Stacked Cell

Abstract

A laminated battery according to the present disclosure comprises a first cell, a second cell, and a bonding layer interposed between the first cell and the second cell, wherein the bonding layer includes a conductive section and an insulating section, and the first cell and the second cell are electrically connected via the conductive section.

Description

[Technical Field]

[0001] This disclosure relates to stacked batteries. [Background technology]

[0002] By placing a solid electrolyte layer containing a lithium-ion conductive solid electrolyte between a positive electrode active material layer and a negative electrode active material layer, and then pressing it under high pressure, a battery made entirely of solid materials can be constructed.

[0003] Patent Document 1 discloses a stacked solid-state battery comprising first and second single cells and an internal current collector layer interposed between the first and second single cells. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2012 / 020699 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The purpose of this disclosure is to provide a battery with improved reliability. [Means for solving the problem]

[0006] A stacked battery according to one embodiment of this disclosure is First cell, Second single cell, and A junction layer disposed between the first cell and the second cell. Equipped with, The bonding layer includes a conductive portion and an insulating portion. The first cell and the second cell are electrically connected via the conductive part. [Effects of the Invention]

[0007] The present disclosure provides a battery with improved reliability.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a cross-sectional view and a plan view showing a schematic configuration of a laminated battery 1000 according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view and a plan view showing a schematic configuration of a laminated battery 1100 in a modified example of the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view and a plan view showing a schematic configuration of a laminated battery 1200 according to the second embodiment. [Figure 4] FIG. 4 is a cross-sectional view and a plan view showing a schematic configuration of a laminated battery 1300 according to the third embodiment. [Figure 5] FIG. 5 is a cross-sectional view and a plan view showing a schematic configuration of a laminated battery 1400 according to the fourth embodiment. [Figure 6] FIG. 6 is a cross-sectional view and a plan view showing a schematic configuration of a laminated battery 1500 according to the fifth embodiment. [Figure 7] FIG. 7 is a cross-sectional view and a plan view showing a schematic configuration of a laminated battery 1600 according to the sixth embodiment. [Figure 8] FIG. 8 is a cross-sectional view and a plan view showing a schematic configuration of a laminated battery 1700 according to the seventh embodiment. <​​​​​​​​​​​​​​​​​​ In this specification, terms indicating relationships between elements, such as parallelism, and terms indicating the shape of elements, such as rectangles, as well as numerical ranges, are not expressions that represent only strict meanings, but rather expressions that include substantially equivalent ranges, such as differences of a few percent.

[0012] Each figure is a schematic diagram and not necessarily a strictly accurate representation. Therefore, for example, the scale may not necessarily match in each figure. Also, in each figure, substantially identical components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0013] In this specification and in the drawings, the x, y, and z axes 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. In this specification, "thickness direction" refers to the direction perpendicular to the plane on which each layer is stacked.

[0014] In this specification, “plan view” means a view of the battery along the stacking direction, and “thickness” in this specification means the length of the battery and each layer in the stacking direction.

[0015] In this specification, unless otherwise specified, in a battery and each layer constituting the battery, "side surface" means the surface of the battery and each layer along the stacking direction, and "main surface" means a surface other than the side surface.

[0016] In this specification, "inside" and "outside" refer to the central side of the battery and the peripheral side of the battery, respectively, when the battery is viewed along the stacking direction.

[0017] In this specification, the terms "upper" and "lower" in the battery configuration do not refer to the upward (vertically upward) and downward (vertically downward) directions in absolute spatial perception, but rather to terms defined by the relative positional relationship based on the stacking order in the stacked configuration. Furthermore, the terms "upper" and "lower" apply not only when two components are spaced apart and another component exists between them, but also when two components are placed in close proximity and touching each other.

[0018] (First Embodiment) The stacked battery of the first embodiment will be described below.

[0019] The stacked battery of the first embodiment comprises a first cell, a second cell, and a junction layer disposed between the first and second cells. The junction layer includes a conductive portion and an insulating portion. The first and second cells are electrically connected via the conductive portion.

[0020] The laminated battery of the first embodiment has a bonding layer that includes conductive and insulating parts. Therefore, compared to, for example, a case where the first and second cells are bonded together by a bonding layer that includes only conductive parts, thermal expansion in the bonding layer can be reduced, suppressing cracking and warping during thermal shock and preventing cracks. Furthermore, compared to, for example, a case where the first and second cells are bonded together by a bonding layer that includes only insulating parts, the laminated battery of the first embodiment suppresses delamination of the bonding layer and, due to the good thermal conductivity of the bonding layer, can withstand stress caused by thermal shock. Thus, in the laminated battery of the first embodiment, since the bonding layer includes conductive and insulating parts, which have different properties, the stress applied to the battery in response to temperature changes can be distributed, for example. Therefore, by appropriately setting the arrangement position, arrangement shape, size, and material of the conductive and insulating parts, the laminated battery of the first embodiment can efficiently suppress warping and expansion of the battery caused by pressure bonding and temperature changes. Furthermore, by appropriately setting the placement position, shape, size, and material of the conductive and insulating parts according to the bonding state and area between the individual cells, the stress applied to the battery can be controlled over a wide range. Therefore, the stacked battery of the first embodiment can suppress structural defects (e.g., delamination and cracking) at the joints between individual cells caused by thermal expansion or warping due to thermal shock and thermal cycling. As described above, the stacked battery of the first embodiment has high reliability.

[0021] As described in the [Background Art] section, Patent Document 1 discloses a stacked solid-state battery comprising first and second single cells and an internal current collector layer interposed between the first and second single cells. Here, the first and second single cells each consist of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked in order. The internal current collector layer is in contact with the respective positive electrode layers of the first and second single cells, or with the respective negative electrode layers of the first and second single cells, and contains a specific conductive material that is ionically conductive. However, this internal current collector layer is for connecting the first and second single cells in parallel and does not have an insulating portion. For this reason, in a stacked solid-state battery, it is not possible to suppress the expansion and thermal expansion of the battery as in the present invention.

[0022] In the stacked battery of the first embodiment, the first single cell and the second single cell may each comprise a first electrode layer, a solid electrolyte layer, and a second electrode layer in that order. The first electrode layer may include a first current collector and a first active material layer, and the second electrode layer may include a second current collector and a second active material layer.

[0023] Figure 1 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1000 of the first embodiment.

[0024] Figure 1(a) is a cross-sectional view of the stacked battery 1000 of the first embodiment. Figure 1(b) is a plan view of the stacked battery 1000 of the first embodiment viewed from below in the z-axis direction. Figure 1(a) shows a cross-section at the position indicated by line II in Figure 1(b).

[0025] The stacked battery 1000 comprises a first cell 100, a second cell 200, and a junction layer 400 disposed between the first cell 100 and the second cell 200. The junction layer 400 includes a conductive portion 410 and an insulating portion 420.

[0026] As shown in Figure 1, the conductive part 410 and the insulating part 420 may be separated. In this case, there may be a cavity between the conductive part 410 and the insulating part 420. That is, there may be a space enclosed by the conductive part 410, the insulating part 420, the first cell 100, and the second cell 200.

[0027] The conductive part 410 and the insulating part 420 may be in contact. When the conductive part 410 and the insulating part 420 are in contact, they can absorb stress from each other, further suppressing warping and deformation of the battery caused by pressure bonding and temperature changes.

[0028] The first cell 100 and the second cell 200 are electrically connected via a conductive part 410.

[0029] With the above configuration, the reliability of the stacked battery 1000 can be improved.

[0030] The first cell 100 comprises a first current collector 110, a first active material layer 120, a solid electrolyte layer 130, a second active material layer 140, and a second current collector 150 in this order.

[0031] The second cell 200 comprises a first current collector 210, a first active material layer 220, a solid electrolyte layer 230, a second active material layer 240, and a second current collector 250 in this order.

[0032] The stacked battery 1000 is, for example, an all-solid-state battery.

[0033] The stacked battery 1000 may be a primary battery or a secondary battery.

[0034] In Figure 1, the first cell 100 and the second cell 200 are stacked in series to form a battery pack. The first cell 100 and the second cell 200 have a thin rectangular parallelepiped structure.

[0035] The first cell 100 and the second cell 200 may be connected in series or in parallel.

[0036] The first cell 100 is joined to the second cell 200 by a junction layer 400.

[0037] The first current collector 110, the first current collector 210, the first active material layer 120, the first active material layer 220, the solid electrolyte layer 130, the solid electrolyte layer 230, the second active material layer 140, the second active material layer 240, the second current collector 150, and the second current collector 250 may all have a rectangular shape in plan view. Examples of shapes other than rectangles include circles, ellipses, or polygons. The shape does not have to be rectangular.

[0038] Hereinafter, the first current collector 110 and the first current collector 210 may be collectively referred to simply as "the first current collector." The second current collector 150 and the second current collector 250 may be collectively referred to simply as "the second current collector." The first current collector 110, the first current collector 210, the second current collector 150, and the second current collector 250 may be collectively referred to simply as "the current collector." The first active material layer 120 and the first active material layer 220 may be collectively referred to simply as "the first active material layer." The second active material layer 140 and the second active material layer 240 may be collectively referred to simply as "the second active material layer." The first active material layer 120, the first active material layer 220, the second active material layer 140, and the second active material layer 240 may be collectively referred to simply as "the active material layer." The solid electrolyte layer 130 and the solid electrolyte layer 230 are sometimes collectively referred to simply as "solid electrolyte layer." The first cell 100 and the second cell 200 are sometimes collectively referred to simply as "cell."

[0039] The first current collector and the first active material layer may be a positive electrode current collector and a positive electrode active material layer, respectively. In this case, the second current collector and the second active material layer may be a negative electrode current collector and a negative electrode active material layer, respectively.

[0040] The specific configuration of the stacked battery 1000 will be described below.

[0041] The material of the current collector is not particularly limited, as long as it is a conductive material.

[0042] Examples of current collector materials include stainless steel, nickel, aluminum, iron, titanium, copper, palladium, gold, platinum, or alloys of two or more of these materials. Foils, plates, or meshes made from these materials can be used as current collectors.

[0043] The first current collector is made of aluminum (Young's modulus: approximately 70 x 10). 9 N / m 2 Thermal expansion coefficient: 24 × 10 -6 / K) may be used as the second current collector, and copper (Young's modulus: approximately 120 × 10) may be used as the second current collector. 9 N / m 2 Thermal expansion coefficient: 16 × 10-6 / K) May be used.

[0044] The material of the current collector may be selected considering the manufacturing process, operating temperature, operating pressure, the battery operating potential applied to the current collector, or conductivity. The current collector material may also be selected considering the tensile strength or heat resistance required by the battery.

[0045] The current collector may have a thickness of, for example, 10 μm or more and 100 μm or less.

[0046] The surface of the current collector may be processed to have an uneven, rough surface in order to improve bonding or wettability during coating. That is, the surface of the current collector may have an embossed shape. The surface roughness Rz of the current collector may be 1 μm or more and 10 μm or less.

[0047] The bonding layer 400 is a layer that bonds the first cell 100 and the second cell 200. The bonding layer 400 includes a conductive portion 410 and an insulating portion 420. The first cell 100 and the second cell 200 are electrically connected via the conductive portion 410.

[0048] The bonding layer 400 may consist only of a conductive portion 410 and an insulating portion 420.

[0049] In the stacked battery 1000, two single cells are joined using a bonding layer 400 that includes a conductive part 410 and an insulating part 420. Therefore, the stress generated by the differences in hardening stress and thermal expansion characteristics of the bonding layers is dispersed and does not concentrate simultaneously at the bonding interface. For example, while the thermal expansion coefficient of the metal used for the current collector is about 20 ppm / K, the conductive part 410 is made of a material with a thermal expansion coefficient of about 7 ppm / K to 15 ppm / K, and the insulating part 420 is made of a material with a thermal expansion coefficient of about 3 ppm / K to 5 ppm / K. If the difference in thermal expansion coefficients between the current collector and the conductive part 410 is large, the insulating part 420 may be softer than the current collector, or softer than both the current collector and the conductive part 410. The Young's modulus of the material used for the insulating part 420 may be smaller than the Young's modulus of the current collector material, or smaller than the Young's modulus of both the current collector material and the conductive part 410 material. As a result, the insulating portion 420 can particularly absorb stress caused by differences in hardening stress and thermal expansion characteristics of the layers being joined. Therefore, it is possible to obtain a laminated battery that suppresses delamination and cracking of the joint surface and reduces warping and deformation. This action improves the durability of the laminated battery against thermal shock and thermal cycling.

[0050] At least one selected from the group consisting of a conductive part 410 and an insulating part 420 may be in contact with at least one selected from the group consisting of a first cell 100 and a second cell 200. The conductive part 410 and the insulating part 420 may be in contact with the first cell 100 and the second cell 200.

[0051] In Figure 1, both the conductive part 410 and the insulating part 420 are in direct contact with the surface of the second current collector 150 of the first cell 100 and the surface of the first current collector 210 of the second cell 200.

[0052] At least a portion of the bonding layer 400 may be embedded in at least one selected from the group consisting of the first cell 100 and the second cell 200. At least one selected from the group consisting of the conductive portion 410 and the insulating portion 420 may be embedded in at least one selected from the group consisting of the first cell 100 and the second cell 200.

[0053] The conductive portion 410 and the insulating portion 420 may have portions embedded in at least one selected from the group consisting of a first cell 100 and a second cell 200. The conductive portion 410 and the insulating portion 420 may have portions embedded in at least one selected from the group consisting of a second current collector 150 of the first cell 100 and a first current collector 210 of the second cell 200. This allows the conductive portion 410 and the insulating portion 420 to be firmly fixed to the cell. As a result, delamination of the cell can be reduced even when subjected to impact or thermal shock such as a thermal cycle. Therefore, a highly reliable battery with suppressed warping and deformation can be realized.

[0054] The conductive portion 410 and the insulating portion 420 may have portions embedded in the first current collector 210 of the second cell 200 by about 1 μm to 2 μm. The conductive portion 410 and the insulating portion 420 may have portions embedded in the first current collector 210 of the second cell 200 by about 10% of the thickness of the current collector.

[0055] As shown in Figure 1(b), the conductive portion 410 may be located in the center of the stacked battery 1000 in a plan view.

[0056] The conductive part 410 is electrically conductive.

[0057] The conductive portion 410 may include a conductive resin material. This allows for a wide range of control over the deformation of the single cell's joint (e.g., delamination and warping due to thermal expansion) through the elasticity (deformability) of the resin material, while maintaining electrical connection. As a result, the durability of the joint surface against flexural stress and thermal shock can be increased. Therefore, the reliability of the battery can be improved.

[0058] The conductive part 410 may contain a metal. Examples of metals include Ag, Cu, Ni, or Fe. By using these metals, a low-resistance electrical connection can be achieved while maintaining the deformability of the resin material, resulting in a highly durable bond with the single cell. Therefore, a battery with low resistance loss and high reliability can be realized. In addition, because the conductive part 410 has high conductivity, heat generation due to Joule heating is reduced. Therefore, the effect of temperature on degrading the characteristics of the battery can be suppressed.

[0059] The conductive part 410 may contain silver.

[0060] The conductive part 410 may contain two or more metals.

[0061] Examples of the metal shape included in the conductive part 410 include particulate, flaky, or plate-like forms.

[0062] The conductive part 410 may contain conductive resin and metal particles. For example, the conductive part 410 may contain Ag particles and thermosetting resin.

[0063] The conductive portion 410 may have a thickness of 1 μm or more and 5 μm or less.

[0064] The conductive part 410 may be softer than the current collector. For example, the conductive part 410 may be softer than the second current collector 150 of the first cell 100 and the first current collector 210 of the second cell 200.

[0065] The difference in softness, i.e., hardness, between the conductive part 410 and the current collector can be compared by applying a rigid indenter and comparing the relative relationship of hardness from the size relationship of the traces, similar to the Vickers hardness. For example, the indenter can be pressed against each part of the battery cross-section with the same force and compared from the concave state. Also, the relative relationship of hardness can be estimated from the metal composition.

[0066] The material of the conductive part 410 may have a Young's modulus of about 10×10 9 N / m 2 The material of the conductive part 410 may also have a Young's modulus of 10×10 9 N / m 2 or more.

[0067] The Ag particles contained in the conductive part 410 may be approximately spherical. The Ag particles may have a particle size of 0.5 μm or more and 1 μm or less.

[0068] The content of Ag particles in the conductive part 410 may be 50% by mass or more and 70% by mass or less with respect to other materials constituting the conductive part 410.

[0069] The conductive part 410 may select the metal content to adjust the hardness or thermal conductivity. The conductive part 410 may contain, for example, a resin material (e.g., Young's modulus: 1×10 9 N / m 2 to 3×10 9 N / m 2 level) and metal particles (e.g., Ag (Young's modulus: about 80×10 9 N / m 2 )).

[0070] The bonding layer 400 may be a coating film. The conductive part 410 may also be a coating film.

[0071] For example, the conductive portion 410 may be manufactured by coating it with a conductive paste containing metal particles and a thermosetting resin. This results in a conductive portion 410 in which the metal particles are oriented in a plate-like manner. This allows for broad control of stress and thermal expansion in the longitudinal and transverse directions. As the conductive paste containing metal particles and a thermosetting resin, a highly conductive metal paste containing high-melting-point (e.g., 400°C or higher) highly conductive metal particles, or a thermosetting conductive paste containing metal particles and a resin with a low melting point (preferably below the curing temperature of the conductive paste, for example, 300°C or lower) may be used. A conductive paste containing silver metal particles and a thermosetting resin may also be used.

[0072] Examples of materials with high melting point, high conductivity metal particles include silver, copper, nickel, zinc, aluminum, palladium, gold, platinum, or alloys of these metals.

[0073] Examples of materials for low-melting-point metal particles with a melting point of 300°C or less include tin, tin-zinc alloys, tin-silver alloys, tin-copper alloys, tin-aluminum alloys, tin-lead alloys, indium, indium-silver alloys, indium-zinc alloys, indium-tin alloys, bismuth, bismuth-silver alloys, bismuth-nickel alloys, bismuth-tin alloys, bismuth-zinc alloys, or bismuth-lead alloys. By using a conductive paste containing such low-melting-point metal particles, even if the thermosetting temperature is low, for example below the melting point of high-conductivity metal particles with a high melting point, solid-phase and liquid-phase reactions proceed at the contact points between the metal particles in the conductive paste and the metal constituting the current collector. As a result, an alloy is formed at the interface between the conductive paste and the surface of the current collector. An example of the alloy formed is a silver-copper alloy, which is a highly conductive alloy, when silver or a silver alloy is used for the conductive metal particles and copper is used for the current collector. By combining conductive metal particles with a current collector, silver-nickel alloys or silver-palladium alloys can also be formed. This configuration allows for stronger bonding between individual cells, suppressing, for example, delamination of the bonding surface due to thermal cycling or impact.

[0074] Examples of shapes for high-melting-point, highly conductive metal particles and low-melting-point metal particles include spherical, flaky, or needle-shaped forms.

[0075] The particle size of high-melting-point, highly conductive metal particles and low-melting-point metal particles is not particularly limited. For example, since alloy formation proceeds at lower temperatures as the particle size decreases, the particle size and particle shape are appropriately selected considering the influence of thermal history on process design and battery characteristics.

[0076] The resin used in the thermosetting conductive paste can function as a binding binder, and may be selected based on the manufacturing process, considering factors such as printability and coatability. The resin used in the thermosetting conductive paste includes, for example, thermosetting resins. Examples of thermosetting resins include, (i) Amino resins such as urea resin, melamine resin, and guanamine resin, (ii) Epoxy resins such as bisphenol A type, bisphenol F type, phenol novolac type, and alicyclic type, (iii) Oxetane resin, (iv) Phenolic resins such as resol type and novolac type, and (v) Examples include silicone-modified organic resins such as silicone epoxy and silicone polyester. Only one of these materials may be used as the resin, or two or more of these materials may be used in combination.

[0077] The conductive portion 410 may be a laminated film rather than a coated film. The conductive portion 410 may have a laminated structure in which layers with different metal particle content, material types, or shapes are stacked. This allows for control over a wider range of interfacial bonding or conductivity reliability.

[0078] The conductive part 410 may have pores. The hardness of the conductive part 410 can also be adjusted by the amount of pores. Increasing the amount of pores makes the conductive part 410 softer.

[0079] Pores can be encapsulated, for example, by stirring the conductive paste used to form the conductive portion 410. The pore diameter is, for example, 0.1 μm to 5 μm. The encapsulated pores can also be removed by a reduced pressure treatment below atmospheric pressure at room temperature. That is, the amount of encapsulated pores can be adjusted by the pressure or duration of the reduced pressure treatment.

[0080] The pores may be filled with gas. Any gas can be filled by performing a series of processes from stirring to curing of the paste in such a gas atmosphere. This allows for the selection and filling of a gas that will not adversely affect the current collector or solid electrolyte when in contact. Examples of such gases include oxygen, nitrogen, or argon.

[0081] The arrangement, shape, and quantity of pores can be evaluated by observing a cross-section of the conductive portion 410 using an optical microscope or scanning electron microscope (SEM).

[0082] By observing the polished cross-section at, for example, 500 to 2000 times magnification, the porosity can be calculated from the ratio of the pore area to the non-pore area.

[0083] The insulating portion 420 is a part of the bonding layer 400 with a lower electronic conductivity than the conductive portion 410. The insulating portion 420 is, for example, substantially non-electronically conductive. In this specification, substantially non-electronically conductive means that the electronic conductivity is 10 μS / m or less, and may be, for example, 1 μS / m or less. The insulating portion 420 may not even have to be electronically conductive.

[0084] The insulating portion 420 may include at least one selected from the group consisting of insulating resin materials (hereinafter also referred to as "insulating resin materials") and oxides. This allows for a wide range of control over deformation (e.g., delamination and warping due to thermal expansion) and thermal conductivity at the joints between the individual cells.

[0085] The insulating resin material may be an epoxy resin. The epoxy resin may be thermosetting. The thermal conductivity of the epoxy resin may be, for example, less than 1 W / m·K.

[0086] The oxide may be alumina (i.e., aluminum oxide). The thermal conductivity of aluminum oxide is 20 W / m·K to 30 W / m·K, and its Young's modulus is 300 × 10⁻¹⁰. 9 N / mm to 400 x 10 9 It is N / mm.

[0087] The insulating portion 420 may have a thickness of 1 μm or more and 5 μm or less.

[0088] The insulating portion 420 may be softer than the conductive portion 410.

[0089] The insulating portion 420 may be softer than the current collector and the conductive portion 410. For example, the insulating portion 420 may be softer than the second current collector 150 of the first cell 100, the first current collector 210 of the second cell 200, and the conductive portion 410. This allows the insulating portion 420 to preferentially absorb deformation (e.g., warping) of the cell joints caused by flexural stress or thermal shock. As a result, the durability of the electrical connection state of the conductive portion 410 is improved. Therefore, the characteristics and reliability of the cell can be improved.

[0090] The material for the insulating part 420 is 1 × 10 9 N / m 2 The above and 3 × 10 9 N / m 2 It may have the following Young's modulus:

[0091] As shown in Figure 1(b), the insulating portion 420 may be provided in a frame shape along the outer edge of the stacked battery 1000 in a plan view. The width of the frame may be approximately 1000 μm.

[0092] The material of the insulating part 420 may be thermosetting. Considering productivity, the curing temperature of the insulating part 420 material may be the same as that of the conductive part 410 so that it can cure simultaneously with the conductive part 410. The curing temperature is, for example, 120°C to 200°C. Because large batteries have a large heat capacity, the curing state may differ between the outer edge and the center of the battery. Therefore, in large batteries, curing progresses more slowly in the center than at the outer edge. For this reason, the curing distribution within the battery is such that the outer edge becomes harder. By increasing the heating rate for thermosetting or performing heat treatment for a shorter time, the resin located at the outer edge of the battery can be selectively hardened. The heating rate for thermosetting is, for example, 500°C / hour to 800°C / hour. The curing time is, for example, 1 minute to 10 minutes. This can improve the impact resistance of the corners and sides of the battery.

[0093] To ensure a uniform distribution of curing temperatures within the battery, resin materials with different curing temperatures may be used for the outer edge and the center. For example, a material with a relatively lower curing temperature may be used in the center. The difference in curing temperature between the outer edge material and the center material depends on the battery size (heat capacity) and curing conditions, but may be between 5°C and 30°C. This ensures a uniform curing state throughout the entire insulating portion 420.

[0094] The thermal conductivity or hardness may be adjusted by incorporating insulating and highly thermally conductive oxide particles, such as alumina, into the insulating portion 420. This can suppress differences in the hardening state within the large cell.

[0095] The particle size of the oxide particles may be, for example, 0.5 μm or more and 1 μm or less. The content of oxide particles may be, for example, 5 volume% or more and 30 volume% or less. The particle size and content may be selected considering the viscosity and wettability of the resin paste forming the insulating portion 420, as well as defects such as cracking of the cured film and bonding properties.

[0096] The insulating portion 420 may be a coating film.

[0097] For example, the insulating portion 420 may be manufactured by coating it with an insulating paste containing an insulating resin material. The resin used in the insulating paste can function as a binding binder, and may be selected based on factors such as printability and coatability, depending on the manufacturing process employed.

[0098] The insulating portion 420 may be a laminated film instead of a coated film.

[0099] The insulating portion 420 may have pores. The hardness of the insulating portion 420 can also be adjusted by the amount of pores. Increasing the amount of pores makes the insulating portion 420 softer.

[0100] In the insulating portion 420, the method and effect of incorporating pores into the paste are the same as those for the conductive portion 410.

[0101] The current collector, conductive part 410, and insulating part 420 may be hard in that order. The degree of hardness between the current collector and the conductive part 410, and the degree of hardness between the conductive part 410 and the insulating part 420 are adjustable.

[0102] In the bonding layer 400, the conductive portion 410 and the insulating portion 420 may have the same thickness. This makes it easier for both the conductive portion 410 and the insulating portion 420 to contact the second current collector 150 of the first cell 100 and the first current collector 210 of the second cell. As a result, a low-resistance electrical connection and a strong interlayer bond can be obtained. Therefore, a battery with low resistance loss and high reliability can be realized. In addition, because the bonding surfaces are parallel, the misalignment of the cells during stacking is reduced, thus improving the shape accuracy of the stacked battery.

[0103] At least one selected from the group consisting of conductive parts 410 and insulating parts 420 may be located at the outer edge of the bonding layer 400 in a plan view of the stacked battery 1000. This allows the individual cells to be bonded at their outer edges, thereby suppressing warping and deformation of the individual cells, which tend to become apparent at the outer edges. As a result, delamination (e.g., delamination between the current collector and the active material layer), which tends to occur at the outer edges (especially at the corners), is reduced. Therefore, a battery with excellent properties and reliability can be realized.

[0104] At least one of the group consisting of conductive parts 410 and insulating parts 420 may be provided in a frame-like or grid-like manner. As a result, the conductive part 410 or insulating part 420 acts as a skeletal structure, suppressing warping and deformation of the battery without increasing its mass. Therefore, warping and deformation of the battery can be suppressed while preventing a decrease in the battery's mass energy density.

[0105] The insulating portion 420 may be positioned on the outer edge side of the stacked battery 1000 in a plan view, relative to the conductive portion 410. This reduces the risk of the conductive portion 410 spreading to the sides of the battery during printing, which can lead to short circuits and performance degradation due to reduced resistance. It also reduces the risk of metal ions (e.g., Ag ions) that may be contained in the conductive portion 410 leaching out to the sides of the stacked battery 1000, which can degrade battery performance. With this configuration, the stacked battery 1000 has high reliability because it can prevent short circuits while suppressing deformation and warping of the battery. The insulating portion 420 may be provided so as to surround the conductive portion 410 in a plan view of the battery.

[0106] A portion of the bonding layer 400 may be exposed on the surface of the stacked battery 1000. At least one selected from the group consisting of the conductive portion 410 and the insulating portion 420 may be exposed on the surface of the stacked battery 1000. At least one selected from the group consisting of the conductive portion 410 and the insulating portion 420 may be exposed on the side surface of the stacked battery 1000.

[0107] The bonding layer 400 may have exposed portions that protrude outward from the outer edges of the first cell 100 and the second cell 200. At least one selected from the group consisting of the conductive portion 410 and the insulating portion 420 may have exposed portions that protrude outward from the outer edges of the first cell 100 and the second cell 200.

[0108] With the above configuration, the exposed parts can absorb shocks during the manufacturing process and protect the sides of the battery. As a result, the shedding of active material from the sides of the battery and deformation of the current collector can be reduced.

[0109] The insulating portion 420 may be exposed on the surface of the stacked battery 1000. The insulating portion 420 may have an exposed portion that protrudes outward from the outer edges of the first cell 100 and the second cell 200. With the above configuration, the exposed portion can absorb shocks during the manufacturing process, etc. As a result, the detachment of active material from the side of the battery and deformation of the ends of the current collector can be suppressed. Therefore, degradation of the battery's characteristics and short circuits can be suppressed.

[0110] The exposed portion of the insulating part 420 is formed, for example, by applying a paste that forms the insulating part 420 to the side surface of the stacked battery 1000 by screen printing, or by stamp transfer.

[0111] The degree of exposure of the insulating portion 420 may be 10 μm or more. That is, the insulating portion 420 may protrude 10 μm or more from the side surface of the battery.

[0112] The surface of the insulating portion 420 may be processed to have an uneven, rough surface. That is, the surface of the insulating portion 420 may have an embossed shape. This makes it easier for air to be discharged to the outside through the uneven surface when the current collector is laminated on the insulating portion 420, thereby suppressing the retention of air within the bonding surface. Since the parallelism of the bonding surfaces between individual cells is improved, a battery with excellent shape accuracy and reliability can be realized.

[0113] The surface of the embossed insulating portion 420 may be the surface that comes into contact with the first cell 100 or the second cell 200.

[0114] The surface of the insulating portion 420 that contacts the second cell 200 may have an embossed shape. That is, the embossed shape of the insulating portion 420 may be on the surface of the second cell 200 that contacts the first current collector 210. This reduces the air gap (air pocket) at the connection surface when the insulating portion 420 and the current collector are pressurized together.

[0115] The surface roughness Rz of the insulating portion 420 may be approximately 1 μm. This rough surface can be formed by pressurizing using a mold having an embossed surface with irregularities. Alternatively, the embossed shape may be formed by friction with coarse sandpaper or by sandblasting.

[0116] The first active material layer may be a positive electrode active material layer. The positive electrode active material layer contains positive electrode active material.

[0117] The positive electrode active material is a substance in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted into or removed from its crystal structure at a higher potential than the negative electrode, and oxidation or reduction occurs as a result.

[0118] The positive electrode active material is, for example, a compound containing lithium and a transition metal element. This compound is, for example, an oxide containing lithium and a transition metal element, or a phosphoric acid compound containing lithium and a transition metal element.

[0119] An example of an oxide containing lithium and a transition metal element is LiNi x M 1-xLithium nickel composite oxides such as O2 (where M is at least one selected from the group consisting of Co, Al, Mn, V, Cr, Mg, Ca, Ti, Zr, Nb, Mo, and W, and 0 < x < 1 is satisfied), layered oxides such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2), or lithium manganate having a spinel structure (for example, LiMn2O4, Li2MnO3, or LiMnO2).

[0120] An example of a phosphate compound containing lithium and a transition metal element is lithium iron phosphate (LiFePO4) having an olivine structure.

[0121] As the positive electrode active material, sulfides such as sulfur (S) and lithium sulfide (Li2S) may be used. In this case, lithium niobate (LiNbO3) or the like may be coated on or added to the positive electrode active material particles.

[0122] Only one of these materials may be used as the positive electrode active material, or two or more of these materials may be combined and used.

[0123] In order to enhance lithium ion conductivity or electron conductivity, the positive electrode active material layer may contain, in addition to the positive electrode active material, materials other than the positive electrode active material. That is, the positive electrode active material layer may be a binder layer. Examples of such materials are solid electrolytes such as inorganic solid electrolytes and sulfide solid electrolytes, conductive aids such as acetylene black, or binders for binding such as polyethylene oxide and polyvinylidene fluoride.

[0124] The positive electrode active material layer may be in contact with the surface of the positive electrode current collector. The positive electrode active material layer may cover the entire main surface of the positive electrode current collector.

[0125] The positive electrode active material layer may have a thickness of 5 μm or more and 300 μm or less.

[0126] The second active material layer may be a negative electrode active material layer. The negative electrode active material layer contains a negative electrode active material.

[0127] A negative electrode active material is a substance in which metal ions such as lithium (Li) ions or magnesium (Mg) ions are inserted into or removed from its crystal structure at a lower potential than that of the positive electrode, and oxidation or reduction occurs as a result.

[0128] Examples of negative electrode active materials include carbon materials such as natural graphite, artificial graphite, graphite carbon fiber, and resin-fired carbon, or alloying materials combined with a solid electrolyte. Examples of alloying materials include LiAl, LiZn, Li3Bi, Li3Cd, Li3Sb, Li4Si, Li 4.4 Pb, Li 4.4 Sn, Li 0.17 C, and lithium alloys such as LiC6, lithium titanate (Li4Ti5O 12 ) Oxides of lithium and transition metal elements, such as zinc oxide (ZnO), or silicon oxide (SiO2). x It is a metal oxide such as ).

[0129] The negative electrode active material may consist of only one of these materials, or a combination of two or more of these materials.

[0130] To enhance lithium-ion conductivity or electronic conductivity, the negative electrode active material layer may contain materials other than the negative electrode active material. Examples of such materials include solid electrolytes such as inorganic solid electrolytes and sulfide solid electrolytes, conductive additives such as acetylene black, or binding binders such as polyethylene oxide and polyvinylidene fluoride.

[0131] The negative electrode active material layer may be in contact with the surface of the negative electrode current collector. The negative electrode active material layer may cover the entire main surface of the negative electrode current collector.

[0132] The negative electrode active material layer may have a thickness of 5 μm or more and 300 μm or less.

[0133] In Figure 1, the first active material layer 120, the first active material layer 220, the second active material layer 140, and the second active material layer 240 all have the same shape, position, and size in a plan view, but are not limited to this.

[0134] The solid electrolyte layer 130 is located between the first active material layer 120 and the second active material layer 140, and the solid electrolyte layer 230 is located between the first active material layer 220 and the second active material layer 240. In other words, the solid electrolyte layer is located between the first active material layer and the second active material layer. The solid electrolyte layer may also be in direct contact with both the first active material layer and the second active material layer.

[0135] The solid electrolyte layer contains a solid electrolyte. For example, the solid electrolyte layer contains a solid electrolyte as its main component. Here, the main component is the component that is present in the solid electrolyte layer in the largest mass percentage. The solid electrolyte layer may consist only of a solid electrolyte.

[0136] The solid electrolyte material may be a known solid electrolyte for batteries that does not have electronic conductivity but has ionic conductivity.

[0137] Solid electrolyte materials, for example, have the property of conducting metal ions such as lithium ions or magnesium ions.

[0138] As the solid electrolyte, sulfide-based solid electrolytes, oxide-based solid electrolytes, or halide solid electrolytes can be used.

[0139] Examples of sulfide-based solid electrolytes include the Li2S-P2S5 system, Li2S-SiS2 system, Li2S-B2S3 system, Li2S-GeS2 system, Li2S-SiS2-LiI system, Li2S-SiS2-Li3PO4 system, Li2S-Ge2S2 system, Li2S-GeS2-P2S5 system, or Li2S-GeS2-ZnS system.

[0140] Oxide-based solid electrolytes are, for example, lithium-containing metal oxides, lithium-containing metal nitrides, lithium phosphate (Li3PO4), or lithium-containing transition metal oxides. Examples of lithium-containing metal oxides are Li2O-SiO2 or Li2O-SiO2-P2O5. Examples of lithium-containing metal nitrides are Li x P y O 1-z N z (where 0 < z ≤ 1). An example of a lithium-containing transition metal oxide is lithium titanate.

[0141] Halide solid electrolytes are, for example, compounds containing Li, M, and X. Alternatively, halide solid electrolytes are, for example, compounds composed of Li, M, and X. Here, M is at least one selected from the group consisting of metal elements and metalloid elements other than Li. X is at least one selected from the group consisting of F, Cl, Br, and I.

[0142] "Metalloid elements" are B, Si, Ge, As, Sb, and Te. "Metal elements" are all elements contained in Groups 1 to 12 of the periodic table (excluding hydrogen), and all elements contained in Groups 13 to 16 of the periodic table (excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se).

[0143] To improve the ionic conductivity of halide solid electrolytes, M may contain Y. M may be Y.

[0144] Halide solid electrolytes are, for example, Li a Me b Y c It may be a compound represented by X6. Here, the mathematical formulas: a + mb + 3c = 6, and c > 0 are satisfied. The value of m represents the valence of Me.

[0145] To improve the ionic conductivity of the halide solid electrolyte, Me may be at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb.

[0146] To improve the ionic conductivity of the halide solid electrolyte, X may include at least one selected from the group consisting of Cl and Br.

[0147] The halide solid electrolyte may include, for example, at least one selected from the group consisting of Li3YCl6 and Li3YBr6.

[0148] As a solid electrolyte, only one of these materials may be used, or two or more of these materials may be used in combination.

[0149] The solid electrolyte layer may contain, in addition to the solid electrolyte, a binding binder such as polyethylene oxide or polyvinylidene fluoride.

[0150] The solid electrolyte layer may have a thickness of 5 μm or more and 150 μm or less.

[0151] The material of the solid electrolyte may be composed of aggregates of particles or of a sintered structure.

[0152] Figure 2 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1100 in a modified example of the first embodiment.

[0153] Figure 2(a) is a cross-sectional view of the stacked battery 1100 in a modified example of the first embodiment. Figure 2(b) is a plan view of the stacked battery 1100 in a modified example of the first embodiment, viewed from below in the z-axis direction. Figure 2(a) shows a cross-section at the position indicated by line II-II in Figure 2(b).

[0154] The stacked battery 1100 comprises a first cell 100, a junction layer 400, a second cell 200, a junction layer 401, and a third cell 300. The stacked battery 1100 is configured such that the third cell 300 is further junctioned to the stacked battery 1000 by the junction layer 401. The junction layer 401 includes a conductive portion 411 and an insulating portion 421. The third cell 300 and the stacked battery 1000 are electrically connected via the conductive portion 411.

[0155] The third cell 300 comprises a first current collector 310, a first active material layer 320, a solid electrolyte layer 330, a second active material layer 340, and a second current collector 350 in this order.

[0156] In this way, by connecting multiple single cells in series or parallel to form a multilayer structure, a high-voltage, high-capacity stacked battery can be realized.

[0157] The stacked battery of the first embodiment may comprise four or more single cells. That is, one or more additional single cells may be bonded to the stacked battery 1100.

[0158] (Second Embodiment) The stacked battery of the second embodiment will now be described. Matters described in the first embodiment may be omitted as appropriate.

[0159] Figure 3 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1200 of the second embodiment.

[0160] Figure 3(a) is a cross-sectional view of the stacked battery 1200 of the second embodiment. Figure 3(b) is a plan view of the stacked battery 1200 of the second embodiment viewed from below in the z-axis direction. Figure 3(a) shows a cross-section at the position indicated by line III-III in Figure 3(b).

[0161] In the stacked battery 1200 shown in Figure 3(a), the insulating portion 422 is provided between the conductive portion 412 and the first current collector 210 of the second cell 200.

[0162] The insulating portion 422 may be positioned between the first cell and the conductive portion 412. The insulating portion 422 may be positioned between the conductive portion 412 and the second current collector 150. That is, the insulating portion 422 may be positioned between the first cell 100 or the second cell 200 and the conductive portion 412.

[0163] As shown in Figure 3, the conductive portion 412 and the insulating portion 422 may be in contact. The conductive portion 412 and the insulating portion 422 may be in contact in a way that they overlap in a plan view. For example, as shown in Figure 3, if the conductive portion 412 covers the insulating portion 422 in an overlapping manner, even if a material that is prone to peeling is used for the insulating portion 422, the conductive portion 412 will suppress it, making it difficult for the insulating portion 422 to peel off.

[0164] As long as electrical connection between the first cell and the second cell is ensured via the bonding layer 400, the size and shape of the conductive part 412 and the insulating part 422 are not particularly limited.

[0165] With the above configuration, it is possible to realize a highly reliable battery that suppresses warping and deformation.

[0166] The insulating portion 422 may have a thickness of 1 μm or more and 3 μm or less.

[0167] The insulating portion 422 may be located in the center of the stacked battery 1200.

[0168] The insulating portion 422 may have a portion embedded in the current collector by approximately 1 μm to 2 μm. The current collector has, for example, a thickness of approximately 20 μm.

[0169] The surface of the insulating portion 422 may be processed to have an uneven, rough surface. That is, the surface of the insulating portion 422 may have an embossed shape. This makes it easier for air to be discharged to the outside through the uneven surface when the current collector is laminated on the insulating portion 422, thereby suppressing the retention of air within the bonding surface. In addition, since the wettability of the surface with an embossed shape is improved, when a conductive paste is applied or printed to form the conductive portion 412 on the embossed surface of the insulating portion 422, the shape and thickness can be controlled with high precision. As a result, it is possible to prevent the conductive portion 412 from protruding onto the side wall and causing a short circuit. Furthermore, since the parallelism of the bonding surfaces between individual cells is improved, a battery with excellent shape accuracy and reliability can be realized.

[0170] The surface of the insulating portion 422 that contacts the second cell 200 may have an embossed shape. That is, the embossed shape of the insulating portion 422 may be on the surface of the second cell 200 that contacts the first current collector 210. This reduces the air gap (air pocket) at the connection surface when the insulating portion 422 and the current collector are pressurized together.

[0171] The surface of the embossed insulating portion 422 may be the surface that comes into contact with the conductive portion 412. This reduces the air gap (air pocket) remaining at the joint surface when the insulating portion 422 and the conductive portion 412 come into contact.

[0172] The surface roughness Rz of the insulating portion 422 may be approximately 1 μm. This rough surface can be formed by pressurizing using a mold having an embossed surface with irregularities. Alternatively, the embossing may be formed by friction with coarse sandpaper or by sandblasting. Embossing allows the conductive portion 412 to be wetted without repelling the paste or ink, even when using a resin material with poor wettability. Therefore, the conductive portion 412 can be accurately coated or printed onto the insulating portion 422 in the desired shape and thickness.

[0173] In the stacked battery 1200 shown in Figure 3(a), the conductive portion 412 is in direct contact with the insulating portion 422. The conductive portion 412 may also cover the entire main surface of one of the insulating portions 422.

[0174] Of the conductive portion 412, the portion overlapping with the insulating portion 422 may have a thickness of 1 μm or more and 5 μm or less, while the other portions may have a thickness of 5 μm or more and 10 μm or less. This ensures that the sides of the insulating portion 422, which are prone to peeling due to differences in the deformability of the insulating portion 422 and the current collector, or due to temperature cycling, are covered with the conductive portion 412. Therefore, peeling from the edges of the insulating portion 422 due to tensile or compressive stress caused by thermal shock can be suppressed. Consequently, the reliability of the stacked battery 1200 can be improved.

[0175] The conductive portion 412 does not need to be positioned on the outer edge of the stacked battery 1200 in a plan view, in order to prevent it from flowing out to the side of the stacked battery 1200 and causing a short circuit.

[0176] In a plan view, the conductive portion 412 may be larger than the insulating portion 422.

[0177] In the stacked battery according to the second embodiment, three or more single cells may be stacked, similar to the stacked battery 1100 according to a modified example of the first embodiment.

[0178] (Third embodiment) The stacked battery of the third embodiment will now be described. Matters described in the above embodiments may be omitted as appropriate.

[0179] Figure 4 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1300 of the third embodiment.

[0180] Figure 4(a) is a cross-sectional view of the stacked battery 1300 of the third embodiment. Figure 4(b) is a plan view of the stacked battery 1300 of the third embodiment viewed from below in the z-axis direction. Figure 4(a) shows a cross-section at the position indicated by the line IV-IV in Figure 4(b).

[0181] As shown in Figure 4, in the stacked battery 1300, the bonding layer 400 comprises a plurality of conductive parts 413. The insulating part 423 is provided in a frame shape along the outer edge of the stacked battery 1300 in a plan view.

[0182] The stacked battery 1300, equipped with multiple conductive parts 413, allows for adjustment of warping and deformation of large-format batteries. It also allows for adjustment of localized stress within the battery. Furthermore, the separation of the conductive parts 413 from the screen printing plate during printing is improved in accordance with the reduction in the area of ​​each conductive part 413. As a result, tensile stress that acts on the current collector during printing of the conductive parts 413, which could cause the current collector to peel off, can be suppressed. Therefore, stress that causes structural defects in the battery during the manufacturing of the conductive parts 413 can be reduced. In addition, when the area of ​​the printed pattern is small, the linearity, positional accuracy, and thickness accuracy of the printed pattern are improved compared to screen printing with a large-area pattern. Therefore, the pattern shape and thickness accuracy during screen printing of the conductive parts 413 are improved, enabling stable control of warping and deformation in the stacked battery 1300. From the above, the stacked battery 1300 can suppress localized warping and deformation with high precision, even in large-format batteries.

[0183] Multiple conductive parts 413 may be arranged in a distributed manner to accommodate the warping and deformation of the battery. This makes it easier to suppress the warping and deformation of the battery.

[0184] The multiple conductive parts 413 may have a configuration in which the conductive parts 413 are regularly arranged at predetermined intervals in a plan view of the stacked battery 1300. This makes it possible to control the effect of reducing warping and deformation at each position on the surface of the individual cells.

[0185] Some of the multiple conductive parts 413 may be replaced by insulating parts instead of conductive parts 413.

[0186] The stacked battery according to the third embodiment may satisfy at least one of the following (A) and (B). (A) The bonding layer includes multiple conductive parts. (B) The bonding layer includes multiple insulating parts.

[0187] If (A) above is satisfied, the multiple conductive parts may have a configuration in which the conductive parts are regularly arranged at predetermined intervals when viewed from above in a plan view of the stacked battery. If (B) above is satisfied, the multiple insulating parts may have a configuration in which the insulating parts are regularly arranged at predetermined intervals when viewed from above in a plan view of the stacked battery. The multiple conductive parts and insulating parts may have a configuration in which the conductive parts and insulating parts are regularly arranged at predetermined intervals when viewed from above in a plan view of the stacked battery. In this case as well, the above-mentioned effects can be expected.

[0188] If (A) above is satisfied, the multiple conductive parts may have a configuration in which the conductive parts are periodically arranged in a plan view of the stacked battery. If (B) above is satisfied, the multiple insulating parts may have a configuration in which the insulating parts are periodically arranged in a plan view of the stacked battery. The multiple conductive parts and insulating parts may have a configuration in which the conductive parts and insulating parts are periodically arranged in a plan view of the stacked battery.

[0189] The multiple conductive parts 413 and multiple insulating parts are arranged in a distributed manner to accommodate the warping and deformation of the battery, thereby making it easier to suppress warping and deformation.

[0190] In the stacked battery according to the third embodiment, three or more single cells may be stacked, similar to the stacked battery according to the modified example of the first embodiment.

[0191] (Fourth Embodiment) The following describes a stacked battery according to the fourth embodiment. Matters described in the above embodiments may be omitted as appropriate.

[0192] Figure 5 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1400 of the fourth embodiment.

[0193] Figure 5(a) is a cross-sectional view of the stacked battery 1400 of the fourth embodiment. Figure 5(b) is a plan view of the stacked battery 1400 of the fourth embodiment viewed from below in the z-axis direction. Figure 5(a) shows a cross-section at the position indicated by the VV line in Figure 5(b).

[0194] As shown in Figure 5, the stacked battery 1400 has a bonding layer 400 which includes conductive parts 414a, 414b, and 414c. Conductive parts 414a, 414b, and 414c have different hardnesses. Hereinafter, conductive parts 414a, 414b, and 414c may be collectively referred to simply as "conductive part 414". In other words, the stacked battery 1400 differs from the stacked battery 1300 in that multiple conductive parts 414 include conductive parts composed of materials with different hardnesses.

[0195] Some of the multiple conductive parts 414 may be insulating parts instead of conductive parts 414. In the stacked battery according to the fourth embodiment, if the bonding layer 400 includes multiple conductive parts 414, the conductive parts 414 may include first conductive parts and second conductive parts having different hardnesses, and if the bonding layer 400 includes multiple insulating parts, the multiple insulating parts may include first insulating parts and second insulating parts having different hardnesses.

[0196] With the above configuration, it is possible to accommodate different stresses at different locations on the surface of a single cell. In other words, by arranging different materials, appropriate control can be achieved according to the location and degree of stress. As a result, even with large and / or thin-layer cells, partial warping or deformation can be suppressed with greater precision.

[0197] The first conductive part may be harder than the second conductive part, and in a plan view of the stacked battery, the first conductive part may be positioned closer to the outer edge of the battery than the second conductive part. Similarly, the first insulating part may be harder than the second insulating part, and in a plan view of the stacked battery, the first insulating part may be positioned closer to the outer edge of the battery than the second insulating part. In Figure 5(b), conductive part 414a may correspond to the second conductive part, and conductive part 414b may correspond to the first conductive part. That is, conductive part 414b may be harder than conductive part 414a. By placing a harder material at the outer edge, warping and deformation can be effectively suppressed at the outer edge, where warping and deformation are more likely to occur. Therefore, a highly reliable battery can be realized.

[0198] The hardness of the conductive part 414 can be adjusted by the metal content in the conductive part 414. For example, in the stacked battery 1400 shown in Figure 5(b), the central conductive part 414a contains about 60% by mass of Ag particles, the outer conductive part 414b contains 70% by mass of Ag particles, and the square-shaped conductive parts 414c contain 75% by mass of Ag particles. In this case, the hardness may increase in the order of conductive part 414c, conductive part 414b, and conductive part 414a.

[0199] A hard metal (for example, Ni or Fe) may be mixed with Ag. The hardness may be controlled by adjusting the mixing ratio.

[0200] The hardness may be controlled by the components of the thermosetting resin material.

[0201] The hardness may be adjusted by incorporating pores into the conductive part 414.

[0202] Generally, when applying pressure with a uniaxial press, warping becomes apparent on the outer edge side, so the conductive part on the outer side (outer edge side) may be made harder than the inner side (center).

[0203] The differences in hardness of multiple conductive parts 414 and the differences in hardness of multiple insulating parts can be compared in the same way as with Vickers hardness, by applying a rigid indenter and comparing the relative sizes of the indentations. For example, the indentation can be compared by pressing the indenter with the same force onto each part of the battery cross-section and observing the resulting indentation. The relative hardness can also be estimated from the metal composition.

[0204] The metal or pore content in the conductive portion 414 can be compared by observing the cross-section using a SEM or similar method, based on the area ratio of metal components, resin components, and pores.

[0205] The multiple conductive parts 414 and insulating parts may each contain materials with different hardnesses. This allows for different stresses to be accommodated at different locations on the surface of the single cell. In other words, by arranging different materials, appropriate control can be achieved according to the location and degree of stress. This is particularly effective in suppressing warping and deformation of large, thin-layer batteries.

[0206] In the stacked battery according to the fourth embodiment, three or more single cells may be stacked, similar to the stacked battery according to the modified example of the first embodiment.

[0207] (Fifth embodiment) The stacked battery of the fifth embodiment will now be described. Matters described in the above embodiments may be omitted as appropriate.

[0208] Figure 6 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1500 of the fifth embodiment.

[0209] Figure 6(a) is a cross-sectional view of the stacked battery 1500 of the fifth embodiment. Figure 6(b) is a plan view of the stacked battery 1500 of the fifth embodiment viewed from below in the z-axis direction. Figure 6(a) shows a cross-section at the position indicated by the line VI-VI in Figure 6(b).

[0210] As shown in Figure 6(b), the stacked battery 1500 differs from the stacked battery 1000 in that the conductive part 415 is in contact with the insulating part 425. In Figure 6(b), a portion of the main surface of the conductive part 415 overlaps with a portion of the main surface of the insulating part 425. In Figure 6(b), the portion where the conductive part 415 and the insulating part 425 are in contact is shown as the contact portion 500.

[0211] With the above configuration, the conductive part 415 is joined to the insulating part 425 at the contact part 500, resulting in a strong bonding layer 400. In addition, the bending of the current collector is buffered by the contact part 500, thereby suppressing deformation of the stacked battery.

[0212] The contact portion 500 may have a shape in which the longer side is in the direction of the shorter side of the stacked battery 1500 in a plan view, as shown in Figure 6(b).

[0213] The contact portion 500 may have a shape in which the longer side is in the longitudinal direction of the stacked battery 1500 when viewed from above. This makes it easier to suppress deformation as warping is likely to occur in the longitudinal direction of the stacked battery 1500.

[0214] In the stacked battery according to the fifth embodiment, three or more single cells may be stacked, similar to the stacked battery according to the modified example of the first embodiment.

[0215] (Sixth Embodiment) The stacked battery of the sixth embodiment will now be described. Matters described in the above embodiments may be omitted as appropriate.

[0216] Figure 7 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1600 of the sixth embodiment.

[0217] Figure 7(a) is a cross-sectional view of the stacked battery 1600 of the sixth embodiment. Figure 7(b) is a plan view of the stacked battery 1600 of the sixth embodiment viewed from below in the z-axis direction. Figure 7(a) shows a cross-section at the position indicated by the line VII-VII in Figure 7(b).

[0218] The stacked battery 1600 shown in Figure 7 is configured to further include a side insulating member 600 on the side surface of the stacked battery 1000 of the first embodiment. The side insulating member 600 is in contact with the side surface of the stacked battery 1000.

[0219] The side insulating members 600 prevent short circuits between individual cells, short circuits between connected individual cells, and adhesion of foreign matter. This suppresses the deterioration of the performance of the stacked battery 1600. Therefore, the reliability of the stacked battery 1600 can be improved.

[0220] The material of the side insulating member 600 may be a thermosetting resin. For example, this resin may be an epoxy resin.

[0221] The side insulating member 600 may be in contact with and fixed to the side surface of the stacked battery 1000. The side insulating member 600 may cover at least a portion of the side surface of the stacked battery 1000, or it may cover the entire side surface of the stacked battery 1000.

[0222] The side insulating member 600 may have a thickness of 30 μm or more and 100 μm or less.

[0223] The side insulating member 600 may be in contact with and fixed to a portion of the bonding layer 400. The side insulating member 600 may also be in contact with at least one selected from the group consisting of the conductive portion 410 and the insulating portion 420. This enhances the adhesion of the side insulating member 600 through an anchoring effect, improving the mechanical strength of the stacked battery 1600. As a result, a battery with superior performance that is resistant to impact and deformation can be realized.

[0224] As shown in Figure 7, the stacked battery 1600, the side insulating member 600 may be in contact with the insulating portion 420, or it may be in contact with and fixed to the insulating portion 420.

[0225] In the stacked battery according to the sixth embodiment, three or more single cells may be stacked, similar to the stacked battery according to the modification of the first embodiment. That is, a side insulating member 600 may be provided on the side surface of the stacked battery 1100 according to the modification of the first embodiment.

[0226] (Seventh Embodiment) The seventh embodiment will now be described. Matters described in the above embodiments may be omitted as appropriate.

[0227] Figure 8 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1700 of the seventh embodiment.

[0228] Figure 8(a) is a cross-sectional view of the stacked battery 1700 of the seventh embodiment. Figure 8(b) is a plan view of the stacked battery 1700 of the seventh embodiment viewed from below in the z-axis direction. Figure 8(a) shows a cross-section at the position indicated by the line VIII-VIII in Figure 8(b).

[0229] The stacked battery 1700 shown in Figure 8 has a configuration in which a side insulating member 610 is further provided on the side of the stacked battery 1200.

[0230] Since the stacked battery 1700 is equipped with a side insulating member 610, it can suppress the degradation of battery performance, similar to the stacked battery 1600. Therefore, the reliability of the stacked battery 1700 can be improved.

[0231] The material of the side insulating member 610 may be a thermosetting resin. For example, this resin may be an epoxy resin.

[0232] The side insulating member 610 may have a thickness of 30 μm or more and 100 μm or less.

[0233] The side insulating member 610 may be in contact with and fixed to the side of the stacked battery 1200.

[0234] In the stacked battery 1700 shown in Figure 8, the side insulating member 610 is embedded in the joint surface of the first cell 100 and the second cell 200. The side insulating member 610 may be in contact with and fixed to a part of the main surface of the first current collector 210, a part of the main surface of the second current collector 150, and a part of the conductive part 412. That is, the side insulating member 610 may be in contact with at least a part of the main surface of the first cell 100 or the second cell 200. As a result, the adhesion of the side insulating member 610 is enhanced by an anchoring effect, improving the mechanical strength of the stacked battery 1700. As a result, a battery with excellent performance that is resistant to impact and deformation can be realized. Furthermore, if a part of the side of the conductive part 412 is covered with the side insulating member 610 and the conductive part 412 is integrated with the upper and lower current collectors, a battery with high reliability that is resistant to impact and stress can be realized.

[0235] (Eighth embodiment) The eighth embodiment will now be described. Matters described in the above embodiments may be omitted as appropriate.

[0236] Figure 9 is a cross-sectional view and a plan view showing the schematic configuration of the stacked battery 1800 of the eighth embodiment.

[0237] Figure 9(a) is a cross-sectional view of the stacked battery 1800 of the eighth embodiment. Figure 9(b) is a plan view of the stacked battery 1800 of the eighth embodiment viewed from below in the z-axis direction. Figure 9(a) shows a cross-section at the position indicated by the line IX-IX in Figure 9(b).

[0238] As shown in Figure 9, the stacked battery 1800, like the stacked battery 1600 and the stacked battery 1700, is equipped with a side insulating member 620 on the side of the stacked battery. It differs from the stacked battery 1600 in that the insulating portion 428 has a protruding portion that extends outward from the outer edge of the first cell 100 and the second cell 200. The side insulating member 620 covers the protruding portion of the insulating portion 428.

[0239] With the above configuration, the protruding portion of the insulating part 428 can absorb impacts to the side of the battery during the manufacturing process, etc. As a result, the detachment of active material from the side of the battery and deformation of the end of the current collector can be suppressed. In addition, the adhesion of the side insulating member 620 is enhanced by the anchoring effect, improving the mechanical strength of the stacked battery 1800. As a result, a battery with excellent performance that is resistant to impact and deformation can be realized.

[0240] The protruding portion of the insulating part 428 is formed, for example, by applying a paste to form the insulating part 428 to the side surface of the stacked battery 1000 using screen printing, or by stamp transfer.

[0241] The degree of exposure of the insulating portion 428 may be 10 μm or more. That is, the insulating portion 428 may protrude 10 μm or more from the side surface of the stacked battery 1800.

[0242] Similar to the insulating portion 428, the conductive portion 410 may have protruding portions that extend outward from the outer edges of the first cell 100 and the second cell 200. With this configuration, the protruding portions can cushion impacts during the manufacturing process and protect the sides of the battery. As a result, the detachment of active material from the sides of the battery and deformation of the current collector can be reduced. In addition, the adhesion of the side insulating member 620 is enhanced by the anchoring effect, improving the mechanical strength of the stacked battery 1800. Therefore, a battery with excellent performance that is resistant to impact and deformation can be realized while suppressing characteristic degradation and short circuits.

[0243] [Battery manufacturing method] The following describes an example of a manufacturing method for the stacked battery according to this disclosure.

[0244] Here, as an example, we will describe the manufacturing method of the stacked battery 1000 according to the first embodiment.

[0245] In the following, the first current collector 110 and the first active material layer 120 are the positive electrode, and the second active material layer 140 and the second current collector 150 are the negative electrode. That is, the first current collector 110 is the positive electrode current collector, the first active material layer 120 is the positive electrode active material layer, the second active material layer 140 is the negative electrode active material layer, and the second current collector 150 is the negative electrode current collector.

[0246] First, pastes are prepared for printing and forming the positive electrode active material layer and the negative electrode active material layer. As the solid electrolyte used in the mixture of the positive electrode active material layer and the negative electrode active material layer, for example, a glass powder of Li2S-P2S5 sulfide with an average particle size of approximately 2 μm and mainly composed of triclinic crystals is prepared. This glass powder is, for example, 3 × 10 -3 S / cm or more and 4×10 -3 It has an ionic conductivity of S / cm or less.

[0247] As a positive electrode active material, for example, a layered Li·Ni·Co·Al composite oxide (e.g., LiNi) has an average particle size of approximately 3 μm. 0.8 Co 0.15 Al 0.05 O2 powder is used. A paste for the positive electrode active material layer is prepared by dispersing a mixture containing the above-mentioned positive electrode active material and the above-mentioned glass powder in an organic solvent or the like.

[0248] As the negative electrode active material, for example, natural graphite powder with an average particle size of approximately 4 μm is used. A paste for the negative electrode active material layer is prepared by dispersing a mixture containing the above-mentioned negative electrode active material and the above-mentioned glass powder in an organic solvent or the like.

[0249] Next, an Al foil with a thickness of approximately 20 μm is prepared as the positive electrode current collector. A Cu foil with a thickness of approximately 20 μm is prepared as the negative electrode current collector. By screen printing, a paste for the positive electrode active material layer is printed on one surface of the Al foil in a predetermined shape and with a thickness of approximately 50 μm or more and 100 μm or less. Similarly, a paste for the negative electrode active material layer is printed on one surface of the Cu foil in a predetermined shape and with a thickness of approximately 50 μm or more and 100 μm or less. The pastes for the positive electrode active material layer and the pastes for the negative electrode active material layer are dried at a temperature of 80°C or higher and 130°C or lower. In this way, a positive electrode active material layer is formed on the positive electrode current collector, and a negative electrode active material layer is formed on the negative electrode current collector. The positive electrode and negative electrode each have a thickness of 30 μm or more and 60 μm or less.

[0250] Next, a paste for a solid electrolyte layer is prepared by dispersing the mixture containing the aforementioned glass powder in an organic solvent or the like.

[0251] The paste for the solid electrolyte layer described above is printed onto the positive electrode active material layer and the negative electrode active material layer using a metal mask to a thickness of, for example, about 100 μm. It is then dried at a temperature between 80°C and 130°C.

[0252] Next, a solid electrolyte layer printed on the positive electrode active material layer and a solid electrolyte layer printed on the negative electrode active material layer are stacked so that they are in contact with and facing each other. The stacked laminate is then housed in a die-shaped container with a rectangular outline.

[0253] Next, between the pressurized mold plate and the laminate, the elastic modulus is 5 × 10 6 An elastic sheet with a Pa of approximately Pa (thickness 50 μm to 100 μm) is inserted.

[0254] The elastic sheet may be embossed on the surface in contact with the plate-like member so that its surface roughness Rz is approximately 1 μm or more and 10 μm or less. The surface roughness Rz of the elastic sheet may be, for example, 1 μm or more and 5 μm or less.

[0255] Subsequently, the pressurized mold is heated to a temperature of 50°C or higher and 80°C or lower while pressurized at a pressure of 300 MPa or higher and 350 MPa or lower for approximately 90 seconds. As a result, a first cell is obtained in which a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector are stacked.

[0256] Next, a thermosetting conductive paste containing Ag particles and a thermosetting epoxy-based insulating resin material are screen-printed onto the main surface of the second current collector of the first cell to a thickness of approximately 1 μm or more and 5 μm or less, respectively. These form the conductive and insulating parts of the bonding layer. Subsequently, the second cell, manufactured in the same manner as the first cell, is placed on top of this in a series connection. After that, the first cell, bonding layer, and second cell are subjected to a load of approximately 10 kg / cm². 2 The two parts are then crimped together. At this time, the conductive part and the insulating part may be embedded in the first current collector of the second cell by a depth of approximately 1 μm or more and 3 μm or less from the main surface of the first current collector of the second cell. This creates an anchoring effect and provides a strong bond.

[0257] Then, the pressure (for example, about 1 kg / cm²) 2 While applying a heat treatment, the product is kept still and subjected to a heat curing treatment at approximately 100°C to 130°C for 40 to 100 minutes. Then, it is slowly cooled to room temperature. In this way, the stacked battery 1000 of the first embodiment is obtained.

[0258] Furthermore, if you wish to increase the number of single cells connected in series, that is, if you wish to stack three or more single cells, you should repeat the steps up to the point before the heat curing treatment, and then perform the heat curing treatment.

[0259] If you want to form a thin bonding layer, for example, a thin conductive part, you can use finer or flaky conductive particles such as Ag particles.

[0260] Furthermore, a low-melting-point metal can be added to the conductive paste with the aim of forming an alloy with the current collector during hardening.

[0261] The method and sequence of forming the battery are not limited to the above examples.

[0262] In the above manufacturing method, examples of applying the paste for the positive electrode active material layer, the paste for the negative electrode active material layer, the paste for the solid electrolyte layer, the conductive paste, and the insulating resin material by printing are shown, but it is not limited thereto. As the printing method, for example, a doctor blade method, a calendar method, a spin coating method, a dip coating method, an inkjet method, an offset method, a die coating method, or a spray method may be used.

[0263] As described above, the laminated battery of the present disclosure has been described based on the embodiments, but the present disclosure is not limited to these embodiments. For example, a battery combining the laminated battery of the second embodiment and the laminated battery of the third embodiment may be configured. As long as it does not depart from the gist of the present disclosure, various modifications conceived by those skilled in the art to the embodiments, and another form constructed by combining some components in the embodiments are also included in the scope of the present disclosure.

Industrial Applicability

[0264] The laminated battery according to the present disclosure can be used as a secondary battery such as an all-solid-state lithium-ion battery used in, for example, various electronic devices or automobiles.

Description of Reference Numerals

[0265] 100 First single battery 110, 210, 310 First current collector 120, 220, 320 First active material layer 130, 230, 330 Solid electrolyte layer 140, 240, 340 Second active material layer 150, 250, 350 Second current collector 200 Second single battery 300 Third single battery 400, 401 Bonding layer 410, 411, 412, 413, 414a, 414b, 414c, 415 Conductive part 420, 421, 422, 423, 424, 425, 428 Insulation part 500 Contact area 600, 610, 620 Side insulating material 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800 Stacked Cells

Claims

1. First single cell, Second single cell, and A junction layer disposed between the first cell and the second cell. Equipped with, The bonding layer includes a conductive portion and an insulating portion. A stacked battery in which the first cell and the second cell are electrically connected via the conductive part.

2. In the bonding layer, the conductive portion and the insulating portion have the same thickness. The stacked battery according to claim 1.

3. The conductive part includes a conductive resin material. The stacked battery according to claim 1 or 2.

4. The conductive resin material contains silver, The stacked battery according to claim 3.

5. The insulating portion is disposed between the first cell or the second cell and the conductive portion. The stacked battery according to claim 1.

6. The insulating portion includes at least one selected from the group consisting of insulating resin materials and oxides. The stacked battery according to claim 1.

7. The insulating part is softer than the conductive part. The stacked battery according to claim 1.

8. At least one selected from the group consisting of the conductive portion and the insulating portion is located at the outer edge of the bonding layer in a plan view of the stacked battery. The stacked battery according to claim 1.

9. A portion of the bonding layer is exposed on the surface of the stacked battery. The stacked battery according to claim 1.

10. At least one selected from the group consisting of the conductive part and the insulating part is provided in a frame-like or grid-like manner. The stacked battery according to claim 1.

11. Satisfying at least one of the following (A) and (B): (A) The bonding layer includes a plurality of the conductive parts (B) The bonding layer includes a plurality of the insulating portions The stacked battery according to claim 1.

12. If condition (A) above is met, the plurality of conductive parts include a first conductive part and a second conductive part having different hardnesses from each other. If (B) above is satisfied, the stacked battery according to claim 11, wherein the plurality of insulating parts include a first insulating part and a second insulating part having different hardnesses.

13. The first conductive portion is harder than the second conductive portion, and in a plan view of the stacked battery, the first conductive portion is located closer to the outer edge of the battery than the second conductive portion. The first insulating portion is harder than the second insulating portion, and in a plan view of the stacked battery, the first insulating portion is located closer to the outer edge of the battery than the second insulating portion. The stacked battery according to claim 12.

14. If condition (A) above is met, the plurality of conductive parts have a configuration in which the conductive parts are regularly arranged at predetermined intervals in a plan view of the stacked battery, If (B) above is satisfied, the plurality of insulating parts have a configuration in which the insulating parts are regularly arranged at predetermined intervals in a plan view of the stacked battery. The stacked battery according to claim 11.

15. At least one selected from the group consisting of the conductive portion and the insulating portion has a portion embedded in at least one selected from the group consisting of the first cell and the second cell. The stacked battery according to claim 1.

16. The conductive part is in contact with the insulating part. The stacked battery according to claim 1.

17. The surface of the insulating part has an embossed shape. The stacked battery according to claim 1.

18. The aforementioned surface is the surface that is in contact with the first cell or the second cell. The stacked battery according to claim 17.

19. The aforementioned surface is the surface that is in contact with the conductive part. The stacked battery according to claim 17.

20. Further comprising side insulating members, The aforementioned side insulating member is in contact with the side surface of the stacked battery, The stacked battery according to claim 1.

21. The side insulating member is in contact with at least one selected from the group consisting of the conductive portion and the insulating portion. The stacked battery according to claim 20.

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