region 92, when focusing on a single power generation layer 100, that single power generation layer 100 is recessed compared to the current collector 200 adjacent to it. In the recessed region 92, each of the multiple power generation layers 100 is recessed compared to the current collector 200, forming multiple recesses 20. Specifically, the power generation layer 100 is recessed compared to both the electrode current collector 210 and the counter electrode current collector 220 adjacent to it in the stacking direction. In the recessed region 92, for example, when viewed from the z-axis direction, each side surface of the multiple power generation layers 100 is located inward compared to each side surface of the multiple current collectors 200. In other words, in the recessed region 92, each of the multiple current collectors 200 protrudes more than each of the multiple power generation layers 100. Specifically, the electrode current collectors 210 and counter electrode current collectors 220 adjacent to both sides of the power generation layer 100 in the stacking direction all protrude more than the power generation layer 100.

[0139] Furthermore, in the recessed region 92, the multiple recesses 20 formed by the recession of each power generation layer 100 are aligned along the stacking direction (z-axis direction) of the power generation element 10. This makes it easier to form the recessed region 92.

[0140] Furthermore, on the sides 11 and 12, that is, in a plan view of the sides 11 and 12, the continuous region 91 and the recessed region 92 are adjacent in a direction perpendicular to the stacking direction of the power generation element 10. Also, on the sides 11 and 12, the continuous region 91 is positioned so as to sandwich the recessed region 92 from both sides in a direction perpendicular to the stacking direction of the power generation element 10. In other words, the recessed region 92 is positioned to separate the continuous region 91. Therefore, the recess 20 is the space surrounded by the power generation layer 100 in the continuous region 91 and the current collector 200 in the recessed region 92.

[0141] Furthermore, on sides 11 and 12, the length of the recessed region 92 perpendicular to the stacking direction of the power generation element 10 is greater than the length of the continuous region 91 perpendicular to the stacking direction of the power generation element 10. This increases the contact area between the current collector 200 and the terminals in the recessed region 92, thereby improving the high-current characteristics of the battery 1. Hereinafter, the length of the continuous region 91 and the recessed region 92 perpendicular to the stacking direction may be referred to as "width". Note that if the continuous region 91 and / or recessed region 92 are separated on sides 11 and 12, the width of the continuous region 91 and / or recessed region 92 is the sum of the widths of the separated continuous region 91 and / or recessed region 92.

[0142] In each recess 20, for example, the main surface of the current collector 200 adjacent to the corresponding recessed power generation layer 100 on the recess 20 side is exposed. This allows the counter electrode terminal 31 or electrode terminal 32 to be electrically connected within the recess 20. The main surface of the current collector 200 on the recess 20 side may be covered by an electrode layer 110 or a counter electrode layer 120. In this case, the thickness of the electrode layer 110 or counter electrode layer 120 is, for example, one-fifth or less of the thickness of the electrode layer 110 or counter electrode layer 120 in areas where the recess 20 is not formed.

[0143] The recess 20 is, for example, a stepped recess, but is not limited to this; it may also be a recess with a tapered shape or a recess with a curved surface.

[0144] The maximum depth of the recess 20 is greater than, for example, the thickness of each corresponding power generation layer 100, i.e., the width of the recess 20 in the stacking direction. This increases the connection area between the counter electrode terminal 31 or electrode terminal 32 and the current collector 200 when the counter electrode terminal 31 or electrode terminal 32 is connected to the current collector 200 within the recess 20, thereby improving high-current characteristics.

[0145] Furthermore, the maximum depth of the recess 20 may be 4.5 times or more the thickness of the current collector 200 adjacent to the recess 20. This ensures a connection area 10 times or more when both the front and back surfaces and sides of the main surface of the current collector 200 are connected to the terminal, compared to when only the side portion of the current collector 200 is connected to the terminal. Furthermore, the maximum depth of the recess 20 may be 9 times or more the thickness of the current collector 200 adjacent to the recess 20. This ensures a connection area 10 times or more when one side and sides of the main surface of the current collector 200 are connected to the terminal, compared to when only the side portion of the current collector 200 is connected to the terminal.

[0146] Note that side surfaces 13 and 14 are composed only of a continuous region 91, for example, without including a recessed region 92, but are not limited to this and may include both a continuous region 91 and a recessed region 92. Also, the structures of side surfaces 11 and 12 are not limited to being formed on side surfaces 11 and 12 that are in a backward positional relationship. For example, instead of side surfaces 11 and 12, the structures of side surfaces 11 and 12 may be formed on two adjacent (orthogonal) side surfaces, such as side surfaces 11 and 13.

[0147] In the recessed region 92, the counter electrode terminal 31 and the electrode terminal 32 each cover the main surface of a current collector 200 adjacent to each power generation layer 100 and are electrically connected to the main surface of the current collector 200. The counter electrode terminal 31 and the electrode terminal 32 are, for example, in contact with the main surface of the current collector 200. Specifically, in the recessed region 92 of the side surface 11, the counter electrode terminal 31 covers the main surface on the recess 20 side of a counter electrode current collector 220 that protrudes adjacent to the recess 20 and is electrically connected to the counter electrode current collector 220. In the recessed region 92 of the side surface 12, the electrode terminal 32 covers the main surface on the recess 20 side of an electrode current collector 210 that protrudes adjacent to the recess 20 and is electrically connected to the electrode current collector 210. As a result, the counter electrode terminal 31 functions as an extraction electrode of the counter electrode layer 120, and the electrode terminal 32 functions as an extraction electrode of the electrode layer 110. By connecting all the counter electrode terminals 31 together and all the electrode terminals 32 together, the entire battery 1 can be connected in parallel. Note that the counter electrode terminals 31 may be connected to either the upper or lower main surface of the counter electrode current collector 220. Similarly, the electrode terminals 32 may be connected to either the upper or lower main surface of the electrode current collector 210. In this way, by connecting the counter electrode terminals 31 and the electrode terminals 32 to recessed areas 92 on different sides, the connection area between the counter electrode terminals 31 and the counter electrode current collector 220 and the connection area between the electrode terminals 32 and the electrode current collector 210 can be increased.

[0148] The counter electrode terminal 31 is positioned within the recess 20, spaced apart from the side surface of the power generation layer 100. The counter electrode terminal 31 may be in contact with the counter electrode layer 120, or with both the counter electrode layer 120 and the solid electrolyte layer 130, as long as it is not in contact with the electrode layer 110 of the power generation layer 100.

[0149] The electrode terminals 32 are positioned within the recess 20, spaced apart from the side surface of the power generation layer 100. The electrode terminals 32 may be in contact with the electrode layer 110, or with both the electrode layer 110 and the solid electrolyte layer 130, as long as they are not in contact with the counter electrode layer 120 in the power generation layer 100.

[0150] Furthermore, the counter electrode terminal 31 and the electrode terminal 32 are not connected to the main surface 15 and main surface 16 of the power generation element 10, for example, but may be connected to the main surface 15 and main surface 16.

[0151] The counter electrode terminal 31 and electrode terminal 32 are foil-shaped leads made of a metal such as nickel, stainless steel, aluminum, or copper. The method of connecting the counter electrode terminal 31 and electrode terminal 32 to the current collector 200 is not particularly limited, and methods such as bonding or welding can be used. When bonding, solder, conductive adhesive, or conductive adhesive tape can be used for bonding. The counter electrode terminal 31 and electrode terminal 32 are formed using the same material, but they may be formed using different materials.

[0152] As described above, in battery 1, sides 11 and 12 include a continuous region 91 and a recessed region 92. This allows terminals for extracting current (e.g., a counter electrode terminal 31 and an electrode terminal 32) to be connected to the main surface of the current collector 200 on the recessed side 20 in the recessed region 92. Therefore, compared to connecting terminals to the side of the current collector 200, the connection area between the terminals and the current collector 200 can be increased, and the resistance of the connection part can be reduced, thereby improving the high-current characteristics. In addition, the increased connection area between the terminals and the current collector 200 increases the mechanical connection strength between the terminals and the current collector 200, thereby improving the reliability of battery 1.

[0153] Furthermore, in the recessed region 92, the current collector 200 protrudes beyond the side surface of the power generation layer 100. On the other hand, in the continuous region 91, the current collector 200, whose side surface is aligned with the tip of the current collector 200 that protrudes in the recessed region 92, is stacked with the power generation layer 100, which has an electrode layer 110, a counter electrode layer 120, and a solid electrolyte layer 130. Normally, when a current collector 200 protrudes, the protruding portion of the current collector 200 is prone to deformation as it moves in the stacking direction. However, the current collector 200 that protrudes in the recessed region 92 is supported by the power generation layer 100 in the adjacent continuous region 91, making it difficult to move and making it easier to maintain a constant spacing between the current collectors 200. Therefore, during the manufacturing process of the battery 1 and during use of the battery 1, contact between the current collectors 200 and short circuits, as well as discharge short circuits due to proximity, are suppressed, thereby improving reliability. In particular, because the recessed region 92 is sandwiched between the continuous region 91 on both sides, the current collector 200 in the recessed region 92 is supported by the power generation layer 100 in the continuous region 91 on both sides, making it easier for the current collector 200 to be taut, and making it easier to maintain the spacing between the current collectors 200 in the recessed region 92. In addition, on the side surfaces 11 and 12, the power generation layer 100 is recessed only in the recessed region 92 of the continuous region 91 and the recessed region 92, so the area in which the power generation layer 100 is recessed can be reduced, and the energy density can be increased.

[0154] [Example 1] Next, we will describe Modification 1 of Embodiment 1. In the following description of Modification 1, we will focus on the differences from Embodiment 1, and omit or simplify the explanation of the similarities. The same applies to Modifications 2 and beyond, which will be described below; in the description of each Modification, we will focus on the differences from Embodiment 1 and each Modification, and omit or simplify the explanation of the similarities.

[0155] Figure 4 is a side view of the battery according to Modification 1 of Embodiment 1. Figure 4 is a top view of the side 11 as seen from the front. Figures 5A and 5B are cross-sectional views of the battery according to Modification 1 of Embodiment 1. Figure 5A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 5B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0156] As shown in Figures 4 to 5B, the battery 1a according to this modified example differs from the battery 1 according to Embodiment 1 in that it further includes an insulating member 40.

[0157] The insulating member 40 covers at least a portion of the side surface of each power generation layer 100 in the recessed region 92 and is in contact with the side surface of the power generation layer 100. The insulating member 40 is, for example, an insulating layer having insulating properties. In the battery 1a, the insulating member 40 is located inside the recess 20 in the recessed region 92 and completely covers the side surface of each power generation layer 100. In other words, the side surface of the power generation layer 100 is not exposed in the recess 20. The insulating member 40 covers the side surfaces of the electrode layer 110, the solid electrolyte layer 130, and the counter electrode layer 120 collectively in the recessed region 92. In this way, by covering the side surface of the power generation layer 100 with the insulating member 40, material collapse and short circuits on the side surfaces of the electrode layer 110, the solid electrolyte layer 130, and the counter electrode layer 120 can be suppressed.

[0158] Furthermore, in the recessed area 92, the insulating member 40 covers a portion of the main surface of the current collector 200 adjacent to the recess 20. Specifically, in the recess 20, the insulating member 40 continuously covers the side surface of the power generation layer 100 and the main surface of the current collector 200, and is in contact with the side surface of the power generation layer 100 and the main surface of the current collector 200.

[0159] The insulating member 40 is formed using an electrically insulating insulating material. The insulating member 40 is formed, for example, by coating with an insulating paste containing an insulating material. The insulating member 40 includes, for example, a resin. By including a resin in the insulating member 40, the impact resistance of the battery 1a can be increased, and the stress applied to the battery 1a due to temperature changes and expansion and contraction during charging and discharging can be alleviated.

[0160] The resin is, for example, an epoxy resin, but is not limited to this. Inorganic materials may also be used as insulating materials. Usable insulating materials are selected based on various properties such as flexibility, gas barrier properties, impact resistance, and heat resistance.

[0161] The counter electrode terminal 31 and the electrode terminal 32 are each positioned within the recess 20, spaced apart from the insulating member 40. However, at least one of the counter electrode terminal 31 and the electrode terminal 32 may be in contact with the insulating member 40.

[0162] [Differentiation 2] Next, a modified example 2 of Embodiment 1 will be described.

[0163] Figures 6A and 6B are cross-sectional views of a battery according to a modified example 2 of Embodiment 1. Figure 6A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 6B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0164] As shown in Figures 6A and 6B, the battery 1b according to this modified example differs from the battery 1a according to Modification 1 of Embodiment 1 in that it is equipped with a counter electrode terminal 31b and an electrode terminal 32b, which are examples of conductive members, instead of the counter electrode terminal 31 and electrode terminal 32. The contact locations of the counter electrode terminal 31b and electrode terminal 32b with the power generation element 10 are different from those of the counter electrode terminal 31 and electrode terminal 32.

[0165] The counter electrode terminal 31b covers the main surfaces on both sides of the counter electrode current collector 220 that protrudes adjacent to the recess 20 in the recessed region 92 of the side surface 11, and is electrically connected to the main surfaces on both sides of the counter electrode current collector 220. The counter electrode terminal 31b also covers the side surface of the counter electrode current collector 220 that protrudes adjacent to the recess 20. The counter electrode terminal 31b continuously covers one main surface, side surface, and the other main surface of the counter electrode current collector 220 that protrudes adjacent to the recess 20. For example, the counter electrode terminal 31b is in contact with the main surfaces and side surfaces on both sides of the counter electrode current collector 220 that protrudes adjacent to the recess 20. In addition, the counter electrode terminal 31b is in contact with the insulating member 40 that covers the side surface of the power generation layer 100 within the recess 20, and is separated from the power generation layer 100 via the insulating member 40.

[0166] The electrode terminal 32b covers the main surfaces on both sides of the electrode current collector 210 that protrudes adjacent to the recess 20 in the recessed region 92 of the side surface 12, and is electrically connected to the main surfaces on both sides of the electrode current collector 210. The electrode terminal 32b also covers the side surface of the electrode current collector 210 that protrudes adjacent to the recess 20. The electrode terminal 32b continuously covers one main surface, side surface, and the other main surface of the electrode current collector 210 that protrudes adjacent to the recess 20. For example, the electrode terminal 32b is in contact with the main surfaces and side surfaces on both sides of the electrode current collector 210 that protrudes adjacent to the recess 20. In addition, the electrode terminal 32b is in contact with the insulating member 40 that covers the side surface of the power generation layer 100 within the recess 20, and is separated from the power generation layer 100 via the insulating member 40.

[0167] Thus, in battery 1b, the terminals for current extraction are electrically connected to the main surfaces on both sides of the current collector 200 that protrude in the recessed region 92. This increases the connection area between the terminals and the current collector 200, thereby improving high-current characteristics and enhancing reliability by increasing the mechanical connection strength between the terminals and the current collector.

[0168] [Difference 3] Next, a modified example 3 of Embodiment 1 will be described.

[0169] Figures 7A and 7B are cross-sectional views of a battery according to a modification 3 of Embodiment 1. Figure 7A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 7B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0170] As shown in Figures 7A and 7B, the battery 1c according to this modified example differs from the battery 1 according to Embodiment 1 in that it further includes an electrode insulating member 41 and a counter electrode insulating member 42, which are examples of insulating members, respectively.

[0171] The electrode insulating member 41 and the counter electrode insulating member 42 have different contact locations with the power generation element 10 compared to the insulating member 40 described above.

[0172] The electrode insulating member 41 covers the electrode current collector 210 and the electrode layer 110 in the recessed region 92 on the side surface 11, and is in contact with the electrode current collector 210 and the electrode layer 110. Specifically, the electrode insulating member 41 covers the electrode layer 110 of each power generation layer 100 and each electrode current collector 210 included in the plurality of current collectors 200 in the recessed region 92 on the side surface 11. The electrode insulating member 41 covers the main surfaces and sides on both sides of the electrode current collector 210 that protrudes adjacent to the recess 20 in the recessed region 92 on the side surface 11. The electrode insulating member 41 continuously covers the electrode current collector 210 and one or two electrode layers 110 adjacent to the electrode current collector 210. The electrode insulating member 41 is not in contact with, for example, the counter electrode current collector 220. The electrode insulating member 41 completely covers the electrode current collector 210 and the electrode layer 110 in, for example, the recess 20. In other words, the electrode current collector 210 and the electrode layer 110 are not exposed in the recess 20. However, a portion of the electrode current collector 210 and the electrode layer 110 may be exposed in the recess 20.

[0173] Furthermore, the electrode insulating member 41 covers at least a portion of the solid electrolyte layer 130 in the recessed region 92 on the side surface 11. Therefore, the electrode insulating member 41 continuously covers at least a portion of the solid electrolyte layer 130 of one of the two adjacent power generation layers 100, and at least a portion of the solid electrolyte layer 130 of the other power generation layer 100. This reduces the risk of exposing the electrode layer 110 even if the width (length in the z-axis direction) of the electrode insulating member 41 fluctuates due to manufacturing variations. As a result, contact between the counter electrode terminal 31, the electrode current collector 210, and the electrode layer 110, preventing short circuits, is suppressed. In addition, the side surface of the solid electrolyte layer 130, which is formed from a powdery material, has very fine irregularities. Therefore, the electrode insulating member 41 penetrates these irregularities, improving the adhesion strength of the electrode insulating member 41 and enhancing its insulation reliability. Furthermore, the electrode insulating member 41 may further cover at least a portion of the counter electrode layer 120 in the recessed region 92 on the side surface 11. In addition, the electrode insulating member 41 has a striped shape when viewed in plan with respect to the side surface 11.

[0174] The counter electrode insulating member 42 covers the counter electrode current collector 220 and the counter electrode layer 120 in the recessed region 92 on the side surface 12, and is in contact with the counter electrode current collector 220 and the counter electrode layer 120. Specifically, the counter electrode insulating member 42 covers the counter electrode layer 120 of each power generation layer 100 and each counter electrode current collector 220 included in the plurality of current collectors 200 in the recessed region 92 on the side surface 12. The counter electrode insulating member 42 covers the main surfaces and sides on both sides of the counter electrode current collector 220 that protrudes adjacent to the recess 20 in the recessed region 92 on the side surface 12. The counter electrode insulating member 42 continuously covers the counter electrode current collector 220 and one or two counter electrode layers 120 adjacent to the counter electrode current collector 220. The counter electrode insulating member 42 is not in contact with, for example, the electrode current collector 210. The counter electrode insulating member 42 completely covers the counter electrode current collector 220 and the counter electrode layer 120 in the recess 20, for example. In other words, the counter electrode current collector 220 and the counter electrode layer 120 are not exposed in the recess 20. However, a portion of the counter electrode current collector 220 and the counter electrode layer 120 may be exposed in the recess 20.

[0175] Furthermore, the counter electrode insulating member 42 covers at least a portion of the solid electrolyte layer 130 in the recessed region 92 on the side surface 12. Therefore, the counter electrode insulating member 42 continuously covers at least a portion of the solid electrolyte layer 130 of one of the two adjacent power generation layers 100, and at least a portion of the solid electrolyte layer 130 of the other power generation layer 100. This provides the same effect as when the electrode insulating member 41 covers the solid electrolyte layer 130. The counter electrode insulating member 42 may further cover at least a portion of the electrode layer 110 in the recessed region 92 on the side surface 12. In addition, the counter electrode insulating member 42 has a stripe shape when viewed in plan with respect to the side surface 12.

[0176] Thus, in battery 1c, in the recessed region 92 of the side surface 11 where the counter electrode terminal 31 is connected to the counter electrode current collector 220, the electrode current collector 210 and the electrode layer 110 are covered by the electrode insulating member 41, thereby suppressing contact between the counter electrode terminal 31 and the electrode current collector 210 and the electrode layer 110, which would cause a short circuit. Furthermore, in battery 1c, in the recessed region 92 of the side surface 12 where the electrode terminal 32 is connected to the electrode current collector 210, the counter electrode current collector 220 and the counter electrode layer 120 are covered by the counter electrode insulating member 42, thereby suppressing contact between the electrode terminal 32 and the counter electrode current collector 220 and the counter electrode layer 120, which would cause a short circuit. This improves the reliability of battery 1c.

[0177] [Differentiation Example 4] Next, a modified example 4 of Embodiment 1 will be described.

[0178] Figures 8A and 8B are cross-sectional views of a battery according to a modification 4 of Embodiment 1. Figure 8A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 8B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0179] As shown in Figures 8A and 8B, the battery 1d according to this modified example differs from the battery 1c according to Modified Example 3 of Embodiment 1 in that it is equipped with a counter electrode terminal 31d and an electrode terminal 32d, which are examples of conductive members, instead of the counter electrode terminal 31 and electrode terminal 32, respectively.

[0180] The counter electrode terminal 31d and electrode terminal 32d have a different arrangement compared to the counter electrode terminal 31 and electrode terminal 32.

[0181] The counter electrode terminal 31d covers the main surfaces on both sides of the counter electrode current collector 220 that protrudes adjacent to the recess 20 in the recessed region 92 of the side surface 11, and is electrically connected to the main surfaces on both sides of the counter electrode current collector 220. The counter electrode terminal 31d also covers the side surface of the counter electrode current collector 220 that protrudes adjacent to the recess 20. The counter electrode terminal 31d continuously covers one main surface, side surface and the other main surface of the counter electrode current collector 220 that protrudes adjacent to the recess 20. For example, the counter electrode terminal 31d is in contact with the main surfaces and side surfaces on both sides of the counter electrode current collector 220 that protrudes adjacent to the recess 20. In addition, the counter electrode terminal 31d is in contact with the counter electrode layer 120 within the recess 20. In other words, the counter electrode terminal 31d covers the main surfaces on both sides of the counter electrode current collector 220 over the entire depth of the recess 20. This increases the contact area between the counter terminal 31d and the counter current collector 220, thereby improving the high-current characteristics of the battery 1d.

[0182] The electrode terminal 32d covers the main surfaces on both sides of the electrode current collector 210 that protrudes adjacent to the recess 20 in the recessed region 92 of the side surface 12, and is electrically connected to the main surfaces on both sides of the electrode current collector 210. The electrode terminal 32d also covers the side surface of the electrode current collector 210 that protrudes adjacent to the recess 20. The electrode terminal 32d continuously covers one main surface, side surface, and the other main surface of the electrode current collector 210 that protrudes adjacent to the recess 20. For example, the electrode terminal 32d is in contact with the main surfaces and side surfaces on both sides of the electrode current collector 210 that protrudes adjacent to the recess 20. In addition, the electrode terminal 32d is in contact with the electrode layer 110 within the recess 20. In other words, the electrode terminal 32d covers the main surfaces on both sides of the electrode current collector 210 over the entire depth of the recess 20. This increases the contact area between the electrode terminal 32d and the electrode current collector 210, thereby improving the high-current characteristics of the battery 1d.

[0183] [Difference 5] Next, a modified example 5 of Embodiment 1 will be described.

[0184] Figures 9A and 9B are cross-sectional views of a battery according to a modification 5 of Embodiment 1. Figure 9A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 9B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0185] As shown in Figures 9A and 9B, the battery 1e according to this modified example differs from the battery 1c according to Modified Example 3 of Embodiment 1 in that it is equipped with a counter electrode terminal 31e and an electrode terminal 32e, which are examples of conductive materials, instead of the counter electrode terminal 31 and electrode terminal 32, respectively.

[0186] The counter electrode terminal 31e and electrode terminal 32e have a different arrangement compared to the counter electrode terminal 31 and electrode terminal 32.

[0187] The counter electrode terminal 31e covers the recessed region 92 and the electrode insulating member 41 on the side surface 11, and is electrically connected to the counter electrode layer 120 and the counter electrode current collector 220. Specifically, the counter electrode terminal 31e covers the electrode insulating member 41 and the portion of the recessed region 92 on the side surface 11 that is not covered by the electrode insulating member 41.

[0188] The counter electrode terminals 31e penetrate into each recess 20 and, in the recessed area 92 on the side surface 11 that is not covered by the electrode insulating member 41, are in contact with the main surfaces and side surfaces of the counter electrode current collector 220 and the side surfaces of the counter electrode layer 120, thereby electrically connecting to the main surfaces of the counter electrode current collector 220 and the side surfaces of the counter electrode layer 120. Since the counter electrode layer 120 is made of a powdered material, it has very fine irregularities, similar to the solid electrolyte layer 130. The penetration of the counter electrode terminals 31e into the irregularities on the side surfaces of the counter electrode layer 120 improves the adhesion strength of the counter electrode terminals 31e and enhances the reliability of the electrical connection.

[0189] The counter electrode terminal 31e is electrically connected to each of the counter electrode layers 120 of the multiple power generation layers 100. In other words, the counter electrode terminal 31e plays a part in electrically connecting each power generation layer 100 in parallel. The counter electrode terminal 31e covers the recessed region 92 collectively, over almost the entire area in the stacking direction of the power generation elements 10 in the recessed region 92.

[0190] In the power generation element 10, the uppermost and lowermost layers are counter electrode current collectors 220, respectively. Near the upper and lower ends of the side surface 11, the counter electrode terminals 31e cover a portion of the main surface of the counter electrode current collectors 220 located in the uppermost and lowermost layers from the outside. As a result, the counter electrode terminals 31e are resistant to external forces from the z-axis direction, and detachment is suppressed. In addition, since the connection area between the counter electrode terminals 31e and the counter electrode current collectors 220 is increased, the connection resistance between the counter electrode terminals 31e and the counter electrode current collectors 220 is reduced, and the high-current characteristics can be improved.

[0191] The electrode terminal 32e covers the recessed region 92 and the counter electrode insulating member 42 on the side surface 12, and is electrically connected to the electrode layer 110 and the electrode current collector 210. Specifically, the electrode terminal 32e covers the counter electrode insulating member 42 and the portion of the recessed region 92 on the side surface 12 that is not covered by the counter electrode insulating member 42.

[0192] The electrode terminals 32e penetrate into each recess 20 and, in the recessed area 92 on the side surface 12 that is not covered by the counter electrode insulating member 42, are in contact with the main surfaces and side surfaces of the electrode current collector 210 and the side surfaces of the electrode layer 110, thereby electrically connecting to the main surfaces of the electrode current collector 210 and the side surfaces of the electrode layer 110. Since the electrode layer 110 is formed from a powdery material, it has very fine irregularities, similar to the solid electrolyte layer 130. The electrode terminals 32e penetrate into the irregularities on the side surfaces of the electrode layer 110, improving the adhesion strength of the electrode terminals 32e and enhancing the reliability of the electrical connection.

[0193] The electrode terminals 32e are electrically connected to each electrode layer 110 of the multiple power generation layers 100. In other words, the electrode terminals 32e play a part in electrically connecting each power generation layer 100 in parallel. The electrode terminals 32e cover almost the entire recessed region 92 in the stacking direction of the power generation elements 10 within the recessed region 92.

[0194] The counter electrode terminal 31e and the electrode terminal 32e are formed using a conductive resin material or the like. Alternatively, the counter electrode terminal 31e and the electrode terminal 32e may be formed using a metallic material such as solder. The usable conductive material is selected based on various properties such as flexibility, gas barrier properties, impact resistance, heat resistance, and solder wettability. The counter electrode terminal 31e and the electrode terminal 32e are formed using the same material, but they may be formed using different materials.

[0195] Furthermore, external electrodes may be formed on the counter electrode terminal 31e and electrode terminal 32e by other methods such as plating, printing, or soldering. Forming external electrodes can improve the mountability of the battery 1e, for example.

[0196] As described above, the counter electrode terminal 31e and the electrode terminal 32e not only function as extraction electrodes for the battery 1e, but also play a role in the parallel connection of multiple power generation layers 100. Since the counter electrode terminal 31e and the electrode terminal 32e are formed to closely cover the recessed region 92, their volumes can be reduced. In other words, because the volume of the terminals can be reduced, the volumetric energy density of the battery 1e can be improved.

[0197] [Modification 6] Next, a modified example 6 of Embodiment 1 will be described.

[0198] Figure 10 is a side view of a battery according to a modification 6 of Embodiment 1. Figure 10 is a top view of the side 11 as seen from the front.

[0199] As shown in Figure 10, the battery 1f according to this modified example differs from the battery 1a according to Modification 1 of Embodiment 1 in that the receding region 92 is separated into multiple parts by the continuous region 91.

[0200] In battery 1f, a portion of the continuous region 91 is positioned to separate the recessed region 92. The recessed region 92 is separated into two by the continuous region 91 on the side surface 11. That is, on the side surface 11, each power generation layer 100 is recessed at multiple locations compared to the current collector 200 adjacent to each power generation layer 100, forming multiple recesses 20 relative to each power generation layer 100. Each of the separated recessed regions 92 is sandwiched on both sides by the continuous region 91 in a direction perpendicular to the stacking direction of the power generation elements 10. The cross-sectional structure obtained by cutting each of the separated recessed regions 92 is, for example, the same as the cross-sectional structure of battery 1a shown in Figure 5A.

[0201] Thus, in battery 1f, the separation of the recessed region 92 reduces the individual widths of the separated recessed region 92. As a result, the current collectors 200 protruding in the recessed region 92 become less likely to move, and the spacing between the current collectors 200 is more easily maintained. Therefore, during the manufacturing process of battery 1f and during use of battery 1f, contact between the current collectors 200 and short circuits are further suppressed, thereby improving reliability.

[0202] In addition, on the side 12, the receding area 92 may be separated into multiple sections, similar to the side 11.

[0203] [Difference 7] Next, a modified example 7 of Embodiment 1 will be described.

[0204] Figure 11 is a side view of a battery according to modification 7 of Embodiment 1. Figure 11 is a plan view of the side 11 as seen from the front.

[0205] As shown in Figure 11, the battery 1g according to this modified example differs from the battery 1f according to modified example 6 of Embodiment 1 in that it has a larger number of separated recessed regions 92.

[0206] In battery 1g, the recessed area 92 is separated into three or more, specifically five, sections on the side surface 11. In this way, the number of separated recessed areas 92 increases compared to battery 1f, and the width of each separated recessed area 92 becomes even smaller, further suppressing contact and short circuits between the current collectors 200.

[0207] In addition, on the side 12, the receding region 92 may be separated into three or more sections, similar to the side 11.

[0208] [Differentiation 8] Next, a modified example 8 of Embodiment 1 will be described.

[0209] Figure 12 is a side view of a battery according to modification 8 of Embodiment 1. Figure 12 is a top view of the side 11 as seen from the front.

[0210] As shown in Figure 12, the battery 1h according to this modified example differs from the battery 1e according to modified example 5 of Embodiment 1 in that the retracted region 92 is separated into multiple parts.

[0211] In battery 1h, the recessed region 92 is separated into three or more, specifically five, sections on the side surface 11. The cross-sectional structure obtained by cutting each separated recessed region 92 is, for example, the same as the cross-sectional structure of battery 1e shown in Figure 9A.

[0212] This provides an effect that combines the effects of the battery 1e according to Modification 5 of Embodiment 1 and the battery 1g according to Modification 7 of Embodiment 1.

[0213] In addition, on the side 12, the receding region 92 may be separated into three or more sections, similar to the side 11.

[0214] [Modification 9] Next, a modified example 9 of Embodiment 1 will be described.

[0215] Figure 13 is a side view of a battery according to modification 9 of Embodiment 1. Figure 13 is a top view of the side 11 as seen from the front.

[0216] As shown in Figure 13, the battery 1i according to this modified example differs from the battery 1f according to modified example 6 of Embodiment 1 in that the counter electrode terminal 31 is connected to one of the multiple separated recessed regions 92 and the electrode terminal 32 is connected to another one.

[0217] In battery 1i, the multiple recessed regions 92 on the side surface 11 include a recessed region 92a to which the counter electrode terminal 31 is connected and a recessed region 92b to which the electrode terminal 32 is connected. The cross-sectional structure obtained by cutting through recessed region 92a is the same as, for example, the cross-sectional structure of the recessed region 92 on the side surface 11 of battery 1a shown in Figure 5A. Similarly, the cross-sectional structure obtained by cutting through recessed region 92b is the same as, for example, the cross-sectional structure of the recessed region 92 on the side surface 12 of battery 1a shown in Figure 5A.

[0218] Thus, in the battery 1i, both the counter electrode terminal 31 and the electrode terminal 32 are connected to one side 11, allowing both electrode terminals to be formed on the same side. Therefore, for example, when mounting the battery 1i on a circuit board, an electrical connection between the circuit board and the battery 1i can be easily formed.

[0219] [Example 10] Next, a modified example 10 of Embodiment 1 will be described.

[0220] Figures 14A and 14B are cross-sectional views of a battery according to a modified example 10 of Embodiment 1. Figure 14A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 14B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0221] As shown in Figures 14A and 14B, the battery 1j according to this modified example differs from the battery 1e according to modified example 5 of Embodiment 1 in that it further includes a continuous region insulating member 43, which is an example of an insulating member.

[0222] The continuous region insulating member 43 covers and is in contact with the continuous region 91 on sides 11 and 12. For example, the continuous region insulating member 43 covers the entire continuous region 91 on sides 11 and 12. The continuous region insulating member 43 also covers the edges of the main surface 15 and the main surface 16. Although not shown, the continuous region insulating member 43 may also cover sides 13 and 14.

[0223] The continuous region insulating member 43 is formed from, for example, the same material as the electrode insulating member 41 and the counter electrode insulating member 42. The continuous region insulating member 43 and the electrode insulating member 41, as well as the continuous region insulating member 43 and the counter electrode insulating member 42, may each be integrally formed insulating members. Alternatively, the electrode insulating member 41, the counter electrode insulating member 42, and the continuous region insulating member 43 may be integrally formed insulating members surrounding the outer circumference of the power generation element 10.

[0224] In this way, the continuous region insulating member 43 covers the continuous region 91, protecting the side surface of the power generation layer 100 in the continuous region 91 and suppressing material collapse and short circuits on the side surface of the power generation layer 100.

[0225] [Example 11] Next, a modified example 11 of Embodiment 1 will be described.

[0226] Figure 15 is a side view of a battery according to a modified example 11 of Embodiment 1. Figure 15 is a top view of the side 11 as seen from the front.

[0227] As shown in Figure 15, the battery 1k according to this modified example differs from the battery 1j according to the modified example 10 of Embodiment 1 in that the recessed region 92 is separated into multiple sections, and the counter electrode terminals 31e connected to each of the separated recessed regions 92 are connected.

[0228] In battery 1k, the continuous region insulating member 43 covers not only the continuous regions 91 located at both ends of the side surface 11, but also the continuous regions 91 sandwiched between the recessed regions 92.

[0229] The counter electrode terminal 31e covers the electrode insulating member 41, the continuous region insulating member 43, and the portion of the side surface 11 not covered by the electrode insulating member 41 and the continuous region insulating member 43. In other words, although not shown in the diagram, the continuous region insulating member 43 is also positioned between the continuous region 91 sandwiched between the recessed region 92 and the counter electrode terminal 31e.

[0230] The counter electrode terminal 31e is in contact with the main surfaces and sides of the counter electrode current collector 220 and the side of the counter electrode layer 120, in the portion of the side surface 11 that is not covered by the electrode insulating member 41 and the continuous region insulating member 43, and is electrically connected to the counter electrode current collector 220 and the counter electrode layer 120.

[0231] The counter electrode terminal 31e is also positioned to cover the continuous region insulating member 43 that covers the continuous region 91, and the counter electrode terminals 31e connected to each of the multiple separated recessed regions 92 are connected to each other. In other words, one counter electrode terminal 31e is electrically connected to each of the counter electrode layers 120 of the multiple power generation layers 100 in each of the multiple separated recessed regions 92.

[0232] In this way, by covering the continuous region 91 with the continuous region insulating member 43, even when the recessed region 92 is separated, the counter terminals 31e connected to the separated recessed region 92 can be formed all at once, making it easier to form the counter terminals 31e and extract current using the counter terminals 31e.

[0233] In addition, on the side surface 12, similar to the side surface 11, the recessed region 92 may be separated, and electrode terminals 32e connected to each of the multiple separated recessed regions 92 may be connected.

[0234] [Example 12] Next, a modified example 12 of Embodiment 1 will be described.

[0235] Figures 16A and 16B are cross-sectional views of a battery according to a modified example 12 of Embodiment 1. Figure 16A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 16B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0236] As shown in Figures 16A and 16B, the battery 1m according to this modified example differs from the battery 1j according to the modified example 10 of Embodiment 1 in that, in the retracted region 92, only one of the electrode current collector 210 and the counter electrode current collector 220 protrudes.

[0237] In battery 1m, in the recessed region 92 on the side surface 11, the power generation layer 100 is recessed only from the counter electrode current collector 220 among the electrode current collectors 210 and counter electrode current collectors 220 adjacent to the power generation layer 100, forming a recess 21. Also, in the recessed region 92 on the side surface 11, the electrode current collector 210 is recessed from the counter electrode current collector 220, and when viewed from the z-axis direction, the side surface of the electrode current collector 210 coincides with the side surface of the power generation layer 100. Therefore, in the recessed region 92 on the side surface 11, the counter electrode current collector 220 protrudes from both the electrode current collector 210 and the power generation layer 100. The protruding counter electrode current collector 220 is covered by the counter electrode terminal 31e and is electrically connected to the counter electrode terminal 31e. Thus, since the electrode current collector 210 does not protrude in the recessed region 92 on the side surface 11, contact between the electrode current collector 210 and the counter electrode current collector 220 during the manufacturing process, etc., and a short circuit are suppressed.

[0238] Furthermore, in the recessed region 92 on the side surface 12, the power generation layer 100 is recessed beyond only the electrode current collector 210 of the electrode current collectors 210 and counter electrode current collectors 220 adjacent to the power generation layer 100, forming a recess 22. Also, in the recessed region 92 on the side surface 12, the counter electrode current collector 220 is recessed beyond the electrode current collector 210, and when viewed from the z-axis direction, the side surface of the counter electrode current collector 220 coincides with the side surface of the power generation layer 100. Therefore, in the recessed region 92 on the side surface 12, the electrode current collector 210 protrudes beyond the counter electrode current collector 220 and the power generation layer 100. The protruding electrode current collector 210 is covered by the electrode terminal 32e and is electrically connected to the electrode terminal 32e. In this way, since the counter electrode current collector 220 does not protrude in the recessed region 92 on the side surface 12, contact between the electrode current collector 210 and the counter electrode current collector 220 during the manufacturing process, etc., and a short circuit are suppressed.

[0239] The electrode insulating member 41 covers the electrode current collector 210 and the electrode layer 110 in the recessed region 92 on the side surface 11 and is in contact with the electrode current collector 210 and the electrode layer 110. Specifically, the electrode insulating member 41 continuously covers the side surface of the electrode current collector 210 and the side surfaces of one or two electrode layers 110 adjacent to the electrode current collector 210 in the recessed region 92 on the side surface 11. In a 1m battery, the side surface of the electrode current collector 210 and the side surface of the power generation layer 100 are aligned and flush, so the electrode insulating member 41 can be easily formed. In addition, since the electrode current collector 210 does not protrude from the electrode insulating member 41, contact between the electrode current collector 210 and the counter electrode current collector 220 and short-circuiting are suppressed.

[0240] The counter electrode insulating member 42 covers the counter electrode current collector 220 and the counter electrode layer 120 in the recessed region 92 on the side surface 12, and is in contact with the counter electrode current collector 220 and the counter electrode layer 120. Specifically, the counter electrode insulating member 42 continuously covers the side surface of the counter electrode current collector 220 and the side surfaces of one or two counter electrode layers 120 adjacent to the counter electrode current collector 220 in the recessed region 92 on the side surface 12. In a 1m battery, the side surface of the counter electrode current collector 220 and the side surface of the power generation layer 100 are aligned and flush, so the counter electrode insulating member 42 can be easily formed. In addition, since the counter electrode current collector 220 does not protrude from the counter electrode insulating member 42, contact between the electrode current collector 210 and the counter electrode current collector 220 and short-circuiting are suppressed.

[0241] [Modified example 13] Next, a modified example 13 of Embodiment 1 will be described.

[0242] Figures 17A and 17B are cross-sectional views of a battery according to a modified example 13 of Embodiment 1. Figure 17A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 17B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0243] As shown in Figures 17A and 17B, the modified battery 1n differs from the modified battery 1j of Embodiment 1 (modification 10) in that, in the recessed region 92, a portion of the electrode layer 110, counter electrode layer 120, and solid electrolyte layer 130 of the power generation layer 100 is recessed relative to the current collector 200.

[0244] In battery 1n, in the recessed region 92 on the side surface 11, only the counter electrode layer 120 and the solid electrolyte layer 130 of the power generation layer 100 are recessed from the electrode current collectors 210 and counter electrode current collectors 220 adjacent to both sides of the power generation layer 100, forming a recess 21n. Therefore, in the recessed region 92 on the side surface 11, the counter electrode layer 120 is recessed from the electrode layer 110. In the recessed region 92 on the side surface 11, the entire counter electrode layer 120 is recessed from the electrode current collectors 210 and counter electrode current collectors 220. Also, in the recessed region 92 on the side surface 11, at least a portion of the solid electrolyte layer 130 is recessed from the electrode current collectors 210 and counter electrode current collectors 220. Specifically, the portion of the side surface of the solid electrolyte layer 130 that is not covered by the electrode insulating member 41 is inclined diagonally with respect to the z-axis direction.

[0245] Furthermore, in the recessed region 92 on the side surface 12, only the electrode layer 110 and the solid electrolyte layer 130 of the power generation layer 100 are recessed compared to the electrode current collectors 210 and counter electrode current collectors 220 adjacent to both sides of the power generation layer 100, forming a recess 22n. Therefore, in the recessed region 92 on the side surface 12, the electrode layer 110 is recessed compared to the counter electrode layer 120. In the recessed region 92 on the side surface 12, the entire electrode layer 110 is recessed compared to the electrode current collectors 210 and counter electrode current collectors 220. Also, in the recessed region 92 on the side surface 12, at least a portion of the solid electrolyte layer 130 is recessed compared to the electrode current collectors 210 and counter electrode current collectors 220. Specifically, the portion of the side surface of the solid electrolyte layer 130 that is not covered by the counter electrode insulating member 42 is inclined diagonally with respect to the z-axis direction.

[0246] The electrode insulating member 41 covers the electrode current collector 210 and the electrode layer 110 in the recessed region 92 on the side surface 11, and is in contact with the electrode current collector 210 and the electrode layer 110. Specifically, the electrode insulating member 41 continuously covers the side surface of the electrode current collector 210 and the side surfaces of one or two electrode layers 110 adjacent to the electrode current collector 210 in the recessed region 92 on the side surface 11.

[0247] The counter electrode insulating member 42 covers the counter electrode current collector 220 and the counter electrode layer 120 in the recessed region 92 on the side surface 12, and is in contact with the counter electrode current collector 220 and the counter electrode layer 120. Specifically, the counter electrode insulating member 42 continuously covers the side surface of the counter electrode current collector 220 and the side surfaces of one or two counter electrode layers 120 adjacent to the counter electrode current collector 220 in the recessed region 92 on the side surface 12.

[0248] For example, after forming the electrode insulating member 41 and the counter electrode insulating member 42 on side surfaces 11 and 12, respectively, the side surfaces 11 and 12 are processed in various ways to recede the electrode layer 110, the counter electrode layer 120, and the solid electrolyte layer 130, and relatively make the current collector 200 protrude. At this time, a portion of the electrode insulating member 41 and the counter electrode insulating member 42 is shaved off, slightly reducing the thickness of the electrode insulating member 41 and the counter electrode insulating member 42, and the electrode layer 110 and the counter electrode layer 120, which are made of powder material, recede at a faster rate than the current collector 200. As a result, the cross-sectional shape shown in Figure 17A is formed. Therefore, since the electrode insulating member 41 and the counter electrode insulating member 42 can be formed on the flat side surfaces 11 and 12 before the recesses 21n and 22n are formed, the manufacturing process can be simplified.

[0249] [Example 14] Next, a modified example 14 of Embodiment 1 will be described.

[0250] Figures 18A and 18B are cross-sectional views of a battery according to a modified example 14 of Embodiment 1. Figure 18A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 18B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0251] As shown in Figures 18A and 18B, the battery 1p according to this modified example differs from the battery 1m according to the modified example 12 of Embodiment 1 in that it further comprises a sealing member 70.

[0252] The sealing member 70 exposes at least a part of each of the counter electrode terminal 31e and the electrode terminal 32e, and seals the power generation element 10. The sealing member 70 is provided, for example, so that the power generation element 10, the electrode insulating member 41, the counter electrode insulating member 42, and the continuous region insulating member 43 are not exposed.

[0253] The sealing member 70 is formed, for example, using an electrically insulating insulating material. As the insulating material, generally known materials for battery sealing members such as sealants can be used. As the insulating material, for example, a resin material can be used. Note that the insulating material may be a material that is insulating and does not have ion conductivity. For example, the insulating material may be at least one of an epoxy resin, an acrylic resin, a polyimide resin, and silsesquioxane.

[0254] Note that the sealing member 70 may contain a plurality of different insulating materials. For example, the sealing member 70 may have a multilayer structure. Each layer of the multilayer structure may be formed using a different material and may have different properties.

[0255] The sealing member 70 may contain a particulate metal oxide material. As the metal oxide material, silicon oxide, aluminum oxide, titanium oxide, zinc oxide, cerium oxide, iron oxide, tungsten oxide, zirconium oxide, calcium oxide, zeolite, glass, etc. can be used. For example, the sealing member 70 may be formed using a resin material in which a plurality of particles of the metal oxide material are dispersed.

[0256] The particle size of the metal oxide material is, for example, not more than the interval between the current collectors 200. The particle shape of the metal oxide material is, for example, spherical, ellipsoidal, or rod-shaped, but is not limited thereto.

[0257] By providing the sealing member 70, the reliability of the battery 1p can be improved in various aspects such as mechanical strength, short circuit prevention, and moisture protection.

[0258] (Embodiment 2) Next, Embodiment 2 will be described. In the following description of Embodiment 2, the differences from Embodiment 1 and each modification example of Embodiment 1 will be mainly described, and the description of the common points will be omitted or simplified. The same applies to the modification examples after Modification Example 1 of Embodiment 2 described below. In the description of each modification example, the differences from Embodiment 1, Embodiment 2 and each modification example will be mainly described, and the description of the common points will be omitted or simplified.

[0259] FIGS. 19A and 19B are cross-sectional views of the battery according to Embodiment 2. FIG. 19A is a cross-sectional view at the position where the retreat region 92 is cut, similar to FIG. 2A. Also, FIG. 19B is a cross-sectional view at the position where the continuous region 91 is cut, similar to FIG. 2B.

[0260] As shown in FIGS. 19A and 19B, the battery 2 according to the present embodiment is different from the battery 1 according to Embodiment 1 in that it includes a power generation element 50 instead of the power generation element 10, and includes a connection terminal 33, which is an example of a conductive member, instead of the counter electrode terminal 31 and the electrode terminal 32.

[0261] The power generation element 50, like the power generation element 10, has multiple power generation layers 100 and multiple current collectors 200. Also, in the power generation element 50, like the power generation element 10, each power generation layer 100 is stacked via at least one current collector 200 from the multiple current collectors 200, and is sandwiched between two adjacent current collectors 200 from the multiple current collectors 200. The power generation element 50 differs from the power generation element 10 in that the multiple power generation layers 100 are stacked so that they are electrically connected in series. In the power generation element 50, the configuration is the same as the power generation element 10, except for the order of the layers constituting the power generation layers 100. In the power generation element 50, the multiple power generation layers 100 are stacked aligned along the z-axis so that the order of the layers constituting the power generation layers 100 is the same. As a result, the multiple power generation layers 100 are stacked so that they are electrically connected in series. Of the multiple current collectors 200, all current collectors 200 except for the uppermost and lowermost ones have an electrode layer 110 laminated and in contact with one main surface without an intervening solid electrolyte layer 130, and a counter electrode layer 120 laminated and in contact with the other main surface without an intervening solid electrolyte layer 130. In other words, of the multiple current collectors 200, all current collectors 200 except for the uppermost and lowermost ones are bipolar current collectors in which one main surface is electrically connected to the electrode layer 110 and the other main surface is electrically connected to the counter electrode layer 120.

[0262] The power generation element 50 includes four sides corresponding to the four sides 11, 12, 13, and 14 of the power generation element 10, and two main surfaces corresponding to the two main surfaces 15 and 16 of the power generation element 10. Specifically, as shown in Figures 19A and 19B, the power generation element 50 includes a side 51 corresponding to side 11 of the power generation element 10, and a side 52 corresponding to side 12 of the power generation element 10.

[0263] The sides 51 and 52 of the power generation element 50 include a continuous region 91 and a recessed region 92, similar to the power generation element 10.

[0264] In the recessed area 92, each connection terminal 33 covers the main surface of a current collector 200 adjacent to each power generation layer 100 and is electrically connected to the main surface of the current collector 200. The connection terminal 33 is, for example, in contact with the main surface of the current collector 200. In the recessed area 92 on the side surface 51, the connection terminal 33 covers the main surface of only one of two adjacent current collectors 200. In the recessed area 92 on the side surface 51, current collectors 200 connected to the connection terminal 33 and current collectors 200 not connected to the connection terminal 33 are arranged alternately along the z-axis.

[0265] Furthermore, the connection terminal 33 covers the main surface of only one of the two adjacent current collectors 200 in the recessed area 92 on the side surface 52. In the recessed area 92 on the side surface 52, current collectors 200 connected to the connection terminal 33 and current collectors 200 not connected to the connection terminal 33 are arranged alternately along the z-axis direction.

[0266] This configuration reduces the number of connection terminals 33 connected in the recessed areas 92 on the sides 51 and 52, thereby suppressing short circuits caused by contact between the connection terminals 33 and making it easier to form the connection terminals 33 when connecting them to the current collector 200.

[0267] Furthermore, a current collector 200 connected to a connection terminal 33 in the retracted area 92 on side 51 is not connected to a connection terminal 33 in the retracted area 92 on side 52. A current collector 200 connected to a connection terminal 33 in the retracted area 92 on side 52 is not connected to a connection terminal 33 in the retracted area 92 on side 51. In other words, one connection terminal 33 is connected to one current collector 200.

[0268] For example, the connection terminal 33 can be used to monitor the state of each power generation layer 100 by measuring the potential of the connection terminal 33, thereby preventing overcharging and over-discharging. Furthermore, if there are variations in the charge state among the power generation layers 100, the variations in the charge state can be reduced by using the connection terminal 33 for charging and discharging individual power generation layers 100.

[0269] The connection terminal 33 is formed, for example, using materials and methods similar to those exemplified in the description of the counter electrode terminal 31 and the electrode terminal 32.

[0270] Thus, in the battery 2 according to this embodiment, since the sides 51 and 52 include a continuous region 91 and a recessed region 92, similar to the battery 1 according to Embodiment 1, the connection area between the connection terminal 33 and the current collector 200 can be increased to improve high-current characteristics, and contact between the current collectors 200 can be suppressed, thereby improving reliability. Furthermore, in the sides 51 and 52, the power generation layer 100 recedes only in the recessed region 92 of the continuous region 91 and recessed region 92, so the energy density of the battery 2 can be increased.

[0271] [Example 1] Next, a modified example 1 of Embodiment 2 will be described.

[0272] Figures 20A and 20B are cross-sectional views of a battery according to a modified example 1 of Embodiment 2. Figure 20A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 20B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0273] As shown in Figures 20A and 20B, the battery 2a according to this modified example differs from the battery 2 according to Embodiment 2 in that, of the two sides 51 and 52, only side 51 includes a continuous region 91 and a recessed region 92.

[0274] In battery 2a, the side surface 51 includes a continuous region 91 and a recessed region 92. In the recessed region 92 of the side surface 51, the main surface of each of the multiple current collectors 200 is covered by a connection terminal 33 and electrically connected to the connection terminal 33.

[0275] In battery 2a, side 52 includes only the continuous region 91 of the continuous region 91 and the receding region 92. Therefore, no connection terminals 33 are connected to the multiple current collectors 200 on side 52.

[0276] Thus, in the battery 2a, since the positions of the connection terminals 33 are concentrated on the side surface 51 side, it becomes easy to save space when using the battery 2a.

[0277] [Modified Example 2] Next, a modified example 2 of the second embodiment will be described.

[0278] FIG. 21 is a side view of a battery according to a modified example 2 of the second embodiment. FIG. 21 is a plan view when the side surface 51 is viewed from the front. FIGS. 22A and 22B are cross-sectional views of the battery according to the modified example 2 of the second embodiment. FIG. 22A is a cross-sectional view at the position where the retreat region 92 is cut, similar to FIG. 2A. Further, FIG. 22B is a cross-sectional view at the position where the continuous region 91 is cut, similar to FIG. 2B.

[0279] As shown in FIGS. 21 to 22B, the battery 2b according to this modified example is different from the battery 2a according to the modified example 1 of the second embodiment in that it further includes an insulating member 44.

[0280] The insulating member 44 collectively covers the continuous region 91 and the retreat region 92. Specifically, the insulating member 44 covers the side surfaces of each power generation layer 100 in the retreat region 92 on the side surface 51 and is in contact with the side surfaces of each power generation layer 100. The insulating member 44 is, for example, an insulating layer having insulating properties. In the battery 2b, the insulating member 44 is located inside the recess 20 in the retreat region 92 and completely covers the side surfaces of each power generation layer 100. That is, in the recess 20, the side surfaces of the power generation layers 100 are not exposed. Further, the insulating member 44 covers the continuous region 91 on the side surfaces 51 and 52 and is in contact with the continuous region 91. The insulating member 44 covers all of the continuous region 91 on the side surfaces 51 and 52. Also, the insulating member 44 covers the ends of the upper and lower main surfaces of the power generation element 50.

[0281] Although not shown, the insulating member 44 may cover the side surfaces of the power generation element 50 other than the side surfaces 51 and 52.

[0282] The insulating member 44 is formed, for example, using the materials and methods exemplified in the description of the insulating member 40 above.

[0283] Furthermore, as shown in Figure 21, on the side surface 51, each connection terminal 33 is aligned along the z-axis direction.

[0284] Thus, in battery 2b, the insulating member 44 covers the continuous region 91 and the recessed region 92, thereby suppressing material collapse and short circuits on the side surface of the power generation layer 100.

[0285] [Difference 3] Next, a modified example 3 of Embodiment 2 will be described.

[0286] Figure 23 is a side view of a battery according to a modified example 3 of Embodiment 2. Figure 23 is a top view of the side 51 as seen from the front.

[0287] As shown in Figure 23, the battery 2c according to this modified example differs from the battery 2b according to modified example 2 of Embodiment 2 in the arrangement of the connection terminals 33 in a plan view relative to the side surface 51.

[0288] As shown in Figure 23, in the battery 2c, each connection terminal 33 is arranged on the side surface 51 in a direction inclined with respect to the z-axis. Each connection terminal 33 is arranged so that, for example, when viewed from the z-axis direction, they do not overlap with each other. By arranging the positions of adjacent connection terminals 33 in this offset direction from the z-axis direction, contact between the connection terminals 33 is made less likely, thereby suppressing short circuits.

[0289] Furthermore, each connection terminal 33 may be arranged in random positions, rather than being aligned along a direction inclined with respect to the z-axis, as shown in Figure 23, provided that they do not overlap with each other when viewed from the z-axis direction.

[0290] [Differentiation Example 4] Next, a modified example 4 of Embodiment 2 will be described.

[0291] Figures 24A and 24B are cross-sectional views of a battery according to a modified example 4 of Embodiment 2. Figure 24A is a cross-sectional view taken at the position where the recessed region 92 is cut, similar to Figure 2A. Figure 24B is a cross-sectional view taken at the position where the continuous region 91 is cut, similar to Figure 2B.

[0292] As shown in Figures 24A and 24B, the battery 2d according to this modified example differs from the battery 2a according to Modification 1 of Embodiment 2 in that it further includes a sealing member 70.

[0293] In the battery 2d, the sealing member 70 exposes at least a portion of the connection terminal 33 and seals the power generation element 50. The sealing member 70 is provided, for example, so that the power generation element 50 is not exposed.

[0294] The provision of the sealing member 70 improves the reliability of the battery 2d in various aspects, including mechanical strength, short-circuit prevention, and moisture resistance.

[0295] (Manufacturing method) Next, a method for manufacturing batteries according to each of the embodiments and modified examples described above will be explained.

[0296] A method for manufacturing a battery according to each embodiment and each modification includes, for example, a first step, a second step, and a third step. In the first step, a plurality of unit cells are prepared, each having a structure in which a power generation layer 100 and a current collector 200 are stacked. In the second step, a power generation element 10 or 50 is formed by stacking the plurality of unit cells prepared in the first step. The second step also includes forming a continuous region 91 on the side surface of the power generation element 10 or 50 in which each power generation layer 100 of the plurality of unit cells is not recessed compared to the current collector 200 of the plurality of unit cells adjacent to each power generation layer 100, and a recessed region 92 in which a recess 20 is formed by each power generation layer 100 of the plurality of unit cells being recessed compared to the current collector 200 of the plurality of unit cells adjacent to each power generation layer 100. In the third step, a conductive member is formed to cover the main surface of at least one of the current collectors 200 of the plurality of unit cells adjacent to the recess 20.

[0297] The details of the battery manufacturing methods for each embodiment and each modified example will be described below with reference to Figures 25 to 26C.

[0298] Figure 25 is a flowchart showing an example of a battery manufacturing method according to each embodiment or modification. Figure 25 shows an example of a battery manufacturing method for battery 1p shown in Figures 18A and 18B, representing the batteries according to each embodiment and modification. Note that other batteries according to each embodiment or modification other than battery 1p can also be manufactured by appropriately applying the steps described below. In the manufacturing of batteries according to each embodiment or modification, some steps shown in Figure 25 may be omitted.

[0299] In the example shown in Figure 25, step S11 corresponds to the first step, steps S12 and S13 correspond to the second step, and step S15 corresponds to the third step.

[0300] As shown in Figure 25, first, a plurality of unit cells are prepared, each having a structure in which a power generation layer 100 and a current collector 200 are stacked (step S11). Next, the plurality of formed unit cells are stacked to form a power generation element 10 (step S12). As described above, the power generation layer 100 includes an electrode layer 110, a counter electrode layer 120 positioned opposite the electrode layer 110, and a solid electrolyte layer 130 located between the electrode layer 110 and the counter electrode layer 120. Figures 26A to 26C are cross-sectional views of an example of a unit cell, respectively.

[0301] As shown in Figure 26A, a unit cell 100a has one power generation layer 100 and two current collectors 200. In the unit cell 100a, the power generation layer 100 is positioned between the two current collectors 200, and the power generation layer 100 is in contact with each of the two current collectors 200. Specifically, the electrode layer 110 of the power generation layer 100 is in contact with one of the two current collectors 200, and the counter electrode layer 120 of the power generation layer 100 is in contact with the other of the two current collectors 200.

[0302] Furthermore, as shown in Figures 26B and 26C, unit cell 100b and unit cell 100c each have one power generation layer 100 and one current collector 200.

[0303] In unit cell 100b, the current collector 200 is positioned on the electrode layer 110 side of the power generation layer 100, facing the power generation layer 100 and in contact with the electrode layer 110. In unit cell 100b, the main surface of the counter electrode layer 120 of the power generation layer 100, opposite to the solid electrolyte layer 130 side, is exposed.

[0304] In unit cell 100c, the current collector 200 is positioned opposite the power generation layer 100 on the counter electrode layer 120 side of the power generation layer 100 and is in contact with the counter electrode layer 120. In unit cell 100c, the main surface of the electrode layer 110 of the power generation layer 100, on the side opposite to the solid electrolyte layer 130, is exposed.

[0305] In step S12, for example, at least one type of unit cell from among such unit cells 100a, 100b, and 100c is prepared in accordance with the stacked configuration of the power generation element. When forming the power generation element 10, for example, one unit cell 100a, multiple unit cells 100b, and multiple unit cells 100c are prepared. Then, unit cell 100a is placed at the bottom layer, and unit cells 100b and 100c are stacked alternately upwards. At this time, the unit cells 100b are stacked upside down compared to the orientation shown in Figure 26B. This forms the stacked structure of the power generation element 10.

[0306] The method for forming the power generation element 10 is not limited to this. For example, a unit cell 100a may be placed in the uppermost layer. Alternatively, a unit cell 100a may be placed in a position different from both the uppermost and lowermost layers. Multiple unit cells 100a may also be used. Furthermore, by applying a coating to both sides of a current collector 200, a unit cell unit in which the power generation layer 100 is laminated on both main surfaces of the current collector 200 may be formed, and the formed units may be laminated. In addition, a unit cell consisting of a power generation layer 100 without a current collector 200 may be used as the unit cell.

[0307] Alternatively, the sides of the power generation element 10 may be flattened after stacking multiple unit cells. For example, by cutting the ends of the stack of multiple unit cells together along the stacking direction, a power generation element 10 can be formed in which each side formed as a cut surface is flat. This makes it possible to equalize the area of ​​each layer without being affected by variations in the coating area of ​​each layer. As a result, variations in battery capacity are reduced, and the accuracy of the battery capacity is improved. The cutting process can be performed, for example, by a blade, laser, or jet.

[0308] Furthermore, when forming the power generation element 50, it is possible to form it by stacking multiple unit cells with each layer of the power generation layer 100 facing the same direction.

[0309] Next, recesses 20 are formed in each power generation layer 100 (step S13). This creates a continuous region 91 and a recessed region 92 on the side surfaces 11 and 12 of the power generation element 10.

[0310] In step S13, for example, a recess 20 is formed by a recessing process that recedes a portion of the side surface of the power generation layer 100, causing the current collector 200 adjacent to the power generation layer 100 to protrude. In addition, the recess 20 is formed on a portion of the side surface of the power generation layer 100, excluding the end in that direction, such that the continuous region 91 sandwiches the recessed region 92 from both sides in a direction perpendicular to the stacking direction of the power generation elements 10.

[0311] In the recessing process, recesses 20 are formed on each power generation layer 100 by polishing, sandblasting, brushing, etching, laser irradiation, or plasma irradiation, for example. In the recessing process, protective members are provided on the sides 11 and 12 other than the areas where the recesses 20 are formed, and only the desired areas are recessed. As a result, a power generation element 10 is obtained in which a continuous region 91 and a recessed region 92 are formed on the sides 11 and 12.

[0312] Furthermore, when forming the recess 20 by sandblasting or brushing, for example, the difference in processing speed between the current collector 200 and the power generation layer 100 is used to recede the power generation layer 100, which is more easily abraded.

[0313] Furthermore, when forming the recess 20 by etching, for example, the etching is performed under conditions where the etching rate of the current collector 200 is smaller than the etching rate of each layer of the power generation layer 100, thereby causing the power generation layer 100 to recede.

[0314] Furthermore, when forming the recess 20 by laser irradiation or plasma irradiation, for example, the power generation layer 100 is recessed by performing the irradiation process under conditions where the processing speed of the current collector 200 is smaller than the processing speed of each layer of the power generation layer 100.

[0315] Next, an electrode insulating member 41 and a continuous region insulating member 43 are formed on the side surface 11 of the power generation element 10, and a counter electrode insulating member 42 and a continuous region insulating member 43 are formed on the side surface 12 of the power generation element 10 (step S14).

[0316] The electrode insulating member 41, the counter electrode insulating member 42, and the continuous region insulating member 43 are formed, for example, by coating and curing a fluid resin material. Coating is performed by methods such as inkjet printing, spray printing, screen printing, or gravure printing. Curing is performed by drying, heating, light irradiation, etc., depending on the resin material used. For example, the electrode insulating member 41 and the continuous region insulating member 43 are formed by coating them with the same resin material at once, and the counter electrode insulating member 42 and the continuous region insulating member 43 are also formed by coating them with the same resin material at once. The electrode insulating member 41, the counter electrode insulating member 42, and the continuous region insulating member 43 may all be formed by coating them with the same resin material at once.

[0317] Furthermore, when forming the electrode insulating member 41, the counter electrode insulating member 42, and the continuous region insulating member 43, a protective member may be formed in areas where insulating members should not be formed by masking with tape or other means, or by resist treatment, so that the areas connected to the counter electrode terminal 31e and the electrode terminal 32e are not insulated. After the formation of the electrode insulating member 41, the counter electrode insulating member 42, and the continuous region insulating member 43, the protective member can be removed to ensure conductivity at the connection points with the terminals.

[0318] Note that the order of steps S13 and S14 may be reversed. For example, when forming battery 1n, the electrode insulating member 41, the counter electrode insulating member 42, and the continuous region insulating member 43 are formed first, and then the setback process is performed so that the electrode insulating member 41, the counter electrode insulating member 42, and the continuous region insulating member 43 also function as protective members.

[0319] Next, a counter electrode terminal 31e is formed on the side surface 11 of the power generation element 10, and an electrode terminal 32e is formed on the side surface 12 of the power generation element 10 (step S15). Specifically, in the recessed region 92 of the side surface 11, a counter electrode terminal 31e is formed that is electrically connected to the main surface of the counter electrode current collector 220 adjacent to the recess 20, and in the recessed region of the side surface 12, an electrode terminal 32e is formed that is electrically connected to the main surface of the electrode current collector 210 adjacent to the recess 20.

[0320] For example, the counter electrode terminal 31e is formed by coating and curing a conductive resin over the electrode insulating member 41 and the continuous region insulating member 43, and the portion of the side surface 11 not covered by the electrode insulating member 41 and the continuous region insulating member 43. This electrically connects the counter electrode terminal 31e to the main surface of each counter electrode current collector 220 of the power generation element 10. Similarly, the electrode terminal 32e is formed by coating and curing a conductive resin over the counter electrode insulating member 42 and the continuous region insulating member 43, and the portion of the side surface 12 not covered by the counter electrode insulating member 42 and the continuous region insulating member 43. This electrically connects the electrode terminal 32e to the main surface of each electrode current collector 210 of the power generation element 10. The counter electrode terminal 31e and electrode terminal 32e may also be formed by methods such as printing, plating, vapor deposition, sputtering, welding, soldering, joining, or other methods.

[0321] Next, a sealing member 70 is formed to enclose the power generation element 10 (step S16). The sealing member 70 is formed, for example, by coating the area where the sealing member 70 is to be formed with a fluid resin material so as to expose at least a portion of each of the counter electrode terminal 31e and electrode terminal 32e, and then curing it. The coating is performed by an inkjet method, spray method, screen printing method, or gravure printing method. Curing is performed by drying, heating, light irradiation, etc., depending on the resin material used.

[0322] Through the above process, the battery 1p shown in Figures 18A and 18B can be manufactured.

[0323] In addition, a step may be performed in which the multiple unit cells prepared in step S11 are pressed individually, or after the multiple unit cells have been stacked, in the direction of stacking.

[0324] Furthermore, in the example shown in Figure 25, the formation of recesses 20 in each power generation layer 100 (step S13) was performed after stacking multiple unit cells (step S12), but this is not limited to this. For example, the formation of recesses 20 in each power generation layer 100 (step S13) may be performed before stacking multiple unit cells (step S12). In this case, for example, by stacking multiple unit cells so that the recesses 20 of each power generation layer 100 are aligned in the stacking direction, a continuous region 91 and a recessed region 92 are formed.

[0325] Furthermore, in the setback process for forming the recess 20 in this case, in addition to the example given above, the recess 20 may also be formed by partially cutting the unit cell prepared in step S11, leaving only the current collector 200 of the unit cell in a predetermined area in a plan view. For example, the unit cell is divided by cutting the power generation layer 100 along the stacking direction, and the cutting is stopped just before the current collector 200. By removing one of the divided power generation layers 100, only the current collector 200 of the unit cell can be left in a predetermined area in a plan view.

[0326] (Other embodiments) The batteries relating to this disclosure have been described above based on embodiments and modifications, but this disclosure is not limited to these embodiments and modifications. Within the scope of this disclosure, various modifications to the embodiments and modifications that a person skilled in the art could conceive of, as long as they do not depart from the spirit of this disclosure, as well as other forms constructed by combining some of the components of the embodiments and modifications, are also included.

[0327] For example, in the above embodiments and modifications, the power generation element was stacked such that all of the multiple power generation layers 100 were electrically connected in parallel or in series, but it is not limited to this. In the power generation element, multiple units, each containing multiple power generation layers 100 stacked to be electrically connected in parallel, may be stacked so that they are electrically connected in series. Alternatively, in the power generation element, multiple units, each containing multiple power generation layers 100 stacked to be electrically connected in series, may be stacked so that they are electrically connected in parallel.

[0328] Furthermore, in the above embodiments and modifications, the continuous region 91 was arranged adjacent to both sides of the recessed region 92, but this is not limited to this. For example, the continuous region 91 may be arranged adjacent to only one side of the recessed region 92.

[0329] Furthermore, in the above embodiments and modifications, the recesses 20 in the recessed region were aligned in the stacking direction, but this is not limited to this. For example, the positions of the recesses 20 may differ when viewed from the stacking direction.

[0330] Furthermore, in the above embodiments and modifications, a conductive member such as a terminal was connected to the current collector 200 in the retracted region 92, but this is not limited to this. For example, the battery may not have a conductive member such as a terminal, and a terminal provided on another device outside the battery may be connected to the current collector 200 in the retracted region 92.

[0331] Furthermore, the above embodiments and modifications can be modified, replaced, added, or omitted in various ways within the scope of the claims or their equivalents. [Industrial applicability]

[0332] The battery described herein can be used as a battery for various applications such as electronic devices, electrical appliances, and electric vehicles. [Explanation of symbols]

[0333] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1m, 1n, 1p, 2, 2a, 2b, 2c, 2d batteries 10, 50 power generation elements 11, 12, 13, 14, 51, 52 Side view 15, 16 Main surface 20, 21, 21n, 22, 22n recesses 31, 31b, 31d, 31e Counter terminals 32, 32b, 32d, 32e electrode terminal 33 Connection terminals 40, 44 Insulating material 41 Electrode insulating material 42 Counter electrode insulating member 43 Continuous area insulating member 70 Sealing member 91 Continuous Region 92, 92a, 92b retreat area 100 power generation layers 100a, 100b, 100c unit cells 110 Electrode layer 120 Counterpolar layer 130 Solid electrolyte layer 200 Current collector 210 Electrode current collector 220 Counter electrode current collector

Claims

1. The power generation element has a structure in which multiple power generation layers and multiple current collectors are stacked, Each of the plurality of power generation layers has an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer. The plurality of current collectors include a counter electrode current collector electrically connected to the counter electrode layer and an electrode current collector electrically connected to the electrode layer. The plurality of power generation layers are stacked so as to be electrically connected in parallel, adjacent power generation layers are stacked via at least one current collector from the plurality of current collectors, and each power generation layer of the power generation element is sandwiched between two adjacent current collectors from the plurality of current collectors. The aspect of the aforementioned power generation element is, Each of the aforementioned power generation layers has a first region in which it is not recessed compared to the current collectors adjacent to each of the plurality of current collectors, Each of the aforementioned power generation layers includes a second region in which a recess is formed by the current collector being set back from the current collector adjacent to each of the plurality of current collectors, The second region comprises an insulating member covering the electrode layer and the electrode current collector, and a conductive member covering the second region and the insulating member, and electrically connected to at least one main surface of the counter electrode current collector. battery.

2. In the aforementioned side view, the first region is positioned so as to sandwich the second region from both sides in a direction perpendicular to the stacking direction of the power generation element. The battery according to claim 1.

3. In the second region, the recesses formed by the recession of each power generation layer are aligned along the stacking direction of the power generation elements. The battery according to claim 1 or 2.

4. The maximum depth of the recess is greater than the width of the recess in the stacking direction of the power generation elements. The battery according to claim 1 or 2.

5. The second region is separated by the first region. The battery according to claim 1 or 2.

6. In the aforementioned side view, the length of the second region in a direction perpendicular to the stacking direction of the power generation elements is greater than the length of the first region in a direction perpendicular to the stacking direction of the power generation elements. The battery according to claim 1 or 2.

7. The conductive member covers the main surfaces on both sides of the current collector adjacent to the recess. The battery according to claim 1.

8. The second region further comprises an insulating member covering each of the power generation layers. The battery according to claim 1.

9. In the second region, the counter electrode layer is recessed compared to the electrode layer. The battery according to claim 1.

10. The insulating member further covers at least a portion of the solid electrolyte layer in the second region. The battery according to claim 1.

11. The insulating member further covers the first region. The battery according to any one of claims 8 to 10.

12. The first step is to prepare a plurality of unit cells, each having a structure in which an electrode layer, a counter electrode layer, and a power generation layer having a solid electrolyte layer located between the electrode layer and the counter electrode layer are stacked, and a current collector. The second step includes forming a power generation element by stacking the aforementioned plurality of unit cells, The second step is to connect the plurality of unit cells in parallel, and includes forming a first region on the side surface of the power generation element in which each power generation layer of the plurality of unit cells is not recessed compared to the current collector adjacent to each power generation layer among the current collectors of the plurality of unit cells, and a second region in which a recess is formed by each power generation layer being recessed compared to the current collector adjacent to each power generation layer among the current collectors of the plurality of unit cells, wherein in the second region, an insulating member covers the electrode layer and the electrode current collector electrically connected to the electrode layer, and a conductive member is electrically connected to at least one main surface of a counter electrode current collector that covers the second region and the insulating member and is electrically connected to the counter electrode layer. Battery manufacturing method.

13. In the second step, the first region forms the recesses such that it sandwiches the second region from both sides in a direction perpendicular to the stacking direction of the power generation elements. The method for manufacturing a battery according to claim 12.

14. In the second step described above, the recesses are formed by partial cutting, polishing, sandblasting, brushing, etching, laser irradiation, or plasma irradiation of each power generation layer. A method for manufacturing a battery according to claim 12 or 13.

Images