Manufacturing method of stacked battery

Abstract

This laminated battery production method is for producing a laminated battery in which a plurality of unit battery cells each having a negative electrode layer, a positive electrode layer, and a solid electrolyte layer positioned between the negative electrode layer and the positive electrode layer, are laminated. The method includes: a measurement step for measuring characteristics of each of the plurality of unit battery cells; a lamination step for laminating the plurality of unit battery cells the characteristics of which have been measured in the measurement step; and a cutting-off step for adjusting the areas of the laminated plurality of unit battery cells by collectively cutting off, on the basis of the characteristics of each of the plurality of unit battery cells laminated in the lamination step, the laminated plurality of unit battery cells such that the battery capacity of the laminated battery falls within a predetermined value range.

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a stacked battery. [Background technology]

[0002] Patent Document 1 discloses an electricity storage device in which battery cells using graphene as a conductive additive are connected in series.

[0003] Patent Document 2 discloses that unit batteries having different battery capacities are combined and stacked based on the results of measuring the battery capacity, and a cell sheet is produced in which the stacked unit batteries are connected in parallel.

[0004] Patent Document 3 discloses distributing pressure so that the peripheral portions of a stacked battery are stronger. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-85965 A [Patent Document 2] JP 2017-054871 A [Patent Document 3] JP 2013-200940 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the prior art, further improvement in the battery capacity accuracy and reliability of batteries is desired.

[0007] In stacked batteries as well, high accuracy of battery capacity is important in order to prevent overcharging and over-discharging, improve reliability, and obtain excellent performance.

[0008] On the other hand, the unit battery cells that make up a stacked battery and contain solid electrolytes are thin, which means that they are prone to collapse and internal cracks near the cut surfaces when cut. If the cutting takt time is shortened, these issues with the cut surfaces become more pronounced.

[0009] Therefore, the present disclosure provides a method for manufacturing a stacked battery that can produce a stacked battery with high productivity and improved reliability. [Means for solving the problem]

[0010] A manufacturing method for a stacked battery in one aspect of the present disclosure is a manufacturing method for a stacked battery in which a plurality of unit battery cells are stacked, each unit battery cell having a negative electrode layer, a positive electrode layer, and a solid electrolyte layer located between the negative electrode layer and the positive electrode layer, and includes a measuring step of measuring characteristics of each of the plurality of unit battery cells, a stacking step of stacking the plurality of unit battery cells whose characteristics have been measured, and a cutting step of adjusting an area of ​​the stacked plurality of unit battery cells by collectively cutting the stacked plurality of unit battery cells based on the characteristics of each of the plurality of unit battery cells stacked in the stacking step so that the battery capacity of the stacked battery is within a predetermined value range. Effect of the Invention

[0011] According to the present disclosure, a stacked battery with improved reliability can be manufactured with high productivity. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a stacked battery according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a schematic configuration of a laminated battery including a sealing member according to an embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing a schematic configuration of a stacked battery according to a modified example of the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic configuration of a laminated battery including a sealing member according to a modified example of the embodiment. [Diagram 5] FIG. 5 is a flowchart illustrating a method for manufacturing a stacked battery according to an embodiment. [Figure 6A] FIG. 6A is a cross-sectional view illustrating an example of a layered structure of a laminate formed in a laminate forming step according to an embodiment. [Figure 6B] FIG. 6B is a cross-sectional view illustrating an example of a layered structure of the laminate formed in the laminate forming step according to the embodiment. [Figure 6C] FIG. 6C is a cross-sectional view illustrating an example of a layered structure of the laminate formed in the laminate forming step according to the embodiment. [Figure 6D] FIG. 6D is a cross-sectional view illustrating an example of a layered structure of the laminate formed in the laminate forming step according to the embodiment. [Figure 6E] FIG. 6E is a cross-sectional view illustrating an example of a layered structure of a laminate formed in a laminate forming step according to the embodiment. [Figure 6F] FIG. 6F is a cross-sectional view illustrating an example of a layered structure of the laminate formed in the laminate forming step according to the embodiment. [Figure 6G] FIG. 6G is a cross-sectional view illustrating an example of a layered structure of the laminate formed in the laminate forming step according to the embodiment. [Figure 6H] FIG. 6H is a cross-sectional view illustrating an example of a layered structure of the laminate formed in the laminate forming step according to the embodiment. [Figure 7A] FIG. 7A is a cross-sectional view showing an example of a stacked configuration of unit battery cells formed in a compression step according to an embodiment. [Figure 7B] FIG. 7B is a cross-sectional view showing an example of a stacked configuration of unit battery cells formed in a compression step according to the embodiment. [Figure 7C] FIG. 7C is a cross-sectional view showing an example of a stacked configuration of unit battery cells formed in a compression step according to the embodiment. [Figure 8] FIG. 8 is a schematic diagram showing the relationship between the charged electric quantity and the voltage at the initial stage of charging of a unit battery cell in the embodiment. [Figure 9]FIG. 9 is a cross-sectional view showing a schematic configuration of a stacked battery formed by cutting en bloc at an angle in a cutting step according to the embodiment. [Figure 10A] FIG. 10A is a plan view illustrating an example of cutting positions of stacked unit battery cells in the embodiment. [Figure 10B] FIG. 10B is a plan view illustrating an example of a cutting position of stacked unit battery cells according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Summary of the Disclosure) A manufacturing method for an all-solid-state battery in one aspect of the present disclosure is a manufacturing method for a stacked battery in which a plurality of unit battery cells are stacked, each unit battery cell having an anode layer, a cathode layer, and a solid electrolyte layer located between the anode layer and the cathode layer, the manufacturing method including a measuring step of measuring characteristics of each of the plurality of unit battery cells, a stacking step of stacking the plurality of unit battery cells whose characteristics have been measured, and a cutting step of adjusting an area of ​​the plurality of stacked unit battery cells by collectively cutting the plurality of stacked unit battery cells based on the characteristics of each of the plurality of unit battery cells stacked in the stacking step so that the battery capacity of the stacked battery is within a predetermined value range.

[0014] As a result, before the stacking step, the characteristics of each of the unit battery cells constituting the stacked battery are measured, and for example, the battery capacity of the multiple unit battery cells stacked in the stacking step can be estimated based on the measured characteristics. Therefore, the area of ​​the stacked battery, which is proportional to the battery capacity of the stacked battery, is adjusted by cutting the stacked unit battery cells together based on the measured characteristics, and the battery capacity can be adjusted with high precision. This improves the battery capacity precision of the stacked battery. Also, in the cutting step, by cutting the multiple unit battery cells together on a strong cut object that is integrated by stacking, it is possible to suppress collapse and internal cracks from occurring near the cut surface. This improves the reliability of the stacked battery. Also, by cutting the multiple unit battery cells together, the number of cuts can be significantly reduced compared to cutting the multiple unit battery cells individually. This improves the productivity of the stacked battery.

[0015] Furthermore, if cutting is performed again after collective cutting to adjust the area to adjust the battery capacity, the amount of adjustment is small, and the ratio of the thickness of the cut body to the cutting width is too large, which tends to degrade the quality of the cut surface. In the manufacturing method according to this aspect, the areas of the multiple unit battery cells stacked in the stacking process are adjusted based on characteristics measured in advance, so the cutting positions of the stacked battery can be accurately determined. As a result, there is no need to perform cutting again with a small amount of adjustment, and the quality of the cut surface of the stacked battery can be improved.

[0016] Therefore, the method for manufacturing a stacked battery according to this embodiment makes it possible to manufacture stacked batteries with high productivity.

[0017] Furthermore, for example, in the measuring step, charge / discharge characteristics of each of the plurality of unit battery cells may be measured as the characteristics.

[0018] This allows the electrical quantity and voltage related to the battery capacity to be measured by measuring the charge / discharge characteristics, making it possible to accurately estimate the battery capacity of the multiple unit battery cells stacked in the stacking process.

[0019] Also, for example, in the measuring step, the charge / discharge characteristics may be measured in a range of 10% or less of the battery capacity of the plurality of unit battery cells.

[0020] As a result, the charge / discharge characteristics are measured in a partial region of the battery capacity of the unit battery cell, so the measurement time for the charge / discharge characteristics can be shortened compared to the case of full charge. Furthermore, since the amount of increase in the voltage of the unit battery cell relative to the amount of charged electricity at the beginning of charging is correlated with the battery capacity, the battery capacity of the unit battery cell can be derived even from the charge / discharge characteristics measured in a partial region of the battery capacity. This allows the stacked battery to be manufactured with high productivity. Furthermore, since the amount of electricity charged is small, even if the negative electrode layer and the positive electrode layer come into contact with each other during manufacturing to cause a short circuit, the amount of current flow is small and heat generation, etc. is suppressed. This allows the safety of the stacked battery to be improved during manufacturing.

[0021] For example, the measurement time for the charge / discharge characteristics may be one minute or less.

[0022] As a result, even if the measurement time for the charge / discharge characteristics is short, the increase in voltage of the unit battery cell relative to the amount of charged electricity at the beginning of charging correlates with the battery capacity, so the battery capacity of the unit battery cell can be derived, thereby enabling stacked batteries to be manufactured with high productivity.

[0023] Furthermore, for example, in the measuring step, impedance of each of the plurality of unit battery cells may be measured as the characteristic.

[0024] As a result, since the impedance and battery capacity of a unit battery cell are correlated, the battery capacity of the unit battery cell can be derived simply by measuring the impedance of the unit battery cell, thereby enabling stacked batteries to be manufactured with high productivity.

[0025] Also, for example, the cutting direction of the collective cutting may be inclined with respect to the stacking direction of the plurality of unit battery cells.

[0026] This makes it possible to increase the distance between the negative electrode layer and the positive electrode layer at the cut surface, thereby reducing the risk of short circuiting at the cut surface, and thus making it possible to manufacture a stacked battery with improved reliability.

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0028] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component arrangements and connection forms, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, components that are not described in the independent claims are described as optional components.

[0029] In addition, each figure is a schematic diagram and is not necessarily illustrated precisely. Therefore, for example, the scales in each figure do not necessarily match. In addition, in each figure, substantially the same configurations are given the same reference numerals, and duplicated explanations are omitted or simplified.

[0030] Furthermore, in this specification, terms indicating the relationship between elements, such as "parallel," terms indicating the shape of an element, such as "rectangle," and numerical ranges are not expressions that only express a strict meaning, but are expressions that include a substantially equivalent range, for example, a difference of about a few percent.

[0031] In this specification and the 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 thickness direction of the battery. The positive direction of the z-axis is the upper side in the z-axis direction, and the negative direction of the z-axis is the lower side in the z-axis direction. In this specification, the "thickness direction" refers to the direction along the stacking direction in the stacked battery and unit battery cells, in other words, the direction perpendicular to the main surface of each layer.

[0032] In addition, in this specification, the term "planar view" refers to the case where the stacked battery and unit battery cells are viewed along the thickness direction.

[0033] In addition, in this specification, the "area" of a stacked battery and a unitary battery cell refers to the area of ​​the stacked battery and the unitary battery cell in a plan view.

[0034] In this specification, the negative electrode current collector and the positive electrode current collector may be collectively referred to simply as "current collectors", and the negative electrode active material layer and the positive electrode active material layer may be collectively referred to simply as "active material layers".

[0035] (Embodiment) First, the configuration of the stacked battery according to this embodiment will be described.

[0036] FIG. 1 is a cross-sectional view showing a schematic configuration of a stacked battery 1000 according to the present embodiment.

[0037] As shown in FIG. 1, the stacked battery 1000 in this embodiment includes a plurality of unit battery cells 2000. Specifically, the stacked battery 1000 has a structure in which a plurality of unit battery cells 2000 are stacked. The plurality of unit battery cells 2000 are electrically connected in series to form the stacked battery 1000. The stacked battery 1000 is, for example, a secondary battery that can be repeatedly charged and discharged. In the illustrated example, five unit battery cells 2000 are stacked, but the number of stacked unit battery cells 2000 is not particularly limited. The number of stacked unit battery cells 2000 may be two or more and four or less, or may be six or more.

[0038] Each unit battery cell 2000 has an anode layer 100, a cathode layer 200, and a solid electrolyte layer 300 located between the anode layer 100 and the cathode layer 200. The multiple unit battery cells 2000 are stacked so that the electrodes face in the same direction. That is, in the stacked battery 1000, adjacent unit battery cells 2000 are stacked so that the anode layer 100 of one unit battery cell 2000 and the cathode layer 200 of the other unit battery cell 2000 are adjacent to each other. This makes the stacked battery 1000 a series-connected stacked battery in which the multiple unit battery cells 2000 are electrically connected in series.

[0039] The negative electrode layer 100 and the positive electrode layer 200 face each other via the solid electrolyte layer 300. In the illustrated example, the unit battery cell 2000 has a pair of the negative electrode layer 100 and the positive electrode layer 200 facing each other via the solid electrolyte layer 300, but is not limited thereto, and the unit battery cell 2000 may have two or more of at least any one of the negative electrode layer 100, the positive electrode layer 200, and the solid electrolyte layer 300.

[0040] In each unit battery cell 2000, the anode layer 100, the solid electrolyte layer 300, and the cathode layer 200 are stacked in this order along the thickness direction (z-axis direction) of the unit battery cell 2000. More specifically, in each unit battery cell 2000, the anode current collector 120, the anode active material layer 110, the solid electrolyte layer 300, the cathode active material layer 210, and the cathode current collector 220 are stacked in this order along the thickness direction of the unit battery cell 2000.

[0041] The negative electrode layer 100 includes a negative electrode active material layer 110 and a negative electrode current collector 120. The negative electrode active material layer 110 is located between a solid electrolyte layer 300 and the negative electrode current collector 120. The thickness of the negative electrode active material layer 110 is, for example, not limited to, 5 μm or more and 300 μm or less.

[0042] The negative electrode active material layer 110 includes, for example, a negative electrode active material as an electrode material. As the negative electrode active material contained in the negative electrode active material layer 110, for example, a negative electrode active material such as graphite or metallic lithium can be used. As the material of the negative electrode active material, various materials capable of extracting and inserting ions such as lithium (Li) or magnesium (Mg) can be used.

[0043] The material contained in the negative electrode active material layer 110 may be, for example, a solid electrolyte such as an inorganic solid electrolyte. The inorganic solid electrolyte may be, for example, a sulfide solid electrolyte or an oxide solid electrolyte. The sulfide solid electrolyte may be, for example, a mixture of lithium sulfide (Li2S) and diphosphorus pentasulfide (P2S5). The material contained in the negative electrode active material layer 110 may be, for example, a conductive agent such as acetylene black, carbon black, graphite, or carbon fiber, or a binding binder such as polyvinylidene fluoride.

[0044] The negative electrode current collector 120 is in contact with the negative electrode active material layer 110. The thickness of the negative electrode current collector 120 is, for example, 5 μm to 100 μm, but is not limited thereto. The negative electrode current collector 120 is a member having electrical conductivity. The negative electrode current collector 120 may be, for example, a thin film having electrical conductivity. As a material constituting the negative electrode current collector 120, for example, metals such as stainless steel (SUS), aluminum (Al), copper (Cu), and nickel (Ni) can be used. Specifically, as the negative electrode current collector 120, for example, metal foils such as SUS foil, Cu foil, and Ni foil can be used.

[0045] Note that another layer such as a bonding layer made of a conductive material may be provided between the negative electrode active material layer 110 and the negative electrode current collector 120. The negative electrode layer 100 does not need to include the negative electrode current collector 120. For example, a current collector of an adjacent unit battery cell 2000, an electrode for extraction, or a substrate supporting the stacked battery 1000 may function as a current collector for the negative electrode active material layer 110. In other words, the negative electrode layer 100 may include only the negative electrode active material layer 110 out of the negative electrode active material layer 110 and the negative electrode current collector 120.

[0046] The positive electrode layer 200 includes a positive electrode active material layer 210 and a positive electrode current collector 220. The positive electrode active material layer 210 is located between the solid electrolyte layer 300 and the positive electrode current collector 220. The thickness of the positive electrode active material layer 210 is, for example, not less than 5 μm and not more than 300 μm, but is not limited to this.

[0047] The positive electrode active material layer 210 contains, for example, a positive electrode active material as an electrode material. The positive electrode active material is a material that constitutes a counter electrode to the negative electrode active material.

[0048] Examples of the positive electrode active material contained in the positive electrode active material layer 210 that can be used include lithium cobalt oxide composite oxide (LCO), lithium nickel oxide composite oxide (LNO), lithium manganese oxide composite oxide (LMO), lithium-manganese-nickel composite oxide (LMNO), lithium-manganese-cobalt composite oxide (LMCO), lithium-nickel-cobalt composite oxide (LNCO), and lithium-nickel-manganese-cobalt composite oxide (LNMCO).

[0049] As the positive electrode active material, various materials capable of extracting and inserting ions such as Li or Mg can be used.

[0050] The material contained in the positive electrode active material layer 210 may be, for example, a solid electrolyte such as an inorganic solid electrolyte. The inorganic solid electrolyte may be, for example, a sulfide solid electrolyte or an oxide solid electrolyte. The sulfide solid electrolyte may be, for example, a mixture of lithium sulfide (Li2S) and diphosphorus pentasulfide (P2S5). The surface of the positive electrode active material may be coated with a solid electrolyte. The material contained in the positive electrode active material layer 210 may be, for example, a conductive agent such as acetylene black, carbon black, graphite, or carbon fiber, or a binding binder such as polyvinylidene fluoride.

[0051] The positive electrode current collector 220 is in contact with the positive electrode active material layer 210. The thickness of the positive electrode current collector 220 is, for example, 5 μm to 100 μm, but is not limited thereto. The positive electrode current collector 220 is a member having electrical conductivity. The positive electrode current collector 220 may be, for example, a thin film having electrical conductivity. As a material constituting the negative electrode current collector 120, for example, metals such as stainless steel (SUS), aluminum (Al), copper (Cu), and nickel (Ni) can be used. Specifically, as the positive electrode current collector 220, for example, metal foils such as SUS foil, Cu foil, and Ni foil can be used.

[0052] Note that another layer such as a bonding layer made of a conductive material may be provided between the positive electrode active material layer 210 and the positive electrode current collector 220. The positive electrode layer 200 does not need to include the positive electrode current collector 220. For example, a current collector of an adjacent unit battery cell 2000, an electrode for extraction, or a substrate supporting the stacked battery 1000 may function as a current collector for the positive electrode active material layer 210. In other words, the positive electrode layer 200 may include only the positive electrode active material layer 210 out of the positive electrode active material layer 210 and the positive electrode current collector 220.

[0053] The solid electrolyte layer 300 is disposed between the negative electrode active material layer 110 and the positive electrode active material layer 210. The solid electrolyte layer 300 is in contact with both the negative electrode active material layer 110 and the positive electrode active material layer 210. The thickness of the solid electrolyte layer 300 may be 5 μm or more and 300 μm or less, or may be 5 μm or more and 100 μm or less.

[0054] In this embodiment, the negative electrode active material layer 110, the positive electrode active material layer 210, and the solid electrolyte layer 300 are maintained in a parallel plate shape. This makes it possible to suppress the occurrence of cracking or collapse due to bending. The negative electrode active material layer 110, the positive electrode active material layer 210, and the solid electrolyte layer 300 may be smoothly curved together.

[0055] The solid electrolyte layer 300 is a layer containing an electrolyte material. As the electrolyte material, a generally known electrolyte for batteries can be used. The solid electrolyte layer 300 contains a solid electrolyte as an electrolyte. The unit battery cell 2000 may be, for example, an all-solid-state battery.

[0056] 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, a mixture of lithium sulfide (Li2S) and diphosphorus pentasulfide (P2S5) can be used. In addition to the electrolyte material, the solid electrolyte layer 300 may contain a binder such as polyvinylidene fluoride.

[0057] The stacked battery 1000 is formed by, for example, integrating unit battery cells 2000 that constitute the stacked battery 1000 by adhesion or bonding. Furthermore, the side end faces (end faces perpendicular to the stacking direction) of the stacked battery 1000 are formed by cutting all of the stacked unit battery cells 2000 collectively along the stacking direction. This allows the area to be adjusted so that the battery capacity of the stacked battery 1000 falls within a predetermined range. The method of adjusting the area to keep the battery capacity within the predetermined range will be described later.

[0058] The laminated battery according to this embodiment may further include a sealing member. Fig. 2 is a cross-sectional view showing a schematic configuration of a laminated battery 1000A including a sealing member 700 according to this embodiment. As shown in Fig. 2, the laminated battery 1000A includes the sealing member 700, a negative electrode current collector lead 320, and a positive electrode current collector lead 330 in addition to the configuration of the laminated battery 1000 described above.

[0059] The negative electrode current collector lead 320 and the positive electrode current collector lead 330 are connected to the negative electrode current collector 120 and the positive electrode current collector 220, respectively, of the unit battery cells 2000 at both ends in the stacking direction, and are terminals for extracting current from the stacked battery 1000A. Examples of materials that can be used to form the negative electrode current collector lead 320 and the positive electrode current collector lead 330 include metals such as nickel, stainless steel, aluminum, and copper.

[0060] The sealing member 700 is disposed so as to cover all of the stacked unit battery cells 2000. A portion of the negative electrode current collector lead 320 and the positive electrode current collector lead 330 is exposed and not covered by the sealing member 700. The sealing member 700 is formed, for example, using an electrically insulating material.

[0061] For example, the sealing member 700 is a member containing a first material. The sealing member 700 may be, for example, a member containing the first material as a main component. The sealing member 700 may be, for example, a member made of only the first material.

[0062] The first material may be, for example, a commonly known material for sealing members of batteries, such as a sealant. The first material may be, for example, a resin material. The first material may be an insulating material that does not have ion conductivity. For example, the first material may be at least one of an epoxy resin, an acrylic resin, a polyimide resin, and a silsesquioxane.

[0063] The sealing member 700 may contain a particulate metal oxide material. Examples of the metal oxide material that may be used include silicon oxide, aluminum oxide, titanium oxide, zinc oxide, cerium oxide, iron oxide, tungsten oxide, zirconium oxide, calcium oxide, zeolite, and glass. For example, the sealing member 700 may be formed using a resin material in which a plurality of particles made of a metal oxide material are dispersed.

[0064] By providing the sealing member 700, the reliability of the stacked battery 1000A can be improved in various respects, such as mechanical strength, short-circuit prevention, and moisture resistance.

[0065] [Variations] Next, a modified example of the embodiment will be described. In the following description, the differences from the above embodiment will be mainly described, and the description of the commonalities will be omitted or simplified as appropriate.

[0066] 3 is a cross-sectional view showing a schematic configuration of a stacked battery 1100 in this modified example, which differs from the stacked battery 1000 of the embodiment in that a plurality of unit battery cells 2000 are electrically connected in parallel.

[0067] 3, the stacked battery 1100 in this modification includes a plurality of unit battery cells 2000. Specifically, the stacked battery 1100 has a structure in which a plurality of unit battery cells 2000 are stacked. The plurality of unit battery cells 2000 are electrically connected in parallel to form the stacked battery 1100. The stacked battery 1100 also includes a negative electrode current collector lead 340 and a positive electrode current collector lead 350.

[0068] Among the multiple unit battery cells 2000, adjacent unit battery cells 2000 are stacked with the electrode orientation reversed. That is, in the stacked battery 1100, the multiple unit battery cells 2000 are stacked such that the negative electrode layers 100 or the positive electrode layers 200 of two adjacent unit battery cells 2000 are adjacent to each other. This makes the stacked battery 1100 a parallel-connected stacked battery in which the multiple unit battery cells 2000 are electrically connected in parallel.

[0069] In each unit battery cell 2000, the negative electrode layer 100, the solid electrolyte layer 300, and the positive electrode layer 200 are alternately stacked in this order and in reverse order along the thickness direction (z-axis direction) of the unit battery cell 2000.

[0070] The negative electrode current collector lead 340 and the positive electrode current collector lead 350 are conductors used for charging / discharging, monitoring the voltage between the terminals, etc. The negative electrode current collector lead 340 is electrically connected to the negative electrode current collector 120 of the negative electrode layer 100 of each of the multiple unit battery cells 2000. The positive electrode current collector lead 350 is electrically connected to the positive electrode current collector 220 of the positive electrode layer 200 of each of the multiple unit battery cells 2000.

[0071] 3, the unit battery cells 2000 constituting the stacked battery 1100 are integrated by, for example, adhesion or bonding. Furthermore, the side end faces (end faces perpendicular to the stacking direction) of the stacked battery 1100 are formed by cutting all of the stacked unit battery cells 2000 collectively along the stacking direction. This allows the area to be adjusted so that the battery capacity of the stacked battery 1100 falls within a predetermined range. The method of adjusting the area to keep the battery capacity within the predetermined range will be described later.

[0072] The stacked battery according to this modification may further include a sealing member. Fig. 4 is a cross-sectional view showing a schematic configuration of a stacked battery 1100A according to this modification including a sealing member 700. As shown in Fig. 4, the stacked battery 1100A includes a sealing member 700 in addition to the configuration of the stacked battery 1100 described above.

[0073] The sealing member 700 is disposed so as to cover all of the stacked unit battery cells 2000. Parts of the negative electrode current collector lead 340 and the positive electrode current collector lead 350 are not covered by the sealing member 700 and are exposed.

[0074] By disposing the sealing member 700, the same effects as those of the above-mentioned stacked battery 1000A can be obtained.

[0075] [Laminated battery manufacturing method] Next, a method for manufacturing the laminated battery according to this embodiment will be described. Although a method for manufacturing the laminated battery 1000 will be mainly described below, the laminated battery 1100 can also be manufactured by a similar method.

[0076] The method for manufacturing a stacked battery according to this embodiment includes a stack forming step, a compression step, a measurement step, a selection step, a stacking step, and a cutting step. Each step will be described in detail below. FIG. 5 is a flow chart for explaining the method for manufacturing a stacked battery according to this embodiment. Note that the manufacturing method in the following explanation of each step is an example, and is not limited to the following method.

[0077] (1) Laminate formation process First, the laminate formation step will be described. In the manufacturing method of a stacked battery according to this embodiment, the laminate formation step is performed first. In the laminate formation step, materials for each layer that constitutes the unit battery cell 2000 are laminated to form a laminate (step S11 in FIG. 5).

[0078] 6A to 6H are cross-sectional views showing examples of the stacking configuration of the laminate formed in the laminate formation step. In the laminate formation step, for example, as shown in Fig. 6A and Fig. 6B, a laminate in which a negative electrode active material layer 110 is stacked on a negative electrode current collector 120, and a laminate in which a positive electrode active material layer 210 is stacked on a positive electrode current collector 220 are formed.

[0079] Furthermore, as shown in FIGS. 6C and 6D, a laminate may be formed in which a solid electrolyte layer 300 is laminated on each of the negative electrode active material layer 110 of the laminate shown in FIG. 6A and the positive electrode active material layer 210 of the laminate shown in FIG. 6B.

[0080] Furthermore, as shown in FIGS. 6E and 6F, a laminate in which negative electrode active material layers 110 are laminated on both sides of a negative electrode current collector 120, and a laminate in which positive electrode active material layers 210 are laminated on both sides of a positive electrode current collector 220 may be formed.

[0081] 6G, a stack may be formed in which a positive electrode active material layer 210 is stacked on the solid electrolyte layer 300 of the stack shown in FIG. 6C. As shown in FIG. 6H, a stack may be formed in which a negative electrode active material layer 110 is stacked on the solid electrolyte layer 300 of the stack shown in FIG. 6D. Note that the stack shown in FIG. 6A to FIG. 6H is an example, and the stack configuration of the stack is not limited to the example shown in FIG. 6A to FIG. 6H. For example, the stack may have the same stack configuration as the unit battery cell 2000.

[0082] The laminate can be formed, for example, by applying a paste-like paint in which the materials for the negative electrode active material layer 110, the positive electrode active material layer 210, and the solid electrolyte layer 300 are kneaded together with a solvent onto the surface of a current collector or each layer, and then drying the applied paint. The formed laminate may also be compressed in the stacking direction.

[0083] The method of compression is not particularly limited, and a flat press, a roll press, an air or gas pressure bag press, a hydrostatic press, or various other methods can be applied.

[0084] (2) Compression process Next, the compression step will be described. In the compression step, the stacks formed in the stack formation step are combined and compressed as necessary to form a unit battery cell 2000 (step S12 in FIG. 5).

[0085] In the compression step, for example, at least two of the laminates shown in Fig. 6A to Fig. 6H are laminated such that the negative electrode active material layer 110 and the positive electrode active material layer 210 face each other with the solid electrolyte layer 300 interposed therebetween. At this time, at least two laminates are laminated such that one of the negative electrode active material layer 110, the solid electrolyte layer 300, and the positive electrode active material layer 210 faces the other of the negative electrode active material layer 110, the solid electrolyte layer 300, and the positive electrode active material layer 210, and are compressed in the lamination direction to bond the laminates together. In addition, when the laminate includes all layers of the unit battery cell 2000, the laminates may be compressed in the lamination direction without being combined. In this way, for example, the unit battery cell 2000 is formed.

[0086] The stacking structure of the unit battery cell formed in the compression step is not limited to the stacking structure of the unit battery cell 2000. FIGS. 7A to 7C are cross-sectional views showing examples of stacking structures of unit battery cells formed in the compression step. As shown in FIGS. 7A and 7B, when the stacking body shown in FIGS. 6G and 6H is used, it may be compressed in the stacking direction without being combined with other stacking bodies to form a unit battery cell 2000A or 2000B composed of the negative electrode active material layer 110, the solid electrolyte layer 300, and the positive electrode active material layer 210 and the negative electrode current collector 120 or the positive electrode current collector 220. Also, as shown in FIG. 7C, a unit battery cell 2000C may be formed in which active material layers are stacked on both sides of each of the two current collectors, and a solid electrolyte layer 300 is further stacked on the side opposite to the current collector of the active material layer. Also, one of the solid electrolyte layers 300 located at both ends in the stacking direction of the unit battery cell 2000C may not be stacked. Furthermore, the unit battery cells shown in FIGS. 7A to 7C are just examples, and the stacking configuration of the unit battery cells is not limited to the examples shown in FIGS. 7A to 7C.

[0087] The compression method in the compression step is not particularly limited, and a flat press, a roll press, an air or gas pressure bag press, a hydrostatic press, or any other method can be applied.

[0088] In the laminate formation step and compression step, for example, a plurality of unit battery cells 2000 are formed in the number required for the laminated battery 1000. In addition, for example, a plurality of unit battery cells 2000 designed with the same material and shape are formed.

[0089] In this embodiment, as long as the unit battery cells 2000 that constitute the stacked battery are formed, there are no particular limitations on the method of forming the unit battery cells 2000, and the unit battery cells 2000 may be formed by processes other than the above two processes.

[0090] (3) Measurement process Next, the measurement step will be described. In the measurement step, the characteristics of each of the plurality of unit battery cells 2000 formed in the compression step are measured (step S13 in FIG. 5). Specifically, in the measurement step, characteristics for deriving the battery capacity of each of the plurality of unit battery cells 2000 are measured. That is, the battery capacity of each of the plurality of unit battery cells 2000 is derived based on the measured characteristics of each of the plurality of unit battery cells 2000. The battery capacity is the amount of electricity when fully charged.

[0091] In the measurement process, for example, electrical characteristics of electrical behavior such as charge and discharge characteristics are measured as the characteristics. Also, in the measurement process, mechanical characteristics such as mechanical behavior during compression may be measured as the characteristics. For example, the battery capacity of the unit battery cell 2000 may be derived directly by measuring the charge and discharge characteristics at full charge as the electrical characteristics, or the battery capacity of the unit battery cell 2000 may be derived by measuring electrical characteristics or mechanical characteristics correlated with the battery capacity and estimating the battery capacity.

[0092] The measurement of the electrical characteristics of the electrical behavior can be, for example, impedance measurement or charge / discharge characteristic measurement, etc. In other words, in the measurement step, the impedance or charge / discharge characteristic of each of the multiple unit battery cells 2000 may be measured as the characteristics.

[0093] In impedance measurement, there is a tendency for the impedance to decrease as the battery capacity of the unit battery cell 2000 increases. Furthermore, as the compression bonding of the unit battery cell 2000 progresses, the battery capacity of the unit battery cell 2000 increases and the impedance of the unit battery cell 2000 decreases. Using this, the battery capacity of the unit battery cell 2000 is estimated by measuring the impedance.

[0094] For example, a plurality of test unit battery cells with different battery capacities are prepared in advance by preparing a plurality of test unit battery cells with different degrees of progress of compression bonding. The test unit battery cells are prepared from the same material and stacking configuration as the unit battery cells constituting the laminated battery to be manufactured. Then, the battery capacity and impedance are measured for each of the prepared test unit battery cells to obtain a correlation between the battery capacity and the impedance. In this way, by measuring the impedance of the unit battery cell 2000 in the measurement process, the degree of progress of compression bonding of the unit battery cell 2000 and the battery capacity can be estimated from the measured impedance and the obtained correlation, and the battery capacity of the unit battery cell 2000 can be derived. Therefore, the battery capacity of the unit battery cell 2000 can be derived simply by measuring the impedance of the unit battery cell 2000, so that the laminated battery 1000 can be manufactured with high productivity.

[0095] The method for preparing the test unit battery cells having different battery capacities is not limited to the above method. For example, a plurality of test unit battery cells having different battery capacities may be prepared by using the same material but having different areas or thicknesses.

[0096] In measuring the charge / discharge characteristics, for example, the unit battery cell 2000 is fully charged, the charge / discharge characteristics are measured, and the battery capacity is derived from the amount of electricity charged and discharged.

[0097] Furthermore, as a measurement of the charge / discharge characteristics, the voltage rise characteristic of the unit battery cell 2000 with respect to the amount of charged electricity at the beginning of charging when charging at a constant current (i.e., a constant charge / discharge rate) may be measured. The battery capacity can also be estimated from such a measurement. FIG. 8 is a schematic diagram showing the relationship between the amount of charged electricity and the voltage at the beginning of charging of the unit battery cell 2000. FIG. 8 shows the voltage (vertical axis) and the amount of charged electricity (horizontal axis) when the unit battery cell 2000 is charged at a constant current. In FIG. 8, the dotted line shows the case where the battery capacity of the unit battery cell 2000 is relatively small, and the solid line shows the case where the battery capacity of the unit battery cell 2000 is relatively large. As shown in FIG. 8, when the battery capacity of the unit battery cell 2000 is small, the voltage rise at the beginning of charging is large, and when the battery capacity of the unit battery cell 2000 is large, the voltage rise at the beginning of charging is small. In other words, when the material and shape of the unit battery cells 2000 are similar or the same, the greater the voltage rise in a short period of time, such as a few seconds to a few minutes at the beginning of charging when charged at a constant current, the smaller the battery capacity when fully charged. Using this, the battery capacity of the unit battery cell 2000 is estimated by measuring the charge and discharge characteristics for a short period of time.

[0098] For example, similarly to the case of the impedance measurement described above, a plurality of test unit battery cells with different battery capacities are prepared. Then, for each of the prepared plurality of test unit battery cells, the battery capacity and the voltage rise per unit time in a short time are measured, and a correlation between the battery capacity and the voltage rise per unit time in a short time is obtained. As a result, by measuring the short-time charge / discharge characteristics of the unit battery cell 2000, the progress of the compression bonding of the unit battery cell 2000 and the battery capacity can be estimated from the measured voltage rise per unit time and the obtained correlation, and the battery capacity of the unit battery cell 2000 can be derived. As a result, the battery capacity of the unit battery cell 2000 can be predicted even in a short time, so that the stacked battery can be quickly moved to the next process of manufacturing the stacked battery. Therefore, the stacked battery 1000 can be manufactured with high productivity. In addition, since the amount of electricity to be charged is small, even if the negative electrode layer 100 and the positive electrode layer 200 come into contact with each other during manufacturing to cause a short circuit, the amount of current flowing is small, and heat generation, etc. is suppressed. This can improve safety during manufacturing of the stacked battery 1000.

[0099] In addition, in obtaining the correlation between the battery capacity and the amount of voltage increase per unit time in a short period of time, the charge / discharge characteristics may be measured under multiple conditions of different charge / discharge rates (in other words, current amounts during charging / discharging) of multiple test unit battery cells, and the correlation at each charge / discharge rate may be obtained. From among the measured charge / discharge rates, an optimal charge / discharge rate for measuring the charge / discharge characteristics may be determined in terms of correlation, measurement time, etc. In addition, in order to improve the accuracy of estimating the battery capacity of the unit battery cell 2000, the charge / discharge characteristics of the unit battery cell 2000 may be measured at multiple charge / discharge rates.

[0100] In the short-time measurement of the charge and discharge characteristics, for example, the charge and discharge characteristics are measured in a region of 10% or less of the battery capacity of the multiple unit battery cells 2000. From the viewpoint of even shorter measurement times, the charge and discharge characteristics may be measured in a region of 5% or less of the battery capacity of the multiple unit battery cells 2000, may be measured in a region of 2% or less, or may be measured in a region of 1% or less. From the viewpoint of manufacturing the stacked battery 1000 with high productivity, the measurement time for the charge and discharge characteristics is, for example, 1 minute or less. From the viewpoint of manufacturing the stacked battery 1000 with even higher productivity, the measurement time for the charge and discharge characteristics may be 30 seconds or less, 10 seconds or less, or 3 seconds or less.

[0101] In addition, in the measurement of the charge / discharge characteristics in a short time, the amount of voltage rise at the beginning of charging may be confirmed, and then discharge may be performed. In addition, when the charge / discharge characteristics are measured in a short time, the amount of current that can be passed after charging is small even if the battery is not discharged, so the battery may proceed to the next manufacturing step without discharging. In addition, when discharging is performed, the amount of voltage drop due to discharging may be confirmed.

[0102] The mechanical properties are measured, for example, by measuring the amount of mechanical deformation, density, hardness, etc. As described above, as the compression bonding of the unit battery cells 2000 progresses, the battery capacity of the unit battery cells 2000 increases. Therefore, by measuring the amount of mechanical deformation, density, hardness, etc. as mechanical properties that can confirm the degree of progress of the compression bonding of the unit battery cells 2000, the battery capacity of the unit battery cells 2000 can be estimated. For example, the greater the amount of mechanical deformation, density, and hardness, the greater the battery capacity of the unit battery cell.

[0103] (4) Selection process Next, the selection step will be described. In the selection step, based on the characteristics of each of the unit battery cells 2000 measured in the measurement step, unit battery cells 2000 to be used in the subsequent stacking step are selected from the formed plurality of unit battery cells 2000 (step S14 in FIG. 5). Specifically, based on the battery capacity derived from the characteristics of each of the unit battery cells 2000 measured in the measurement step, unit battery cells 2000 to be used in the subsequent stacking step are selected from the formed plurality of unit battery cells 2000. For example, from the formed plurality of unit battery cells 2000, unit battery cells 2000 whose battery capacity is within a predetermined range are selected.

[0104] For example, in the manufacture of a series-connected stacked battery 1000, the predetermined range of values ​​is a range equal to or greater than the design value of the battery capacity of the multiple unit battery cells 2000 in the stacked battery 1000. This prevents the stacked battery 1000 from including unit battery cells 2000 with small battery capacities that are prone to degradation and heat generation due to overcharging or overdischarging, thereby improving the reliability of the stacked battery 1000.

[0105] Also, for example, in the manufacture of the parallel-connected stacked battery 1100, the range of the predetermined value is a range in which the variation in the battery capacity of the multiple unit battery cells 2000 is equal to or less than a certain value. The difference in the battery capacity of each of the selected multiple unit battery cells 2000 is, for example, 5% or less, or may be 3% or less, or may be 1% or less. This can reduce the variation in the current flowing through the current collecting lead that draws the current from the electrode, and thus can suppress localized heat generation in the unit battery cells 2000 due to overheating or the like. This can improve the reliability of the stacked battery 1100. Note that, in the manufacture of the series-connected stacked battery 1000, the range of the predetermined value may also be a range in which the variation in the battery capacity of the multiple unit battery cells 2000 is equal to or less than a certain value. This can suppress the occurrence of deterioration and heat generation due to overcharging or overdischarging of the unit battery cells 2000, and can improve the reliability of the stacked battery 1100.

[0106] (5)Lamination process Next, the stacking step will be described. In the stacking step, a plurality of unit battery cells 2000 whose characteristics have been measured in the measurement step and which have been selected in the selection step are stacked (step S15 in FIG. 5). Note that in the manufacturing method according to this embodiment, the stacking step may be performed without performing the selection step. In other words, a plurality of unit battery cells 2000 whose characteristics have been measured in the measurement step may be used in the stacking step without any particular selection.

[0107] In the stacking step, when current collectors are arranged at both ends of the unit battery cells 2000 in the stacking direction, as in the case of the unit battery cells 2000, the current collectors of the multiple unit battery cells 2000 are stacked so as to face each other. When manufacturing a series-connected stacked battery 1000, the multiple unit battery cells 2000 are stacked so that the negative electrode current collector 120 of one of the adjacent unit battery cells 2000 faces the positive electrode current collector 220 of the other of the adjacent unit battery cells 2000. In other words, the multiple unit battery cells 2000 are stacked so that the negative electrode layer 100 of one unit battery cell 2000 and the positive electrode layer 200 of the other unit battery cell 2000 are adjacent to each other in the adjacent unit battery cells 2000. When manufacturing a parallel-connected stacked battery 1100, the multiple unit battery cells 2000 are stacked so that the negative electrode current collectors 120 or the positive electrode current collectors 220 of the adjacent unit battery cells 2000 face each other. In other words, a plurality of unit battery cells 2000 are stacked so that the negative electrode layers 100 or the positive electrode layers 200 of two adjacent unit battery cells 2000 are adjacent to each other.

[0108] Also, for example, adjacent unit battery cells 2000 may be stacked via a conductive material so that the current collectors are electrically connected to each other. The conductive material may be, for example, a metal, a conductive resin, or a conductive adhesive. When adjacent unit battery cells 2000 are joined by a conductive material, a stronger stack structure of unit battery cells 2000 can be formed.

[0109] Furthermore, by integrating multiple unit battery cells 2000 through stacking, a strong and thick stacked structure of multiple unit battery cells 2000 is formed that is less susceptible to collapse and internal cracks near the cut surfaces when the cells are cut together in the subsequent cutting process.

[0110] In addition, in the stacking process, for example, when a current collector and an active material layer are arranged at both ends in the stacking direction in a unit battery cell, such as unit battery cells 2000A and 2000B shown in FIGS. 7A and 7B, adjacent unit battery cells may be stacked with one active material layer facing the other current collector.

[0111] Furthermore, in the stacking step, for example, in the case where solid electrolyte layers 300 are arranged on both ends of the unit battery cells in the stacking direction as in unit battery cell 2000C shown in FIG. 7C , or in the case where solid electrolyte layers 300 and active material layers are arranged on both ends, adjacent unit battery cells may be stacked such that the solid electrolyte layer 300 of one faces the active material layer or solid electrolyte layer 300 of the other.

[0112] A stacked battery can also be produced by stacking unit battery cells 2000A, 2000B, or 2000C in this manner, and, if necessary, stacking additional current collectors or active material layers that are lacking.

[0113] (6) Cutting process Next, the cutting step will be described. In the cutting step, first, the battery capacity of the plurality of unit battery cells 2000 stacked in the stacking step is predicted based on the characteristics of each of the plurality of unit battery cells 2000 measured in the measurement step (step S16 in FIG. 5). Then, based on the battery capacity predicted in step S16, the stacked plurality of unit battery cells 2000 are cut at once to adjust the area of ​​the stacked plurality of unit battery cells 2000 so that the battery capacity of the stacked battery 1000 falls within a predetermined value range (step S17 in FIG. 5). That is, in the cutting step, based on the characteristics of each of the plurality of unit battery cells 2000 stacked in the stacking step, the stacked plurality of unit battery cells 2000 are cut at once to adjust the area of ​​the stacked plurality of unit battery cells 2000 so that the battery capacity of the stacked battery 1000 falls within a predetermined value range. In this way, the stacked battery 1000 is obtained.

[0114] Specifically, in step S16, the battery capacity of the multiple unit battery cells 2000 stacked in the stacking process is predicted based on the battery capacity derived from the characteristics of each of the multiple unit battery cells 2000 measured in the measurement process. For example, when manufacturing a series-connected stacked battery 1000, the battery capacity of the multiple stacked unit battery cells 2000 is predicted by calculating the average battery capacity of each of the unit battery cells 2000 stacked in the stacking process.

[0115] Furthermore, for example, when manufacturing a parallel-connected stacked battery 1100, the battery capacity of the stacked unit battery cells 2000 is predicted by calculating the sum of the battery capacities of the unit battery cells 2000 stacked in the stacking process.

[0116] In step S17, first, based on the battery capacity of the stacked unit battery cells 2000 predicted in step S16, the area of ​​the stacked unit battery cells 2000 is determined so that the battery capacity of the stacked battery 1000 falls within a predetermined range. Then, all of the stacked unit battery cells 2000 are cut at once to adjust the area of ​​the stacked unit battery cells 2000 to the determined area. This makes it possible to improve the battery capacity accuracy of the manufactured stacked battery 1000. Furthermore, by cutting at once on a strong cut object in which the unit battery cells 2000 are integrated by stacking, it is possible to prevent collapse and internal cracks from occurring near the cut surface.

[0117] The predetermined value range of the battery capacity is determined by the design of the battery capacity of the stacked battery 1000, and is, for example, a range in which the variation falls within a certain range with respect to the design value of the battery capacity of the stacked battery 1000. The predetermined value range may be, for example, within a range of ±2.5%, ±1.5%, or ±0.5% with respect to the design value of the battery capacity of the stacked battery 1000.

[0118] The battery capacity of the stacked battery 1000 is proportional to, for example, the area of ​​the stacked battery 1000. Therefore, for example, as the unit battery cells 2000 to be cut at once, unit battery cells 2000 having an area in which the predicted value of the battery capacity of the stacked multiple unit battery cells 2000 is assumed to be larger than the design value of the battery capacity of the stacked battery 1000 are fabricated. Then, the area of ​​the stacked multiple unit battery cells 2000 to be cut is determined from the difference between the design value of the battery capacity of the stacked battery 1000 and the predicted value of the battery capacity of the stacked multiple unit battery cells 2000. In this case, the multiple unit battery cells 2000 are cut at once so that the cut areas are the same for each of them. For example, when the design value of the battery capacity of the stacked battery 1000 is Cs, the predicted value of the battery capacity of the stacked multiple unit battery cells 2000 is Cp, and the area of ​​the stacked multiple unit battery cells 2000 before cutting is X, the area Y of the stacked multiple unit battery cells to be cut is calculated by Y=X×(Cp−Cs) / Cp.

[0119] The cutting direction of the collective cutting in the cutting step is, for example, a direction along the stacking direction of the unit battery cells 2000, in other words, a direction perpendicular to the stacking plane. This results in a stacked battery 1000 or 1100 with cut planes parallel to the stacking direction as shown in Fig. 1 or Fig. 3.

[0120] In addition to the method of cutting in a direction perpendicular to the stacking plane of the plurality of unit battery cells 2000, a method of cutting in a direction inclined from the normal direction of the stacking plane of the stacked battery may be used. In other words, the cutting direction of the collective cutting may be inclined with respect to the stacking direction of the plurality of unit battery cells 2000. FIG. 9 is a cross-sectional view showing a schematic configuration of a stacked battery 1000B formed by collective cutting at an incline in the cutting process of this embodiment. In FIG. 9, the location cut in the collective cutting process is shown by a broken line. As shown in FIG. 9, by inclining the cut surface of the stacked battery 1000B from the normal direction of the stacking plane of the stacked battery 1000B, the distance between the negative electrode layer 100 and the positive electrode layer 200 at the cut surface can be increased. Therefore, the risk of short circuit at the cut surface can be reduced. Therefore, a stacked battery 1000B with further improved reliability can be manufactured.

[0121] Furthermore, in such oblique cutting, the cutting distance is longer than in cutting perpendicular to the stacking surface, and therefore peeling and loss of layers are more likely to occur. In the manufacturing method according to the present embodiment, an integrated, strong object to be cut, such as stacked unit battery cells 2000, is cut en bloc, making it less likely for layers to collapse and internal cracks to occur than if unit battery cells 2000 were cut individually, and therefore the manufacturing method according to the present embodiment is particularly effective.

[0122] 9, for example, when cutting the stacked unit battery cells 2000 at an angle, the stacked unit battery cells 2000 are cut at two locations in a direction that is inclined with respect to the stacking direction. The stacked unit battery cells 2000 are cut at two locations so that the cut surfaces are parallel to each other. This keeps the area of ​​each of the stacked unit battery cells 2000 the same.

[0123] The two cut surfaces do not have to be parallel, and cutting may be performed collectively at an incline at only one location. For example, in the stacking step, the multiple unit battery cells 2000 are stacked in order along the stacking direction based on the battery capacity derived from the characteristics of each of the multiple unit battery cells 2000 measured in the measurement step, such that the battery capacity of the unit battery cells 2000 derived in the measurement step becomes larger or smaller. Then, the multiple unit battery cells 2000 with larger battery capacity are cut collectively at an incline so that the area after cutting of the unit battery cells 2000 with larger battery capacity becomes smaller. This makes it possible to reduce the difference in battery capacity between the multiple unit battery cells 2000, and further improve the reliability of the stacked battery.

[0124] 10A and 10B are plan views for explaining examples of cutting positions of stacked unit battery cells 2000. As shown in FIG. 10A, for example, the unit battery cells 2000 stacked in the stacking process are cut at the position of a dashed line C1 along one side of the rectangular unit battery cells 2000 in a plan view. As shown in FIG. 10B, the unit battery cells 2000 stacked in the stacking process may be cut at the position of a dashed line C2 passing through two perpendicular sides of the unit battery cells 2000 in a plan view so that the cut portion includes a corner of the unit battery cell 2000. By cutting at the position of the dashed line C2, the corner of the unit battery cell 2000 that is vulnerable to external impact is removed, so that the reliability of the stacked battery 1000 can be improved. Even if the area to cut the unit battery cells 2000 is small, it is not necessary to remove a long and narrow area as in the case of cutting along the side of the unit battery cell 2000 in a plan view, and the unit battery cells 2000 can be easily cut. In the illustrated example, the wire is cut at only one location, but it may be cut at multiple locations.

[0125] The bulk cutting may be performed by, for example, shear cutting, score cutting, razor cutting, ultrasonic cutting, laser cutting, jet cutting, or other various cutting methods. For example, shear cutting may use various cutting blades such as a Goebel slit blade, a gang slit blade, a rotary chopper blade, or a shear blade. For bulk cutting, a Thomson blade may be used.

[0126] Furthermore, after cutting all at once, the stacked unit battery cells 2000 may be compressed in the stacking direction, thereby increasing the battery capacity and volumetric energy density of the stacked battery 1000.

[0127] Finally, as necessary, as a step of finishing the stacked battery, leads, a sealing member, an exterior body, etc. are arranged on the obtained stacked battery (step S18 in FIG. 5). Note that the stacked battery may be further compressed after step S18.

[0128] As described above, the manufacturing method of the laminated battery according to the present embodiment is a manufacturing method of a laminated battery 1000 in which a plurality of unit battery cells 2000, each having an anode layer 100, a cathode layer 200, and a solid electrolyte layer 300 located between the anode layer 100 and the cathode layer 200, are stacked. The manufacturing method of the laminated battery 1000 includes a measuring step, a stacking step, and a cutting step. In the measuring step, the characteristics of each of the plurality of unit battery cells 2000 are measured. In the stacking step, the plurality of unit battery cells 2000 whose characteristics have been measured in the measuring step are stacked. In the cutting step, the stacked plurality of unit battery cells 2000 are cut at once based on the characteristics of each of the plurality of unit battery cells 2000 stacked in the stacking step, thereby adjusting the area of ​​the stacked plurality of unit battery cells 2000 so that the battery capacity of the laminated battery 1000 falls within a predetermined value range.

[0129] As a result, before the stacking step, the characteristics of each of the unit battery cells 2000 constituting the stacked battery 1000 are measured, and for example, the battery capacity of the multiple unit battery cells 2000 stacked in the stacking step can be predicted based on the measured characteristics. Therefore, the area of ​​the stacked battery 1000, which is proportional to the battery capacity of the stacked battery 1000, is adjusted by cutting the stacked multiple unit battery cells 2000 at once based on the measured characteristics, and the battery capacity can be adjusted with high precision. This improves the battery capacity precision of the stacked battery 1000. Furthermore, in the cutting step, the multiple unit battery cells 2000 are integrated by stacking, and thus collapse and internal cracks can be prevented from occurring near the cut surface by cutting at once. This improves the reliability of the stacked battery 1000. Furthermore, compared to cutting the multiple unit battery cells 2000 individually, the number of cuts can be significantly reduced by cutting at once. This improves the productivity of the stacked battery 1000.

[0130] Furthermore, if cutting is performed again to adjust the area to adjust the battery capacity after collective cutting, the ratio of the thickness of the object to be cut to the cutting width is too large because the amount of adjustment is small, and the quality of the cut surface is likely to deteriorate. In the manufacturing method according to the present embodiment, the areas of the multiple unit battery cells 2000 stacked in the stacking process are adjusted based on characteristics measured in advance, making it possible to accurately determine the cutting positions of the stacked battery. As a result, there is no need to perform cutting again with a small amount of adjustment, and the quality of the cut surface of the stacked battery 1000 can be improved.

[0131] Therefore, the method for manufacturing a stacked battery according to this embodiment makes it possible to manufacture the stacked battery 1000 with high productivity and improved reliability.

[0132] (Other embodiments) Although the stacked battery according to the present disclosure has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as the present disclosure does not deviate from the gist of the present disclosure, various modifications conceivable by a person skilled in the art to the embodiments and other forms constructed by combining some of the components in the embodiments are also included in the scope of the present disclosure.

[0133] For example, in the above embodiment, the stacked battery is a series-connected or parallel-connected stacked battery, but is not limited thereto. The stacked battery may be a stacked battery in which series and parallel connections are combined, in which the positive electrode layers or the negative electrode layers of the series-connected stacked batteries are stacked so as to be electrically connected to each other.

[0134] In the above embodiment, the plurality of unit battery cells are formed by stacking and compressing the layers that individually constitute the unit battery cells, but this is not limited to the above. For example, the plurality of unit battery cells may be formed by forming a unit battery cell of a size that can be divided into two or more units, and then dividing the unit battery cell.

[0135] Furthermore, the above-described embodiment can be modified, replaced, added, omitted, and the like in various ways within the scope of the claims or their equivalents. [Industrial Applicability]

[0136] The laminated battery according to the present disclosure can be used as a battery in electronic devices, electric appliances, electric vehicles, and the like. [Explanation of symbols]

[0137] 100 Negative electrode layer 110 Negative electrode active material layer 120 Negative electrode current collector 200 Positive electrode layer 210 Cathode active material layer 220 Positive electrode current collector 300 solid electrolyte layer 320, 340 Negative current collector lead 330, 350 Positive current collector lead 700 Sealing member 1000, 1000A, 1100, 1100A stacked battery 2000, 2000A, 2000B, 2000C unit battery cells

Claims

1. A method for manufacturing a stacked battery in which a plurality of unit battery cells are stacked, each unit battery cell having an anode layer, a cathode layer, and a solid electrolyte layer located between the anode layer and the cathode layer, comprising: a measuring step of measuring characteristics of each of the plurality of unit battery cells; a stacking step of stacking the plurality of unit battery cells whose characteristics have been measured; and a cutting step of adjusting an area of ​​the stacked unit battery cells by collectively cutting the stacked unit battery cells based on the characteristics of each of the unit battery cells stacked in the stacking step so that the battery capacity of the stacked battery falls within a predetermined value range. A method for manufacturing a stacked battery.

2. In the measuring step, the charge / discharge characteristics of each of the plurality of unit battery cells are measured as the characteristics. A method for producing the laminated battery according to claim 1 .

3. In the measuring step, the charge / discharge characteristics are measured in a range of 10% or less of the battery capacity of the plurality of unit battery cells. The method for producing the laminated battery according to claim 2 .

4. The measurement time for the charge / discharge characteristics is 1 minute or less. The method for producing the laminated battery according to claim 2 or 3.

5. In the measuring step, the impedance of each of the plurality of unit battery cells is measured as the characteristic. A method for producing the laminated battery according to claim 1 .

6. The cutting direction of the collective cutting is inclined with respect to the stacking direction of the plurality of unit battery cells. A method for producing the laminated battery according to any one of claims 1 to 5.

Images