Battery and method for manufacturing a battery

Abstract

To provide batteries and other devices that achieve both miniaturization and high reliability. [Solution] The battery 1 comprises a power generation element 10 and an outer casing 20 made of laminate film that seals the power generation element 10. The outer casing 20 is positioned to surround the power generation element 10 in a plan view with respect to the main surface of the power generation element 10 and has an overlapping portion 30 in which laminate films are overlapped. The overlapping portion 30 has a folded portion 40 in a plan view, which is the portion where the overlapping portions 30 overlap each other, as the end of the overlapping portion 30 opposite to the power generation element 10 is folded back toward the power generation element side. The folded portion 40 includes an adhesive region 41 in a plan view where the overlapping overlapping portions 30 are bonded to each other on their inner surfaces, and a non-adhesive region 42 between the folded position R of the overlapping portion 30 and the adhesive region 41 in a plan view, where the overlapping overlapping portions 30 are not bonded to each other.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses folding back a heat-sealed portion of a laminated battery cell.

[0003] Patent Document 2 discloses folding back a heat-sealed portion of a laminated battery cell multiple times.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the prior art, further miniaturization and reliability improvement of batteries are desired.

[0006] In particular, miniaturization and reliability of a battery housed in a laminated film-type exterior body are important points in practical characteristics.

[0007] Therefore, the present disclosure provides a battery and a method for manufacturing the same that can achieve both miniaturization and high reliability when using an exterior body composed of a laminated film.

Means for Solving the Problems

[0008] A battery according to one aspect of the present disclosure comprises a power generation element and an outer casing made of a laminate film that seals the power generation element, wherein the outer casing is positioned to surround the power generation element in a plan view with respect to the main surface of the power generation element and has an overlapping portion where the laminate films are overlapped, the overlapping portion has a folded portion where the end of the overlapping portion opposite to the power generation element side is folded back toward the power generation element side, the folded portion includes an adhesive region where the overlapping overlapping portions are bonded to each other on their inner surfaces in the plan view, and a non-adhesive region between the folded position of the overlapping portion and the adhesive region in the plan view, where the overlapping overlapping portions are not bonded to each other in the plan view.

[0009] A method for manufacturing a battery according to one aspect of the present disclosure includes the steps of: sealing the power generation element with an outer casing made of laminate film by covering the power generation element with a laminate film and forming an overlapping portion by overlapping the laminate film at a position that surrounds the power generation element in a plan view with respect to the main surface of the power generation element; folding back the end of the overlapping portion opposite to the power generation element side toward the power generation element side to form a folded portion which is a portion where the overlapping portions overlap in a plan view; and forming an adhesive region in the folded portion where the overlapping portions that overlap in a plan view are bonded to each other on their inner surfaces, and a non-adhesive region between the folded position of the overlapping portion and the adhesive region in a plan view, where the overlapping portions that overlap in a plan view are not bonded to each other. [Effects of the Invention]

[0010] According to this disclosure, a battery using an outer casing made of laminate film can achieve both miniaturization and high reliability. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a top view of a battery according to Embodiment 1. [Figure 2] Figure 2 is a cross-sectional view of the battery according to Embodiment 1. [Figure 3] Figure 3 is a flowchart showing an example of a method for manufacturing the battery according to Embodiment 1. [Figure 4A] Figure 4A is a cross-sectional view of an example of a unit cell according to Embodiment 1. [Figure 4B] Figure 4B is a cross-sectional view of another example of the unit cell according to Embodiment 1. [Figure 4C] Figure 4C is a cross-sectional view of yet another example of the unit cell according to Embodiment 1. [Figure 5] Figure 5 is a cross-sectional view of a power generation element having a plurality of battery cells according to Embodiment 1. [Figure 6A] Figure 6A is a top view of the electrode lead and the counter electrode lead according to Embodiment 1. [Figure 6B] Figure 6B is a side view of the electrode lead and the counter electrode lead according to Embodiment 1. [Figure 7] Figure 7 is a top view of the battery during manufacturing according to Embodiment 1. [Figure 8] Figure 8 is a top view of the battery according to Modification 1 of Embodiment 1. [Figure 9] Figure 9 is a top view of the battery during manufacturing according to Modification 1 of Embodiment 1. [Figure 10] Figure 10 is a top view of the battery according to Modification 2 of Embodiment 1. [Figure 11] Figure 11 is a cross-sectional view of the battery according to Modification 2 of Embodiment 1. [Figure 12] Figure 12 is a top view of the battery during manufacturing according to Modification 2 of Embodiment 1. [Figure 13] Figure 13 is a top view of the battery according to Embodiment 2. [Figure 14] Figure 14 is a top view of the battery according to Embodiment 3. [Figure 15] Figure 15 is a cross-sectional view of the battery according to Embodiment 3.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] (Summary of the Present Disclosure) As an overview of the present disclosure, examples of a battery and a method for manufacturing the battery according to the present disclosure will be shown below.

[0013] The battery according to the first aspect of the present disclosure includes a power generation element and an exterior body composed of a laminate film that seals the power generation element. The exterior body is positioned so as to surround the power generation element in a plan view with respect to the main surface of the power generation element, and has an overlapping portion where the laminate films are overlapped. The overlapping portion has a folded portion which is a portion where the overlapping portions overlap each other in the plan view, because the end portion of the overlapping portion on the side opposite to the power generation element side is folded back toward the power generation element side. The folded portion includes an adhesion region where the overlapping portions that overlap each other in the plan view are adhered to each other on their inner surfaces, and a non-adhesion region which is a region between the folding position of the overlapping portion in the plan view and the adhesion region, and where the overlapping portions that overlap each other in the plan view are not adhered to each other.

[0014] Thereby, in a battery using an exterior body composed of a laminate film, miniaturization and high reliability can be achieved simultaneously.

[0015] Specifically, while effectively suppressing the intrusion of moisture that causes deterioration of the power generation element into the exterior body by the overlapping portion surrounding the power generation element, since the end portion of the overlapping portion on the side opposite to the power generation element side is folded back toward the power generation element side, the projected area of the battery can be reduced. Also, when forming the adhesion region by adhering the folded portion, if there is no non-adhesion region, the adhesion operation is performed up to the vicinity of the folding position, so there is a risk of damage to the metal layer in the laminate film. In this aspect, since a non-adhesion region exists between the folding position and the adhesion region in the folded portion, such damage to the metal layer in the laminate film is suppressed, and a decrease in the moisture barrier effect by the exterior body can be suppressed. Therefore, miniaturization and high reliability of a battery using an exterior body composed of a laminate film can be achieved simultaneously.

[0016] Furthermore, for example, a battery according to a second aspect of this disclosure is a battery according to a first aspect, wherein the power generation element may be sealed under reduced pressure within the outer casing.

[0017] This reduces the amount of moisture inside the casing and also allows for a thinner battery.

[0018] Furthermore, for example, a battery according to a third aspect of this disclosure is a battery according to the first or second aspect, wherein in the overlapping portion, the overlapping laminate films may be heat-fused together.

[0019] This further suppresses the intrusion of moisture into the exterior.

[0020] Furthermore, for example, a battery according to a fourth aspect of this disclosure is a battery according to any one of the first to third aspects, wherein in the adhesive region, the overlapping portions may be bonded together by heat fusion.

[0021] This allows the overlapping parts to be bonded together without increasing the volume or weight of the battery.

[0022] Furthermore, for example, a battery according to a fifth aspect of the present disclosure is a battery according to any one of the first to fourth aspects, wherein a gap may be formed between the overlapping portions that overlap in the plan view in the non-adhesive region.

[0023] This allows for a larger bending radius in the overlapping portion at the folded-over section, further suppressing damage to the metal layer in the laminate film. Additionally, the void provides cushioning in the folded-over section, mitigating mechanical external forces and protecting the power generation element from them.

[0024] Furthermore, for example, a battery according to a sixth aspect of this disclosure may be a battery according to a fifth aspect, further comprising a first member that closes off a portion of the gap.

[0025] As a result, the overlapping portion with a gap in the non-adhesive area is held by the first member, and the strength of the folded portion can be increased.

[0026] Furthermore, for example, a battery according to the seventh aspect of the present disclosure is a battery according to any one of the first to sixth aspects, further comprising a second member disposed between the overlapping portions that overlap in the plan view in the non-adhesive region.

[0027] This reinforces the folded portion with the second component, further enhancing the mechanical reliability of the battery.

[0028] Furthermore, for example, the battery according to the eighth aspect of this disclosure is the battery according to the seventh aspect, and the second member may include at least one of metal and ceramic.

[0029] This increases the rigidity of the second component, further enhancing the mechanical reliability of the battery.

[0030] Furthermore, for example, the battery according to the ninth aspect of this disclosure is a battery according to any one of the first to eighth aspects, and the power generation element may be an all-solid-state battery.

[0031] This allows for the protection of all-solid-state batteries, which are prone to material collapse and other issues, by an external casing.

[0032] Furthermore, a method for manufacturing a battery according to a tenth aspect of the present disclosure includes the steps of: sealing the power generation element with an outer casing made of laminate film by covering the power generation element with a laminate film and forming an overlapping portion by overlapping the laminate film at a position surrounding the power generation element in a plan view with respect to the main surface of the power generation element; folding back the end of the overlapping portion opposite to the power generation element side toward the power generation element side to form a folded portion which is a portion where the overlapping portions overlap in a plan view; and forming an adhesive region in the folded portion where the overlapping portions that overlap in a plan view are bonded to each other on their inner surfaces, and a non-adhesive region which is a region between the folded position of the overlapping portion and the adhesive region in a plan view, where the overlapping portions that overlap in a plan view are not bonded to each other.

[0033] This makes it possible to manufacture batteries that achieve both miniaturization and high reliability, as described above.

[0034] Furthermore, for example, the battery manufacturing method according to the 11th aspect of this disclosure is the battery manufacturing method according to the 10th aspect, wherein in the step of sealing the power generation element, the power generation element may be sealed with the outer casing by heat-sealing the overlapping laminate films of the overlapping portions together.

[0035] This further suppresses the intrusion of moisture into the exterior.

[0036] Furthermore, for example, a battery manufacturing method according to the 12th aspect of this disclosure is a battery manufacturing method according to the 10th or 11th aspect, wherein in the step of forming the adhesive region and the non-adhesive region, the adhesive region may be formed by heat-fusing the overlapping portions together.

[0037] This allows the overlapping parts to be bonded together without increasing the volume or weight of the battery.

[0038] Furthermore, for example, a battery manufacturing method according to the 13th aspect of this disclosure is a battery manufacturing method according to any one of the 10th to 12th aspects, wherein in the step of forming the adhesive region and the non-adhesive region, a gap may be formed between the overlapping portions in the non-adhesive region that overlap in a plan view.

[0039] This allows for a larger bending radius in the overlapping portion at the folded-over section, further suppressing damage to the metal layer in the laminate film. Additionally, the void provides cushioning in the folded-over section, mitigating mechanical external forces and protecting the power generation element from them.

[0040] Furthermore, for example, a battery manufacturing method according to a 14th aspect of this disclosure is a battery manufacturing method according to a 13th aspect, which may further include the step of closing a portion of the void with a first member.

[0041] As a result, the overlapping portion with a gap in the non-adhesive area is held by the first member, and the strength of the folded portion can be increased.

[0042] Furthermore, for example, a battery manufacturing method according to a 15th aspect of the present disclosure is a battery manufacturing method according to any one of the 10th to 14th aspects, which may further include the step of arranging a second member between the overlapping portions that overlap in a plan view in the non-adhesive region.

[0043] This reinforces the folded portion with the second component, further enhancing the mechanical reliability of the battery.

[0044] Furthermore, for example, the battery manufacturing method according to the 16th aspect of this disclosure is a battery manufacturing method according to any one of the 10th to 15th aspects, and the power generation element may be an all-solid-state battery.

[0045] This allows for the protection of all-solid-state batteries, which are prone to material collapse and other issues, by an external casing.

[0046] Embodiments of the present disclosure will be described below with reference to the drawings.

[0047] The embodiments described below are all general 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.

[0048] 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.

[0049] Furthermore, in this specification, terms indicating relationships between elements such as parallelism, terms indicating the shape of elements such as rectangles, and numerical ranges do not represent only strict meanings, but also include substantially equivalent ranges, such as differences of a few percent.

[0050] 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 are parallel to the first side and the second side perpendicular to the first side of the rectangle, respectively, when the plan view shape of the power generation element of the battery is rectangular. The z axis is parallel to the thickness direction and the stacking direction of the power generation element.

[0051] Furthermore, in this specification, the "stacking direction" of the power generation element coincides with the direction normal to the main surface of each layer of the current collector and battery cell. Also, in this specification, "plan view" means a view from a direction perpendicular to the main surface of the power generation element, unless otherwise specified.

[0052] 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."

[0053] 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.

[0054] (Embodiment 1) The following describes the battery according to Embodiment 1.

[0055] [composition] First, the configuration of the battery according to Embodiment 1 will be described.

[0056] Figure 1 is a top view of the battery 1 according to this embodiment. Figure 2 is a cross-sectional view of the battery 1 according to this embodiment. Specifically, Figure 1 is a plan view of the battery 1 as seen from the positive z-axis side, that is, a plan view of the upper main surface 15 of the power generation element 10. In Figure 1, the plan view shapes of the power generation element 10 and the air gap 45, as well as the boundary of the overlapping portion 30 in the outer casing 20, are shown by dashed lines. Figure 2 shows a cross-section along the line II-II shown in Figure 1. In this disclosure, for clarity, the overlapping portion 30 in the outer casing 20 is given a dot pattern in the plan view of the battery, such as in Figure 1. In addition, the folded portion 40 of the overlapping portion 30 has a dot pattern with a higher density than other parts.

[0057] As shown in Figures 1 and 2, the battery 1 comprises a power generation element 10, an outer casing 20, an electrode lead 91, a counter electrode lead 92, and a sleeve 93.

[0058] The power generation element 10 has a structure in which one or more battery cells 100 and one or more current collectors are stacked along the thickness direction.

[0059] The plan view shape of the power generation element 10 is rectangular, as shown in Figure 1, for example. In other words, the shape of the power generation element 10 is a flattened rectangular parallelepiped. Here, "flattened" means that the thickness (i.e., the length in the z-axis direction) is shorter than the length of each side of the main face (i.e., the respective lengths in the x-axis and y-axis directions) or the maximum width. The plan view shape of the power generation element 10 may also be other polygons such as a square, hexagon, or octagon, or it may be circular or elliptical. Note that in cross-sectional views such as Figure 2, the thickness of each layer is exaggerated to make the layered structure of the power generation element 10 easier to understand.

[0060] The power generation element 10 includes four side surfaces 11, 12, 13, and 14 and two main surfaces 15 and 16, as shown in Figures 1 and 2. The main surfaces 15 and 16 are the surfaces of the power generation element 10 with the largest area. In this embodiment, the side surfaces 11, 12, 13, and 14, as well as the main surfaces 15 and 16, are all flat surfaces.

[0061] Sides 11 and 13 face away from each other and are parallel to each other. Sides 12 and 14 face away from each other and are parallel to each other. The front directions of sides 11 and 13 intersect, specifically perpendicular to, the front directions of sides 12 and 14. Also, sides 11, 12, 13 and 14 are erected perpendicular to main surfaces 15 and 16 from each side of main surfaces 15 and 16. Sides 11, 12, 13 and 14 are parallel to the stacking direction. Also, sides 11 and 12, 12 and 13, 13 and 14, and 11 and 14 are adjacent to each other and intersect, specifically perpendicular to, each of them.

[0062] The main surfaces 15 and 16 are opposite each other and parallel to each other. Main surface 15 is the uppermost surface of the power generation element 10. Main surface 16 is the lowermost surface of the power generation element 10.

[0063] As shown in Figure 2, the power generation element 10 has a plurality of current collectors and a battery cell 100. The plurality of current collectors include an electrode current collector 140 electrically connected to the electrode layer 110 and a counter electrode current collector 150 electrically connected to the counter electrode layer 120. In the power generation element 10, the electrode current collector 140, the battery cell 100, and the counter electrode current collector 150 are stacked in this order along the thickness direction (z-axis direction) of the power generation element 10. The battery cell 100 is the minimum configuration of the power generation section of the battery and is also called a unit cell. In some cases, the battery cell 100 and the current collectors stacked on the battery cell 100 are collectively referred to as a unit cell.

[0064] In the example shown in Figure 2, the power generation element 10 has one battery cell 100, but this is not particularly limited, and there may be two or more. In this case, the multiple battery cells 100 are stacked via current collectors, and each battery cell 100 is sandwiched between current collectors. In this case, the multiple battery cells 100 may be connected in series or in parallel.

[0065] The battery cell 100 includes an electrode layer 110, a counter electrode layer 120, and an 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 the battery cell 100, the electrode layer 110, the electrolyte layer 130, and the counter electrode layer 120 are stacked in this order along the z-axis direction.

[0066] The electrode layer 110 is one of the positive and negative electrode layers of the battery cell 100. The counter electrode layer 120 is the other of the positive and negative electrode layers of the battery cell 100. In the following explanation, we will describe the case where the electrode layer 110 is the negative electrode layer and the counter electrode layer 120 is the positive electrode layer as an example.

[0067] The electrode layer 110 is located on the main surface of the electrode current collector 140. 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.

[0068] 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.

[0069] Furthermore, as the material contained in the electrode layer 110, a solid electrolyte such as an inorganic solid electrolyte may be used. As the inorganic solid electrolyte, for example, a sulfide solid electrolyte or an oxide solid electrolyte may be used. As the sulfide solid electrolyte, for example, a mixture of lithium sulfide (Li2S) and phosphorus pentasulfide (P2S5) may be used. Furthermore, as the material contained in the electrode layer 110, a conductive agent such as acetylene black, or a binding binder such as polyvinylidene fluoride may be used.

[0070] The electrode layer 110 is produced by applying a paste-like coating, which is made by kneading the materials containing the electrode layer 110 together with a solvent, onto the main surface of, for example, an electrode current collector 140, and drying it. In order to increase the density of the electrode layer 110, the electrode current collector 140 (also called an electrode plate) to which the electrode layer 110 has been coated 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.

[0071] The counter electrode layer 120 is located on the main surface of the counter electrode current collector 150. 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.

[0072] 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.

[0073] 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.

[0074] The counter electrode layer 120 is produced by kneading the materials containing the counter electrode layer 120 together with a solvent to create a paste-like coating, which is then applied to the main surface of the counter electrode current collector 150, for example, and dried. To increase the density of the counter electrode layer 120, the counter electrode current collector 150 (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.

[0075] The electrolyte layer 130 is placed between the electrode layer 110 and the counter electrode layer 120. The electrolyte layer 130 is in contact with both the electrode layer 110 and the counter electrode layer 120. The electrolyte layer 130 has, for example, lithium ion conductivity. The 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 electrolyte layer 130 may be 5 μm or more and 300 μm or less, or 5 μm or more and 100 μm or less.

[0076] The electrolyte layer 130 includes, for example, a solid electrolyte. In this case, the power generation element 10 is, for example, an all-solid-state battery. As the solid electrolyte, for example, 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. In addition to the electrolyte material, the electrolyte layer 130 may also contain a binding binder such as polyvinylidene fluoride.

[0077] In this embodiment, the electrode layer 110, the counter electrode layer 120, and the electrolyte layer 130 are maintained in a parallel, flat plate shape. This suppresses the occurrence of cracks or collapse due to curvature. Alternatively, the electrode layer 110, the counter electrode layer 120, and the electrolyte layer 130 may be smoothly curved together.

[0078] The electrode current collector 140 and the counter electrode current collector 150 are each conductive foil-shaped, plate-shaped, or mesh-shaped members. The electrode current collector 140 and the counter electrode current collector 150 may each be, for example, a conductive thin film. In the example shown in Figure 1, the electrode current collector 140 and the counter electrode current collector 150 are each composed of a single metal foil. The electrode current collector 140 and the counter electrode current collector 150 may each have a multilayer structure of multiple current-collecting layers made of multiple metal foils or the like.

[0079] The electrode current collector 140 and the counter electrode current collector 150 can be made from materials such as stainless steel (SUS), aluminum (Al), copper (Cu), or nickel (Ni). The electrode current collector 140 and the counter electrode current collector 150 may be made from different materials.

[0080] The thickness of the electrode current collector 140 and the counter electrode current collector 150 is, for example, 5 μm to 200 μm, but is not limited to this.

[0081] The electrode layer 110 is in contact with the main surface of the electrode current collector 140. In the case of the electrode current collector 140 sandwiched between two battery cells 100, the electrode layer 110 is in contact with each of the two main surfaces. In the bottom electrode current collector 140, the electrode layer 110 is in contact with only one of the two main surfaces (specifically the top surface). The electrode current collector 140 may also include a connecting layer, which is a layer containing a conductive material, provided in the portion that is in contact with the electrode layer 110.

[0082] The main surface of the counter electrode current collector 150 is in contact with the counter electrode layer 120. In the case of the counter electrode current collector 150 sandwiched between two battery cells 100, the counter electrode layer 120 is in contact with each of the two main surfaces. In the uppermost counter electrode current collector 150, the counter electrode layer 120 is in contact with only one of the two main surfaces (specifically the bottom surface). The counter electrode current collector 150 may also include a connecting layer, which is a layer containing a conductive material, provided in the portion in contact with the counter electrode layer 120.

[0083] The outer casing 20 seals the power generation element 10 enclosed within it. The power generation element 10 is, for example, vacuum-sealed within the outer casing 20. Vacuum sealing reduces the amount of moisture inside the outer casing 20 and also reduces the thickness of the battery 1.

[0084] The outer casing 20 is made of laminate film. In the example shown in Figure 2, the outer casing 20 is made of two laminate films 21a and 21b that are positioned to sandwich the power generation element 10 from above and below.

[0085] The outer casing 20 is, for example, rectangular in plan view. In the example shown in Figure 1, in plan view, each rectangle of the power generation element 10 and the outer casing 20 has two sides parallel to the x-axis and opposite to each other, and two sides parallel to the y-axis and opposite to each other.

[0086] As shown in Figures 1 and 2, the exterior body 20 has an overlapping portion 30 formed by overlapping laminate films 21a and 21b. In a plan view, the overlapping portion 30 is positioned to surround the power generation element 10. In a plan view, the overlapping portion 30 extends outside the power generation element 10. In a plan view, the power generation element 10 is surrounded by the overlapping portion 30. A gap may also be formed between the power generation element 10 and the overlapping portion 30. In the overlapping portion 30, for example, the overlapping laminate films 21a and 21b are heat-sealed together. In Figure 2, the boundary between the overlapping laminate films 21a and 21b is shown by a solid line, but in reality, the boundary may not be visible due to heat sealing. This is also true for other cross-sectional views described later. Furthermore, the outer casing 20 is not limited to two laminate films 21a and 21b, but may also be a single laminate film folded, or a single bag-shaped laminate film. In this case, the overlapping portion 30 near the folded edges and edges other than the opening of the bag does not need to be heat-sealed, as this allows for sealing of the power generation element 10. Also, the overlapping portion 30 does not need to completely surround the power generation element 10. For example, the outer casing 20 may be made of a single laminate film, and on the negative side in the y-axis direction of the power generation element 10, this single laminate film may be folded back to cover the side surface 12.

[0087] Known laminate films can be used for laminate films 21a and 21b. Laminate films 21a and 21b have a laminated structure of a resin layer made of a thermoplastic resin such as polyethylene resin or polypropylene resin and a metal layer made of a metal such as aluminum. In the laminated structure, both ends in the lamination direction are made of resin layers, and the metal layer is arranged between the resin layers at both ends. Laminate films 21a and 21b have a three-layer structure in which a first resin layer, a metal layer, and a second resin layer are laminated in this order. The types of thermoplastic resin and metal used in laminate films 21a and 21b are not particularly limited. Note that the laminated structure of laminate films 21a and 21b is not shown in each figure.

[0088] The thickness of the laminate films 21a and 21b is, for example, 50 μm to 300 μm. The thickness of the metal layer in the laminate films 21a and 21b is, for example, 5 μm to 50 μm.

[0089] The overlapping portion 30 is located on the positive x-axis side, negative x-axis side, positive y-axis side, and negative y-axis side of the power generation element 10 in a plan view. The overlapping portion 30 is provided along all sides 11, 12, 13, and 14 of the power generation element 10 in a plan view. Furthermore, the portion of the overlapping portion 30 inside the folded portion 40 described below is parallel to, for example, the main surfaces 15 and 16 of the power generation element 10. In other words, the portion of the overlapping portion 30 adjacent to the power generation element 10 is a planar region parallel to the main surfaces 15 and 16 of the power generation element 10.

[0090] As shown in Figure 2, the portion of the overlapping portion 30 adjacent to the power generation element 10 is offset in the negative z-axis direction from the center of the power generation element 10 in the thickness direction of the power generation element 10. Alternatively, the portion of the overlapping portion 30 adjacent to the power generation element 10 may be offset in the positive z-axis direction from the center of the power generation element 10 in the thickness direction of the power generation element 10, or it may be located at the center of the power generation element 10.

[0091] The overlapping portion 30 has a folded portion 40 in plan view, which is the portion where the overlapping portions 30 overlap each other, because at the end of the overlapping portion 30 opposite to the power generation element 10, the end of the overlapping portion 30 opposite to the power generation element 10 is folded back toward the power generation element 10. In the folded portion 40, the portion of the overlapping portion 30 toward the tip of the folding position R overlaps with the portion of the overlapping portion 30 between the folding position R and the power generation element 10 in plan view. In the examples shown in Figures 1 and 2, the overlapping portion 30 is folded back only once in the folded portion 40, and the overlapping portion 30 is doubled. Also, in the folded portion 40, the overlapping portion 30 is folded back toward the power generation element 10 via the positive z-axis direction. Furthermore, at the end of the folded portion 40 opposite to the power generation element 10, that is, near the folding position R, the overlapping portion 30 is curved. In this specification, "folded back" means bent and turned, and is used to include curving when bending the overlapping portion 30, as shown in Figure 2. The folding position R is the end of the overlapping portion 30 on the turned side of the folded portion 40, that is, the part of the folded portion 40 furthest from the power generation element 10 in a plan view. The shape of the folded portion 40 is fixed by bonding the overlapping portions 30 together in the adhesive region 41, which will be described later. The formation of the folded portion 40 makes it possible to reduce the projected area (area in a plan view) of the battery 1. The width of the folded portion 40, that is, the length of the folded portion 40 in the direction of folding, is, for example, 1 mm or more and 10 mm or less. This makes it possible to achieve both adhesion between the overlapping portions 30 in the folded portion 40 and a small area of ​​the battery 1.

[0092] In the example shown in Figures 1 and 2, the overlapping portion 30 is provided with two folded portions 40 that sandwich the power generation element 10. The two folded portions 40 are located on the positive and negative sides in the x-axis direction of the power generation element 10. In other words, both ends of the overlapping portion 30 in the x-axis direction are folded portions 40. One of the two folded portions 40 faces the side surface 11 without passing through the power generation element 10, and the other of the two folded portions 40 faces the side surface 13 without passing through the power generation element 10. Each of the two folded portions 40 extends along the y-axis direction in a plan view, and the folded portions 40 are provided over the entire x-axis end of the overlapping portion 30. In a plan view, the two folded portions 40 are spaced apart from the power generation element 10 and do not overlap with the power generation element 10.

[0093] In the battery 1, the folded portion 40 is not provided on the positive y-axis side portion of the power generation element 10 in the superimposed portion 30 where the electrode lead 91 and counter electrode lead 92 are drawn out from the outer casing 20, nor on the negative y-axis side portion on the opposite side.

[0094] The folded portion 40 includes an adhesive region 41 and a non-adhesive region 42. In the example shown in Figure 1, in plan view, the adhesive region 41 and the non-adhesive region 42 extend along the y-axis.

[0095] The adhesive region 41 is the area in the folded portion 40 where the overlapping portions 30 that overlap in a plan view are bonded together on their inner surfaces. In the example shown in Figure 2, in the folded portion 40, the overlapping portions 30 are folded so that the laminate film 21a is on the inside of the laminate film 21a and 21b. Therefore, the inner surface of the overlapping portions 30 that overlap in a plan view in the adhesive region 41 is the surface of the laminate film 21a. Also, the inner surface of the overlapping portions 30 that overlap in a plan view is the upper surface of the overlapping portions 30 before folding. In the adhesive region 41, for example, the overlapping portions 30 that overlap in a plan view are bonded together by heat fusion. Therefore, in the adhesive region 41, the laminate films 21a and 21b are heat fused together in a quadruple layer. In the adhesive region 41, the overlapping portions 30 that overlap in a plan view may be bonded together using a method other than heat fusion, such as an adhesive.

[0096] In the examples shown in Figures 1 and 2, the overlapping portion 30 in the adhesive region 41 is parallel to the main surfaces 15 and 16 of the power generation element 10. Furthermore, in a plan view, the adhesive region 41 is formed over a certain range from the end of the folded portion 40 on the power generation element 10 side. Note that there may be areas in the folded portion 40 on the power generation element 10 side where the overlapping portions 30 are not bonded together.

[0097] The non-adhesive region 42 is the region in the folded portion 40 between the folding position R of the overlapping portion 30 in a plan view and the adhesive region 41, where the overlapping portions 30 in a plan view are not adhered to each other. The folding position R of the overlapping portion 30 in the folded portion 40 is located at the end of the folded portion 40 opposite to the power generation element 10 side. In the folded portion 40, the overlapping portion 30 is bent and folded in the non-adhesive region 42. By forming a region where the overlapping portions 30 in a plan view are not adhered to each other for a predetermined distance from the folding position R, damage to the metal layer in the laminate films 21a and 21b can be suppressed, and the reduction in the moisture-blocking effect of the outer casing 20 can be suppressed.

[0098] In the non-adhesive region 42, the overlapping portions 30 that overlap in a plan view are not in contact with each other. A gap 45 is formed between the overlapping portions 30 in the non-adhesive region 42 in a plan view. In the non-adhesive region 42 in a plan view, the overlapping portions 30 face each other in the thickness direction of the adhesive region 41, with the gap 45 in between. Therefore, the thickness of the non-adhesive region 42 is greater than the thickness of the adhesive region 41. These thicknesses are the lengths in the z-axis direction in Figure 2.

[0099] The gap 45 is the space enclosed by the inner surface of the overlapping portion 30 in the folded portion 40. In the example shown in Figures 1 and 2, the gap 45 is a through hole that extends along the y-axis direction, which is perpendicular to the direction in which the overlapping portion 30 is folded, and penetrates the folded portion 40, with openings of the gap 45 formed at both ends of the folded portion 40 in the y-axis direction.

[0100] The formation of a gap 45 in the non-adhesive region 42 allows for a larger bending radius of the overlapping portion 30 in the folded portion 40, further suppressing damage to the metal layers in the laminate films 21a and 21b. Furthermore, the gap 45 provides cushioning to the folded portion 40, mitigating mechanical external forces and protecting the power generation element 10 from them. Additionally, the folded portion 40 forms a pipe-like structure, increasing its mechanical strength against external forces that would bend the power generation element 10.

[0101] In the thickness direction of the adhesive region 41, the distance between opposing overlapping portions 30 separated by a gap 45 is, for example, 0.2 mm to 10 mm. Furthermore, the bending radius of the inner surface of the overlapping portion 30 in the folded portion 40 may be, for example, twice or more the thickness of a single laminate film 21a or 21b, or four times or more the thickness of a single laminate film 21a or 21b. Specifically, the bending radius of the inner surface of the overlapping portion 30 in the folded portion 40 may be, for example, 0.2 mm to 10 mm, 0.5 mm to 10 mm, or 2 mm to 10 mm. This further suppresses damage to the metal layer in the laminate films 21a and 21b in the folded portion 40.

[0102] The electrode lead 91 and the counter electrode lead 92 are extraction electrodes connected to the power generation element 10. The electrode lead 91 and the counter electrode lead 92 are each made of a conductive material such as metal. The electrode lead 91 is connected to the electrode current collector 140 on its main surface 16, for example. The counter electrode lead 92 is connected to the counter current collector 150 on its main surface 15, for example. The electrode lead 91 and the counter electrode lead 92 may be connected to the end face of the current collector, or they may be integrated with the current collector. For example, the electrode current collector 140 and the counter electrode current collector 150 may have a part that functions as a current collector and a part that functions as a lead.

[0103] Parts of the electrode leads 91 and counter electrode leads 92 are positioned inside the casing 20. The electrode leads 91 and counter electrode leads 92 are drawn out from the y-axis positive end of the casing 20 via an overlapping portion 30 located on the y-axis positive side of the power generation element 10. This allows the power generation element 10 to be charged and discharged from outside the casing 20.

[0104] The sleeve 93 is positioned between the electrode lead 91 and the outer casing 20, and between the counter electrode lead 92 and the outer casing 20, at the point where the electrode lead 91 and the counter electrode lead 92 are drawn out from the outer casing 20. The sleeve 93 is made of an insulating material that can be heat-sealed to both the electrode lead 91 and the counter electrode lead 92 and the outer casing 20. The placement of the sleeve 93 between the electrode lead 91 and the outer casing 20, and between the counter electrode lead 92 and the outer casing 20 ensures airtightness and insulation between the electrode lead 91 and the counter electrode lead 92 and the outer casing 20.

[0105] [Manufacturing method] Next, a method for manufacturing the battery 1 according to this embodiment will be described. Note that the manufacturing method described below is just one example, and the method for manufacturing the battery 1 according to this embodiment is not limited to the following example.

[0106] Figure 3 is a flowchart showing an example of a method for manufacturing the battery 1 according to this embodiment.

[0107] As shown in Figure 3, first, the power generation element 10 is prepared (step S10). For example, a unit cell having a battery cell 100 is prepared. Since the power generation element 10 has one battery cell 100, the unit cell can be used as is as the power generation element 10. If the power generation element 10 has multiple battery cells 100, the power generation element 10 is prepared by stacking the prepared unit cells. Figures 4A to 4C are cross-sectional views of an example of a unit cell, respectively.

[0108] As shown in Figure 4A, the unit cell 100a has one battery cell 100, an electrode current collector 140, and a counter electrode current collector 150. In the unit cell 100a, the battery cell 100 is positioned between the electrode current collector 140 and the counter electrode current collector 150, and the battery cell 100 is in contact with both the electrode current collector 140 and the counter electrode current collector 150. Specifically, the electrode layer 110 of the battery cell 100 is in contact with the electrode current collector 140, and the counter electrode layer 120 of the battery cell 100 is in contact with the counter electrode current collector 150. The unit cell 100a has the same configuration as the power generation element 10 described above.

[0109] Furthermore, as shown in Figure 4B, the unit cell 100b has one battery cell 100 and one electrode current collector 140. In the unit cell 100b, the electrode current collector 140 is positioned opposite the battery cell 100 on the electrode layer 110 side of the battery cell 100 and is in contact with the electrode layer 110. In the unit cell 100b, the main surface of the counter electrode layer 120 of the battery cell 100, opposite to the electrolyte layer 130 side, is exposed.

[0110] Furthermore, as shown in Figure 4C, a unit cell 100c has one battery cell 100 and one counter electrode current collector 150. In unit cell 100c, the counter electrode current collector 150 is positioned opposite the battery cell 100 on the counter electrode layer 120 side of the battery cell 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 battery cell 100, opposite to the electrolyte layer 130 side, is exposed.

[0111] When stacking unit cells, at least one of the above-mentioned unit cells 100a, 100b, and 100c is prepared in accordance with the stacking configuration of the power generation element in the battery 1 to be manufactured. Figure 5 is a cross-sectional view of a power generation element 10a having a plurality of battery cells 100 according to this embodiment. The battery 1 may have a power generation element 10a instead of a power generation element 10. Note that batteries according to each of the modifications and embodiments described later may also have a power generation element 10a.

[0112] The power generation element 10a is a stacked battery in which multiple battery cells 100 are stacked in series via bipolar current collectors 160. The power generation element 10a is, for example, an all-solid-state battery. When preparing the power generation element 10a, for example, one unit cell 100a and two unit cells 100b or 100c are prepared and stacked. The electrode current collectors 140 or counter electrode current collectors 150 sandwiched between the battery cells 100 function as bipolar current collectors 160. Alternatively, only unit cells 100a may be stacked. In this case, two current collectors are placed between the battery cells 100. Unit cells may also be stacked so that the battery cells 100 can be connected in parallel.

[0113] Next, electrode leads 91 and counter leads 92 are formed on the main surface of the power generation element 10 (step S20). First, the electrode leads 91 and counter leads 92 are prepared. Figure 6A is a top view of the electrode leads 91 and counter leads 92. Figure 6B is a side view of the electrode leads 91 and counter leads 92. As shown in Figures 6A and 6B, the electrode leads 91 and counter leads 92 are inserted into the sleeve 93. The electrode leads 91 inserted into the sleeve 93 are connected to the electrode current collector 140 on the main surface 16, and the counter leads 92 inserted into the sleeve 93 are connected to the counter current collector 150 on the main surface 15.

[0114] Next, the power generation element 10 is sealed with the outer casing 20 (step S30). Figure 7 is a top view of the battery 2 during the manufacturing process according to this embodiment.

[0115] As shown in Figure 7, for example, the power generation element 10, on which electrode leads 91 and counter electrode leads 92 are formed, is covered and sandwiched from both sides in the thickness direction of the power generation element 10 by two laminate films 21a and 21b that constitute the outer casing 20, and the laminate films 21a and 21b are overlapped at a position that surrounds the power generation element 10 in a plan view to form an overlapping portion 30. At this time, the tip ends of the electrode leads 91 and counter electrode leads 92 are exposed. Then, the power generation element 10 is sealed with the outer casing 20 by heat-sealing the laminate films 21a and 21b of the overlapping portion 30 together. As shown in Figure 7, the overlapping portion 30 is formed in all directions on the outside of the power generation element 10 in a plan view, such as the positive side in the x-axis direction, the negative side in the x-axis direction, the positive side in the y-axis direction, and the negative side in the y-axis direction. As a result, the power generation element 10 is completely surrounded by the overlapping portion 30 in a plan view. For example, the overlapping portions 30 on the positive x-axis side, negative x-axis side, positive y-axis side, and negative y-axis side of the power generation element 10 are sequentially heat-sealed with a sealer or the like. However, as described above, the overlapping portions 30 near the folded edges when the outer casing 20 is formed by folding a single laminate film, and near the edges other than the opening of the bag when it is formed from a single bag-shaped laminate film, do not need to be heat-sealed.

[0116] Furthermore, the sealing of the power generation element 10 by the outer casing 20 is performed in a reduced-pressure atmosphere, such as in a vacuum chamber. This seals the power generation element 10 to the outer casing 20 under reduced pressure. Note that when sealing the power generation element 10 under reduced pressure, it is not necessary to perform all sealing operations in a reduced-pressure atmosphere; it is sufficient for the operation to be performed in a reduced-pressure atmosphere at least when the thermal fusion of all overlapping portions 30 is completed, that is, when the path between the power generation element 10 and the outside environment within the outer casing 20 is completely blocked.

[0117] Furthermore, in forming the battery 2, a cup-shaped laminate film 21a may be used, which has a recess pre-formed in the area that overlaps with the power generation element 10 in a plan view. This reduces the stress on the corners of the power generation element 10, which would be significantly bent during sealing, thereby suppressing damage to the power generation element 10 or the laminate film 21a and reducing the risk of short circuits. Using a cup-shaped laminate film with a recess formed in the outer casing 20 is particularly effective when the thickness of the power generation element 10 is large, and may be applied to a stacked battery such as a power generation element 10a, for example.

[0118] The power generation element 10 is sealed by the outer casing 20, which suppresses the intrusion of moisture (water vapor) and other substances into the outer casing 20 that could cause deterioration of the power generation element 10. The laminate films 21a and 21b contain a metal layer, such as an aluminum layer, and therefore have a very high moisture-blocking effect in the thickness direction. On the other hand, in the direction perpendicular to the thickness direction of the laminate films 21a and 21b, moisture can penetrate into the outer casing 20 without going through the metal layer. For example, moisture can easily penetrate into the outer casing 20 from the edges of the laminate films 21a and 21b in the direction perpendicular to the thickness direction. In the battery 2, an overlapping portion 30 is formed so as to surround the power generation element 10, and a certain length is heat-sealed, which suppresses the intrusion of moisture from the edges of the outer casing 20. However, in the state of the battery 2, the projected area of ​​the outer casing 20 (i.e., the area in a plan view) is large, which is disadvantageous for miniaturization.

[0119] Next, the end of the overlapping portion 30 opposite to the power generation element 10 is folded back toward the power generation element 10 to form a folded portion 40, which is the part where the overlapping portions 30 overlap in a plan view (step S40). Then, by bonding a part of the overlapping overlapping portions 30 in the folded portion 40 in a plan view, a bonded area 41 and a non-bonded area 42 are formed in the folded portion 40 (step S50).

[0120] For example, using the dashed line shown in Figure 7 as the folding point, the portions on both sides of the power generation element 10 in the x-axis direction in the overlapping portion 30 are bent and curved, thereby folding back the region 50 of the overlapping portion 30 outside the dashed line toward the power generation element 10. At this time, as shown in Figures 1 and 2, the overlapping portion 30 is folded back once in the folding portion 40 so that the overlapping portions 30 come into contact with each other on their inner surfaces. Also, near the folding point R in the folding portion 40, the overlapping portions 30 are folded back so that they are separated from each other in a plan view, without completely folding them. Then, a region is secured at a predetermined distance from the folding point R in a plan view where the overlapping portions 30 are not adhered to each other in a plan view, and the overlapping portions 30 in the folding portion 40 are adhered to each other on their inner surfaces in a plan view. For example, the overlapping portions 30 are heat-fused together by thermocompression using a heater or the like. As a result, an adhesive region 41 and a non-adhesive region 42 are formed in the folded portion 40 as shown in Figures 1 and 2, fixing the shape of the folded portion 40. In addition, a gap 45 is formed between the overlapping portions 30 in the non-adhesive region 42 in a plan view. This results in the battery 1 shown in Figures 1 and 2.

[0121] In this way, the formation of the folded portion 40 reduces the projected area of ​​the outer casing 20 compared to the battery 2 before the formation of the folded portion 40. Specifically, the area of ​​region 50 is reduced. Therefore, by reducing the projected area of ​​the outer casing 20, which does not directly contribute to power generation, the area efficiency of the battery 1 can be improved. Furthermore, if the non-adhesive region 42 on the folding position R side of the folded portion 40 is bonded, large bending stresses and heat are applied to the laminate films 21a and 21b in the vicinity of the folding position R due to the bonding operation, which may damage the metal layers of the laminate films 21a and 21b. In particular, the metal layers of the laminate films 21a and 21b are usually very thin and therefore prone to damage. If the metal layers of the laminate films 21a and 21b are damaged in the vicinity of the folding position R, the moisture-blocking effect of the outer casing 20, which was enhanced by securing the width of the overlapping portion 30, will be significantly reduced. In battery 1, a non-adhesive region 42 is formed in the folded portion 40, thereby suppressing damage to the metal layer in the laminate films 21a and 21b, and preventing a decrease in the moisture-blocking effect of the outer casing 20. Therefore, it is possible to achieve both miniaturization and high reliability of battery 1 using the outer casing 20.

[0122] Furthermore, in the adhesive region 41, the overlapping portions 30 that overlap in a plan view of the folded portion 40 are bonded to each other on their inner surfaces, making it possible to form the folded portion 40 with the minimum number of folds.

[0123] Furthermore, in battery 1, the formation of a gap 45 in the non-adhesive region 42 allows for a larger bending radius of the overlapping portion 30 in the folded portion 40, further suppressing damage to the metal layers in the laminate films 21a and 21b.

[0124] [Example 1] Next, a battery according to Modification 1 of Embodiment 1 will be described. In the following, the differences from Embodiment 1 will be the main focus of the explanation, and the similarities will be omitted or simplified.

[0125] Figure 8 is a top view of the battery 1a according to this modified example. As shown in Figure 8, the battery 1a according to this modified example differs from the battery 1 according to Embodiment 1 in that the overlapping portion 30 further includes a folded portion 40a.

[0126] The folded portion 40a is the portion where the overlapping portions 30 overlap in a plan view, as the end of the overlapping portion 30 opposite to the power generation element 10 is folded back toward the power generation element 10 on the negative side in the y-axis direction of the power generation element 10. In the battery 1a, the negative end of the overlapping portion 30 in the y-axis direction is the folded portion 40a. The folded portion 40a faces the side surface 12 without passing through the power generation element 10. The folded portion 40a extends along the x-axis direction in a plan view, and the folded portion 40b is provided over the entire negative end of the overlapping portion 30 in the y-axis direction.

[0127] The folded portion 40a has the same configuration as the folded portion 40, except that it is located on the negative side in the y-axis direction of the power generation element 10. Specifically, similar to the folded portion 40, the folded portion 40a includes an adhesive region 41 and a non-adhesive region 42, and a gap 45 is formed between the overlapping portions 30 that overlap in a plan view in the non-adhesive region 42. In the folded portion 40a, in a plan view, the adhesive region 41 and the non-adhesive region 42 extend along the x-axis direction. In addition, in the folded portion 40a, the gap 45 is a through hole that extends along the x-axis direction and penetrates the folded portion 40a in a plan view, and openings of the gap 45 are formed at both ends of the folded portion 40a in the x-axis direction.

[0128] In battery 1a, the superimposed portion 30 includes not only the folded portion 40 but also the folded portion 40a, which further enhances the mechanical reliability of battery 1a. Furthermore, since the outer casing 20 is made even smaller, battery 1a can be made even more compact.

[0129] Battery 1a is manufactured, for example, via battery 2a in the process of being manufactured, as shown in Figure 9. Figure 9 is a top view of battery 2a in the process of being manufactured according to this modified example. Battery 2a is manufactured, for example, by forming notches 36 at two corners of the overlapping portion 30 on the negative side in the y-axis direction in a plan view of battery 2 shown in Figure 7. This makes it possible to form the folded portions 40 on both sides in the x-axis direction of the power generation element 10 and the folded portion 40a on the negative side in the y-axis direction so that they do not overlap with each other.

[0130] For example, using the dashed line shown in Figure 9 as the folding point, the portion of the overlapping portion 30 on the negative side in the y-axis direction of the power generation element 10 is bent and curved, thereby folding back the region 50a of the overlapping portion 30 outside the dashed line toward the power generation element 10. At this time, the overlapping portion 30 is folded back once so that the overlapping portions 30 contact each other on their inner surfaces at the folded portion 40a. Furthermore, near the folding point R in the folded portion 40a, the overlapping portions 30 are folded back so that they are separated from each other in a plan view, without completely folding them. Then, a region is secured at a predetermined distance from the folding point R in a plan view where the overlapping portions 30 are not adhered to each other in a plan view, and the overlapping portions 30 in the folded portion 40a are adhered to each other on their inner surfaces in a plan view. As a result, an adhered region 41 and a non-adhered region 42 are formed in the folded portion 40a as shown in Figure 8, and the shape of the folded portion 40a is fixed. Furthermore, a gap 45 is formed between the overlapping portions 30 in a plan view of the non-adhesive region 42. The folded portion 40 is formed in the same manner as in battery 1. This results in battery 1a shown in Figure 8.

[0131] As shown in Figures 8 and 9, the edges between two adjacent sides of the power generation element 10 (sides 11, 12, 13, and 14) may be chamfered. In other words, the corners of the power generation element 10 in plan view may be chamfered. This causes the corners of the power generation element 10 to recede inward in plan view, ensuring a sufficient distance between the notch 36 and the overlapping portion 30 between the power generation element 10. As a result, the intrusion of moisture into the exterior body 20 can be suppressed.

[0132] [Differentiation 2] Next, a battery relating to Modification 2 of Embodiment 1 will be described. In the following, the differences between Embodiment 1 and Modification 1 of Embodiment 1 will be explained, and the explanation of common points will be omitted or simplified.

[0133] Figure 10 is a top view of the battery 1b according to this modified example. Figure 11 is a cross-sectional view of the battery 1b according to this modified example. Figure 11 shows a cross-section along the line XI-XI shown in Figure 10. As shown in Figures 10 and 11, the battery 1b according to this modified example differs from the battery 1a according to Modification 1 of Embodiment 1 in that the overlapping portion 30 further includes a folded portion 40b.

[0134] The folded portion 40b is the portion where the overlapping portions 30 overlap in a plan view, as the end of the overlapping portion 30 opposite to the power generation element 10 on the positive side in the y-axis direction of the power generation element 10 is folded back toward the power generation element 10. In the battery 1b, the end of the overlapping portion 30 on the positive side in the y-axis direction is the folded portion 40b. The folded portion 40b faces the side surface 14 without passing through the power generation element 10. The folded portion 40b extends along the x-axis direction in a plan view, and the folded portion 40b is provided over the entire positive end of the overlapping portion 30 in the y-axis direction.

[0135] The folded portion 40b has the same configuration as the folded portion 40, except that it is located on the positive side in the y-axis direction of the power generation element 10. Specifically, similar to the folded portion 40, the folded portion 40b includes an adhesive region 41 and a non-adhesive region 42, and a gap 45 is formed between the overlapping portions 30 that overlap in a plan view in the non-adhesive region 42. In the folded portion 40b, in a plan view, the adhesive region 41 and the non-adhesive region 42 extend along the x-axis direction. In addition, in the folded portion 40b, the gap 45 is a through hole that extends along the x-axis direction and penetrates the folded portion 40b in a plan view, and openings of the gap 45 are formed at both ends of the folded portion 40b in the x-axis direction.

[0136] In battery 1b, the superimposed portion 30 includes a folded portion 40b in addition to the folded portions 40 and 40a, which further enhances the mechanical reliability of battery 1b. Furthermore, since the outer casing 20 is made even smaller, battery 1b can be made even smaller.

[0137] In battery 1b, the electrode lead 91 and the counter electrode lead 92 are drawn out from the outer casing 20 at the folded portion 40b. Also, at the folded portion 40b, the electrode lead 91 and the counter electrode lead 92 are folded back together with the overlapping portion 30. Therefore, in battery 1b, the drawn-out portions of the electrode lead 91 and the counter electrode lead 92 extend toward the negative side in the y-axis direction and overlap with the power generation element 10 in a plan view. In addition, the electrode lead 91 and the counter electrode lead 92 each overlap the outer casing 20 in a plan view.

[0138] Battery 1b is manufactured, for example, via battery 2b in the process of being manufactured, as shown in Figure 12. Figure 12 is a top view of battery 2b in the process of being manufactured according to this modified example. Battery 2b is manufactured, for example, by forming notches 36 at two corners of the overlapping portion 30 on the positive y-axis side in a plan view of battery 2a shown in Figure 9. This makes it possible to form the folded portions 40 on both sides in the x-axis direction of the power generation element 10 and the folded portion 40b on the positive y-axis side so that they do not overlap each other.

[0139] For example, using the dashed line shown in Figure 12 as the folding point, the portion of the overlapping portion 30 on the positive y-axis side of the power generation element 10 is bent and curved, thereby folding back the region 50b of the overlapping portion 30 outside the dashed line toward the power generation element 10. At this time, the overlapping portion 30 is folded back so that the overlapping portions 30 contact each other on their inner surfaces at the folded portion 40b. Also, near the folding point R at the folded portion 40b, the overlapping portions 30 are folded back so that they are separated from each other in a plan view, without completely folding them. Then, a region is secured at a predetermined distance from the folding point R in a plan view where the overlapping portions 30 are not adhered to each other in a plan view, and the overlapping portions 30 in the folded portion 40b are adhered to each other on their inner surfaces in a plan view. As a result, an adhered region 41 and a non-adhered region 42 are formed at the folded portion 40b as shown in Figure 10, and the shape of the folded portion 40b is fixed. Furthermore, a gap 45 is formed between the overlapping portions 30 in a plan view of the non-adhesive region 42. The folded portion 40 is formed in the same manner as in battery 1, and the folded portion 40a is formed in the same manner as in battery 1a. This results in battery 1b shown in Figures 10 and 11.

[0140] (Embodiment 2) Next, we will describe the battery according to Embodiment 2. In the following, we will focus on explaining the differences between Embodiment 1 and its various modifications, and will omit or simplify the explanation of the common points.

[0141] Figure 13 is a top view of the battery 201 according to this embodiment. As shown in Figure 13, the battery 201 according to this embodiment differs from the battery 1 according to Embodiment 1 in that it further includes a blocking member 60. The blocking member 60 is an example of a first member.

[0142] The closing member 60 is a member that closes a portion of the gap 45. At least a portion of the closing member 60 enters the gap 45 through the opening at the y-axis end of the folded portion 40 and closes the opening. As a result, the overlapping portions 30 facing each other across the gap 45 in the non-adhesive region 42 are held by the closing member 60, and the strength of the folded portion 40 can be increased.

[0143] In the example shown in Figure 13, two closing members 60 are provided at both ends of a single void 45 in the y-axis direction. As a result, the void 45 is sealed, with openings on both sides in the y-axis direction closed. This increases the repulsive force of the folded portion 40 against external forces, further improving the mechanical reliability of the battery 201.

[0144] Examples of materials that make up the closure member 60 include metals, ceramics, and resins, as well as composite materials containing two or more of these.

[0145] The method for manufacturing the battery 201 further includes, in addition to the method for manufacturing the battery 1 described above, the step of closing a portion of the gap 45 with a closing member 60. For example, the battery 201 is formed by closing the gap 45 with the closing member 60 in relation to the battery 1 described above. The closing member 60 may be bonded to the folded portion 40.

[0146] In the battery 201, battery 1 is further equipped with a sealing member 60, but battery 1a or 1b may also be further equipped with a sealing member 60. In this case, the gap 45 of the folded portion 40a or 40b may also be sealed by the sealing member 60.

[0147] (Embodiment 3) Next, the battery according to Embodiment 3 will be described. In the following, the differences between Embodiments 1 and 2 and the various modifications of Embodiment 1 will be explained, and the explanation of common points will be omitted or simplified.

[0148] Figure 14 is a top view of the battery 301 according to this embodiment, and Figure 15 is a cross-sectional view of the battery 301 according to this embodiment. Figure 15 shows a cross-section along the line XV-XV shown in Figure 14. As shown in Figures 14 and 15, the battery 301 according to this embodiment differs from the battery 1 according to Embodiment 1 in that it further includes a reinforcing member 70. The reinforcing member 70 is an example of a second member.

[0149] The reinforcing member 70 is positioned between the overlapping portions 30 that overlap in a plan view within the non-adhesive region 42. The upper and lower surfaces of the reinforcing member 70 are in contact with the overlapping portions 30, and the reinforcing member 70 holds the upper overlapping portion 30 in the non-adhesive region 42.

[0150] The reinforcing member 70 is, for example, a rod-shaped member extending in the same direction as the non-adhesive region 42. The reinforcing member 70 may also be a pipe-shaped member with a hollow formed in the center of the rod. The length of the reinforcing member 70 in the extending direction may be longer than the length of the power generation element 10 in that direction. By including the reinforcing member 70 in the battery 301, the folded portion 40 is reinforced by the reinforcing member 70, further increasing the mechanical reliability of the battery 301.

[0151] The reinforcing member 70 has higher rigidity than, for example, the exterior body 20. Examples of materials constituting the reinforcing member 70 include metal, ceramic, and resin, as well as composite materials containing two or more of these. The reinforcing member 70 includes, for example, at least one of metal and ceramic.

[0152] The method for manufacturing the battery 301 further includes, in addition to the method for manufacturing the battery 1 described above, the step of placing a reinforcing member 70 between overlapping portions 30 that overlap in a plan view in the non-adhesive region 42. For example, when forming the folded portion 40, the overlapping portion 30 is folded over so that the reinforcing member 70 is sandwiched between the overlapping portions 30. Alternatively, for example, after forming a gap 45 as in the battery 1, the reinforcing member 70 is inserted into the gap 45.

[0153] In the example shown in Figure 14, the battery 301 is configured such that the gap 45 in the battery 1 is completely filled by the reinforcing member 70. However, the reinforcing member 70 may be arranged so that a portion of the gap 45 in the battery 1 remains. In addition, in at least one of the folded portions 40, 40a, and 40b of the batteries 1a, 1b, or 201, at least a portion of the gap 45 may be filled by the reinforcing member 70.

[0154] (Other embodiments) Although one or more embodiments of batteries and methods for manufacturing batteries have been described above based on embodiments and modifications, this disclosure is not limited to these embodiments. Within the scope of this disclosure, various modifications that a person skilled in the art could conceive of are applied to these embodiments and modifications, as well as forms constructed by combining components from different embodiments and modifications, are also included without departing from the spirit of this disclosure.

[0155] For example, in the above embodiment, the power generation element 10 was an all-solid-state battery, but it is not limited to this. The power generation element 10 may also be a liquid battery containing an electrolyte and a separator.

[0156] Furthermore, for example, in the above embodiment, a gap 45 was formed in the non-adhesive region 42, but this is not limited to this. In the non-adhesive region 42, a gap 45 does not need to be formed as long as the overlapping portions 30 that overlap in a plan view are not adhered to each other, and the overlapping portions 30 that overlap in a plan view may be in contact with each other.

[0157] Furthermore, each of the above embodiments can be modified, replaced, added, or omitted in various ways within the scope of the claims or their equivalents. [Industrial applicability]

[0158] 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]

[0159] 1, 1a, 1b, 2, 2a, 2b, 201, 301 batteries 10, 10a power generation element 11, 12, 13, 14 Side view 15, 16 Main surface 20 Exterior 21a, 21b Laminating film 30 Overlapping portion 36 Notches 40, 40a, 40b Folded section 41 Adhesive area 42 Non-adhesive area 45 void 50, 50a, 50b area 60 Closure member 70 Reinforcement member 91 Electrode Leads 92 Opposite Lead 93 sleeves 100 battery cells 100a, 100b, 100c unit cells 110 Electrode layer 120 Counterpolar layer 130 Electrolyte layer 140 Electrode current collector 150 Counter-pole current collector 160 Bipolar Current Collector

Claims

1. Power generation elements, An outer casing made of laminate film that seals the power generation element, Equipped with, The exterior body is, In a plan view with respect to the main surface of the power generation element, the laminate film is positioned to surround the power generation element and has an overlapping portion where the laminate film is superimposed. The aforementioned superimposed portion is The end of the overlapping portion opposite to the power generation element side is folded back toward the power generation element side, so that in the plan view, the overlapping portions overlap, which is the folded portion. The aforementioned folded portion is, The plan view includes an adhesive region where the overlapping portions are bonded to each other on their inner surfaces, and a non-adhesive region between the folding position of the overlapping portions and the adhesive region in the plan view, where the overlapping portions are not bonded to each other. battery.

2. The power generation element is sealed under reduced pressure within the outer casing. The battery according to claim 1.

3. In the overlapping portion, the overlapping laminate films are heat-fused together. The battery according to claim 1.

4. In the aforementioned bonding region, the overlapping portions are bonded together by heat fusion. The battery according to claim 1.

5. A gap is formed between the overlapping portions that overlap in the plan view within the non-adherent region. The battery according to claim 1.

6. The system further comprises a first member that closes off a portion of the aforementioned gap. The battery according to claim 5.

7. The non-adhesive region further comprises a second member positioned between the overlapping portions that overlap in a plan view. The battery according to claim 1.

8. The second member includes at least one of metal and ceramic, The battery according to claim 7.

9. The aforementioned power generation element is an all-solid-state battery. The battery according to any one of claims 1 to 8.

10. The steps include: covering the power generation element with a laminate film, and sealing the power generation element with an outer casing made of the laminate film by overlapping the laminate film at a position that surrounds the power generation element in a plan view with respect to the main surface of the power generation element; The steps include: folding back the end of the overlapping portion opposite to the power generation element side toward the power generation element side to form a folded portion which is the part where the overlapping portions overlap in a plan view; The method includes the step of forming an adhesive region in the folded portion where the overlapping portions that overlap in a plan view are bonded to each other on their inner surfaces, and a non-adhesive region between the folded position of the overlapping portion in a plan view and the adhesive region, where the overlapping portions that overlap in a plan view are not bonded to each other. Battery manufacturing method.

11. In the step of sealing the power generation element, the overlapping laminate films of the overlapping portions are heat-fused together to seal the power generation element with the outer casing. A method for manufacturing a battery according to claim 10.

12. In the step of forming the adhesive region and the non-adhesive region, the adhesive region is formed by heat-fusing the overlapping portions together. A method for manufacturing a battery according to claim 10.

13. In the step of forming the adhesive region and the non-adhesive region, a gap is formed between the overlapping portions in the non-adhesive region that overlap in a plan view. A method for manufacturing a battery according to claim 10.

14. The step further includes closing a portion of the aforementioned gap with the first member. A method for manufacturing a battery according to claim 13.

15. The step further includes arranging a second member between the overlapping portions that overlap in the plan view within the non-adhesive region, A method for manufacturing a battery according to claim 10.

16. The aforementioned power generation element is an all-solid-state battery. A method for manufacturing a battery according to any one of claims 10 to 15.

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