Battery and method for manufacturing a battery

Abstract

A battery (1) is provided with an enclosure (200), a power generation element (100a), a power generation element (100b), and an electron conduction layer (110) positioned between the power generation element (100a) and the power generation element (100b). Each of the power generation element (100a) and the power generation element (100b) is a laminate that includes an electrode layer (101), a counter electrode layer (103), and a solid electrolyte layer (102) positioned between the electrode layer (101) and the counter electrode layer (103). The power generation element (100a), the power generation element (100b), and the electron conduction layer (110) are laminated in the enclosure (200). At least one side surface of the power generation element (100a) and the power generation element (100b) contacts an inner surface (201) of the enclosure (200).

Description

Technical Field

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

Background Art

[0002] Conventionally, a battery in which a solid electrolyte layer, an electrode layer, and a current collector member are laminated inside an electrically insulating insulating frame is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art, it is desired to realize a battery with a high energy density.

Means for Solving the Problems

[0005] A battery according to one aspect of the present disclosure includes a housing, a first power generation element, a second power generation element, and an electron conduction layer positioned between the first power generation element and the second power generation element. The first power generation element and the second power generation element are each a laminate including an electrode layer, a counter electrode layer, and a solid electrolyte layer positioned between the electrode layer and the counter electrode layer. The first power generation element, the second power generation element, and the electron conduction layer are laminated within the housing, and at least one side surface of the first power generation element and the second power generation element is in contact with the inner surface of the housing.

[0006] A method for manufacturing a battery according to one aspect of the present disclosure is a method for manufacturing a battery comprising a first power generation element and a second power generation element, each being a laminate comprising an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer, the method comprising: putting a material for forming the first power generation element, a material for forming an electron conduction layer, and a material for forming the second power generation element into a housing in this order; and pressing each of the materials put into the housing. [Effects of the Invention]

[0007] According to this disclosure, it is possible to realize batteries with high energy density. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view of a battery according to an embodiment. [Figure 2] Figure 2 is a diagram illustrating the manufacturing method of a battery according to an embodiment. [Figure 3] Figure 3 is a diagram illustrating the manufacturing method of a battery according to an embodiment. [Figure 4] Figure 4 is a diagram illustrating the manufacturing method of a battery according to an embodiment. [Figure 5] Figure 5 is a diagram illustrating the manufacturing method of a battery according to an embodiment. [Figure 6] Figure 6 is a diagram illustrating a modified example of the battery manufacturing method according to the embodiment. [Figure 7] Figure 7 shows a scanning electron microscope image of a cross-section of an electron-conducting layer using metal foil. [Figure 8] Figure 8 shows a scanning electron microscope image of a cross-section of an electron-conducting layer using powder. [Modes for carrying out the invention]

[0009] (Summary of this disclosure) Several examples of batteries related to this disclosure are shown below.

[0010] <1>A housing, a first power generation element, a second power generation element, an electronic conduction layer positioned between the first power generation element and the second power generation element, and comprising the first power generation element and the second power generation element are each a laminate including an electrode layer, a counter electrode layer, and a solid electrolyte layer positioned between the electrode layer and the counter electrode layer, the first power generation element, the second power generation element, and the electronic conduction layer are laminated within the housing, at least one side surface of the first power generation element and the second power generation element is in contact with the inner surface of the housing, a battery.

[0011] Thus, by having at least one side surface of the first power generation element and the second power generation element in contact with the inner surface of the housing, the inside of the housing can be filled with the power generation elements, effectively utilizing the space inside the housing. For example, the space inside the housing can be utilized to the maximum extent. Therefore, a battery with a high energy density can be realized. Also, by providing two power generation elements, the first power generation element and the second power generation element, a high-voltage battery can be realized when the power generation elements are connected in series, and a high-capacity battery can be realized when the power generation elements are connected in parallel.

[0012] <2>The electronic conduction layer contains an electronic conduction material, the electronic conduction material is in powder form, the battery according to <1>.

[0013] Thereby, the powder of the electronic conduction material spreads between the first power generation element and the second power generation element inside the housing, and the electronic conduction layer can adhere closely to the inner surface of the housing. Therefore, contact between the first power generation element and the second power generation element is suppressed, and a battery with a higher energy density can be realized.

[0014] <3>The electronic conduction layer consists only of the electronic conduction material, the battery according to <2>.

[0015] This eliminates the inclusion of materials that inhibit electron conduction in the electron conduction layer, resulting in stable battery characteristics. Consequently, it becomes possible to realize batteries with higher energy density.

[0016] <4> The electron conductive layer has grain boundaries formed in the powder of the electron conductive material. <2> or <3> The battery listed.

[0017] As a result, the electron conduction layer is formed with grain boundaries remaining, allowing the electron conduction material to spread more easily between the first and second power generation elements within the housing, and enabling the electron conduction layer to adhere closely to the inner surface of the housing. Therefore, a battery with a higher energy density can be realized.

[0018] <5> The first power generation element and the second power generation element are electrically connected in series. <1> from <5> The battery listed in one of the following items.

[0019] As a result, the electron conduction layer prevents contact between the first and second power generation elements connected in series, thereby suppressing short circuits (specifically, ion conduction short circuits) between the first and second power generation elements, and enabling the realization of a battery with a higher voltage.

[0020] <6> At least one of the electrode layer, counter electrode layer, and solid electrolyte layer in at least one of the first power generation element and the second power generation element does not contain a binder. <1> from <5> The battery listed in one of the following items.

[0021] <7> At least one of the first power generation element and the second power generation element does not contain a binder. <6> The battery listed.

[0022] Since binders are materials that do not contribute to the charge-discharge reaction, omitting them allows for an increase in the proportion of materials that contribute to the charge-discharge reaction within the battery. Therefore, it is possible to realize batteries with higher energy density.

[0023] <8> The thickness of the electron conduction layer is 15 μm or more and 300 μm or less. <1> from <7> The battery listed in one of the following items.

[0024] By having an electron conduction layer thickness of 15 μm or more, contact between the first and second power generation elements is suppressed, enabling the realization of a battery with a higher energy density. Furthermore, by having an electron conduction layer thickness of 300 μm or less, the volume occupied by the electron conduction layer within the housing can be reduced, enabling the realization of a battery with an even higher energy density.

[0025] <9> A void is formed in the aforementioned electron conduction layer. <1> from <8> The battery listed in one of the following items.

[0026] This allows the void to relieve the stress corresponding to the electron conduction layer, thereby suppressing damage to the electron conduction layer. Consequently, contact between the first and second power generation elements due to damage to the electron conduction layer is suppressed, enabling the realization of a battery with a higher energy density.

[0027] <10> The housing has an insulating portion in contact with the side surface and a conductive portion electrically connected to the first power generation element. <1> from <9> The battery listed in one of the following items.

[0028] This allows the housing to be used for current extraction while ensuring insulation on the sides of the first and second power generation elements. Therefore, miniaturization is possible without the need for leads or other components to extract current, enabling the realization of a battery with a higher energy density.

[0029] <11> The housing further comprises a current collector disposed on the opposite side of the second power generation element from the electron conduction layer side, The conductive portion is the bottom plate portion of the housing that faces the electron conduction layer with the first power generation element in between, The housing has an opening formed therein that exposes the current collector. <10> The battery listed.

[0030] This makes it possible to realize a battery in which current can be easily extracted from both sides in the stacking direction of the laminate consisting of the first power generation element, the electron conduction layer, and the second power generation element.

[0031] <12> Each of the first power generation element, the second power generation element, and the electron conductive layer is in contact with the inner surface. <1> from <11> The battery listed in one of the following items.

[0032] This allows for maximum utilization of the space within the enclosure, enabling the creation of batteries with higher energy density.

[0033] Furthermore, several examples of battery manufacturing methods related to this disclosure are shown below.

[0034] <13> A method for manufacturing a battery comprising a first power generation element and a second power generation element, each being a laminate containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer, A step of placing the material for forming the first power generation element, the material for forming the electron conduction layer, and the material for forming the second power generation element into the housing in this order, The process includes pressing each material placed in the aforementioned housing, Battery manufacturing method.

[0035] In this way, by pressing each material placed in the housing, the inside of the housing can be filled with a first power generation element, a second power generation element, and an electron conduction layer, allowing for effective use of the space inside the housing. For example, the space inside the housing can be utilized to its maximum potential. Therefore, batteries with high energy density can be manufactured. Furthermore, by forming two power generation elements, a first power generation element and a second power generation element, a battery with a high voltage can be manufactured when the power generation elements are connected in series, and a battery with a high capacity can be manufactured when the power generation elements are connected in parallel.

[0036] <14> The material for forming the powdered electron-conducting layer is placed into the housing. <13> The battery manufacturing method described above.

[0037] In this way, when the powdered electron-conducting material is introduced into the housing and pressed, the electron-conducting material is spread out within the housing, forming an electron-conducting layer that separates the first and second power-generating elements. As a result, contact between the first and second power-generating elements is suppressed, and a battery with a higher energy density can be manufactured.

[0038] <15> The material for forming the powdered first power generation element and the material for forming the powdered second power generation element are placed into the housing. <13> or <14> The battery manufacturing method described above.

[0039] This allows the powdered material to be pressed and the inside of the enclosure to be filled with the first and second power generation elements, effectively utilizing the space inside the enclosure. Therefore, it is possible to manufacture batteries with higher energy density.

[0040] <16> A material for forming the pellet-shaped first power generation element and a material for forming the pellet-shaped second power generation element are placed into the housing. <13> or <14> The battery manufacturing method described above.

[0041] This allows batteries to be manufactured using a simpler process.

[0042] The embodiments will be described in detail below with reference to the drawings.

[0043] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, processes, and order of processes 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.

[0044] 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.

[0045] 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.

[0046] Furthermore, in this specification, the "stacking direction" coincides with the direction normal to the main surface of each layer. Also, in this specification, "plan view" refers to the view from a direction perpendicular to the main surface of the power generation element, unless otherwise specified, such as when used alone.

[0047] 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. Moreover, 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.

[0048] 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.

[0049] (Embodiment) The following describes a battery according to an embodiment.

[0050] [composition] First, the configuration of the battery 1 according to this embodiment will be described.

[0051] Figure 1 is a cross-sectional view of a battery 1 according to an embodiment. As shown in Figure 1, the battery 1 comprises a power generation unit 10 having a power generation element 100a, a power generation element 100b and an electron conductive layer 110, a housing 200 housing the power generation unit 10, and a current collector 300. The battery 1 is, for example, an all-solid-state battery. Alternatively, the battery 1 is, for example, a lithium-ion secondary battery.

[0052] The power generation unit 10 is a laminate in which the layers of power generation elements 100a and 100b, as well as the electron conduction layer 110, are stacked. The shape of the power generation unit 10 is, for example, a flat columnar body, a rectangular prism such as a cuboid, a polygonal prism other than a rectangular prism, a cylinder, or an elliptical prism. Therefore, the plan view shape of the power generation unit 10 is, for example, a quadrilateral such as a rectangle or square, a polygon other than a quadrilateral such as a hexagon or octagon, a circle, or an ellipse. In cross-sectional views such as Figure 1, the thickness of each layer is exaggerated to make the layer structure of the power generation unit 10 easier to understand. Also, the relationship between the thickness of each layer and the housing 200 is not limited to the example shown in Figure 1.

[0053] The power generation unit 10 includes a side surface 11, a main surface 15, and a main surface 16. The side surface 11 is the surface connecting the outer periphery of the main surface 15 and the outer periphery of the main surface 16. The side surface 11 is, for example, a surface parallel to the stacking direction of the power generation unit 10. The main surfaces 15 and 16 are surfaces perpendicular to the thickness direction of each layer. The main surfaces 15 and 16 are facing away from each other and are parallel to each other. The main surface 15 is the uppermost surface of the power generation unit 10. The main surface 16 is the lowermost surface of the power generation unit 10.

[0054] The power generation unit 10 is formed, for example, by pressing powder material for the power generation unit 10 within the housing 200 and is held within the housing 200. All sides 11 and the main surface 16 of the power generation unit 10 are, for example, all covered by the housing 200 and in contact with the inner surface of the housing 200.

[0055] The power generation unit 10 comprises multiple power generation elements, in the example shown in Figure 1, two power generation elements 100a and 100b. Power generation elements 100a and 100b are, for example, the minimum configuration of a battery and are also called unit cells. Power generation elements 100a and 100b are electrically connected in series and stacked via an electron conduction layer 110. In the example shown in Figure 1, power generation element 100a is the power generation element located at the bottom of the power generation unit 10, and power generation element 100b is the power generation element located at the top of the power generation unit 10. In the example shown in Figure 1, the power generation unit 10 has two power generation elements, but this is not limited to two. For example, the power generation unit 10 may have three or more power generation elements. In this case, each adjacent power generation element is stacked via the electron conduction layer 110.

[0056] The power generation elements 100a and 100b are laminates each containing an electrode layer 101, a counter electrode layer 103 positioned opposite the electrode layer 101, and a solid electrolyte layer 102 located between the electrode layer 101 and the counter electrode layer 103. The electrode layer 101 and the counter electrode layer 103 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 power generation elements 100a and 100b, the electrode layer 101, the solid electrolyte layer 102, and the counter electrode layer 103 are laminated in this order along the direction normal to the main surface of each layer. Furthermore, in the power generation unit 10, the power generation elements 100a and 100b are laminated via an electron conduction layer 110 so that the order of the layers constituting the power generation elements 100a and 100b is the same.

[0057] The electrode layer 101 is one of the positive and negative electrode layers of the power generation element. The counter electrode layer 103 is the other of the positive and negative electrode layers of the power generation element. In the following explanation, we will describe the case where the electrode layer 101 is the negative electrode layer and the counter electrode layer 103 is the positive electrode layer as an example.

[0058] The electrode layer 101 is composed of, for example, an electrode material. The electrode material includes a negative electrode active material. The electrode material is, for example, a powder. Being a powder also means being composed of aggregates of multiple particles. Specifically, the electrode material is, for example, a compacted powder formed by compressing powder.

[0059] The shape of the particles constituting the electrode material is not particularly limited, but can be, for example, needle-shaped, spherical, ellipsoidal, or flaky. The same applies to the particle shape of the powders of other materials described later.

[0060] As the negative electrode active material contained in the electrode material of the electrode layer 101, various materials capable of releasing and inserting ions such as lithium (Li) or magnesium (Mg) can be used. Examples of negative electrode active materials include graphite, metallic lithium, and lithium compounds. Examples of lithium compounds include LiAl, LiZn, Li3Bi, Li3Cd, Li3Sb, Li4Si, and Li 4.4 Pb, Li 4.4 Sn, Li 0.17 Lithium alloys such as C, LiC6, and lithium titanate (Li4Ti5O 12 ) oxides of lithium and transition metal elements, zinc oxide (ZnO) and silicon oxide (SiO x Metal oxides such as ) can be used.

[0061] Furthermore, the electrode material of the electrode layer 101 may contain a solid electrolyte, such as an inorganic solid electrolyte. As an inorganic solid electrolyte, for example, a sulfide solid electrolyte or an oxide solid electrolyte may be used. As a sulfide solid electrolyte, for example, a mixture of lithium sulfide (Li2S) and phosphorus pentasulfide (P2S5) may be used. In addition, the electrode material of the electrode layer 101 may contain a conductive agent, such as acetylene black.

[0062] The thickness of the electrode layer 101 is, for example, 5 μm or more and 2000 μm or less.

[0063] The counter electrode layer 103 is composed of, for example, a counter electrode material. The counter electrode material is the material that constitutes the counter electrode of the electrode material. The counter electrode material includes a positive electrode active material. The counter electrode material is, for example, a powder. Specifically, the counter electrode material is, for example, a compact formed by compressing powder.

[0064] As the material for the positive electrode active material contained in the counter electrode material of the counter electrode layer 103, various materials capable of releasing and inserting ions such as Li or Mg can be used. Examples of positive electrode active materials that can be used include lithium cobalt oxide composite oxide (LCO), lithium nickel oxide composite oxide (LNO), lithium manganese oxide composite oxide (LMO), lithium-manganese-nickel oxide composite oxide (LMNO), lithium-manganese-cobalt oxide composite oxide (LMCO), lithium-nickel-cobalt oxide composite oxide (LNCO), and lithium-nickel-manganese-cobalt oxide composite oxide (LNMCO). The surface of the positive electrode active material may be coated with a solid electrolyte.

[0065] Furthermore, the counter electrode material of the counter electrode layer 103 may, for example, contain at least one of a solid electrolyte such as an inorganic solid electrolyte and a conductive agent such as acetylene black, similar to the electrode material described above.

[0066] The thickness of the counter electrode layer 103 is, for example, between 5 μm and 2000 μm.

[0067] The solid electrolyte layer 102 is in contact with the electrode layer 101 and the counter electrode layer 103, respectively. The solid electrolyte layer 102 is composed of, for example, an electrolyte material. The electrolyte material contains a solid electrolyte. The solid electrolyte has, for example, lithium ion conductivity. The electrolyte material is, for example, a powder. Specifically, the electrolyte material is, for example, a compact formed by compressing powder.

[0068] As the solid electrolyte contained in the electrolyte material of the solid electrolyte layer 102, 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.

[0069] The thickness of the solid electrolyte layer 102 is, for example, 5 μm to 500 μm, or 5 μm to 100 μm.

[0070] The power generation elements 100a and 100b each do not contain, for example, a binder. Specifically, the electrode layer 101, counter electrode layer 103, and solid electrolyte layer 102 of the power generation elements 100a and 100b each do not contain a binder. As a result, since the power generation elements 100a and 100b do not contain a binder that does not contribute to the charge-discharge reaction, the proportion of active material and solid electrolyte in the power generation elements 100a and 100b increases, and the energy density of the battery 1 can be increased.

[0071] A binder is an adhesive material that plays the role of bonding the materials of each layer together and adjacent layers together. Examples of binders include resins, elastomers, or rubbers. In addition, some of the electrode layers 101, counter electrode layer 103, and solid electrolyte layer 102 of the power generation elements 100a and 100b may contain a binder. Furthermore, in this specification, "binder-free" means substantially free of a binder, specifically meaning completely free of a binder, or inevitably present in amounts of 100 ppm or less as an impurity.

[0072] Furthermore, the power generation elements 100a and 100b do not contain solvents, such as organic solvents. Specifically, the electrode layer 101, counter electrode layer 103, and solid electrolyte layer 102 of the power generation elements 100a and 100b do not contain solvents. This suppresses the degradation of the materials in each layer due to solvents, thereby improving battery performance. However, some layers among the electrode layer 101, counter electrode layer 103, and solid electrolyte layer 102 of the power generation elements 100a and 100b may contain solvents. In this specification, "solvent-free" means substantially free of solvents, specifically meaning completely free of solvents, and inevitably containing solvents at a concentration of 50 ppm or less as impurities.

[0073] The electrode layer 101, the counter electrode layer 103, and the solid electrolyte layer 102 are maintained, for example, in a parallel plate shape.

[0074] Furthermore, in this embodiment, the side surfaces of the electrode layer 101, the solid electrolyte layer 102, and the counter electrode layer 103 coincide when viewed along the stacking direction. More specifically, in power generation elements 100a and 100b, the shapes and sizes of the electrode layer 101, the solid electrolyte layer 102, and the counter electrode layer 103 are the same when viewed along the stacking direction, and their contours coincide.

[0075] The power generation elements 100a and 100b and the electron conduction layer 110 are stacked within the housing 200. Furthermore, the sides of each power generation element 100a and 100b, and the sides of the electron conduction layer 110, coincide when viewed along the stacking direction, and constitute the side surface 11 of the power generation unit 10.

[0076] The electron conduction layer 110 is located between the power generation elements 100a and 100b and is in contact with each of them. Specifically, one main surface of the electron conduction layer 110 is in contact with the electrode layer 101 of the power generation element 100a and is electrically connected to the electrode layer 101. The other main surface of the electron conduction layer 110 is in contact with the counter electrode layer 103 of the power generation element 100b and is electrically connected to the 103. As a result, the power generation elements 100a and 100b are electrically connected in series via the electron conduction layer 110. A conductive connecting layer may be placed between the electron conduction layer 110 and at least one of the power generation elements 100a and 100b.

[0077] The electron conduction layer 110, for example, has electron conductivity but not ionic conductivity. The electron conduction layer 110 includes an electron conduction material that has electron conductivity. The electron conduction layer 110 consists of, for example, only an electron conduction material. As a result, the electron conduction layer 110 does not contain any material that inhibits electron conduction, and stable battery characteristics can be obtained.

[0078] The electron-conducting material contained in the electron-conducting layer 110 is, for example, a powder. Specifically, the electron-conducting material contained in the electron-conducting layer 110 is, for example, a compacted powder formed by compressing powder. Each of the multiple particles constituting the electron-conducting material powder has electron conductivity. The electron-conducting material can be, for example, a metal such as stainless steel, aluminum, copper, nickel, or conductive carbon. Furthermore, the electron-conducting material may contain multiple types of conductive substances.

[0079] The thickness of the electron conduction layer 110 is, for example, 15 μm to 300 μm. A thickness of 15 μm or more for the electron conduction layer 110 suppresses contact between the power generation elements 100a and 100b, thereby suppressing natural discharge and enabling a battery 1 with a higher energy density. Furthermore, a thickness of 300 μm or less for the electron conduction layer 110 reduces the volume occupied by the electron conduction layer 110 within the housing 200, enabling a battery 1 with an even higher energy density.

[0080] As will be explained in more detail later, the electron-conducting layer 110 may have at least one of grain boundaries and voids formed therein.

[0081] The housing 200 is a box-shaped container that houses the power generation unit 10 and the current collector 300, and is responsible for protecting the power generation unit 10. In this embodiment, the housing 200 also functions as a current extraction unit for the power generation unit 10.

[0082] The housing 200 has, for example, a bottom plate portion 210, a side wall portion 220, and a bent portion 230. The bottom plate portion 210, the side wall portion 220, and the bent portion 230 are names given to each part, for example, formed by processing a single member. The housing 200 may also be formed by connecting the bottom plate portion 210, the side wall portion 220, and the bent portion 230, which are made of different members. In addition, an opening 205 is formed in the center of the upper part of the housing 200. The opening 205 exposes the current collector 300. Specifically, the opening 205 exposes the side of the current collector 300 opposite to the power generation element 100b side. Note that the housing 200 does not have to have the bent portion 230.

[0083] The bottom plate portion 210 is plate-shaped and constitutes the bottom of the box-shaped housing 200. The bottom plate portion 210 covers the main surface 16 of the power generation unit 10 and is in contact with the main surface 16. The bottom plate portion 210 has, for example, electron conductivity. In this embodiment, the bottom plate portion 210 is an example of a conductive part. The bottom plate portion 210 is electrically connected to the power generation element 100a. Specifically, the bottom plate portion 210 faces the electron conductive layer 110 with the power generation element 100a in between. The bottom plate portion 210 is in contact with the counter electrode layer 103 of the power generation element 100a and is electrically connected to the counter electrode layer 103. Therefore, in this embodiment, the bottom plate portion 210 can be used to extract current from the positive electrode of the power generation unit 10.

[0084] The side wall portion 220 is erected from the outer periphery of the bottom plate portion 210 upward along the stacking direction, forming the side wall of the box-shaped housing 200. In this embodiment, the surface of the side wall portion 220 on the side facing the power generation unit 10 is the inner surface 201 of the housing 200. When viewed along the stacking direction, the side wall portion 220 surrounds the power generation unit 10 from the side.

[0085] The side wall portion 220 includes a conductive portion 221 and an insulating portion 222. The conductive portion 221 is positioned opposite the side surface 11 via the insulating portion 222. The conductive portion 221 is, for example, plate-shaped. The conductive portion 221 is not in contact with the power generation portion 10 and the current collector 300. The insulating portion 222 is an insulating layer covering the surface of the conductive portion 221 on the power generation portion 10 side. The insulating portion 222 is in contact with the side surface 11 of the power generation portion 10. More specifically, the surface of the insulating portion 222 on the power generation portion 10 side constitutes the inner surface 201, which is part of the inner surface of the housing 200. The power generation element 100a, the power generation element 100b, the electron conductive layer 110, and the current collector 300 are each in contact with the inner surface 201. All sides of each of the power generation element 100a, power generation element 100b, electron conduction layer 110, and current collector 300 are in contact with, for example, the inner surface 201.

[0086] The bent portion 230 extends inward from the upper end of the side wall portion 220 (i.e., the end opposite to the bottom plate portion 210) by bending the upper part of the side wall portion 220. The bent portion 230 covers a portion of the main surface 15 of the power generation unit 10. Specifically, the bent portion 230 covers the main surface 15 via the current collector 300. The bent portion 230 also surrounds the opening 205.

[0087] The bent portion 230 includes a conductive portion 231 and an insulating portion 232. The conductive portion 231 is positioned facing the main surface 15 via the insulating portion 232. The conductive portion 231 is not in contact with the power generation portion 10 or the current collector 300. The insulating portion 232 is an insulating layer that covers the surface of the conductive portion 231 on the power generation portion 10 side. The insulating portion 232 faces the main surface 15 via the current collector 300 and is in contact with the current collector 300.

[0088] The housing 200 is, for example, a composite material composed of an electronically conductive material and an electrically insulating material.

[0089] The base plate portion 210, the conductive portion 221, and the conductive portion 231 are integrally formed as a box-shaped member made of, for example, an electronically conductive material. Examples of electronically conductive materials used to constitute the base plate portion 210, the conductive portion 221, and the conductive portion 231 include metals such as stainless steel, aluminum, copper, and nickel.

[0090] The insulating portion 222 and the insulating portion 232 are integrally formed as a thin film made of an electrical insulating material such as resin. The insulating portion 222 and the insulating portion 232 are formed, for example, by applying resin to the inner surfaces of the conductive portion 221 and the conductive portion 231 in a box-shaped member composed of a bottom plate portion 210 and conductive portions 221 and 231. The electrical insulating material may also be an inorganic material such as ceramic.

[0091] The current collector 300 is positioned within the housing 200 on the side opposite to the electron conduction layer 110 of the power generation element 100b, and is in contact with the main surface 15 of the power generation unit 10. Specifically, the current collector 300 is in contact with the electrode layer 101 of the power generation element 100b and is electrically connected to the electrode layer 101. Therefore, in this embodiment, the current collector 300 can be used to extract the current from the negative electrode of the power generation unit 10. A conductive connecting layer may be placed between the current collector 300 and the power generation element 100b.

[0092] The current collector 300 is, for example, a foil-shaped, plate-shaped, or mesh-shaped member having electrical conductivity. The material used to make up the current collector 300 may be, for example, a metal such as stainless steel, aluminum, copper, or nickel. The metal used for the current collector 300 may be the same as or different from the metal used for the bottom plate portion 210.

[0093] [Manufacturing method] Next, a method for manufacturing the battery 1 according to this embodiment will be described. Note that the method for manufacturing the battery 1 described below is just one example, and the manufacturing method of the battery 1 is not limited to the method described below.

[0094] Figures 2 to 5 are diagrams illustrating the manufacturing method of the battery 1 according to this embodiment.

[0095] In the manufacturing method of battery 1, first, as shown in Figure 2, the housing 200a is set in a press die 50 provided in a press device. The press die 50 is provided with a recess of the same size as the housing 200a, and the housing 200a is set in this recess. The housing 200a is the housing before the bent portion 230 is formed in the housing 200 described above. The housing 200a is a box-shaped container having, for example, a bottom plate portion 210 and a side wall portion 220a that rises upward from the outer circumference of the bottom plate portion 210, with the top of the housing 200a open.

[0096] Next, the materials for forming the power generation element 100a are put into the housing 200a. That is, the counter electrode material, electrolyte material, and electrode material for forming each layer of the power generation element 100a are put into the housing 200a in this order. Specifically, as shown in Figure 2, first, the counter electrode material 103a for forming the counter electrode layer 103 of the power generation element 100a, which constitutes the bottom layer of the power generation unit 10, is put into the housing 200a. The counter electrode material 103a is a powdered material. Then, as shown in Figure 3, the counter electrode layer 103 is formed by performing a preliminary press on the counter electrode material 103a put into the housing 200a using a columnar press pin 51 provided on the press device. By putting the powdered counter electrode material 103a into the housing 200a and pressing it in this way, the counter electrode layer 103 can be formed by compressing the counter electrode material 103a into layers. Furthermore, the preliminary pressing helps to prevent the next material to be introduced from mixing with the counter electrode material 103a. The pressure of the preliminary pressing is not particularly limited and is set according to the material being pressed, but for example, it is between 20 MPa and 100 MPa.

[0097] Similar to the counter electrode layer 103, powdered electrolyte material for forming the solid electrolyte layer 102 of the power generation element 100a is introduced into the housing 200a on which the counter electrode layer 103 is formed, and the introduced electrolyte material is subjected to preliminary pressing to form the solid electrolyte layer 102. Next, powdered electrode material for forming the electrode layer 101 of the power generation element 100a is introduced into the housing 200a on which the counter electrode layer 103 and the solid electrolyte layer 102 are formed, and the introduced electrode material is subjected to preliminary pressing to form the electrode layer 101. As a result, as shown in Figure 4, a power generation element 100a is formed inside the housing 200a on the bottom plate portion 210 of the housing 200a, with the counter electrode layer 103, solid electrolyte layer 102, and electrode layer 101 stacked in that order from bottom to top.

[0098] Next, as shown in Figure 4, an electron conductive material 110a for forming the electron conductive layer 110 is introduced into the housing 200a on which the power generation element 100a is formed. The electron conductive material 110a is a powder material. Then, the electron conductive layer 110 is formed by performing a preliminary press on the electron conductive material 110a introduced into the housing 200a. In this way, by introducing the powdery electron conductive material 110a containing voids into the housing 200a, the electron conductive material 110a is spread out within the housing 200a, and an electron conductive layer 110 that separates the power generation element 100a and the power generation element 100b can be formed.

[0099] Next, the materials for forming the power generation element 100b are introduced into the housing 200a, which already has the power generation element 100a and the electron conduction layer 110 formed on it. In other words, the counter electrode material, electrolyte material, and electrode material for forming each layer of the power generation element 100b are introduced into the housing 200a in this order. For example, the introduction of materials and preliminary pressing are repeated in the same manner as for the power generation element 100a, thereby forming the power generation element 100b on the electron conduction layer 110 inside the housing 200. In this way, a laminate is formed in which the materials for forming the power generation element 100a, the materials for forming the electron conduction layer 110, and the materials for forming the power generation element 100b are introduced into the housing 200a in this order, with the power generation element 100a, the electron conduction layer 110, and the power generation element 100b stacked from bottom to top in this order. The materials introduced in this process are powdered materials that do not contain solvents.

[0100] Then, as shown in Figure 5, the power generation element 100a, the electron conduction layer 110, and the power generation element 100b, which are formed by each material introduced into the housing 200a, are pressed together. This forms the power generation unit 10. The pressure of this press is not particularly limited and is set according to the material being pressed, but for example, it is between 200 MPa and 1000 MPa. In this way, by going through the process of pressing each material introduced into the housing 200a, the power generation element 100a, the power generation element 100b, and the electron conduction layer 110, which are held in close contact with the inner surface of the side wall portion 220a of the housing 200a, are formed. Note that this press may be performed after each layer of material is introduced, instead of the preliminary press described above. In other words, this press may be performed in the middle of the process of introducing materials into the housing 200a.

[0101] Finally, within the housing 200a, the current collector 300 is placed on the power generation element 100b, and the side wall portion 220a that protrudes above the current collector 300 is bent by crimping or other means to form a bent portion 230. This results in the battery 1 shown in Figure 1.

[0102] In the above-described manufacturing method, powdered material was placed in the housing 200a as the material for forming the power generation elements 100a and 100b, but this is not the only method. Figure 6 is a diagram illustrating a modified example of the manufacturing method of the battery 1 according to this embodiment.

[0103] The material used to form the power generation elements 100a and 100b, which are placed in the housing 200a, may be in pellet form. For example, the battery 1 is manufactured using the above manufacturing method, except that the material used to form the power generation elements 100a and 100b is changed from a powder to a pellet. Specifically, as shown in Figure 6, first, pellet-shaped counter electrode material 103b for forming the counter electrode layer 103 of the power generation element 100a is placed in the housing 200a. When using pellet-shaped counter electrode material 103b, for example, it is not necessary to perform the preliminary pressing described above.

[0104] The pelletized counter electrode material 103b is formed, for example, by placing powdered counter electrode material into a mold separate from the housing 200a and pressing it to compact it. In other words, the pelletized counter electrode material 103b is, for example, a compacted powder. The pressing pressure in this case is, for example, the pressure of the preliminary press or the main press described above. Alternatively, the powdered counter electrode material may be pressed using a flat plate press device to form a flat plate-shaped counter electrode material, and then the pelletized counter electrode material 103b may be formed by punching out the flat plate-shaped counter electrode material to match the shape of the internal space of the housing 200a. Depending on the thickness of the counter electrode material 103b, the counter electrode material 103b may become a pelletized material with a fairly flattened film shape, but in this specification, materials with a film shape are also included in the definition of pelletized material. In this specification, a pelletized material means a material that is integrated so that the material does not easily separate, like a compacted powder.

[0105] For each layer of power generation element 100a and power generation element 100b, other than the counter electrode layer 103 of power generation element 100a, pelletized material is placed in the housing 200a to form the counter electrode material, electrolyte material, or electrode material for each layer, thereby forming power generation elements 100a and 100b within the housing 200a. The pelletized material can be formed in the same way as the counter electrode material 103b. Alternatively, pelletized material in which the counter electrode material, electrolyte material, and electrode material are laminated may be placed in the housing 200a.

[0106] Through this process, a laminate of the power generation element 100a, the electron conductive layer 110, and the power generation element 100b, as shown in Figure 5, is formed inside the housing 200a. Then, in the same manner as described above, the current collector 300 is placed and the bent portion 230 is formed to obtain the battery 1 shown in Figure 1.

[0107] In this way, by introducing pelletized material into the housing 200a as the material for forming the power generation elements 100a and 100b, the battery 1 can be manufactured using a simpler manufacturing process. Furthermore, the materials of each layer of the power generation elements 100a and 100b are less likely to mix, improving the battery characteristics of the battery 1.

[0108] [Effects, etc.] As described above, in battery 1, the sides of each of the stacked power generation elements 100a and 100b are in contact with the inner surface 201, which is the inner surface of the housing 200. As a result, the inside of the housing 200 is filled with power generation elements 100a and 100b, so the internal space of the housing 200 can be effectively utilized. For example, the internal space of the housing 200 can be utilized to the maximum extent. Therefore, battery 1 with high energy density can be realized. In addition, since the sides of power generation elements 100a and 100b are in close contact with the side wall portion 220 of the housing 200, they are strongly constrained in the vertical direction of the side wall portion 220. As a result, degradation of voltage and capacity caused by repeated expansion and contraction of the active material during the charge and discharge process is suppressed. Furthermore, in battery 1, power generation elements 100a and 100b are electrically connected in series, so battery 1 with high voltage and high energy density can be realized.

[0109] Furthermore, in battery 1, the electron conductive material constituting the electron conductive layer 110 is in powder form. This allows the electron conductive material powder to spread between the power generation elements 100a and 100b within the housing 200, enabling the electron conductive layer 110 to adhere closely to the inner surface 201 of the housing 200. Therefore, the electron conductive layer 110 is present at all positions between the power generation elements 100a and 100b, suppressing short circuits (specifically, ionic short circuits) between the power generation elements 100a and 100b. In particular, it can suppress short circuits at the ends of the power generation elements 100a and 100b, where short circuits are prone to occur. In addition, since natural discharge is more likely to occur when the power generation elements 100a and 100b come into contact, suppressing contact between the power generation elements 100a and 100b increases the capacity of battery 1.

[0110] Here, the point that short circuits between power generation element 100a and power generation element 100b are suppressed will be explained using the results of manufacturing and charging / discharging a battery.

[0111] First, the battery 1 manufactured using the above-described manufacturing method was charged and discharged using powder in the electron conduction layer 110. Specifically, the manufactured battery 1 was charged under conditions of a cutoff voltage of 5.5V and a current rate of 0.05C. Then, the charged battery 1 was discharged under conditions of a cutoff voltage of 2.0V and a current rate of 0.05C. As a result, the average discharge voltage during discharge was 4.2V. The average discharge voltage is the time average of the voltage during discharge. Next, when the battery 1 using metal foil in the electron conduction layer 110 was charged and discharged, the average discharge voltage was 3.4V, and the discharge capacity was also lower than that of the electron conduction layer 110 using powder as described above. Furthermore, since the average discharge voltage when discharging a battery with one power generation element was 2.1V, it can be seen that in the battery 1 manufactured using powder in the electron conduction layer 110, power generation elements 100a and 100b are electrically connected in series without a short circuit.

[0112] Figure 7 is a scanning electron microscope image of a cross-section of an electron conduction layer 110 using metal foil. Figure 8 is a scanning electron microscope image of a cross-section of an electron conduction layer 110 using powder. As shown in Figure 7, the electron conduction layer 110 using metal foil has a continuous composition, and no voids or grain boundaries are observed. On the other hand, as shown in Figure 8, the electron conduction layer 110 using powder has grain boundaries 111 (white areas in the scanning electron microscope image) and voids 112 (black areas in the scanning electron microscope image) formed in the powder. Thus, the formation of grain boundaries 111 and voids 112 in the electron conduction layer 110 makes it easier for the electron conduction material in the electron conduction layer 110 to move, and the electron conduction material spreads more easily between the power generation elements 100a and 100b inside the housing 200. Therefore, the electron conduction layer 110 can adhere closely to the inner surface 201 of the housing 200, and contact between the power generation elements 100a and 100b can be suppressed. Furthermore, because voids 112 are formed in the electron conduction layer 110, the stress on the electron conduction layer 110 can be relieved by the voids 112, thereby suppressing damage to the electron conduction layer 110.

[0113] (Other embodiments) The battery and battery manufacturing method described above have been explained based on embodiments, but this disclosure is not limited to these embodiments. Within the scope of this disclosure, various modifications to the embodiments that a person skilled in the art could conceive, as long as they do not deviate from the spirit of this disclosure, and other forms constructed by combining some of the components of the embodiments, are also included.

[0114] For example, in the above embodiment, the power generation element 100a and the power generation element 100b were electrically connected in series, but this is not limited to this. The power generation element 100a and the power generation element 100b may be electrically connected in parallel. This can increase the capacity of the battery 1. In this case, the housing 200 may be configured to have a conductive part that is electrically connected to the electron conduction layer 110 between the power generation element 100a and the power generation element 100b.

[0115] Furthermore, although the above embodiment mainly described an example in which a powdered electron conductive material is used for the electron conductive layer 110, the invention is not limited to this. A metal foil may also be used for the electron conductive layer 110. For example, by using a metal foil with an area larger than the main surfaces of the power generation elements 100a and 100b, or by adjusting the pressure in the preliminary and final pressing, the power generation elements 100a and 100b can not come into contact, thereby suppressing short circuits between them. In addition, a porous metal or a porous conductive resin may be used as the electron conductive material for forming the electron conductive layer 110.

[0116] Furthermore, in the above embodiment, for example, the sides of the power generation elements 100a and 100b were in contact with the inner surface 201 of the housing 200, but this is not limited to this. Only one side of the power generation elements 100a and 100b may be in contact with the inner surface 201 of the housing 200.

[0117] Furthermore, in the above embodiment, the side wall portion 220 and the bent portion 230 of the housing 200 were composed of a conductive portion and an insulating portion, respectively, but this is not limited to this. At least one of the side wall portion 220 and the bent portion 230 may be composed of an insulating portion only. Also, if the bottom plate portion 210 and the bent portion 230 are insulated in the housing 200, the bent portion 230 may be composed of a conductive portion 231 only. In this case, the battery 1 does not need to be equipped with a current collector 300, and the conductive portion 231 contacts the main surface 15 and functions as a current collector. Also, in this case, the conductive portion 231 of the bent portion 230 may cover the entire main surface 15.

[0118] Furthermore, although the bottom plate portion 210 was made of an electronically conductive material in the above embodiment, it is not limited to this. A part of the bottom plate portion 210 may be made of an electrically insulating material. In other words, the bottom plate portion 210 may include a conductive portion and an insulating portion.

[0119] Furthermore, in the above embodiment, for example, the housing 200 was a composite member composed of an electronically conductive material and an electrical insulating material, but it is not limited to this. The housing 200 may be composed entirely of an electrical insulating material. In this case, for example, an opening for extracting current from the power generation unit 10 is formed in the housing 200.

[0120] Furthermore, although the above embodiment describes an example in which the ions conducting in battery 1 are lithium ions, it is not limited to this. The ions conducting in battery 1 may be ions other than lithium ions, such as sodium ions, magnesium ions, potassium ions, calcium ions, or copper ions.

[0121] Furthermore, the above embodiments may be modified, replaced, added, or omitted in various ways within the scope of the claims or their equivalents. [Industrial applicability]

[0122] The battery relating to this disclosure can be used, for example, as a secondary battery such as an all-solid-state battery used in various electronic devices or automobiles. [Explanation of Symbols]

[0123] 1 battery 10 Power Generation Section 11 Side view 15, 16 Main surface 50 press molds 51 Press pin 100a, 100b power generation elements 101 Electrode layer 102 Solid electrolyte layer 103 Polar Layer 103a, 103b Counter electrode materials 110 Electron Conduction Layer 110a Electronic Conductive Materials 111 Grain boundaries 112 void 200, 200a enclosure 201 Inner surface 205 Opening 210 Bottom plate part 220, 220a Side wall section 221, 231 Conductive parts 222, 232 Insulation part 230 Bending section 300 Current collector

Claims

1. The casing and The first power generation element and The second power generation element, An electron conduction layer located between the first power generation element and the second power generation element, Within the housing, a current collector is disposed on the side of the second power generation element opposite to the electron conduction layer side, Equipped with, The first power generation element and the second power generation element are each laminates comprising an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer. The first power generation element, the second power generation element, and the electron conductive layer are stacked within the housing. At least one side of the first power generation element and the second power generation element is in contact with the inner surface of the housing. The current collector is a foil-shaped, plate-shaped, or mesh-shaped member having electronic conductivity. The aforementioned electron conductive layer includes a powder electron conductive material. battery.

2. The aforementioned electron conductive layer consists solely of the aforementioned electron conductive material. The battery according to claim 1.

3. The electron conductive layer has grain boundaries formed in the powder of the electron conductive material. The battery according to claim 1.

4. The first power generation element and the second power generation element are electrically connected in series. The battery according to claim 1.

5. At least one of the electrode layer, counter electrode layer, and solid electrolyte layer in at least one of the first power generation element and the second power generation element does not contain a binder. The battery according to any one of claims 1 to 4.

6. At least one of the first power generation element and the second power generation element does not contain a binder. The battery according to claim 5.

7. The thickness of the electron conduction layer is 15 μm or more and 300 μm or less. The battery according to any one of claims 1 to 4.

8. A void is formed in the aforementioned electron conduction layer. The battery according to any one of claims 1 to 4.

9. The housing has an insulating portion in contact with the side surface and a conductive portion electrically connected to the first power generation element. The battery according to any one of claims 1 to 4.

10. The conductive portion is the bottom plate portion of the housing that faces the electron conductive layer with the first power generation element in between, The housing has an opening formed therein that exposes the current collector. The battery according to claim 9.

11. Each of the first power generation element, the second power generation element, and the electron conductive layer is in contact with the inner surface. The battery according to any one of claims 1 to 4.

12. A method for manufacturing a battery comprising a first power generation element and a second power generation element, each being a laminate containing an electrode layer, a counter electrode layer, and a solid electrolyte layer located between the electrode layer and the counter electrode layer, A step of placing the material for forming the first power generation element, the material for forming the powdery electron conductive layer, and the material for forming the second power generation element into the housing in this order, A process of pressing each material placed in the aforementioned housing, The process includes arranging an electronically conductive foil, plate, or mesh-shaped current collector on the side of the second power generation element opposite to the electron-conducting layer within the housing, Battery manufacturing method.

13. The material for forming the powdered first power generation element and the material for forming the powdered second power generation element are placed into the housing. The method for manufacturing a battery according to claim 12.

14. A material for forming the pellet-shaped first power generation element and a material for forming the pellet-shaped second power generation element are placed into the housing. The method for manufacturing a battery according to claim 12.

Images