Battery, method for producing battery, and device for producing battery

Abstract

A battery according to the present disclosure comprises: a current collector that has a first main surface and a second main surface which is on the opposite side from the first main surface; a first unit cell that is provided on the first main surface; and a second unit cell that is provided on the second main surface. The current collector has: a body part which is a portion sandwiched between the first unit cell and the second unit cell; and a protruding part which protrudes past a first side surface of the first unit cell and a second side surface of the second unit cell. When the thickness of a tip end of the protruding part is represented as t and the thickness of the body part is represented as T, the expression t<T is satisfied.

Description

Battery, battery manufacturing method, and battery manufacturing device

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

[0002] Patent Document 1 discloses a manufacturing method and a manufacturing device in which an upper mold including a blade portion is placed on a laminate placed on a mounting surface of a lower mold, and the laminate is divided between the upper mold and the lower mold. In the dividing step, the blade portion is brought close to the lower mold within a range where the blade portion does not pass through the lower mounting surface, thereby dividing the laminate.

[0003] Patent Document 2 discloses a manufacturing method and a manufacturing device in which the density of the active material is increased by pressing the coating portion with a press roller having a protruding portion, and the active material is cut in a state of increased density with a blade provided at the apex of the protruding portion.

[0004] JP 2023-163628 A JP 2018-026334 A

[0005] The pressing and cutting processes disclosed in Patent Documents 1 and 2 may cause the active material to slip off, burrs to form on the current collector, or cracks in the active material layer or the current collector, which may result in a short circuit between the positive and negative electrodes of the battery, thereby reducing the reliability of the battery.

[0006] Therefore, the present disclosure provides a highly reliable battery, a battery manufacturing method, and a battery manufacturing apparatus.

[0007] A battery according to one aspect of the present disclosure includes a current collector having a first main surface and a second main surface opposite the first main surface, a first unit cell provided on the first main surface, and a second unit cell provided on the second main surface, wherein the current collector has a main body portion sandwiched between the first unit cell and the second unit cell, and protrusions protruding beyond each of a first side surface of the first unit cell and a second side surface of the second unit cell, and wherein when a thickness of a tip of the protrusion is t and a thickness of the main body portion is T, the relationship t<T is satisfied.

[0008] A method for manufacturing a battery according to one aspect of the present disclosure includes the steps of: preparing a current collector having a first main surface on which first unit cells are provided and a second main surface on which second unit cells are provided, the second main surface being opposite the first main surface; and causing a first blade to bite into the current collector from the first main surface side and a second blade to bite into the current collector from the second main surface side without crossing each other.

[0009] A battery manufacturing apparatus according to one aspect of the present disclosure includes a control unit that controls the movement of a first blade and a second blade, and a holding unit for holding a current collector having a first main surface on which a first unit cell is provided and a second main surface on which a second unit cell is provided, the second main surface being opposite to the first main surface, and the control unit causes the first blade to bite into the current collector from the first main surface side and the second blade to bite into the current collector from the second main surface side without crossing each other.

[0010] According to the present disclosure, a highly reliable battery can be realized.

[0011] FIG. 1 is a plan view of a battery according to an embodiment. FIG. 2A is a cross-sectional view showing an example of a battery according to an embodiment. FIG. 2B is a cross-sectional view showing another example of a battery according to an embodiment. FIG. 3 is a flowchart showing an example of a method for manufacturing a battery according to an embodiment. FIG. 4 is a side view of a laminate used in manufacturing a battery according to an embodiment. FIG. 5A is a side view illustrating shearing in a method for manufacturing a battery according to a comparative example. FIG. 5B is a side view illustrating shearing in a method for manufacturing a battery according to a comparative example. FIG. 6 is a perspective view showing the state of a cut surface of a battery according to a comparative example. FIG. 7 is a side view showing the positional relationship between a laminate and two blades in a method for manufacturing a battery according to an embodiment. FIG. 8 is a cross-sectional view of a laminate in a state where two blades have bitten into a current collector in a method for manufacturing a battery according to an embodiment. FIG. 9 is a side view showing the movement of two blades in a cutting step according to an embodiment. FIG. 10 is a cross-sectional view showing the progress of shearing beyond the elastic limit of a current collector according to an embodiment. FIG. 11 is a perspective view of a laminate after cutting according to an embodiment. FIG. 12 is a cross-sectional view of the vicinity of a cut portion of an example of a battery according to an embodiment. FIG. 13 is a cross-sectional view of the vicinity of a cut portion of another example of a battery according to an embodiment. Fig. 14 is a flowchart showing a modified example of the manufacturing method of a battery according to the embodiment. Fig. 15 is a side view showing a modified example of the movement of two blades in the cutting step according to the embodiment. Fig. 16 is a cross-sectional view of a laminate in a state where two blades have bitten into a current collector according to Modification 1 of the embodiment. Fig. 17 is a cross-sectional view of the vicinity of the cut portion of an example of a battery according to Modification 1 of the embodiment. Fig. 18 is a cross-sectional view of a laminate in a state where two blades have bitten into a current collector according to Modification 2 of the embodiment. Fig. 19 is a cross-sectional view of the vicinity of the cut portion of an example of a battery according to Modification 2 of the embodiment. Fig. 20 is a side view of a manufacturing apparatus for a battery according to each embodiment and each modification.

[0012] (Findings that Form the Basis of the Present Disclosure) The shape of a battery can be formed by shearing using a die press, which is commonly used for metal plates and circuit boards, or by shearing using a guillotine or scissors method. However, in a laminate in which active material layers are formed on both sides of a current collector, problems such as slippage of the active material, burrs on the current collector, or cracks in the active material layer or current collector occur. For this reason, it is necessary to adjust at least one condition, such as the shape of the blade, such as the blade edge shape or blade inclination, or the way the blade is inserted into the workpiece to be cut, or the position control of the blade in the press mold.

[0013] Patent Document 1 describes that a typical press cutting method should be used, and that cutting should be performed within a range where the upper die does not pass through the lower die. However, it is inevitable that one of the upper and lower dies will pass through layers of opposite polarity, and when pressurized and sheared with a flat-surfaced cutting blade, fine powder between the opposite polarities and burrs on the current collector are generated. This can lead to short circuits between the positive and negative electrodes, which can impair the reliability of the battery.

[0014] In Patent Document 2, the cutting edges of the upper and lower blades rotate around a rotation axis that is parallel to the main surface of the electrode material to be cut. Because the cutting edges of the upper and lower blades trace a trajectory of oscillation relative to the electrode material, the pressure of the blades is applied to the edge of the electrode material after cutting, which may cause damage and cause the active material to collapse.

[0015] Therefore, the present disclosure provides a highly reliable battery, a battery manufacturing method, and a battery manufacturing apparatus.

[0016] A battery according to a first aspect of the present disclosure includes a current collector having a first main surface and a second main surface opposite to the first main surface, a first unit cell provided on the first main surface, and a second unit cell provided on the second main surface, wherein the current collector has a main body portion sandwiched between the first unit cell and the second unit cell, and protrusions protruding beyond each of a first side surface of the first unit cell and a second side surface of the second unit cell, and wherein when a thickness of a tip of the protrusion is t and a thickness of the main body portion is T, the relationship t<T is satisfied.

[0017] Such protrusions are formed by cutting the current collector with two blades until the current collector's elastic limit is exceeded, causing the current collector to tear. In other words, in the manufacture of a battery according to this embodiment, the two blades are not intersected, so the protrusions of the current collector are less likely to extend in a direction perpendicular to the main surface. This prevents burrs on the current collector from extending and contacting the active material layer, causing a short circuit. Furthermore, because the movement direction of the two blades can be perpendicular to the main surface, damage to the battery's edges can be reduced and active material collapse can be suppressed. This improves the reliability of the battery according to this embodiment.

[0018] A battery according to a second aspect of the present disclosure is a battery according to the first aspect, wherein the protrusion has a first inclined surface inclined with respect to the first main surface and a second inclined surface inclined with respect to the second main surface, and the distance between the first inclined surface and the second inclined surface becomes narrower as they approach the tip.

[0019] As a result, the amount of protrusion of the protrusions formed to be torn off is sufficiently small, making it possible to prevent the protrusions from coming into contact with the active material layer or the like and causing a short circuit.

[0020] A battery according to a third aspect of the present disclosure is a battery according to the second aspect, wherein the angle between a first direction perpendicular to the first main surface and the first side surface is smaller than the angle between the first direction and the first inclined surface, and the angle between the first direction and the second side surface is smaller than the angle between the first direction and the second inclined surface.

[0021] This reduces the amount of protrusion of the protrusions, so that even if the protrusions are bent, they are less likely to come into contact with the active material layer, making it possible to suppress the occurrence of short circuits.

[0022] A battery according to a fourth aspect of the present disclosure is the battery according to any one of the first to third aspects, wherein the first unit cell has a first protrusion protruding from a main surface opposite to a main surface facing the first main surface, the second unit cell has a second protrusion protruding from a main surface opposite to a main surface facing the second main surface, the first protrusion being provided along the first side surface, and the second protrusion being provided along the second side surface.

[0023] This allows the reliability of the battery to be improved, as with the batteries according to other embodiments.

[0024] 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 the length of the protrusion on a line passing through the position on the first side closest to the current collector and perpendicular to the first main surface is shorter than the thickness of the main body portion.

[0025] This reduces the thickness of the protrusions from their bases, reducing the amount of protrusion. Therefore, even if the protrusions are bent, they are less likely to come into contact with the active material layer, thereby preventing the occurrence of short circuits.

[0026] A battery according to a sixth aspect of the present disclosure is the battery according to the fifth aspect, further comprising: a first conductive adhesive layer provided on the first main surface and adhering the first main surface to the first unit cell; and a second conductive adhesive layer provided on the second main surface and adhering the second main surface to the second unit cell, wherein at least one of the first conductive adhesive layer and the second conductive adhesive layer is spaced apart from the current collector on a line that passes through a position on the first side surface closest to the current collector and is perpendicular to the first main surface.

[0027] This makes it possible to improve the bonding strength between the first unit cell and the current collector, and between the second unit cell and the current collector, by the first conductive adhesive layer and the second conductive adhesive layer.

[0028] A battery according to a seventh aspect of the present disclosure is the battery according to the fifth aspect, further comprising: a first conductive adhesive layer provided on the first main surface and adhering the first main surface to the first unit cell; and a second conductive adhesive layer provided on the second main surface and adhering the second main surface to the second unit cell, wherein the first unit cell and the first conductive adhesive layer are spaced apart and / or the second unit cell and the second conductive adhesive layer are spaced apart on a line that passes through a position of the first side surface closest to the current collector and is perpendicular to the first main surface.

[0029] This makes it possible to improve the adhesion between the first unit cell and the current collector, and between the second unit cell and the current collector, by the first conductive adhesive layer and the second conductive adhesive layer.

[0030] A method for manufacturing a battery according to an eighth aspect of the present disclosure includes the steps of: preparing a laminate including a current collector having a first main surface and a second main surface opposite the first main surface, a first unit cell provided on the first main surface, and a second unit cell provided on the second main surface; and causing a first blade and a second blade to bite into the current collector from the first main surface side and the second main surface side, respectively, without crossing each other.

[0031] As a result, by causing the first blade and the second blade to bite into the current collector, the current collector will tear if the elastic limit of the current collector is exceeded. This makes it possible to manufacture a battery of a predetermined shape. In the battery manufacturing method according to this aspect, the first blade and the second blade do not cross, so the protrusions of the current collector are less likely to extend in a direction perpendicular to the main surface. In other words, it is possible to prevent burrs on the current collector from extending and contacting the active material layer, etc., resulting in a short circuit. Furthermore, because the movement direction of the first blade and the second blade can be made perpendicular to the main surface, damage to the edge of the battery can be reduced and the collapse of the active material can be suppressed. This makes it possible to manufacture a highly reliable battery.

[0032] A battery manufacturing method according to a ninth aspect of the present disclosure is the battery manufacturing method according to the eighth aspect, further including a step of moving the first blade and the second blade that have dug into the current collector in a direction parallel to the first main surface and perpendicular to the direction in which each blade tip extends.

[0033] This makes it easier to tear the current collector. For example, the closest distance between the first blade and the second blade can be increased, which can prevent the first blade and the second blade from coming into contact with each other and causing damage. In addition, the protrusions tend to protrude parallel to the main surface of the current collector, which can further reduce the possibility of the protrusions coming into contact with the active material layer or the like and causing a short circuit.

[0034] A battery manufacturing method according to a tenth aspect of the present disclosure is a battery manufacturing method according to the eighth aspect, wherein in the biting step, the first blade and the second blade are bitten into the current collector until the current collector is torn.

[0035] This allows the current collector to be torn at a predetermined position by bringing the first blade and the second blade close to each other, which reduces the amount of protrusion compared to when the first blade and the second blade are moved in a direction parallel to the main surface of the current collector, thereby improving the reliability of the battery.

[0036] A battery manufacturing method according to an eleventh aspect of the present disclosure is a battery manufacturing method according to any one of the eighth to tenth aspects, wherein in the biting step, the first blade and the second blade are moved from a state in which their cutting edges are facing each other in a direction in which their cutting edges approach each other, thereby biting into the current collector.

[0037] By aligning the blade edges so that they face each other, the position at which the current collector is torn can be stabilized, the amount of protrusion can be reduced, and the reliability of the battery can be improved.

[0038] A battery manufacturing apparatus according to a twelfth aspect of the present disclosure includes a control unit that controls the movement of a first blade and a second blade; and a holding unit that holds a stack including a current collector having a first main surface and a second main surface opposite the first main surface, a first unit cell provided on the first main surface, and a second unit cell provided on the second main surface, wherein the control unit causes the first blade to bite into the current collector from the first main surface side and the second blade to bite into the current collector from the second main surface side without crossing each other.

[0039] As a result, by causing the first blade and the second blade to bite into the current collector, the current collector will tear if the elastic limit of the current collector is exceeded. This makes it possible to manufacture batteries of a predetermined shape. In the battery manufacturing apparatus according to this embodiment, the first blade and the second blade do not cross, so protrusions on the current collector are less likely to extend in a direction perpendicular to the main surface. In other words, it is possible to prevent burrs on the current collector from extending and contacting the active material layer, etc., resulting in a short circuit. Furthermore, because the movement direction of the first blade and the second blade can be made perpendicular to the main surface, damage to the edge of the battery can be reduced and the collapse of the active material can be suppressed. This makes it possible to manufacture highly reliable batteries.

[0040] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0041] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not described in the independent claims are described as optional components.

[0042] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0043] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel or perpendicular, terms indicating the shape of elements, such as quadrilateral or trapezoidal, and numerical ranges are not expressions that express only the strict meaning, but also expressions that include a substantially equivalent range, for example, a difference of about a few percent. For example, the corners of a polygon such as a quadrilateral or trapezoid may be rounded or may have a chamfered shape.

[0044] In this specification and drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional Cartesian coordinate system. In each embodiment, the z-axis direction is the stacking direction of the layers constituting the battery. When the planar shape of the battery or laminate is rectangular, the y-axis direction is the direction parallel to one side of the rectangular shape. In this specification, the positive side of the z-axis may be considered to be "upward" and the negative side of the z-axis may be considered to be "downward."

[0045] Furthermore, in this specification, the terms "above" and "below" do not refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in a stacked configuration. Furthermore, the terms "above" and "below" are applied not only to a case where two components are arranged with a gap between them and another component exists between the two components, but also to a case where two components are arranged closely together and the two components are in contact with each other.

[0046] In this specification, unless otherwise specified, "plan view" refers to a view from a direction perpendicular to the main surface of the current collector (z-axis direction). In the case of a flat member such as a plate, layer, foil, or film, the "main surface" refers to the main surface of the member, for example, the surface with the largest area or the surface opposite to the surface with the largest area. The main surface is usually flat, but may include minute irregularities or curvatures.

[0047] Furthermore, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing between components of the same type.

[0048] (Embodiment) [Configuration] First, the configuration of a battery according to an embodiment will be described with reference to Figures 1, 2A, and 2B. Figure 1 is a plan view of a battery 10 according to the present embodiment. Figures 2A and 2B are cross-sectional views showing an example of a battery 10 according to the present embodiment. Figures 2A and 2B each show a cross section taken along line II-II in Figure 1.

[0049] 2A and 2B are both batteries 10 including a current collector 150, unit cells 101 and 102, and conductive adhesive layers 141 and 142. The unit cells 101 and 102 each include an electrode active material layer 110, a counter electrode active material layer 120, and a solid electrolyte layer 130. The solid electrolyte layer 130 is located between the electrode active material layer 110 and the counter electrode active material layer 120.

[0050] The counter electrode active material layer 120 is an active material layer having a polarity different from that of the electrode active material layer 110. For example, the electrode active material layer 110 is a negative electrode active material layer containing a negative electrode active material, and the counter electrode active material layer 120 is a positive electrode active material layer containing a positive electrode active material. Note that the electrode active material layer 110 may be a positive electrode active material layer containing a positive electrode active material, and the counter electrode active material layer 120 may be a negative electrode active material layer containing a negative electrode active material.

[0051] The orientation of the unit cells 102 provided on the main surface 150b of the current collector 150 is different between the battery 10A and the battery 10B.

[0052] In the battery 10A, electrode active material layers 110 of the same polarity are provided on both main surfaces of the current collector 150. Specifically, the electrode active material layer 110 of the unit cell 101 is disposed on the main surface 150a of the current collector 150 via a conductive adhesive layer 141. The electrode active material layer 110 of the unit cell 102 is disposed on the main surface 150b of the current collector 150 via a conductive adhesive layer 142. By electrically connecting the counter electrode active material layer 120 of the unit cell 101 and the counter electrode active material layer 120 of the unit cell 102, the two unit cells 101 and 102 can be electrically connected in parallel. For example, a current collector (not shown) is disposed on each of the main surface 101a of the unit cell 101 and the main surface 102a of the unit cell 102, and the two current collectors (counter electrode current collectors) are electrically connected to each other. This allows the two unit cells 101 and 102 to be connected in parallel between the counter electrode current collector and the current collector 150 (electrode current collector).

[0053] In the battery 10B, active material layers of opposite polarity are provided on both main surfaces of the current collector 150. Specifically, the electrode active material layer 110 of the unit cell 101 is disposed on the main surface 150a of the current collector 150 via a conductive adhesive layer 141. The counter electrode active material layer 120 of the unit cell 102 is disposed on the main surface 150b of the current collector 150 via a conductive adhesive layer 142. The current collector 150 is a so-called bipolar current collector, and in the battery 10B, the two unit cells 101 and 102 can be electrically connected in series. For example, a counter electrode current collector (not shown) is disposed on the main surface 101a of the unit cell 101, and an electrode current collector (not shown) is disposed on the main surface 102a of the unit cell 102. The series connection of the two unit cells 101 and 102 is realized between the counter electrode current collector and the electrode current collector.

[0054] The following description will focus on the configuration of battery 10A. When there is no need to distinguish between battery 10A and battery 10B, such as when describing a configuration common to both batteries 10A and 10B, the description will be made as battery 10. In addition, in Figures 2A and 2B and other cross-sectional views and side views described below, the thickness of each layer is mainly exaggerated and does not necessarily represent an accurate relationship in size.

[0055] As shown in FIG. 1 , the battery 10 is, for example, a rectangular plate-like battery in a planar view. The battery 10 is an all-solid-state battery that does not contain a liquid electrolyte. A side surface corresponding to at least one side of the battery 10 in a planar view corresponds to a cut surface cut using two blades. Details of the cut surface will be described later using FIG. 12 and the like. In this embodiment, the side surfaces corresponding to at least two sides of the battery 10 in a planar view (the positive and negative sides of the x-axis) are the cut surfaces. Alternatively, all of the side surfaces corresponding to the four sides of the battery 10 may be cut surfaces. Note that FIG. 1 omits illustration of the slope of the side surface, protrusions 152, and the like.

[0056] The unit cell 101 is an example of a first unit cell and is provided on the main surface 150a of the current collector 150. The unit cell 102 is an example of a second unit cell and is provided on the main surface 150b of the current collector 150. The unit cells 101 and 102 have substantially the same layer configuration. Specifically, the unit cells 101 and 102 each include an electrode active material layer 110, a counter electrode active material layer 120, and a solid electrolyte layer 130. The electrode active material layer 110, the counter electrode active material layer 120, and the solid electrolyte layer 130 are maintained in a parallel plate shape. Note that in the battery 10A, the order of layers when traced along the positive direction of the z axis is different between the unit cells 101 and 102. On the other hand, in the battery 10B, the order of layers when traced along the positive direction of the z axis is the same between the unit cells 101 and 102.

[0057] The electrode active material layer 110 includes, for example, a negative electrode active material as an electrode material. Examples of the negative electrode active material included in the electrode active material layer 110 include graphite and metallic lithium. Various materials capable of extracting and inserting ions such as lithium (Li) or magnesium (Mg) can be used as the negative electrode active material.

[0058] Furthermore, as a material contained in the electrode active material layer 110, for example, 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, lithium sulfide (Li ２ S) and diphosphorus pentasulfide (P２ S ５ The electrode active material layer 110 may contain a conductive material such as acetylene black, or a binder such as polyvinylidene fluoride.

[0059] The thickness of the electrode active material layer 110 is, for example, not less than 5 μm and not more than 300 μm, but is not limited to this.

[0060] The counter electrode active material layer 120 includes, for example, a positive electrode active material as a counter electrode material. Examples of the positive electrode active material contained in the counter electrode active material layer 120 include lithium cobalt oxide composite oxide (LCO), lithium nickel oxide composite oxide (LNO), lithium manganese oxide composite oxide (LMO), lithium-manganese-nickel composite oxide (LMNO), lithium-manganese-cobalt composite oxide (LMCO), lithium-nickel-cobalt composite oxide (LNCO), and lithium-nickel-manganese-cobalt composite oxide (LNMCO). Various materials capable of extracting and inserting ions such as Li or Mg can be used as the positive electrode active material.

[0061] Furthermore, as a material contained in the counter electrode active material layer 120, for example, a solid electrolyte such as an inorganic solid electrolyte may be used. As the inorganic solid electrolyte, a sulfide solid electrolyte or an oxide solid electrolyte may be used. As the sulfide solid electrolyte, for example, Li ２ S and P ２ S ５ A mixture of these materials may be used. The surface of the positive electrode active material may be coated with a solid electrolyte. The counter electrode active material layer 120 may contain a conductive material such as acetylene black or a binder such as polyvinylidene fluoride.

[0062] The thickness of the counter electrode active material layer 120 is, for example, not less than 5 μm and not more than 300 μm, but is not limited to this.

[0063] The solid electrolyte layer 130 is located between the electrode active material layer 110 and the counter electrode active material layer 120. The solid electrolyte layer 130 is in surface contact with each of the electrode active material layer 110 and the counter electrode active material layer 120. The solid electrolyte layer 130 is a layer containing an electrolyte material. A generally known solid electrolyte for batteries can be used as the electrolyte material. The thickness of the solid electrolyte layer 130 may be, for example, 5 μm or more and 300 μm or less, or 5 μm or more and 100 μm or less.

[0064] As the solid electrolyte, for example, a solid electrolyte such as an inorganic solid electrolyte can be used. As the inorganic solid electrolyte, a sulfide solid electrolyte or an oxide solid electrolyte can be used. As the sulfide solid electrolyte, for example, Li ２ S and P ２ S ５ The solid electrolyte layer 130 may contain, in addition to the electrolyte material, a binder such as polyvinylidene fluoride.

[0065] The current collector 150 is a conductive foil-, plate-, or mesh-like member. The current collector 150 may be, for example, a conductive thin film. Examples of materials that can be used to form the current collector 150 include metals such as stainless steel (SUS), aluminum (Al), copper (Cu), and nickel (Ni). The thickness of the current collector 150 is, for example, 5 μm or more and 100 μm or less, but is not limited to this.

[0066] The current collector 150 has main surfaces 150a and 150b. The main surface 150a is an example of a first main surface. The main surface 150b is an example of a second main surface opposite to the first main surface. As shown in FIG. 2A , the current collector 150 includes a main body portion 151 and protrusions 152.

[0067] The main body 151 is a portion sandwiched between the unit cells 101 and 102. Specifically, the main body 151 is a portion of the current collector 150 that overlaps both the unit cells 101 and 102 in a plan view. The protrusions 152 are portions that protrude beyond the side surface 101 b of the unit cell 101 and the side surface 102 b of the unit cell 102. The specific configurations of the main body 151 and the protrusions 152 will be described later.

[0068] The conductive adhesive layer 141 is an example of a first conductive adhesive layer and is provided on the main surface 150a of the current collector 150 to bond the main surface 150a to the unit cell 101. The conductive adhesive layer 141 is, for example, a layer made of conductive carbon, but is not limited to this. Alternatively, the unit cell 101 may be in contact with the main surface 150a without providing the conductive adhesive layer 141.

[0069] The conductive adhesive layer 142 is an example of a second conductive adhesive layer and is provided on the main surface 150b of the current collector 150 to bond the main surface 150b to the unit cell 102. The conductive adhesive layer 142 is, for example, a layer made of conductive carbon, but is not limited to this. Alternatively, the unit cell 102 may be in contact with the main surface 150b without providing the conductive adhesive layer 142.

[0070] [Manufacturing Method] Next, a manufacturing method for the battery 10 according to the present embodiment will be described in comparison with a conventional manufacturing method.

[0071] Fig. 3 is a flowchart showing a method for manufacturing the battery 10 according to this embodiment. Fig. 4 is a side view of the laminate 100 used in manufacturing the battery 10 according to this embodiment.

[0072] 3, first, the laminate 100 shown in Fig. 4 is prepared (S10), i.e., a current collector 150 having a main surface 150a on which unit cells 101 are provided and a main surface 150b on which unit cells 102 are provided. The method for forming the laminate 100 is not particularly limited, but may be, for example, as follows.

[0073] First, conductive carbon paste is applied onto each of the main surfaces 150 a and 150 b of the current collector 150 to form the conductive adhesive layers 141 and 142 .

[0074] Next, a paste-like paint in which the materials contained in the electrode active material layer 110 are kneaded together with a solvent is applied to the upper surface of the conductive adhesive layer 141 and the lower surface of the conductive adhesive layer 142, and then dried, thereby producing the electrode active material layers 110 on both surfaces of the current collector 150. In order to increase the density of the electrode active material layer 110, the laminate including the electrode active material layer 110 and the current collector 150 may be pressed after drying. Note that if the conductive adhesive layers 141 and 142 are not provided, the paste-like paint may be applied directly to the main surfaces 150a and 150b of the current collector 150.

[0075] Next, a paste-like paint in which the materials contained in the solid electrolyte layer 130 are kneaded together with a solvent is applied to each of the main surfaces of the two electrode active material layers 110 and dried to produce the solid electrolyte layer 130. In order to increase the density of the solid electrolyte layer 130, the laminate including the solid electrolyte layer 130 may be pressed after drying.

[0076] Next, a paste-like paint in which the materials contained in the counter electrode active material layer 120 are kneaded together with a solvent is applied to each main surface of the two solid electrolyte layers 130 and dried to produce the counter electrode active material layer 120. In order to increase the density of the counter electrode active material layer 120, the laminate 100 including the counter electrode active material layer 120 may be pressed after drying.

[0077] In this manner, the laminate 100 shown in Fig. 4 is formed. In the laminate 100, the edges are formed in a stepped shape, but at least some of the edges of the layers may be flush. Alternatively, one layer may be formed to cover another layer, such as the solid electrolyte layer 130 covering the edge of the electrode active material layer 110.

[0078] The laminate 100 shown in Fig. 4 is used to manufacture the battery 10A shown in Fig. 2A. When manufacturing the battery 10B shown in Fig. 2B, a laminate can be prepared in which the electrode active material layer 110 and the counter electrode active material layer 120 of the unit cell 102 are interchanged by changing the application order of the paste-like paint for forming the unit cell 102.

[0079] Next, as shown in FIG. 3 , the prepared laminate 100 is cut (S12). Specifically, the laminate 100 is cut by cutting two blades into the current collector 150 without crossing each other. This allows unnecessary portions of the edge of the laminate 100 to be removed, and the battery 10 shown in FIGS. 1 and 2A can be manufactured. Cutting is performed in one to four locations. When cutting in two or more locations, the cuts may be performed simultaneously or sequentially. For example, simultaneous cutting in multiple locations can be performed using an L-shaped or annular blade.

[0080] A conventional cutting method will be described below with reference to Figures 5A and 5B, which are side views illustrating the shearing process in the battery manufacturing method according to the comparative example.

[0081] As shown in FIG. 5A , blades 201x and 202x are used to cut (shear) the laminate 100. The blades 201x and 202x do not have sharp cutting edges. With the lower blade 202x fixed, the laminate 100 is placed on the upper surface of the blade 202x. The laminate 100 is fixed by a jig (not shown) or the like with its lower surface (specifically, the lower surface of the counter electrode active material layer 120 of the unit cell 102) in contact with the upper surface of the blade 202x. In this state, the upper blade 201x is moved downward to shear the laminate 100, as shown in FIG. 5B .

[0082] The blade 201x moves downward so as to penetrate the laminate 100 until the bottom surface of the blade 201x is positioned below the top surface of the blade 202x. That is, in conventional shearing, the cutting edges of the blades 201x and 202x intersect. For this reason, the blades 201x and 202x are usually arranged so as to leave a minute gap 203x to prevent them from colliding. That is, the cutting edges of the blades 201x and 202x are not opposed to each other, but are offset by the gap 203x. The width of the gap 203x is, for example, 5 μm or less. If the gap 203x is too large, proper shearing cannot be performed, and cracks or collapse are likely to occur at the edge of the battery.

[0083] When the gap 203x is narrowed, a portion of the current collector 150 becomes a burr, stretched downward by the blade 201x. The burr is stretched while biting into the cut surface by the blade 201x. For example, when the thickness of the current collector 150 is 15 μm, the length of the burr may exceed 50 μm. The burr that has bitten into the cut surface cannot be easily removed due to its adhesion to the cut surface. Furthermore, the electrode active material layer 110, the counter electrode active material layer 120, and the solid electrolyte layer 130 are crushed, turning into material powder of the battery components at the cut surface.

[0084] FIG. 6 is a perspective view showing the state of a cut surface of a battery according to a comparative example. FIG. 6 schematically illustrates the material powder 110x of the electrode active material layer 110, the material powder 120x of the counter electrode active material layer 120, the material powder 130x of the solid electrolyte layer 130, and the burr 150x of the current collector 150. If the burr 150x is stretched until it contacts the counter electrode active material layer 120, the current collector 150 and the counter electrode active material layer 120 will be electrically connected and short-circuited. Furthermore, because the material powders 110x and 130x are conductive, they will blend into the cut surface of adjacent layers, electrically connect, and short-circuit. Thus, tiny short-circuit paths will be formed at the cut surface, which can reduce the reliability of the battery.

[0085] In contrast, in the manufacturing method of battery 10 according to the present embodiment, as shown in step S12 of Fig. 3, two blades are inserted into current collector 150 without crossing each other, thereby cutting current collector 150 to shreds. This makes it possible to shorten the length of burrs 150x extending in the z-axis direction.

[0086] Fig. 7 is a side view showing the positional relationship between the laminate 100 and two blades 201 and 202 in the manufacturing method of the battery 10 according to the present embodiment. Fig. 8 is a cross-sectional view of the laminate 100 in a state where the two blades 201 and 202 have bitten into the current collector 150 in the manufacturing method of the battery 10 according to the present embodiment. Fig. 8 shows a state in which the cutting edges 201a and 202a of the blades 201 and 202 are closest to each other in the cutting step.

[0087] Blade 201 is an example of a first blade, and blade 202 is an example of a second blade. As shown in FIG. 7 , blades 201 and 202 each have a double-edged shape. Cutting edges 201a and 202a are each sufficiently sharp, but are rounded or slightly flattened to a degree that prevents chipping. Cutting edges 201a and 202a extend parallel to main surfaces 150a and 150b of current collector 150, respectively (specifically, in the y-axis direction). The length of cutting edges 201a and 202a in the y-axis direction is longer than the length of laminate 100 in the y-axis direction. The inclination of blade surfaces 201b and 202b relative to the z-axis direction is, but is not limited to, an angle of 20° to 50°.

[0088] Fig. 9 is a side view showing the movement of two blades 201 and 202 in the cutting step according to the present embodiment. In Fig. 9, the laminate 100 is not shown, and the main surfaces 150a and 150b of the current collector 150 are indicated by dashed lines. (a), (b), and (c) of Fig. 9 show the states of the laminate 100 before, during, and after cutting, respectively.

[0089] As shown in (a) of FIG. 9 and FIG. 7, the blades 201 and 202 are arranged with their cutting edges 201a and 202a facing each other. The dashed line shown in FIG. 7 is a straight line connecting the cutting edge 201a of the blade 201 and the cutting edge 202a of the blade 202, and coincides with the stacking direction of the laminate 100 (i.e., the z-axis direction). The straight line connecting the cutting edges 201a and 202a coincides with the movement direction of the blades 201 and 202. The distance d between the cutting edges 201a and 202a is longer than the thickness of the laminate 100. The blades 201 and 202 are arranged so that the distance between the cutting edge 201a of the blade 201 and the main surface 150a and the distance between the cutting edge 202a of the blade 202 and the main surface 150b are equal to each other.

[0090] As shown in (b) of FIG. 9, the blades 201 and 202 are moved from a state in which the cutting edges 201a and 202a face each other in a direction in which the cutting edges 201a and 202a approach each other. Specifically, the blades 201 and 202 are moved toward each other along the dashed lines shown in FIG. 7. The blade 201 moves in the negative direction of the z-axis, and the blade 202 moves in the positive direction of the z-axis. At this time, the blades 201 and 202 move at the same speed. This ensures that the timing at which the cutting edge 201a of the blade 201 reaches the main surface 150a is the same as the timing at which the cutting edge 202a of the blade 202 reaches the main surface 150b.

[0091] Even after the cutting edges 201a and 202a reach the main surfaces 150a and 150b, the knives 201 and 202 continue to move in the z-axis direction until the distance d between the cutting edges 201a and 202a becomes shorter than the thickness T of the current collector 150, as shown in (c) of FIG. 9 . As a result, as shown in FIG. 8 , the knives 201 and 202 bite into the current collector 150 from the main surface 150a side and the main surface 150b side, respectively. At this time, the knives 201 and 202 do not intersect with each other. That is, the distance d between the cutting edge 201a of the knives 201 and the cutting edge 202a of the knives 202 remains equal to or greater than 0 and equal to or less than the thickness T of the current collector 150. For example, the minimum value of the distance d is equal to or greater than 3 μm and equal to or less than 5 μm. The minimum value of the distance d may be equal to or greater than 30% and equal to or less than 40% of the thickness T of the current collector 150. The upper limit of the range of the minimum value of the distance d is the value at which the current collector 150 exceeds its elastic limit.

[0092] FIG. 10 is a cross-sectional view showing the shearing process of the current collector 150 according to this embodiment, which exceeds its elastic limit. (a) to (c) of FIG. 10 show the state in which the distance d between the blade edges 201a and 202a is just about to reach its minimum value until it reaches its minimum value. As the blade edges 201a and 202a of the blades 201 and 202a respectively bite into the current collector 150, the current collector 150 elastically deforms and gradually becomes thinner, as shown in (a) and (b) of FIG. 10. When the elastic limit of the current collector 150 is exceeded, the current collector 150 is torn off, as shown in (c) of FIG. 10. As a result, the current collector 150 is formed with protrusions 152 tapered at the tip.

[0093] Fig. 11 is a perspective view of the laminate 100 after cutting according to the embodiment. By cutting, the laminate 100 is separated into a portion 10a that will be used as the battery 10 and an unnecessary portion 10b that will not be used as the battery 10. A protrusion 152 is provided on the cut surface of the portion 10a that will be used as the battery 10. Note that Fig. 11 does not illustrate the inclination of the side surfaces 101b and 102b and the raised portions 101p and 102p.

[0094] In addition, although an example is shown here in which the end portion of the laminate 100 is cut off as the unnecessary portion 10b, the portion corresponding to the unnecessary portion 10b may be used as another battery 10. For example, a large laminate 100 may be cut into individual batteries 10 to create the batteries 10.

[0095] [Configuration of Battery Ends] Next, a specific configuration of the ends of the battery 10 will be described with reference to Fig. 12. Fig. 12 is a cross-sectional view of the vicinity of a cut portion of an example of the battery 10 according to the present embodiment.

[0096] 12 , the side surface 101b of the unit cell 101 is an example of a first side surface and is inclined with respect to the main surface 150a of the current collector 150. The side surface 102b of the unit cell 102 is an example of a second side surface and is inclined with respect to the main surface 150b of the current collector 150. The inclinations of the side surfaces 101b and 102b are due to the inclinations of the blade surface 201b of the blade 201 and the blade surface 202b of the blade 202, respectively, shown in FIG.

[0097] The lower end of the side surface 101b of the unit cell 101 is the position of the side surface 101b closest to the current collector 150, specifically, the lower end of the end face of the electrode active material layer 110. In FIG. 12 , a line passing through the lower end of the side surface 101b and parallel to the z-axis is represented by a dashed-dotted line L1. The dashed-dotted line L1 also passes through the upper end of the side surface 102b of the unit cell 102, but is not limited to this. The upper end of the side surface 102b may be located on the positive side of the x-axis (specifically, closer to the center of the battery 10) or on the negative side of the x-axis (specifically, outside the battery 10) of the dashed-dotted line L1. The upper end of the side surface 102b is the position of the side surface 102b closest to the current collector 150.

[0098] In the present embodiment, the dashed-dotted line L1 is used as a boundary line that distinguishes the main body 151 from the protrusion 152. Specifically, the main body 151 is considered to be the portion on the negative side of the x-axis relative to the dashed-dotted line L1, and the protrusion 152 is considered to be the portion on the positive side of the x-axis relative to the dashed-dotted line L1. If the upper end of the side surface 102b is located on the positive side of the x-axis relative to the dashed-dotted line L1, the portion that passes through the upper end of the side surface 102b and is located on the positive side of the x-axis relative to a line parallel to the z-axis may be considered to be the protrusion 152.

[0099] The thickness T of the main body portion 151 is uniform over most of the main body portion. The thickness T is smaller at the end where the protrusion 152 is provided. In this specification, the thickness T of the main body portion 151 refers to the thickness of the uniform portion. For example, the thickness that can be measured at the center of the main body portion 151 in a planar view is considered to be the thickness T of the main body portion 151. Alternatively, the thickness T of the main body portion 151 may be considered to be the average of thickness measurements at any three or ten locations within a range excluding the end of the main body portion 151 (for example, a ring-shaped portion that follows the outline of the main body portion 151 in a planar view and accounts for 20% of the area). The two main surfaces of the main body portion 151 are the main surfaces 150a and 150b of the current collector 150. The main surfaces 150a and 150b are each flat surfaces parallel to the xy plane.

[0100] In battery 10, when the thickness of the tip of protrusion 152 is t and the thickness of main body 151 is T, t<T is satisfied. This is because, as described with reference to FIG. 10 , protrusion 152 was formed when current collector 150 was torn off due to exceeding its elastic limit.

[0101] The protrusion 152 has inclined surfaces 152a and 152b. The inclined surface 152a is an example of a first inclined surface and is inclined with respect to the main surface 150a. When the xy plane passing through the tip of the protrusion 152 is used as a reference, the inclined surface 152a is located on the same side as the main surface 150a (the positive side of the z axis). The inclined surface 152b is an example of a second inclined surface and is inclined with respect to the main surface 150b. When the xy plane passing through the tip of the protrusion 152 is used as a reference, the inclined surface 152b is located on the same side as the main surface 150b (the negative side of the z axis). The tip of the protrusion 152 is the portion of the protrusion 152 that is located furthest on the positive side of the x axis. The distance between the inclined surfaces 152a and 152b decreases toward the tip of the protrusion 152.

[0102] The inclined surfaces 152a and 152b are formed during cutting with the blades 201 and 202. Therefore, the inclined surfaces 152a and 152b may include slight irregularities and curvatures and may not be flat. The same applies to the side surface 101b of the unit cell 101 and the side surface 102b of the unit cell 102. For example, when observed at a predetermined x-z cross section, the angle between the side surface 101b and the dashed-dotted line L1 is smaller than the angle between the inclined surface 152a and the dashed-dotted line L1. Furthermore, the angle between the side surface 102b and the dashed-dotted line L1 is smaller than the angle between the inclined surface 152b and the dashed-dotted line L1. The angle between the inclined surfaces 152a and 152b based on a prototype was, for example, approximately 50° to 65°.

[0103] The protrusion amount D of the protrusion 152 corresponds to the distance between the dashed-dotted line L1 and the dashed-dotted line L2. The dashed-dotted line L2 is a line that passes through the tip of the protrusion 152 and is parallel to the z-axis. Note that the position of the tip of the protrusion 152 may vary depending on the cutting position of the xz cross section. Therefore, for example, the protrusion amount D is considered to be the protrusion amount of the protrusion 152 in the xz cross section that passes through the center of the main body 151 in a plan view. Alternatively, the protrusion amount D may be considered to be the average value of the protrusion amounts of the protrusion 152 at any three or ten cutting positions.

[0104] The more positions where the protrusion amount of the protrusion 152 is zero, the more the possibility of a short circuit can be reduced. For example, the protrusion amount D of the protrusion 152 is smaller than the sum of the thickness T of the current collector 150, the thickness of the conductive adhesive layer 141 or 142, the thickness of the electrode active material layer 110, and the thickness of the solid electrolyte layer 130. For example, the actual measured value of the protrusion amount D based on a prototype was approximately 7 μm to 11 μm. This prevents the protrusion 152 from contacting the counter electrode active material layer 120, thereby sufficiently reducing the possibility of a short circuit. Furthermore, by making the protrusion amount D of the protrusion 152 smaller than the thickness T of the current collector, the possibility of a short circuit can be substantially reduced to zero.

[0105] As described above, in the present embodiment, protrusions 152 are provided by cutting current collector 150 in a tearing manner, so that protrusion amount D of protrusions 152 can be reduced. Since protrusions 152 are less likely to come into contact with layers of the opposite polarity, the occurrence of short circuits is reduced, and the reliability of battery 10 can be improved. Furthermore, current collector 150 can be cut at the positions where cutting edge 201 a of blade 201 and cutting edge 202 a of blade 202 are respectively inserted, so that deviation in the cutting position is reduced, and a battery with high capacity accuracy can be manufactured.

[0106] The protrusions 152 are not present on the unit cell 101 side (positive side of the z-axis) of the main surface 150a of the current collector 150, and are not present on the unit cell 102 side (negative side of the z-axis) of the main surface 150b of the current collector 150. Note that the protrusions 152 may be partially present on the unit cell 101 side (positive side of the z-axis) of the main surface 150a of the current collector 150, or may be partially present on the unit cell 102 side (negative side of the z-axis) of the main surface 150b of the current collector 150. Simply put, part of the protrusions 152 may be bent toward the unit cell 101 side or the unit cell 102 side, or may protrude. In other words, part of the protrusions 152 may have a shape that bends toward the unit cell 101 side or the unit cell 102 side. In other words, part of the protrusions 152 may protrude in the z-axis direction beyond the thickness T. The protruding portion of the protrusion 152 (the length in the z-axis direction) is, for example, less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, or less than 5% of the total length of the protrusion 152 along the y-axis direction. However, the protruding portion of the protrusion 152 is not limited to this and may be less than 60% or less than 70%. The protrusion 152 may be formed over the entire length of the unit cell 101 in the y-axis direction, or may be formed on a portion (i.e., partial) of the total length of the unit cell 101. The smaller the portion of the protrusion 152 that protrudes beyond the thickness T of the current collector 150, the more likely it is that a short circuit will occur, thereby improving the reliability of the battery 10.

[0107] 12 shows an example in which the ends of each of the conductive adhesive layers 141 and 142 are in contact with the unit cell 101 or 102 and are spaced apart from the current collector 150. In other words, each of the conductive adhesive layers 141 and 142 is spaced apart from the current collector 150 along the dashed dotted line L1. The gap between each of the conductive adhesive layers 141 and 142 and the current collector 150 may be an empty space that is not filled with anything, or may be filled with a sealing member (not shown) or the like.

[0108] On the other hand, as shown in FIG. 13 , at least one end of the conductive adhesive layers 141 and 142 may be in contact with the current collector 150, away from the unit cell 101 or 102. FIG. 13 is a cross-sectional view of another example of a battery 10 according to the present embodiment, showing the vicinity of a cut portion. In the example shown in FIG. 13 , the unit cell 101 and the conductive adhesive layer 141 are separated from each other, and the unit cell 102 and the conductive adhesive layer 142 are separated from each other along the dashed-dotted line L1. The gap between the conductive adhesive layer 141 and the unit cell 101 and the gap between the conductive adhesive layer 142 and the unit cell 102 may be an empty space without any filling, or may be filled with a sealing member (not shown) or the like. As shown in FIG. 13 , the conductive adhesive layer 141 may be in contact with the inclined surface 152 a of the protrusion 152, and the conductive adhesive layer 142 may be in contact with the inclined surface 152 b of the protrusion 152.

[0109] Note that the cut surface of the battery 10 at one position may be the cut surface shown in FIG. 12 , and the cut surface at another position may be the cut surface shown in FIG. 13 . That is, the positions of the gaps provided at the ends of the conductive adhesive layers 141 and 142 on the cut surface may differ depending on the position of the battery 10. In one cut surface of the battery 10, the end of the conductive adhesive layer 141 may be in contact with the unit cell 101 as shown in FIG. 12 , and the end of the conductive adhesive layer 142 may be in contact with the current collector 150 as shown in FIG. 13 . Alternatively, in another cut surface of the battery 10, the end of the conductive adhesive layer 142 may be in contact with the unit cell 102 as shown in FIG. 12 , and the end of the conductive adhesive layer 141 may be in contact with the current collector 150 as shown in FIG. 13 .

[0110] In this embodiment, as shown in FIGS. 7 and 8 , the blades 201 and 202 each have a double-edged blade. Therefore, when the blades 201 and 202 are inserted into the current collector 150, the blade surfaces 201b and 202b of the blades 201 and 202 come into contact with each other, thereby applying pressure to the ends of the unit cells 101 and 102. As a result, as shown in FIG. 12 , protrusions 101p and 102p are formed on the main surfaces 101a and 102a of the laminate 100. The main surface 101a is the main surface of the unit cell 101, and is the main surface opposite to the main surface facing the main surface 150a of the current collector 150. The main surface 102a is the main surface of the unit cell 102, and is the main surface opposite to the main surface facing the main surface 150b of the current collector 150.

[0111] The protruding portion 101p is an example of a first protruding portion, and is a portion that protrudes upward from the main surface 101a. The protruding portion 101p is formed so as to extend along the upper end of the side surface 101b of the unit cell 101. The protruding portion 101p is a part of the counter electrode active material layer 120 of the unit cell 101 that is farthest from the current collector 150.

[0112] The protruding portion 102p is an example of a second protruding portion, and is a portion that protrudes downward from the main surface 102a. The protruding portion 102p is formed so as to extend along the lower end of the side surface 102b of the unit cell 102. The protruding portion 102p is a part of the counter electrode active material layer 120 of the unit cell 102 that is farthest from the current collector 150.

[0113] The protrusion amount (protrusion height) H of each of the raised portions 101p and 102p may vary depending on the cutting position of the xz cross section. Therefore, for example, the protrusion amount of each of the raised portions 101p and 102p in the xz cross section passing through the center of the main body portion 151 is regarded as the protrusion amount H. Alternatively, the average value of the protrusion amounts of the raised portions 101p and 102p at any three or ten cutting positions may be regarded as the protrusion amount H. Although an example in which the protrusion amounts H of the raised portions 101p and 102p are the same is shown in FIG. 12 , the present invention is not limited to this.

[0114] The protrusion amount H of the raised portions 101p and 102p is equal to or greater than 0 and equal to or less than the thickness of the counter electrode active material layer 120. When the electrode active material layer 110, instead of the counter electrode active material layer 120, is located at the position farthest from the current collector 150, the protrusion amount H is equal to or greater than 0 and equal to or less than the thickness of the electrode active material layer 110.

[0115] [Modifications] Next, a description will be given of modifications of the battery 10 according to the present embodiment and the manufacturing method of the battery 10. In the following modifications, the description will focus on the differences from the embodiment, and the description of the commonalities will be omitted or simplified.

[0116] <Modification of Manufacturing Method> First, a modification of the manufacturing method will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is a flowchart showing another example of the manufacturing method for battery 10 according to the present embodiment. Fig. 15 is a diagram showing another example of the movement of two blades 201 and 202 in the cutting step according to the present embodiment.

[0117] 14, first, the laminate 100 shown in FIG. 4 is prepared, that is, the current collector 150 having the main surface 150a on which the unit cells 101 are provided and the main surface 150b on which the unit cells 102 are provided (S10). The method for forming the laminate 100 is as described above.

[0118] Next, the two blades 201 and 202 are caused to bite into the current collector 150 without crossing each other (S22). Specifically, as shown in (a) of FIG. 15, the blades 201 and 202 are caused to bite into the current collector 150. The specific movements of the blades 201 and 202 are as described with reference to FIG. 9. In this modification, when the blade tips are in closest proximity to each other, the elastic limit of the current collector 150 is not exceeded. In other words, the current collector 150 is not torn.

[0119] In the manufacturing method of the battery 10 according to this modification, as shown in FIG. 14 , the laminate 100 is cut by laterally moving two blades 201 and 202 that have dug into the current collector 150 (S24). Specifically, as shown in FIG. 15 (b), the blades 201 and 202 are moved in a direction parallel to the main surface 150a of the current collector 150 and perpendicular to the direction in which their blade edges 201a and 202a extend (i.e., in the positive direction of the x-axis). The portion of the current collector 150 sandwiched between the blades 201 and 202 that have dug into the current collector 150 extends in the positive direction of the x-axis, thereby tearing the current collector 150. This tends to limit the protruding direction of the protrusion 152 to the positive direction of the x-axis, making it less likely to adhere to the cut surface. This further reduces the possibility of a short circuit. Furthermore, even if it is difficult to exceed the elastic limit by simply digging the blades 201 and 202 into the current collector 150, the elastic limit can be exceeded almost certainly, and the current collector 150 can be torn off almost certainly.

[0120] It should be noted that instead of moving the blades 201 and 202, the portion 10a to be used as the battery 10 may be moved. Alternatively, instead of moving the blades 201 and 202, the unnecessary portion 10b of the laminate 100 may be moved.

[0121] <Modification 1> Next, the configuration of a blade according to Modification 1 and the cutting portion of battery 10C formed using the blade will be described with reference to Figures 16 and 17. The main differences between battery 10C according to this modification and battery 10 are the inclination of side surfaces 101b and 102b and the absence of raised portions 101p and 102p.

[0122] Fig. 16 is a cross-sectional view of the laminate 100 in a state where two blades 211 and 212 have bitten into the current collector 150 according to the first modified example of the embodiment. Fig. 16 shows a state in which the cutting edges 211a and 212a of the blades 211 and 212 are closest to each other in the cutting process.

[0123] Blade 211 is an example of a first blade, and blade 212 is an example of a second blade. As shown in FIG. 16 , blades 211 and 212 each have a single-edged shape. Cutting edges 211a and 212a are each sufficiently sharp, but are rounded or slightly flattened to a degree that prevents chipping. Cutting edges 211a and 212a extend parallel to main surfaces 150a and 150b of current collector 150, respectively (specifically, in the y-axis direction). The length of cutting edges 211a and 212a in the y-axis direction is longer than the length of laminate 100 in the y-axis direction. The inclination of blade surfaces 211b and 212b relative to the z-axis direction is, but is not limited to, an angle of 15° to 30°.

[0124] In this modification, the blades 211 and 212 are arranged so that the inclined blade surfaces 211b and 212b of the blades 211 and 212 face the unnecessary portion 10b of the laminate 100 and the non-inclined blade back surfaces 211c and 212c face the portion 10a of the laminate 100 that will be used as the battery 10C. By using the single-edged blades 211 and 212, the side surface 101b of the unit cell 101 and the side surface 102b of the unit cell 102 are each parallel to the z-axis direction, as shown in FIG.

[0125] 17 is a cross-sectional view of an example of a battery 10C according to Modification 1 of the embodiment, near a cut portion. In this modification, the side surface 101b of the unit cell 101 is perpendicular to the main surface 150a of the current collector 150. The side surface 102b of the unit cell 102 is perpendicular to the main surface 150b of the current collector 150. Minute irregularities are formed on the side surfaces 101b and 102b due to friction caused by contact with the blade backs 211c and 212c when the blades 211 and 212 move, respectively.

[0126] 12 and 13 are not provided in this modification. This is because the back surfaces 211c of the blade 211 and the back surfaces 212c of the blade 212 are planes parallel to the direction of movement of the blades 211 and 212, and therefore almost no pressure is applied to the ends of the unit cells 101 and 102.

[0127] According to this modification, the side surfaces 101b and 102b are perpendicular to the main surface 150a, and the protrusions 101p and 102p are not provided. As a result, the capacity per volume and per area of ​​the battery according to this modification can be substantially maximized. This allows for the realization of a battery 10 with a high capacity density and high reliability. Furthermore, it is possible to realize a battery 10 with the desired size and capacity value, i.e., a battery 10 having the designed dimensions and capacity value.

[0128] Next, the configuration of a blade according to Modification 2 and the cut portion of battery 10D formed using the blade will be described with reference to Figures 18 and 19. The main difference between battery 10D according to Modification 2 and battery 10C according to Modification 1 is the flatness of side surfaces 101b and 102b.

[0129] Fig. 18 is a cross-sectional view of the laminate 100 in a state where two blades 221 and 222 have bitten into the current collector 150 according to the second modified example of the embodiment. Fig. 18 shows a state in which the cutting edges 221a and 222a of the blades 221 and 222 are closest to each other in the cutting step.

[0130] Blade 221 is an example of a first blade, and blade 222 is an example of a second blade. As shown in FIG. 18 , blades 221 and 222 each have a single-edged shape and have a recess (space) on blade backs 221c and 222c. Blade edges 221a and 222a are each sufficiently sharp, but are rounded or slightly flattened to a degree that prevents chipping. Blade edges 221a and 222a extend parallel to main surfaces 150a and 150b of current collector 150, respectively (specifically, in the y-axis direction). The length of blade edges 221a and 222a in the y-axis direction is longer than the length of laminate 100 in the y-axis direction. The inclination of blade surfaces 221b and 222b relative to the z-axis direction is, but is not limited to, 15° to 30°. The inclination of the relief of the cutting edge backs 221c and 222c is such that the angle (also called relief angle) formed with respect to the z-axis direction is 0.5° or more and 5° or less, but is not limited to this.

[0131] In this modification, the blades 211 and 212 are arranged so that the inclined blade surfaces 211b and 212b of the blades 211 and 212 face the unnecessary portion 10b of the laminate 100 and the blade back surfaces 211c and 212c having recesses face the portion 10a of the laminate 100 that will be used as the battery 10D. By using the single-edged blades 211 and 212, the side surface 101b of the unit cell 101 and the side surface 102b of the unit cell 102 are each parallel to the z-axis direction, as shown in FIG.

[0132] 19 is a cross-sectional view of a cut portion of an example of a battery 10D according to Modification 2 of the embodiment. In this modification, the side surface 101b of the unit cell 101 is perpendicular to the main surface 150a of the current collector 150. The side surface 102b of the unit cell 102 is perpendicular to the main surface 150b of the current collector 150.

[0133] In this modification, the undersides 221c and 222c of the blades 221 and 222 are provided with recesses, so that the undersides 221c and 222c hardly come into contact with the cutting surface when the blades 221 and 222 move. This prevents surface roughening of the side surfaces 101b and 102b due to friction. In other words, the side surfaces 101b and 102b are substantially flat.

[0134] According to this modification, the side surfaces 101b and 102b are perpendicular to the main surface 150a, and the protrusions 101p and 102p are not provided. As a result, the capacity per volume and per area of ​​the battery according to this modification can be substantially maximized. Furthermore, since the roughness of the side surfaces 101b and 102b is sufficiently suppressed, the collapse of the active material can be suppressed. This allows the battery 10D to have a high capacity density and high reliability.

[0135] [Manufacturing Apparatus] Next, a battery manufacturing apparatus according to the above-described embodiment and each of the modifications will be described with reference to Fig. 20. Fig. 20 is a side view of a battery manufacturing apparatus 300 according to this embodiment.

[0136] 20 , the manufacturing apparatus 300 includes a fixed base 310, a lever drive shaft 320, an upper blade drive lever 321, a lower blade drive lever 322, a lever connecting pin 323, an upper linear guide 324, a lower linear guide 325, a horizontal linear guide 330, and a control unit 340. The manufacturing apparatus 300 also includes blades 211 and 212. Note that the manufacturing apparatus 300 may include blades 201 and 202, or blades 221 and 222, instead of the blades 211 and 212. The blades included in the manufacturing apparatus 300 are replaceable.

[0137] The fixed base 310, the lever drive shaft 320, the upper blade drive lever 321, the lower blade drive lever 322, the lever connecting pin 323, the upper linear guide 324, the lower linear guide 325, and the horizontal linear guide 330 are components that make up the cutting mechanism. The control unit 340 controls the movements of the components that make up the cutting mechanism.

[0138] The fixing base 310 is an example of a holding portion for holding the current collector 150 on which the unit cells 101 and 102 are provided, specifically, the stack 100. As shown in Fig. 20 , the stack 100 is placed on the upper surface of the fixing base 310 and is pressed and fixed against the fixing base 310 by a pressing member (not shown) or the like. Note that the means for fixing the stack 100 is not particularly limited, and may be, for example, suction from below or clamping.

[0139] The blade 211 is held by an upper linear guide 324. The upper linear guide 324 is held by an upper blade drive lever 321 so as to be movable up and down. The blade 212 is held by a lower linear guide 325. The lower linear guide 325 is held by a lower blade drive lever 322 so as to be movable up and down.

[0140] The upper blade drive lever 321 and the lower blade drive lever 322 are connected to the lever drive shaft 320 via a lever connecting pin 323. The lever drive shaft 320 can move left and right based on a control signal from the control unit 340. Specifically, when the lever drive shaft 320 moves rightward, the lever connecting pin 323 also moves rightward. When the lever connecting pin 323 moves, the upper blade drive lever 321 and the lower blade drive lever 322 rotate around their respective axes. As a result, the upper linear guide 324 and the blade 211 move downward, and the lower linear guide 325 and the blade 212 move upward. As a result, the blades 211 and 212 each bite into the current collector 150 of the laminate 100.

[0141] The center of lever connecting pin 323 is located at the same height as the center position in the thickness direction of current collector 150. This makes the movement distances of blades 211 and 212 uniform, allowing blades 211 and 212 to bite into current collector 150 at uniform speeds and by uniform amounts.

[0142] The control unit 340 controls the movement of the blades 211 and 212. Specifically, the control unit 340 controls the movement of the blades 211 and 212 by controlling the amount of left-right movement of the lever drive shaft 320. For example, the control unit 340 causes the blade 211 to bite into the current collector 150 from the main surface 150a side of the current collector 150 and the blade 212 to bite into the current collector 150 from the main surface 150b side without crossing each other. In this way, the current collector 150 is cut in a tearing manner, and the battery 10 can be manufactured.

[0143] The control unit 340 is realized, for example, by an LSI (Large Scale Integration), which is an integrated circuit (IC). The integrated circuit is not limited to an LSI and may be a dedicated circuit or a general-purpose processor. For example, the control unit 340 may be a microcontroller. The processor or microcontroller includes, for example, a non-volatile memory in which a program is stored, a volatile memory that is a temporary storage area for executing the program, an input / output port, and a processor that executes the program. The control unit 340 may be a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor in which the connections and settings of circuit cells in the LSI can be reconfigured. The functions performed by the control unit 340 may be realized by software or hardware.

[0144] The horizontal linear guide 330 is provided to perform step S24 shown in Fig. 14. The horizontal linear guide 330 can move the connected upper blade drive lever 321, lower blade drive lever 322, and lever drive shaft 320 together in the left-right direction. That is, when the horizontal linear guide 330 is moved to the right, the blades 211 and 212 also move to the right. Therefore, the blades 211 and 212 can be moved to the right while they are biting into the current collector 150. This allows the current collector 150 to be cut in a tearing manner.

[0145] Note that shortening the minimum value of the distance d (see FIG. 9 ) between the cutting edge 211a of the blade 211 and the cutting edge 212a of the blade 212 improves the cutting effect of the current collector 150. Furthermore, increasing the rigidity of the components constituting the cutting mechanism can suppress deformation of the components constituting the cutting mechanism when force is applied to the components driving the blades 211 and 212. Because gaps inevitably occur between the rotating parts and the sliding parts of the guides, it may be difficult to stop the blades 211a and 212a at a position where they do not come into contact with each other, with the distance d being several micrometers. In such cases, position-limiting stoppers may be incorporated into the blades 211 and 212 to limit the positions of the cutting edges 211a and 212a of the blades 211 and 212. By incorporating position-limiting stoppers into the blades 211 and 212, the final tip positions are more restricted, which is highly effective in protecting the cutting edges 211a and 212a.

[0146] While the battery, the battery manufacturing method, and the battery manufacturing apparatus according to one or more aspects have been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications that a person skilled in the art can make to the present embodiments, and configurations constructed by combining components of different embodiments, are also included within the scope of the present disclosure.

[0147] For example, in the above embodiment, the battery has a rectangular shape in plan view, but this is not limiting. The battery may have another polygonal shape in plan view, such as a hexagon or octagon. The battery may also have a shape with a curved outline, such as a circle or ellipse. By using a blade with a curved cutting edge for cutting, a battery having a shape with a curved outline in plan view can be manufactured.

[0148] Furthermore, for example, in the above embodiment, the upper first blade and the lower second blade are moved evenly up and down and symmetrically with respect to a plane passing through the center of the current collector 150 in the thickness direction. However, this is not limited to this. For example, when the first blade reaches the upper surface of the laminate, the second blade may not have reached the lower surface of the laminate. The electrode active material layer, solid electrolyte layer, and counter electrode active material layer are more fragile than the current collector and are easily penetrated by a blade. Therefore, even if there is a timing difference between the movements of the first blade and the second blade, the timing at which they reach and bite into both main surfaces of the current collector 150 is approximately the same. In this way, even if there is a slight difference in the movement speed or movement of the first blade and the second blade, the current collector 150 can be cut to shreds. Furthermore, the cutting edges of the first blade and the second blade do not necessarily have to face each other. The cutting edges of the first blade and the second blade may be offset in the x-axis direction.

[0149] Furthermore, various modifications, substitutions, additions, omissions, etc. can be made to the above-described embodiments within the scope of the claims or their equivalents.

[0150] Batteries according to the present disclosure may be used in electronic devices, electrical appliances, electric vehicles, and the like.

[0151] 10, 10A, 10B, 10C, 10D Battery 10a Utilized part 10b Unnecessary part 100 Laminate 101, 102 Unit cell 101a, 102a, 150a, 150b Main surface 101b, 102b Side surface 101p, 102p Raised portion 110 Electrode active material layer 120 Counter electrode active material layer 130 Solid electrolyte layer 141, 142 Conductive adhesive layer 150 Current collector 151 Main body 152 Protrusion 152a, 152b Inclined surface 201, 202, 211, 212, 221, 222 Blade 201a, 202a, 211a, 212a, 221a, 222a Blade tip 201b, 202b, 211b, 212b, 221b, 222b Blade surface 211c, 212c, 221c, 222c Blade backing 300 Manufacturing device 310 Fixing base 320 Lever drive shaft 321 Upper blade drive lever 322 Lower blade drive lever 323 Lever connecting pin 324 Upper linear guide 325 Lower linear guide 330 Horizontal linear guide 340 Control unit

Claims

1. A battery comprising: a current collector having a first main surface and a second main surface opposite the first main surface; a first unit cell provided on the first main surface; and a second unit cell provided on the second main surface, wherein the current collector has a main body portion sandwiched between the first unit cell and the second unit cell, and protrusions protruding beyond each of a first side surface of the first unit cell and a second side surface of the second unit cell, wherein when the thickness of the tip of the protrusion is t and the thickness of the main body portion is T, the relationship t<T is satisfied.

2. The battery according to claim 1, wherein the protrusion has a first inclined surface inclined relative to the first main surface and a second inclined surface inclined relative to the second main surface, and the distance between the first inclined surface and the second inclined surface becomes narrower toward the tip.

3. The battery described in claim 2, wherein the angle formed between a first direction perpendicular to the first main surface and the first side surface is smaller than the angle formed between the first direction and the first inclined surface, and the angle formed between the first direction and the second side surface is smaller than the angle formed between the first direction and the second inclined surface.

4. A battery as described in any one of claims 1 to 3, wherein the first unit cell has a first protrusion protruding from a main surface opposite to the main surface facing the first main surface, and the second unit cell has a second protrusion protruding from a main surface opposite to the main surface facing the second main surface, the first protrusion being provided along the first side surface, and the second protrusion being provided along the second side surface.

5. A battery according to any one of claims 1 to 3, wherein the length of the protrusion on a line that passes through a position on the first side surface closest to the current collector and is perpendicular to the first main surface is shorter than the thickness of the main body.

6. The battery according to claim 5, comprising: a first conductive adhesive layer provided on the first main surface and adhering the first main surface to the first unit cell; and a second conductive adhesive layer provided on the second main surface and adhering the second main surface to the second unit cell, wherein at least one of the first conductive adhesive layer and the second conductive adhesive layer is spaced apart from the current collector on a line that passes through a position on the first side surface closest to the current collector and is perpendicular to the first main surface.

7. The battery according to claim 5, comprising: a first conductive adhesive layer provided on the first main surface and adhering the first main surface to the first unit cell; and a second conductive adhesive layer provided on the second main surface and adhering the second main surface to the second unit cell, wherein the first unit cell and the first conductive adhesive layer are spaced apart and / or the second unit cell and the second conductive adhesive layer are spaced apart on a line that passes through a position on the first side surface closest to the current collector and is perpendicular to the first main surface.

8. A method for manufacturing a battery, comprising: a step of preparing a laminate including a current collector having a first main surface and a second main surface opposite the first main surface, a first unit cell provided on the first main surface, and a second unit cell provided on the second main surface; and a step of causing a first blade to bite into the current collector from the first main surface side and a second blade to bite into the current collector from the second main surface side without crossing each other.

9. The method for manufacturing a battery according to claim 8, further comprising the step of moving the first blade and the second blade that have bitten into the current collector in a direction parallel to the first main surface and perpendicular to the direction in which the blade tips extend.

10. The method for manufacturing a battery according to claim 8, wherein in the biting step, the first blade and the second blade are bitten into the current collector until the current collector is torn off.

11. A method for manufacturing a battery according to any one of claims 8 to 10, wherein in the biting step, the first blade and the second blade are moved from a state in which their cutting edges face each other in a direction in which their cutting edges approach each other, thereby biting into the current collector.

12. A battery manufacturing device comprising: a control unit that controls the movement of a first blade and a second blade; and a holding unit that holds a stack comprising a current collector having a first main surface and a second main surface opposite the first main surface, a first unit cell provided on the first main surface, and a second unit cell provided on the second main surface, wherein the control unit causes the first blade to bite into the current collector from the first main surface side and the second blade to bite into the current collector from the second main surface side without crossing each other.

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