LAMINATED BATTERY AND MANUFACTURING METHOD FOR IT

Abstract

Laminated battery (200) with a plurality of power generating elements (100), wherein each of the current-generating elements (100) comprises a first electrode layer (20), a second electrode layer (40) and a solid electrolyte layer (30) inserted between the first electrode layer (20) and the second electrode layer (40), wherein the second electrode layer (40) is a negative electrode layer if the first electrode layer (20) is a positive electrode layer, and the second electrode layer (40) is a positive electrode layer if the first electrode layer (20) is a negative electrode layer, the laminated battery (200) comprises a first collector (110), the majority of the power generating elements (100) are stacked over the first collector (110), wherein the first collector (110) is a positive electrode collector if the first electrode layer (20) is a positive electrode layer, and the first collector (110) is a negative electrode collector if the first electrode layer (20) is a negative electrode layer, a dimension of a principal surface of the first collector (110) is smaller in at least one direction than a dimension of a principal surface of the first electrode layer (20) in the same direction, wherein the direction is a direction perpendicular to a stacking direction (Y) of the current generating elements (100), and an insulating adhesive (120) is arranged at a position outside a principal surface of the first collector (110) and spans an edge of the first collector (110), such that the insulating adhesive (120) binds a principal surface of one of the power generating elements (100) and a principal surface of an adjacent power generating element (100), each principal surface of a power generating element (100) being a surface with a largest total area.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present disclosure relates to a laminated battery. Furthermore, the present disclosure relates to a manufacturing process for the laminated battery. 2. Description of the state of the art

[0002] With the increasing prevalence of secondary batteries, such as lithium-ion batteries, ever higher power outputs are demanded of them. Solid-state batteries, in which a liquid electrolyte is replaced by a solid electrolyte, have moved into the spotlight as high-performance secondary batteries. Typically, all solid-state batteries are equipped with power-generating elements, each comprising a positive electrode, a negative electrode, and a solid electrolyte inserted between the positive and negative electrodes.

[0003] Solid-state batteries are known to be stacked solid-state batteries in which the power-generating elements are stacked on top of each other (see, for example, JP 2017-204 377 A). JP 2017-204 377 A discloses a feature in which, to fix stacked power-generating elements (of a battery unit), a thermoplastic resin is applied as a binder to a main surface of a first collector of a given battery unit, and the thermoplastic resin connects the first collector of the given battery unit and a battery unit located next to the given battery unit.

[0004] From US patent 2018 / 0 198 170 A1, which is considered the closest prior art patent, a laminated battery is known, comprising a plurality of current-generating elements, a positive electrode layer, a negative electrode layer, and a solid electrolyte layer inserted between the positive and negative electrode layers. A first current-generating element is arranged with its positive electrode layer facing a positive electrode collector and positioned above the positive electrode collector. An insulating adhesive is applied to a major surface of the positive electrode collector such that the insulating adhesive bonds a major surface of the positive electrode collector and a major surface of a negative electrode collector positioned above the current-generating element. BRIEF EXPLANATION OF THE INVENTION

[0005] However, in the aforementioned conventional configuration, an insulating thermoplastic resin is used on a main surface of the first collector, in particular on both main surfaces of the first collector, so that there is an area on the collector that cannot be used for current collection. Accordingly, there is still potential for improvement regarding the current collection characteristics.

[0006] Therefore, the present disclosure has the purpose of providing a laminated battery that has better power collection properties.

[0007] A laminated battery disclosed herein comprises the features listed in claim 1.

[0008] Such a configuration makes it possible to provide a laminated battery with better power collection characteristics.

[0009] In a preferred embodiment of the laminated battery disclosed herein, in one stacking direction of the power generating elements, one dimension of the insulating adhesive is larger than one of the first collector.

[0010] In such a configuration, the adhesion or bonding reliability is higher due to the insulating adhesive.

[0011] In a preferred embodiment of the laminated battery disclosed here, the insulating adhesive has cavities inside.

[0012] When the laminated battery is used while being compressed or held, such a configuration makes it possible to limit excessive dimensional changes in the insulating adhesive caused by the pressure of compression or holding.

[0013] A manufacturing process according to the invention for a laminated battery comprises the steps set out in claim 4.

[0014] Such a configuration makes it possible to produce a laminated battery with better power collection properties.

[0015] In a preferred implementation of the method disclosed herein for manufacturing a laminated battery, the manufacturing process further comprises a step in which pressure is applied to the insulating adhesive by applying pressure to a major surface of the power generating elements from a major surface inside towards a major surface outside.

[0016] This arrangement allows excess insulating adhesive to be squeezed out of the stack of power generating elements, making it easy to adjust the dimension of the insulating adhesive in the stacking direction of the power generating elements to a preferred dimension. BRIEF EXPLANATION OF THE DRAWINGS Fig. Figure 1 is a schematic section showing an example of the configuration of a laminated battery according to an embodiment of the present disclosure; Fig. Figure 2 is a schematic section showing an example of the configuration of a power generating element of a laminated battery according to an embodiment of the present disclosure; Fig. Figure 3 is a schematic section showing a modification of the configuration of a laminated battery according to an embodiment of the present disclosure; Fig. Figure 4 is a schematic section showing a further modification of the configuration of a laminated battery according to an embodiment of the present disclosure; Fig. Figure 5 is a schematic representation showing a collector arrangement step in a preferred manufacturing process of the laminated battery according to an embodiment of the present disclosure; Fig. Figure 6 is a schematic representation showing a power generation element arrangement step in a preferred manufacturing process of a laminated battery according to an embodiment of the present disclosure; and Fig. Figure 7 is a schematic representation showing a pressure application step in a preferred manufacturing process of a laminated battery according to an embodiment of the present disclosure. EXPLANATION OF THE PREFERRED EXECUTION FORMS

[0017] Embodiments of the present disclosure are explained below with reference to the accompanying drawings. All features not specifically mentioned in this description that may be necessary for carrying out the present disclosure (e.g., general configurations and manufacturing processes of laminated batteries that are not characteristic of the present disclosure) can be considered a matter of design by a person skilled in the art based on the prior art in the relevant technical field. The present disclosure can be carried out on the basis of the disclosure in this description and the general technical knowledge in the relevant technical field. In the drawings, elements and parts that achieve identical effects are identified by the same reference numerals and are explained below. The dimensional relationships (length, width, thickness, etc.)The dimensions shown in the drawings do not reflect the actual dimensions.

[0018] In this description, the term "battery" generally refers to energy storage devices from which electrical energy can be drawn and fundamentally includes primary and secondary batteries. In this description, the term "secondary battery" generally refers to an energy storage device that can be repeatedly charged and discharged and includes so-called storage batteries (i.e., chemical batteries) such as lithium-ion secondary batteries, nickel-hydride batteries, and nickel-cadmium batteries, as well as capacitors (i.e., physical batteries) such as electrical double-layer capacitors.

[0019] Fig. Figure 1 schematically shows the structure of a laminated battery according to the present embodiment. Fig. Figure 1 is a section along the width direction of a laminated battery equipped with rectangular, plate- or layer-shaped electrodes.

[0020] As in Fig. Figure 1 shows the laminated battery 200 equipped with a plurality of power generating elements 100. In the example shown, the laminated battery 200 is equipped with three power generating elements 100, although the number of power generating elements 100 is not particularly limited as long as it is a plurality, i.e., two or more. The laminated battery 200 can comprise no fewer than 2 and no more than 50, or no fewer than 2 and no more than 20 power generating elements 100.

[0021] Fig. Figure 2 shows the specific configuration that each of the 100 power generation elements has. Fig. 2 is a section along the width direction of the electrodes and the current generating element 100.

[0022] Each current-generating element 100 is provided with a positive electrode layer 20 as a first electrode layer, a negative electrode layer 40 as a second electrode layer, and a solid electrolyte layer 30 inserted between the positive electrode layer 20 and the negative electrode layer 40. The current-generating element 100 can additionally include a negative electrode collector layer 50, as in the example shown. The negative electrode collector layer 50, the negative electrode layer 40, the solid electrolyte layer 30, and the positive electrode layer 20 are stacked sequentially on top of each other in each current-generating element 100. The positive electrode layer 20 faces the negative electrode layer 40 via the solid electrolyte layer 30.

[0023] Since, in the illustrated example, a laminated battery 200 can be efficiently manufactured with a large number of stacked power-generating elements 100, the negative electrode layer 40, the solid electrolyte layer 30, and the positive electrode layer 20 are arranged sequentially on each side of the negative electrode collector layer 50. However, the configuration of the power-generating elements 100 is not limited to this, as long as each power-generating element 100 is provided with a positive electrode layer 20, a solid electrolyte layer 30, and a negative electrode layer 40. For example, the power-generating elements 100 can be configured to each contain a positive electrode layer 20, a solid electrolyte layer 30, a negative electrode layer 40, and any one negative electrode collector layer 50.

[0024] In the illustrated example, the positive electrode layer 20 comprises a positive electrode active material layer 22 and an insulating layer 24 formed at the edges of the positive electrode active material layer 22. As in the illustrated example, the positive electrode layer 20 can comprise the positive electrode active material layer 22 and a functional layer such as the insulating layer 24; alternatively, the positive electrode layer 20 can also comprise only the positive electrode active material layer 22.

[0025] The positive electrode active material layer 22 comprises a positive electrode active material.

[0026] A known material used in solid-state batteries can be used as the positive electrode active material. Examples of positive electrode active materials include lithium transition metal compound oxides such as lithium nickel compound oxides, lithium cobalt compound oxides, lithium manganese compound oxides, lithium nickel cobalt manganese compound oxides, lithium nickel cobalt manganese compound oxides, and the like; as well as lithium compound compounds with an olivine structure such as LiFePO4.

[0027] The average particle size of the positive electrode active material is not particularly limited, but is, for example, not less than 0.5 µm and not more than 20 µm, preferably not less than 1 µm and not more than 10 µm.

[0028] The positive electrode active material layer 22 may also contain a solid electrolyte. The same examples apply to the solid electrolyte as to the solid electrolyte used in the solid electrolyte layer 30 described below.

[0029] The positive electrode active material layer 22 can also contain, as required, a conductive material (e.g., carbon black such as acetylene carbon black, graphite, steam-grown carbon fibers (VGCFs) or carbon nanotubes) and a binder (e.g., a fluorine-based binder such as polyvinylidene fluoride (PVDF) or polyethylene terephthalate (PTFE), or a rubber-based binder such as styrene-butadiene rubber (SBR)).

[0030] The thickness of the positive electrode active material layer 22 is not particularly limited, but is, for example, not less than 0.1 µm and not more than 1000 µm, preferably not less than 10 µm and not more than 500 µm.

[0031] In the present embodiment, in a direction perpendicular to the stacking direction Y of the current-generating elements 100 (i.e., in the direction of the main surface of the current-generating elements 100), the dimension of the positive electrode active material layer 22 is smaller than that of the negative electrode active material layer of the negative electrode layer 40. Therefore, in the present embodiment, the formation area of ​​the negative electrode active material layer is larger than the formation area of ​​the positive electrode active material layer 22. Such a configuration makes it possible to suppress the deposition of metallic lithium.

[0032] In this description, the term "main area" refers to the area with the largest total area.

[0033] In the direction perpendicular to the stacking direction Y of the current-generating elements 100, the dimension of the positive electrode active material layer 22 is set smaller than that of the negative electrode active material layer of the negative electrode layer 40, thereby creating a space at the edges of the positive electrode active material layer 22. Thus, in the present embodiment, the insulating layer 24 is arranged in this space. Short circuits between the positive electrode collector 110 and the negative electrode layer 40 can be prevented by the insulating layer 24.

[0034] The insulating layer 24 comprises an insulating material, in particular, for example, a resin material or an inorganic material.

[0035] The resin material can be either a thermoplastic resin (e.g., an acrylic resin or polypropylene) or a thermosetting resin, but preferably a thermoplastic resin. Thermoplastic resins have the advantage that the insulating layer 24 can be easily shaped by applying it in a molten state and then cooling it.

[0036] A UV-curable resin (for example, a UV-curable acrylic resin) containing a polymerizable monomer and a photopolymerization initiator can be used as the resin material. Such UV-curable resins are advantageous in that they allow for the simple formation of the insulating layer 24 by application and subsequent UV irradiation.

[0037] Examples of inorganic materials include inorganic oxides such as aluminum oxide (Al₂O₃), magnesia (MgO), silicon dioxide (SiO₂), and titanium dioxide (TiO₂); nitrides such as aluminum nitride and silicon nitride; metal hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; clay minerals such as mica, talc, boehmite, zeolites, apatite, and kaolin; and glass fibers. The foregoing may be used individually or in combinations of two or more. Among these, aluminum oxide and boehmite are preferred. In a case where the insulating layer 24 contains an inorganic material (in particular, an inorganic filler), it may contain a binder (e.g., a fluorine-based binder such as PVDF or PTFE, or a rubber-based binder such as SBR). With regard to high mechanical strength of the insulating layer 24, it is advantageous for the insulating layer 24 to be made of an inorganic material.

[0038] The insulating layer 24 can have a multilayered structure. For example, the insulating layer 24 can have a base material layer and an adhesive layer. Accordingly, the insulating layer 24 can be an adhesive tape or an adhesive film with a base material layer and an adhesive layer. The case in which the insulating layer 24 comprises an adhesive tape or an adhesive film is advantageous insofar as it can then be easily and uniformly formed to a preferred thickness.

[0039] The dimensions of the insulating layer 24 are not particularly limited, as long as the insulating layer 24 can fulfill its function of preventing short circuits. The laminated battery 200 is inserted while a holding force is applied to it. Therefore, it is preferred that a holding force is applied to the positive electrode active material layer 22, whereas no holding force is applied to the insulating layer 24. Thus, the thickness of the insulating layer 24 is typically equal to or less than that of the positive electrode active material layer 22, and preferably less than that of the positive electrode active material layer 22. The thickness of the insulating layer 24 is preferably 98% or less of that of the positive electrode active material layer 22, and more preferably 96% or less.In contrast, the thickness of the insulating layer 24 is preferably 20% or more, preferably 30% or more and even more preferably 40% or more of that of the positive electrode active material layer 22, since in this case the short-circuit prevention performance is higher.

[0040] The solid electrolyte layer 30 contains a solid electrolyte.

[0041] A known solid electrolyte used in solid-state batteries can be used here. Examples of solid electrolyte materials include sulfide solid electrolyte materials, oxide solid electrolyte materials, nitride solid electrolyte materials, and halide solid electrolyte materials. Examples of sulfide solid electrolyte materials include sulfide materials such as Li₂S-P₂P₂-based materials (e.g., a sulfide solid electrolyte produced by mixing Li₂S / P₂P₂ (mass ratio) = 50 / 50 or higher, particularly in a ratio of 70 / 30), Li₂S-GeS₂-based materials, Li₂S-GeS₂-P₂P₂-based materials, Li₂S-SiS₂-based materials, Li₂S-B₂S₃-based materials, Li₃PO₄-P₂P₂-based materials, and the like. For example, a material can be used (e.g.LiI-Li₂S-P₂P₂, LiCI-Lil-Li₂S-P₂P₂, LiBr-Lil-Li₂S-P₂P₂, Lil-Li₂S-SiS₂, or Lil-Li₂S-B₂S₃), which is obtained by adding a lithium halide to the aforementioned sulfide materials. Examples of oxide solid electrolyte materials are lithium lanthanum-zirconium mixed oxides (LLZO), Al-doped LLZO, lithium lanthanum-titanium mixed oxides (LLTO), Al-doped LLTO, and lithium phosphate oxynitride (LIPON).

[0042] The average particle size of the solid electrolyte is not particularly limited, but is, for example, not less than 0.1 µm and not more than 10 µm, preferably not less than 0.3 µm and not more than 5 µm.

[0043] The solid electrolyte layer 30 may also contain a binder (e.g. a fluorine-based binder such as PVDF or PTFE or a rubber-based binder such as butadiene rubber (BR) or SBR).

[0044] The thickness of the solid electrolyte layer 30 is not particularly limited, but is, for example, not less than 0.1 µm and not more than 1,000 µm, preferably not less than 0.1 µm and not more than 300 µm.

[0045] In the present embodiment, the entire negative electrode layer 40 is constructed as a negative electrode active material layer. The negative electrode layer 40 can be made up of a negative electrode active material layer and a functional layer.

[0046] The negative electrode active material layer from which the negative electrode layer 40 is made contains a negative electrode active material.

[0047] A known material used in solid-state batteries can be used as the negative electrode active material. Examples of negative electrode active materials include carbon-based negative electrode active materials such as graphite, hard carbon, soft carbon, and carbon nanotubes; silicon-based negative electrode active materials such as silicon dioxide, silicon oxide, silicon carbide, and silicon nitride; and tin-based negative electrode active materials such as tin, tin oxide, tin nitride, and tin-containing alloys.

[0048] The average particle size of the negative electrode active material is not particularly limited, but is, for example, not less than 1 µm and not more than 20 µm, preferably not less than 2 µm and not more than 10 µm.

[0049] Unless otherwise specified, the term “average particle size” in this description refers to a particle size (also referred to as D50 particle size; median size) that is greater than 50% of the particles in a volume-based particle size distribution obtained from a particle size distribution measurement based on a laser diffraction light scattering method.

[0050] The negative electrode active material layer may further contain a solid electrolyte. Examples of solid electrolytes include the same as those mentioned above for use in the solid electrolyte layer 30.

[0051] The negative electrode active material layer can also contain, depending on requirements, a conductive material (e.g., carbon black such as acetylene black, vapor-phase grown carbon fibers (VGCFs) and carbon nanotubes) and a binder (e.g., a fluorine-based binder such as PVDF or PTFE, or a rubber-based binder such as SBR).

[0052] The thickness of the negative electrode layer 40 is not particularly limited, but is, for example, not less than 0.1 µm and not more than 1000 µm, preferably not less than 10 µm and not more than 500 µm.

[0053] The negative electrode collector layer 50 is typically made of a metallic material that is not easily alloyed with Li and exhibits good conductivity. Examples of the metallic material are Cu, Ni, Fe, Ti, Co, Zn, and alloys (e.g., stainless steel) containing at least one of these metals; the metallic material is preferably Cu. The negative electrode collector layer 50 is preferably made of a foil-like body, particularly suitable a copper foil.

[0054] The negative electrode collector layer 50 can have additional layers besides the layer of the aforementioned metallic material.

[0055] The thickness of the negative electrode collector layer 50 is not particularly limited, but with regard to the compromise between the capacity density of the battery and the collector thickness, it is preferably not less than 5 µm and not more than 50 µm and more preferably not less than 8 µm and not more than 40 µm.

[0056] As in Fig. Figure 1 shows the laminated battery 200 with a positive electrode collector 110 as a first collector. The positive electrode collector 110 is arranged between two adjacent power generating elements 100. This means that the power generating elements 100 are stacked above their respective positive electrode collectors 110.

[0057] As in the example shown, the positive electrode collector 110 can still be provided as the outermost layer.

[0058] The positive electrode collector 110 is typically made of a metallic material with good conductivity. Examples of the aforementioned metallic materials are Al, Ni, Cr, Pt, Fe, Ti, Zn, and alloys (e.g., stainless steel or nitrogen-containing alloys) containing at least one of these metals; the metallic material is preferably Al. The positive electrode collector 110 is suitably manufactured from a foil-like body, particularly preferably from an aluminum foil.

[0059] The positive electrode collector 110 can have additional layers besides the layer of the aforementioned metallic material. Examples of other layers are carbon coating layers (e.g., a surface layer containing 15 wt% carbon and 85 wt% PVDF).

[0060] The dimension of the main surface of the positive electrode collector 110 in at least one direction is smaller than that of the main surface of the positive electrode layer 20 in the same direction. Therefore, for example, the dimension of the positive electrode collector 110 is smaller than the dimension of the positive electrode layer 20 in one direction along the long side of a main surface of the positive electrode collector 110 (i.e., in the longitudinal direction of the positive electrode collector 110) and / or in one direction along a short side of the main surface of the positive electrode collector 110 (i.e., in the transverse direction of the positive electrode collector 110).

[0061] In the example shown, the dimension of the main area of ​​the positive electrode collector 110 is smaller in the width direction than that of the main area of ​​the positive electrode layer 20.

[0062] The dimensions of the main surface of the positive electrode collector 110 are preferably equal to or larger than those of the main surface of the positive electrode active material layer 22. Thus, it is possible to collect current over the entire main surface of the positive electrode active material layer 22.

[0063] In a case where the positive electrode collector 110 has a collector strip, the collector strip is not included in the dimension of the main area of ​​the positive electrode collector 110.

[0064] The thickness of the positive electrode collector 110 is not particularly limited, but taking into account the compromise between the capacity density of the battery and the collector thickness, it is preferably not less than 5 µm and not more than 50 µm, and even more preferably not less than 8 µm and not more than 30 µm.

[0065] In the present embodiment, an insulating adhesive 120 is arranged at a position spanning an edge of the positive electrode collector 110, so that it bonds to the main surfaces of two adjacent current generating elements 100.

[0066] Specifically, the insulating adhesive 120 is positioned outside the main surfaces of the positive electrode collector 110 and has a dimension in the stacking direction Y of the power generating elements 100 that is equal to or greater than the thickness of the positive electrode collector 110. The insulating adhesive 120 bonds a main surface of the positive electrode layer 20 of one power generating element 100 and a main surface of a positive electrode layer 20 of an adjacent power generating element 100.

[0067] Such a configuration offers better current collection properties, since the current can be collected from the entire surface of the positive electrode collector 110 that is in contact with the positive electrode active material layer 22.

[0068] In some techniques, power-generating elements are first stacked on top of each other and then fixed by sealing the sides of the resulting stack. However, such techniques often lead to stack misalignment because the sealing occurs after stacking. Furthermore, in cases where the battery thickness is small, it is difficult to fix the power-generating elements by sealing. Moreover, the energy efficiency of the resulting laminated battery is low because an insulating sealing material occupies the edges of the stack of power-generating elements. In contrast, in the present embodiment, each power-generating element 100 is fixed as it is added, thus making stack misalignment less likely. Furthermore, the power-generating elements 100 can be easily fixed even with a thin laminated battery 200.Furthermore, the volume energy efficiency is high, as the volume of the gap between the power generating elements is used to connect 100.

[0069] The insulating adhesive 120 can also be applied at positions separate from the positive electrode collector 110. However, the insulating adhesive 120 is preferably arranged in contact with a side surface of the positive electrode collector 110, since the elements comprising the laminated battery 200 (i.e., the current-generating elements 100 and the positive electrode collector 110) are firmly fixed in this case. Therefore, the insulating adhesive 120 preferably bonds a main surface of the positive electrode layer 20 of a current-generating element 100, a main surface of the positive electrode layer 20 of an adjacent current-generating element 100, and the side surface of the positive electrode collector 110 to one another.

[0070] A portion of the insulating adhesive 120 may protrude from the gaps between the power-generating elements 100. That is, an outer edge section of the insulating adhesive 120 may protrude from the side surface of the laminated battery 200. However, it is preferred that the entire insulating adhesive 120, as in the illustrated example, is located in the gaps between two corresponding power-generating elements 100. That is, the insulating adhesive 120 preferably does not protrude from the side surface of the laminated battery 200.

[0071] Examples of suitable insulating adhesives include hot melt adhesives (such as those based on ethylene-vinyl acetate copolymer (EVA) and those based on polyolefins such as low-density polyethylene (LDPE) or similar); epoxy resin-based adhesives; acrylic resin-based adhesives; urethane resin-based adhesives; silicone resin-based adhesives; rubber-based adhesives; and UV-curable adhesives.

[0072] The laminated battery 200 is used under external pressure. Since the insulating adhesive 120 can be easily compressed to a preferred dimension by the holding force, an adhesive with a low modulus of elasticity is preferred as the insulating adhesive 120. Specifically, a hot melt adhesive or a UV-curable adhesive is preferred as the insulating adhesive 120. The modulus of elasticity of the insulating adhesive 120 is preferably 20 MPa or less.

[0073] Fig. Figure 3 shows a modification of the present embodiment. In the Fig. In the third modification shown, only the positive electrode layer 20, the positive electrode collector 110, and the insulating adhesive 120 are depicted. In this modification, the dimension of the insulating adhesive 120 is larger than that of the positive electrode collector 110 in the Y direction (i.e., in the stacking direction of the current-generating elements 100) (i.e., larger than the thickness of the positive electrode collector 110). With this configuration, the bond is more reliable because the insulating adhesive 120 can be more easily brought into contact with the main surface of the current-generating elements 100.

[0074] Fig. Figure 4 shows a further modification of the present embodiment. In the Fig. In the modification shown in Figure 4, only the positive electrode layer 20, the positive electrode collector 110, and the insulating adhesive 120 are depicted. In this modification, the insulating adhesive 120 has internal cavities 122. The cavities 122 are formed, for example, by bubbles, hollow resin particles, or similar features.

[0075] The laminated battery 200 is used under the influence of external pressure. Thus, the insulating adhesive 120 is compressed by a holding pressure, but the dimensions of the insulating adhesive 120 may deviate significantly from the preferred dimensions due to excessive deformation.

[0076] However, in a case where the insulating adhesive 120 has cavities 122 in its interior, excessively large dimensional changes of the insulating adhesive 120 resulting from the holding pressure can be suppressed by compressing or closing the cavities 122 through the holding pressure.

[0077] Even more advantageous is a combination of the in Fig. 3 modification shown and the one in Fig. 4 modifications shown.

[0078] The laminated battery 200 can be configured such that the positive and negative electrodes are reversed compared to those in the example shown. For example, the laminated battery 200 can have a configuration in which the first collector is a negative electrode collector, the first electrode layer is a negative electrode layer, the second electrode layer is a positive electrode layer, and the second collector layer is a positive electrode collector.

[0079] The following describes a suitable manufacturing process for the laminated battery 200. However, the manufacturing process for the laminated battery 200 is not limited to this.

[0080] A suitable manufacturing process for the laminated battery 200 comprises a step (hereinafter also referred to as the "power generating element preparation step") in which a plurality of power generating elements 100 are prepared, each of which is provided with the positive electrode layer 20 as the first electrode layer, the negative electrode layer 40 as the second electrode layer, and the solid electrolyte layer 30 inserted between the positive electrode layer 20 and the negative electrode layer 40; a step (hereinafter also referred to as the "collector arrangement step") in which the positive electrode collector 110 as the first collector and the insulating adhesive 120 are arranged on the positive electrode layer 20 of a power generating element 100; and a step (hereinafter also referred to as the "power generating element arrangement step") in which another power generating element 100 is arranged on the positive electrode collector 110.In this case, the insulating adhesive 120 is arranged at a position outside the main surface of the positive electrode collector 110, wherein the dimension of the insulating adhesive 120 in the stacking direction Y of the current generating elements 100 is larger than that of the positive electrode collector 110.

[0081] First, the power generation element preparation step is explained. The power generation element 100 used in this manufacturing process can be produced, for example, in the following way.

[0082] A coating paste containing a negative electrode active material, a binder, etc., is applied to a negative electrode collector as a negative electrode collector layer 50 and then dried to form the negative electrode layer 40 (the negative electrode active material layer).

[0083] A coating paste containing a solid electrolyte is next applied to the formed negative electrode layer 40 and then dried to form the solid electrolyte layer 30.

[0084] Meanwhile, a coating paste, which contains, for example, a positive electrode active material, a binder, etc., is applied to a removable base material and then dried to form the positive electrode active material layer 22 of the positive electrode layer 20.

[0085] The positive electrode active material layer 22 is placed onto the solid electrolyte layer 30 and transferred from the removable base material to the solid electrolyte layer 30 under pressure (e.g., approximately 100 MPa). After transfer, the removable base material is detached from the resulting stack. Pressure (e.g., approximately 600 MPa) can be applied to the stack for compaction, bringing the materials comprising the stack into closer contact with each other.

[0086] In a case where the insulating layer 24 is to be provided at the edges of the positive electrode active material layer 22, as in the example described above, the insulating layer 24 can be suitably shaped depending on the insulating material. For example, the insulating layer 24 can be provided by applying a UV-curable resin to the solid electrolyte layer 30 at the edge positions of the positive electrode active material layer 22 and then irradiating it with ultraviolet radiation. In another example, the insulating layer 24 can be provided by applying a molten resin material to the solid electrolyte layer 30 at the edge positions of the positive electrode active material layer 22 and then cooling it.In another example, the insulating layer 24 can be provided by applying a paste containing an inorganic filler to the solid electrolyte layer 30 at the edge positions of the positive electrode active material layer 22 and then drying it. In yet another example, the insulating layer 24 can be provided by applying an adhesive tape to the solid electrolyte layer 30 at the edge positions of the positive electrode active material layer 22.

[0087] Each power generating element 100 can be obtained in the manner described above. In this step, the power generating elements 100 are prepared in a quantity corresponding to their batch number.

[0088] Next, the collector arrangement step will be explained. Fig. Figure 5 shows an overview of the collector arrangement step.

[0089] In the collector assembly step, the positive electrode collector 110 and the insulating adhesive 120 are arranged on a main surface of the positive electrode layer 20 of the prepared power generating element 100.

[0090] The insulating adhesive 120 is applied to the main surface of the positive electrode layer 20 at positions outside the main surface of the positive electrode collector 110. The insulating adhesive 120 can be spaced apart from the positive electrode collector 110 or be in contact with a side surface of the positive electrode collector 110.

[0091] The insulating adhesive 120 is arranged such that its dimension in the stacking direction Y of the current generating elements 100 is larger than that of the positive electrode collector 110 (i.e. larger than the thickness of the positive electrode collector 110).

[0092] In the example shown, the positive electrode collector 110 is applied after the insulating adhesive 120 has been applied. However, the order in which the positive electrode collector 110 and the insulating adhesive 120 are arranged is not particularly restricted. The insulating adhesive 120 can also be applied only after the positive electrode collector 110 has been arranged; alternatively, the positive electrode collector 110 and the insulating adhesive 120 can also be arranged simultaneously.

[0093] In a case where the insulating adhesive is applied by being fed from one side of a stack consisting of an arrangement of a power generating element, a positive electrode collector, and another power generating element, it easily penetrates between the positive electrode collector and the power generating elements due to the pressure with which it is applied. However, in a collector arrangement step such as the one described above, the insulating adhesive 120 is arranged together with the positive electrode collector 110, so that the insulating adhesive 120 has difficulty penetrating between the positive electrode collector 110 and each power generating element 100.

[0094] As with the in Fig. In the modification shown in Figure 3, the dimension of the insulating adhesive 120 in the stacking direction Y of the power generating elements 100 can be made larger than that of the positive electrode collector 110 by increasing the thickness in which the insulating adhesive 120 is applied or the amount of insulating adhesive 120 applied.

[0095] Furthermore, cavities 122 can be created inside the insulating adhesive 120 by introducing air into the insulating adhesive 120 or by using an insulating adhesive 120 that contains hollow resin particles.

[0096] The power generation element arrangement step will be explained next. Fig. Figure 6 shows an overview of the power generation element arrangement step.

[0097] As in the example shown, another power generating element 100 is placed on top of the power generating element 100 on which the positive electrode collector 110 and the insulating adhesive 120 have been applied.

[0098] Depending on requirements, the power generating elements 100 can be joined together in a single joining process. Depending on the type of adhesive used, appropriate treatment may be performed during the joining process. For example, if an adhesive 120 is used as the insulating adhesive, the joining can be accomplished by attaching the additional power generating element 100, followed by a pressing treatment. Similarly, if a hot melt adhesive 120 is used as the insulating adhesive, a pressing treatment under heat (e.g., at a temperature of approximately 140°C and a pressure of approximately 1 MPa) can be performed after attaching the additional power generating element 100.Furthermore, for example, in a case where a UV-curable adhesive is used as insulating adhesive 120, the insulating adhesive 120 can be irradiated with ultraviolet radiation after the further power generation element 100 has been attached.

[0099] The application of pressure or pressing in the above explanation can be achieved, for example, by mechanical pressing or gas pressure.

[0100] Examples of mechanical pressing methods include a method in which a motor is driven, thereby exerting pressure on the stack in its stacking direction via a ball screw, and a method in which a motor is driven, thereby exerting pressure on the stack in its stacking direction via hydraulic pressure. In this case, the energy consumption associated with driving the motor can be reduced to a necessary minimum by providing a mechanical stop that locks a drive component after the pressure has been raised or lowered to a predetermined level.

[0101] Examples of gas pressurization methods include a method in which the stack is pressed in its stacking direction by a pressurized gas from a gas cylinder.

[0102] These steps result in good current collection properties, as current can be collected from the entire surface of the positive electrode collector 110 that is in contact with the positive electrode active material layer 22. Furthermore, each time a current-generating element 100 is placed, it is fixed in place, thus reducing the likelihood of stacking deviations. Additionally, the current-generating elements 100 can be easily attached to the thin laminated battery 200. Moreover, the volume energy efficiency is high, as the volume of the gap between the current-generating elements 100 is used for connection.

[0103] The foregoing manufacturing process may further include a step (hereinafter also referred to as the ‘pressure application step’) in which pressure is applied to the insulating adhesive 120 by applying pressure to a main surface of the current generating elements 100 from a main surface inside towards a main surface outside.

[0104] Fig.Figure 7 shows an example of the pressure application step. In the example shown, a roller 300 applies pressure to the main surface of a current-generating element 100 from the inner surface towards the outer surface. This pressure is applied in such a way that pressure is exerted on the insulating adhesive 120. Specifically, the roller 300 is rotated and simultaneously moved in the direction of arrow A, applying pressure to the main surface of the current-generating element 100, which in turn exerts pressure on the insulating adhesive 120. In the pressure application step, the pressure-applying means is preferably a roller 300, since in this case the point on which the pressure is applied can be changed; however, the pressure-applying means is not limited to this.

[0105] This pressure application step allows excess insulating adhesive 120 to be pushed out of the stack of power-generating elements 100, thereby easily adjusting the dimensions of the insulating adhesive 120 in the stacking direction of the power-generating elements 100 to a preferred dimension. Furthermore, the excess insulating adhesive 120 can be easily removed.

[0106] A hot roller can be used as roller 300. In this case, pressure can simply be applied while heating. Performing the pressure application step while heating is advantageous because excess insulating adhesive 120 can easily be pushed out of the stack of power-generating elements 100. It should be noted that a heat transfer medium other than a hot roller can also be used.

[0107] The laminated battery 200 can be obtained in the manner described above.

[0108] In a case where a positive electrode collector 110 is to be applied to the outermost layer of the laminated battery 200, the positive electrode layer 20 at the outermost surface and the positive electrode collector 110 can be joined by pressing under heat with a hot melt adhesive (e.g. at a temperature of about 140°C and a pressure of about 1 MPa).

[0109] The laminated battery 200 is inserted, with a holding force applied to it so that the layers of the power generating elements 100 are in closer contact with each other. For example, when the laminated battery 200 is in operation, a pressure of not less than 1 MPa and not more than 45 MPa is exerted on the stacked section of the power generating elements, whereas when the laminated battery 200 is not in operation, a pressure of not less than 0 MPa and not more than 1 MPa is exerted on the stacked section of the power generating elements.

[0110] The laminated battery 200 can be used in various applications. Specific examples of such applications include portable power sources for PCs, portable electronic devices, mobile devices, and the like; power sources for vehicle propulsion in electric vehicles (EVs), hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), and the like; as well as storage batteries such as compact energy storage devices. Among the above, the laminated battery 200 is preferably used as a power source for vehicle propulsion. The laminated battery 200 can be used in the form of a battery pack, which is formed by connecting several laminated batteries in series and / or parallel.

[0111] Specific examples relating to the present disclosure have been explained in detail above; however, these examples are merely illustrative and are not intended to limit the claims in any way. The technique described in the claims comprises various modifications and alterations of the specific examples described above.

Claims

[1] Laminated battery (200) with a plurality of power generating elements (100), wherein each of the current-generating elements (100) comprises a first electrode layer (20), a second electrode layer (40) and a solid electrolyte layer (30) inserted between the first electrode layer (20) and the second electrode layer (40), wherein the second electrode layer (40) is a negative electrode layer if the first electrode layer (20) is a positive electrode layer, and the second electrode layer (40) is a positive electrode layer if the first electrode layer (20) is a negative electrode layer, the laminated battery (200) comprises a first collector (110), the majority of the power generating elements (100) are stacked over the first collector (110), wherein the first collector (110) is a positive electrode collector if the first electrode layer (20) is a positive electrode layer, and the first collector (110) is a negative electrode collector if the first electrode layer (20) is a negative electrode layer, a dimension of a principal surface of the first collector (110) is smaller in at least one direction than a dimension of a principal surface of the first electrode layer (20) in the same direction, wherein the direction is a direction perpendicular to a stacking direction (Y) of the current generating elements (100), and an insulating adhesive (120) is arranged at a position outside a principal surface of the first collector (110) and spans an edge of the first collector (110), such that the insulating adhesive (120) binds a principal surface of one of the power generating elements (100) and a principal surface of an adjacent power generating element (100), each principal surface of a power generating element (100) being a surface with a largest total area. [2] Laminated battery (200) according to claim 1, wherein in the stacking direction (Y) of the power generating elements (100) a dimension of the insulating adhesive (120) is larger than a dimension of the first collector (110). [3] Laminated battery (200) according to claim 1 or 2, wherein the insulating adhesive (120) has cavities (122) inside. [4] Manufacturing method of a laminated battery (200) according to claim 1, comprising the following steps: Preparing a plurality of power generating elements (100), each comprising a first electrode layer (20), a second electrode layer (40) and a solid electrolyte layer (30) inserted between the first electrode layer (20) and the second electrode layer (40), wherein the second electrode layer (40) is a negative electrode layer if the first electrode layer (20) is a positive electrode layer, and the second electrode layer (40) is a positive electrode layer if the first electrode layer (20) is a negative electrode layer; Arranging a first collector (110) and an insulating adhesive (120) on the first electrode layer (20) of a current-generating element (100) or of a plurality of current-generating elements (100), wherein a dimension of a principal area of ​​the first collector (110) is smaller in at least one direction than a dimension of a principal area of ​​the first electrode layer (20) in the same direction, wherein the direction is a direction perpendicular to a stacking direction (Y) of the current-generating elements (100), and wherein the first collector (110) is a positive electrode collector if the first electrode layer (20) is a positive electrode layer, and the first collector (110) is a negative electrode collector if the first electrode layer (20) is a negative electrode layer; and Arranging one additional power generating element (100) of the plurality of power generating elements (100) on the first collector (110). [5] Manufacturing method of a laminated battery (200) according to claim 4, wherein the insulating adhesive (120) is arranged at a position outside a main surface of the first collector (110) when the further current generating element (100) is arranged on the first collector (110), and a dimension of the insulating adhesive (120) in a The stacking direction (Y) of the power generating elements (100) is larger than a dimension of the first collector (110). [6] Manufacturing method of a laminated battery (200) according to claim 4 or 5, further comprising the following step: applying pressure to the insulating adhesive (120) by applying pressure to a main surface of the power generating elements (100) from an inner surface of the main surface towards an outer surface of the main surface.

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