Electrode laminate and battery

Abstract

The invention relates to an electrode laminate and a battery. The present disclosure provides an electrode laminate in which a fixing member disposed on a side surface portion is not easily peeled off, and a battery having such an electrode laminate. This electrode laminate (10) is obtained by laminating a positive electrode current collector layer (11), a positive electrode active material layer (12), an electrolyte layer (13), a negative electrode active material layer (14), and a negative electrode current collector layer (15) in this order. In an electrode laminate (10) according to the present disclosure, a fixing member (20) containing a curable resin is disposed on a side surface portion. A positive electrode current collector layer (11) and / or a negative electrode current collector layer (12) among the layers of the electrode laminate (10) of the present disclosure have / has a recessed portion (10a) at an end portion where a fixing member (20) is disposed, and a portion of the fixing member (20) is inserted into the recessed portion (10a). A battery (100) according to the present disclosure has one or more electrode laminates and a laminated film (30) that seals the electrode laminates.

Description

Technical Field

[0001] The present disclosure relates to an electrode stack and a battery. Background Art

[0002] In batteries such as lithium-ion secondary batteries, an electrode stack comprising a positive electrode current collector layer, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer is sometimes used. In order to prevent the layers from shifting, a technique has been developed in which a fixing member containing a curable resin is provided on the side surface of the electrode stack.

[0003] For example, Patent Document 1 discloses an all-solid-state battery comprising an electrode body (electrode stack) and an outer body housing the electrode body, wherein the electrode body (electrode stack) comprises a stack comprising a positive electrode current collecting layer, a positive electrode composite material layer (positive electrode active material layer), a solid electrolyte layer, a negative electrode composite material layer (negative electrode active material layer) and a negative electrode current collecting layer, wherein an electrically insulating protective component (fixing component) is arranged on a side of the stack, the protective component having a groove extending in a direction along which a surface of the stack extends.

[0004] Patent document 2 discloses a method for manufacturing an all-solid-state battery, which comprises a flat-shaped stacked electrode body (electrode stack), an outer body made of a laminate film that accommodates the stacked electrode body, and a resin protective component (fixing component) formed on the side of the stacked electrode body.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2023-071379

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2021-114374 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] The fixing member made of a curable resin may peel off from the electrode stack, resulting in a problem in that the fixing member cannot fully function as the fixing member.

[0011] An object of the present disclosure is to provide an electrode stack in which fixing members arranged on side surfaces are less likely to peel off, and a battery having such an electrode stack.

[0012] Technical solutions to problems

[0013] The inventors of this application have discovered that the above-mentioned problems can be solved by the following technical solutions.

[0014] <Scheme 1>

[0015] An electrode stack,

[0016] The positive electrode current collector layer, the positive electrode active material layer, the electrolyte layer, the negative electrode active material layer and the negative electrode current collector layer are sequentially stacked.

[0017] in,

[0018] A fixing member containing a curable resin is arranged on the side surface.

[0019] The positive electrode current collector layer and / or the negative electrode current collector layer in each layer of the electrode stack has a recessed portion at an end portion where the fixing member is arranged, and a portion of the fixing member intrudes into the recessed portion.

[0020] Option 2

[0021] The electrode stack according to claim 1,

[0022] Only the positive electrode current collector layer and / or the negative electrode current collector layer has the recessed portion.

[0023] <Scheme 3>

[0024] The electrode stack according to claim 2,

[0025] The positive electrode current collector layer has the recessed portion.

[0026] Option 4

[0027] The electrode stack according to claim 3,

[0028] The outermost positive electrode current collector layer has the recessed portion.

[0029] <Scheme 5>

[0030] The electrode stack according to any one of aspects 1 to 4,

[0031] The depth of the recess is not less than 1 mm and not more than 3 mm.

[0032] <Scheme 6>

[0033] A battery having:

[0034] One or more electrode stacks according to any one of claims 1 to 5; and

[0035] A laminate film seals the electrode stack.

[0036] Effects of the Invention

[0037] According to the present disclosure, it is possible to provide an electrode stack in which fixing members arranged on side surfaces are less likely to peel off, and a battery including such an electrode stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic perspective view showing an example of the electrode stack of the present disclosure.

[0039] Figure 2 This is a schematic plan view showing an example of a positive electrode current collector layer having recessed portions in the electrode stack of the present disclosure.

[0040] Figure 3 It is a schematic diagram showing an example of the shape of the recessed portion.

[0041] Figure 4 This is a schematic perspective view showing an example of the battery of the present disclosure.

[0042] Figure 5 It is a schematic perspective view showing an electrode stack according to a comparative example.

[0043] (Explanation of symbols)

[0044] 100: Battery; 10: Electrode stack; 10a: Recess; 11: Positive electrode collector layer; 12: Positive electrode active material layer; 13: Electrolyte layer; 14: Negative electrode active material layer; 15: Negative electrode collector layer; 20: Fixing member; 30: Laminated film; 40: Collector terminal. DETAILED DESCRIPTION

[0045] Below, with reference to the accompanying drawings, embodiments of the present disclosure are described in detail. Furthermore, the present disclosure is not limited to the following embodiments and can be implemented with various modifications within the scope of the disclosed principles. Furthermore, the dimensional relationships in the drawings of the present disclosure do not reflect the actual dimensional relationships.

[0046] Electrode stack

[0047] like Figure 1 As shown, the electrode stack 10 of the present disclosure is sequentially stacked with a positive electrode collector layer 11, a positive electrode active material layer 12, an electrolyte layer 13, a negative electrode active material layer 14, and a negative electrode collector layer 15. In the electrode stack 10 of the present disclosure, a fixing member 20 composed of a curable resin is disposed on a side surface. The positive electrode collector layer 11 and / or the negative electrode collector layer 12 of each layer of the electrode stack 10 of the present disclosure has a recessed portion 10a at the end where the fixing member 20 is disposed, and a portion of the fixing member 20 intrudes into the recessed portion 10a.

[0048] The authors of the present application believe that one of the reasons why the fixing member made of a curable resin peels off from the electrode stack is the stress generated by the curable resin's shrinkage during curing.

[0049] In this regard, the authors of this application have discovered that by providing at least the positive and / or negative current collector layers, among the layers of the electrode stack, with recesses at the ends where the securing member is disposed, and by having a portion of the securing member penetrate into the recesses, it is possible to suppress peeling of the securing member, which comprises a curable resin, from the electrode stack. While not wishing to be bound by any theory, it is believed that this structure increases the contact area between the layers having recesses at their ends, such as the positive and / or negative current collector layers, and the securing member.

[0050] In this disclosure, the term "electrode stack" refers to a stack of layers that constitute a unit cell. Here, the unit cell may be composed of a stack of a positive electrode current collector layer, a positive electrode active material layer, an electrolyte layer (separator), a negative electrode active material layer, and a negative electrode current collector layer.

[0051] In the present disclosure, the surfaces constituting the width of the layers in the electrode stack and the electrode stack are referred to as "surfaces," and the surfaces constituting the thickness of the layers, spanning the surfaces, are referred to as "side surfaces." Therefore, in the present disclosure, "side surface portion" means the portion constituting the aforementioned side surface in the electrode stack.

[0052] like Figure 1 As illustrated, the electrode stack 10 of the present disclosure includes a positive electrode collector layer 11 , a positive electrode active material layer 12 , an electrolyte layer 13 , a negative electrode active material layer 14 , and a negative electrode collector layer 15 stacked in this order.

[0053] In the electrode stack 10 of the present disclosure, the fixing member 20 containing a curable resin is disposed on the side surface. For example, the fixing member can be bonded to the side surface by curing the curable resin.

[0054] The fixing member may be disposed on at least one side surface, and in particular, may be disposed on a pair of opposing side surfaces. When the fixing member is disposed on a pair of opposing side surfaces, the fixing member enhances the effect of preventing the layers of the electrode stack from shifting, and also facilitates prevention of short circuits caused by the intrusion of conductive foreign matter and damage caused by external impact.

[0055] The thickness of the fixing member is not particularly limited and may be, for example, 0.1 mm or more, 0.5 mm or more, or 1.0 mm or more, or 3.0 mm or less, 2.5 mm or less, or 2.0 mm or less. Furthermore, the thickness of the fixing member refers to the length from the end face of the fixing member to the portion of the electrode stack where no recess is formed.

[0056] The curable resin is not particularly limited, and examples thereof include photocurable resins such as ultraviolet curable resins and electron beam curable resins, and thermosetting resins. Furthermore, the curable resin may be a free radical polymerizable resin, a cationic polymerizable resin, or a combination thereof. Specifically, for example, an acrylate-based ultraviolet curable resin may be used.

[0057] The Young's modulus of the fixing member can also be adjusted by controlling the amount of curable resin applied and the degree of curing. The Young's modulus of the fixing member is not particularly limited, and can be, for example, 400 N / mm 2 Above 550N / mm 2 the following.

[0058] The positive electrode current collector layer 11 and / or the negative electrode current collector layer 15 of each layer of the electrode stack 10 of the present disclosure have a recessed portion 10a at the end where the fixing member is disposed, and a portion of the fixing member 20 intrudes into the recessed portion 10a. In this embodiment, layers constituting the electrode stack other than the positive electrode current collector layer and the negative electrode current collector layer may also have recessed portions 10a. The electrode stack 10 of the present disclosure may also include positive electrode current collector layers and negative electrode current collector layers that do not have recessed portions.

[0059] In the electrode stack 10 of the present disclosure, only the positive electrode current collector layer 11 and / or the negative electrode current collector layer 15 may have the recessed portion 10a. That is, in the electrode stack 10 of the present disclosure, the positive electrode current collector layer 11 and / or the negative electrode current collector layer 15 may have the recessed portion 10a, while the positive electrode active material layer 12, the electrolyte layer 13, and the negative electrode active material layer 14 may not have the recessed portion. This structure allows the resistance of a battery having such an electrode stack to be reduced while maintaining the adhesion between the electrode stack and the fixing member.

[0060] In the electrode stack 10 of the present disclosure, only the positive electrode current collector layer 11 may have the recessed portion 10a. Generally, if the surface area of the negative electrode current collector layer in the electrode stack is smaller than that of the positive electrode current collector layer, dendrites are more likely to form on the negative electrode active material layer. If the positive electrode current collector layer has the recessed portion, the surface area of the positive electrode current collector layer can be made smaller than that of the negative electrode current collector layer. As a result, the formation of dendrites can be suppressed while maintaining adhesion between the electrode stack and the fixing member.

[0061] In the electrode stack 10 of the present disclosure, the outermost positive electrode collector layer 11 may have a recess 10a. For example, in the battery of the present disclosure described later, when there are multiple electrode stacks, the positive electrode collector layer is sometimes configured as an inner layer of the electrode stack. Even if a recess is formed at the end of the positive electrode collector layer configured as the inner layer, sometimes the fixing component cannot fully penetrate the recess. By having a recess in the outermost positive electrode collector layer, the fixing component can appropriately penetrate the recess, and as a result, it is possible to effectively suppress the fixing component from peeling off from the electrode stack.

[0062] The shape of the layer having the concave portion is not particularly limited. For example, the shape of the layer having the concave portion may be as follows: Figure 2 The illustrated shape.

[0063] exist Figure 2 , D represents the depth of the recess.

[0064] In the electrode stack 10 disclosed herein, the depth D of the recess can be between 1 mm and 3 mm. This structure can maintain adhesion between the electrode stack and the fixing member while reducing the resistance of a battery having such an electrode stack. Furthermore, the depth D can be appropriately designed, for example, based on the length in the y-direction of the layer having the recess.

[0065] In addition, Figure 2 In FIG, L represents the length of each portion of the positive electrode current collector layer. Specifically, Lr, Lp, Ln, and Ln represent the following lengths, respectively:

[0066] ・Lr=length of the recess

[0067] ・Lp = Length of the parts located at both ends of the concave portion (sometimes referred to as "convex portion" for convenience)

[0068] ・Ln=Length of the part that is neither concave nor convex

[0069] Le = length of the side surface extending in the x-direction of the electrode stack (Lr + Lp + Ln)

[0070] The length Lr and the length Lp can be appropriately designed based on the properties of the curable resin contained in the fixing member, the thickness of the fixing member, etc. If there are multiple recesses, the multiple lengths Lr may be the same or different from each other. The multiple lengths Lp may be the same or different from each other.

[0071] Lr may be, for example, 1 mm or more, 5 mm or more, or 10 mm or more, or 20 mm or less, 15 mm or less, or 10 mm or less.

[0072] Lp may be, for example, not less than 60 mm, not less than 70 mm, or not less than 80 mm, or not more than 140 mm, not more than 130 mm, or not more than 120 mm.

[0073] Ln may be, for example, 1 mm or more, 5 mm or more, or 10 mm or more, or 20 mm or less, 15 mm or less, or 10 mm or less.

[0074] Le may be, for example, greater than or equal to 300 mm, greater than or equal to 350 mm, or greater than or equal to 400 mm, and may be less than or equal to 500 mm, less than or equal to 450 mm, or less than or equal to 400 mm.

[0075] From the viewpoint of effectively suppressing the fixing member from peeling off from the electrode stack, Le / Lp max (The maximum value of Lp) may be 1.6 or more, 1.7 or more, 1.8 or more, or 1.9 or more, and may be 4.0 or less, 3.5 or less, 3.3 or less, 3.1 or less, or 3.0 or less.

[0076] The area S of the recess may be, for example, 10 mm. 2 Above 30mm 2 The area S can be appropriately designed according to the entire area of the layer having the recessed portion.

[0077] The number of recesses may be one or more. In the case where there are more than one recess, the number may be 2 or more than 3, or may be less than 5, less than 4, less than 3, or 2.

[0078] In addition, Figure 1 and 2 In FIG, a quadrilateral-shaped recess is shown, but the shape of the recess is not limited thereto. For example, the shape of the recess is as follows: Figure 3 The shape shown can also be elliptical (see Figure 3 (b) and (e)), triangle (refer to Figure 3 (c)), trapezoid (refer to Figure 3 (d) and (f) etc.

[0079] The method for forming the recessed portion is not particularly limited, and an example thereof includes a method of cutting the end portion of the layer where the recessed portion is to be formed so as to have a predetermined shape and size.

[0080] "Battery"

[0081] like Figure 4 As shown, the battery 100 of the present disclosure includes one or more electrode stacks and a laminate film 30 that seals the electrode stacks. The battery 100 of the present disclosure may further include a current collector terminal 40 that is electrically connected to the current collector foil.

[0082] When the battery of the present disclosure includes a plurality of electrode stacks, the battery may include a positive electrode current collector layer and a negative electrode current collector layer that do not have recessed portions.

[0083] The battery disclosed herein can be a liquid-based battery or a solid-state battery. In particular, the battery disclosed herein can be a solid-state battery. Because solid-state batteries use a solid electrolyte to form the electrolyte layer, the sides of the electrode stack containing this electrolyte layer can be hard and brittle. In this regard, the provision of a fixing member can effectively protect the sides of the electrode stack.

[0084] Furthermore, in the present disclosure, a "solid-state battery" means a battery that uses at least a solid electrolyte as an electrolyte. Thus, a solid-state battery may also use a combination of a solid electrolyte and a liquid electrolyte as an electrolyte. Furthermore, the solid-state battery of the present disclosure may also be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as an electrolyte.

[0085] The battery disclosed herein may be, for example, a lithium-ion secondary battery. Examples of battery applications include power sources for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline vehicles, and diesel vehicles. In particular, it is preferably used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). Furthermore, the battery disclosed herein may be used as a power source for mobile objects other than vehicles (e.g., railways, ships, and aircraft), or as a power source for electrical appliances such as information processing devices.

[0086] <Electrode stack>

[0087] The electrode stack functions as a power generation element of the battery. With regard to the electrode stack, reference can be made to the above description related to the electrode stack of the present disclosure.

[0088] The shape of the electrode stack is not particularly limited, for example Figure 1 As shown in the example, it can have a top portion, a bottom portion opposite to the top portion, and four side portions connecting the top portion and the bottom portion. The shape of the top portion is not particularly limited, and examples thereof include quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms. In addition, the shape of the top portion can be a polygon other than a quadrilateral, or a shape with a curve such as a circle. In addition, the shape of the bottom portion is the same as that of the top portion. The shape of the side portions is not particularly limited, and examples thereof include quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms.

[0089] Laminated film

[0090] The laminate film 30 seals the electrode stack 10. The laminate film 30 may also seal the electrode stack 10 and the current collector terminal 40. Specifically, the laminate film 30 may be wound around the electrode stack 10 and the current collector terminal 40 to seal the electrode stack 10 and the current collector terminal 40 together. Alternatively, the laminate film 30 may be composed of a first film and a second film. In this case, the first and second films may sandwich the electrode stack 10 and the current collector terminal 40 from above and below in the stacking direction of the electrode stack 10 to seal the electrode stack 10 and the current collector terminal 40 together.

[0091] The laminate film may have a sealant resin layer, a metal layer, and a protective resin layer in this order along the thickness direction. Examples of materials for the sealant resin layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the protective resin layer include polyethylene terephthalate (PET) and nylon. The thickness of the sealant resin layer may be, for example, not less than 40 μm and not more than 100 μm. The thickness of the metal layer may be, for example, not less than 30 μm and not more than 60 μm. The thickness of the protective resin layer may be, for example, not less than 20 μm and not more than 60 μm. The thickness of the laminate film may be, for example, not less than 80 μm and not more than 250 μm.

[0092] 〈Current collector terminal〉

[0093] The current collector terminal 40 can be electrically connected to the current collector foil. For example, if the fixing member 20 is disposed on a pair of opposing side surfaces of the electrode stack 10, the current collector terminal 40 can be disposed on the remaining pair of side surfaces. The material of the current collector terminal is not particularly limited as long as it has a current collecting function. For example, it can be the same metal material as the positive and negative electrode current collector layers. The size and shape of the current collector terminal are not particularly limited.

[0094] <other>

[0095] The battery disclosed herein may further include an insulating member. For example, the insulating member may be disposed on the side of the electrode stack from which the positive electrode current collector layer extends, covering layers other than the positive electrode current collector layer. The insulating member may be, for example, a resin or an insulating tape.

[0096] Each layer of the electrode stack

[0097] Next, materials constituting the positive electrode current collector layer, positive electrode active material layer, electrolyte layer, negative electrode active material layer, and negative electrode current collector layer constituting the electrode stack will be described.

[0098] <Positive electrode current collector layer>

[0099] The positive electrode current collector layer is not particularly limited. For example, in the case of a lithium-ion secondary battery, the material used for the positive electrode current collector layer may be, but is not limited to, SUS, nickel, chromium, gold, platinum, aluminum, iron, titanium, zinc, or a material obtained by plating or vapor-depositing nickel, chromium, carbon, or the like onto these metals.

[0100] The surface of the positive electrode current collector layer may be covered with a layer containing a carbon material.

[0101] The shape of the positive electrode current collector layer is not particularly limited, and examples thereof include foil, plate, and mesh. Among these, foil is preferred.

[0102] <Positive Electrode Active Material Layer>

[0103] The positive electrode active material layer contains a positive electrode active material, and may optionally contain a solid electrolyte, a conductive auxiliary agent, and a binder.

[0104] As the positive electrode active material, any known active material can be used. For example, in the case of a lithium ion secondary battery, lithium cobalt oxide, lithium nickel oxide, LiNiO2, or the like can be used as the positive electrode active material. 1 / 3 Co 1 / 3 Mn 1 / 3 Various lithium-containing composite oxides such as O2, lithium manganate, and spinel-based lithium compounds can be used. Alternatively, lithium iron phosphate (LFP) can be used as an olivine-type positive electrode active material. The positive electrode active material can also be in the form of particles, and its size is not particularly limited.

[0105] The positive electrode active material may have a coating layer. The coating layer is a layer containing a material having lithium ion conductivity, low reactivity with the positive electrode active material and the solid electrolyte, and capable of maintaining a coating layer morphology that does not flow even when in contact with the active material and the solid electrolyte. Specific examples of materials constituting the coating layer include LiNbO3, Li4Ti5O 12 , Li3PO4, etc., but not limited to these.

[0106] The material of the solid electrolyte is not particularly limited, and when constituting a lithium ion secondary battery, for example, a sulfide solid electrolyte may be used.

[0107] Examples of sulfide solid electrolytes include, but are not limited to, sulfide amorphous solid electrolytes, sulfide crystalline solid electrolytes, and argyrodite-type solid electrolytes. Specific examples of sulfide solid electrolytes include Li2S-P2S5 systems (Li7P3S 11, Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2 (Li 13 GeP3S 16 、Li 10 GeP2S 12 etc.), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x etc. or combinations thereof, but are not limited to these.

[0108] Sulfide solid electrolytes can be either glass or crystallized glass (glass-like ceramics).

[0109] The conductive additive is not particularly limited. Examples of the conductive additive include VGCF (Vapor Grown Carbon Fiber), acetylene black (AB), Ketjen black (KB), carbon nanotubes (CNT), and carbon nanofibers (CNF), but are not limited to these.

[0110] The binder is not particularly limited, and may be, for example, polyvinylidene fluoride (PVdF), butadiene rubber (BR), styrene butadiene rubber (SBR), or a combination thereof, but is not limited thereto.

[0111] (Electrolyte layer)

[0112] When the battery of the present disclosure is a solid battery, the electrolyte layer contains a solid electrolyte and may optionally contain a conductive auxiliary agent and a binder.

[0113] Regarding the solid electrolyte, the conductive additive, and the binder, reference can be made to the above description related to the positive electrode active material layer of the present disclosure.

[0114] (Negative electrode active material layer)

[0115] The negative electrode active material layer contains a negative electrode active material, and may optionally contain a solid electrolyte, a conductive auxiliary agent, and a binder.

[0116] As the negative electrode active material, any known active material may be used. For example, in the case of a lithium-ion secondary battery, the negative electrode active material may include silicon-based active materials such as silicon, silicon alloys, and silicon oxide; carbon-based active materials such as graphite and hard carbon; various oxide-based active materials such as lithium titanate; metallic lithium; and lithium alloys. The negative electrode active material may also be in the form of particles, and the size thereof is not particularly limited.

[0117] Regarding the solid electrolyte, the conductive additive, and the binder, reference can be made to the above description related to the positive electrode active material layer of the present disclosure.

[0118] (Negative electrode current collector layer)

[0119] The negative electrode current collector layer is not particularly limited. For example, in the case of a lithium-ion battery, the negative electrode current collector layer may be made of copper, copper alloys, or copper-plated or vapor-deposited nickel, chromium, carbon, or the like, but is not limited thereto.

[0120] The shape of the negative electrode current collector layer is not particularly limited, and examples thereof include foil, plate, and mesh. Among these, foil is preferred.

[0121] [Example]

[0122] Example 1

[0123] Battery Manufacturing

[0124] (Preparation of positive electrode active material)

[0125] Lithium niobate was coated onto the positive electrode active material particles (Li 1.15 Ni 1 / 3 Co 1 / 3 Mn 1 / 3 The particles having O2 as the main phase are fired in an air atmosphere to obtain positive electrode active material particles having a coating layer of lithium niobate.

[0126] (Formation of Positive Electrode Active Material Layer)

[0127] The resulting positive electrode active material particles, polyvinylidene fluoride (PVdF), a sulfide solid electrolyte (Li2S-P2S5-based glassy ceramic), vapor-grown carbon fibers (VGCF) (Showa Denko Co., Ltd.), and a dispersant were placed in a polypropylene container and stirred for 30 seconds using an ultrasonic disperser (SMT Co., Ltd., UH-50). The container was then shaken for 3 minutes using a shaker (Shibata Scientific Co., Ltd., TTM-1) and further stirred for 30 seconds using an ultrasonic disperser. This produced a paste-like positive electrode composite material. The resulting positive electrode composite material was applied to an aluminum (Al) foil substrate using a doctor blade method using an applicator. The applied film was then allowed to dry naturally and then dried on a hot plate at 100°C for 30 minutes to form a positive electrode active material layer on the Al foil. The amount of positive electrode composite material applied was adjusted to achieve a thickness of 15 μm when densified at 4 t / cm.

[0128] (Formation of Negative Electrode Active Material Layer)

[0129] Lithium titanate (LTO) particles and polyvinylidene fluoride (PVdF), the same sulfide solid electrolyte and dispersant as described above, were added to a polypropylene container and stirred for 30 minutes using an ultrasonic disperser. This produced a paste-like negative electrode composite material. Using an applicator, the resulting negative electrode composite material was applied to one surface of a copper (Cu) foil serving as the negative electrode current collector layer using a doctor blade method. The applied film was then allowed to dry naturally and then dried on a 100°C hot plate for 30 minutes, forming a negative electrode active material layer on one surface of the Cu foil. Similarly, a negative electrode active material layer was formed on the other surface of the Cu foil.

[0130] (Formation of Solid Electrolyte Layer)

[0131] Heptane, butadiene rubber (BR), the same sulfide solid electrolyte and dispersant as above were added to a polypropylene container and stirred for 30 seconds using an ultrasonic disperser. The container was then shaken for 30 minutes using a shaker (TTM-1, manufactured by Shibata Scientific Co., Ltd.) and further stirred for 30 seconds using an ultrasonic disperser. This produced a paste-like solid electrolyte composite material. The resulting solid electrolyte composite material was applied to an Al foil substrate using a doctor blade method using an applicator. The applied film was then allowed to dry naturally and then dried on a 100°C hot plate for 30 minutes to form a solid electrolyte layer on the Al foil.

[0132] (Fabrication of a Positive Electrode Current Collector Layer Having Recesses)

[0133] Acetylene black, a conductive additive, and an acrylic binder were weighed in a volume ratio of 40:60. Ethyl acetate was then added to prepare a carbon coating composition. The resulting composition was then applied to an Al foil to a film thickness of 2 μm. The applied film was dried at 100°C for 1 hour to obtain an Al foil coated with a carbon layer. Figure 2 The obtained Al foil was cut as shown in the example, thereby obtaining a positive electrode current collector layer having recessed portions.

[0134] (Fabrication of Electrode Laminate)

[0135] The layers were laminated so that the surfaces of both sides of the negative electrode active material layer formed on the negative electrode current collector layer were in contact with the surface of the solid electrolyte layer, and pressurized at 1.6 t / cm. Subsequently, the Al foil, serving as the base material, was peeled off from the solid electrolyte layer. Next, the layers were laminated so that the surface of the positive electrode active material layer was in contact with the surface of the solid electrolyte layer exposed by the peeling, and pressurized at 1.6 t / cm. Subsequently, the Al foil, serving as the base material, was peeled off from the positive electrode active material layer to obtain a laminate. The obtained laminate was pressurized at 5 t / cm. Furthermore, the laminate was cut to an area of 50 mm x 250 mm, and insulating tape was applied to the side of the electrode laminate opposite the side extending from the negative electrode current collector layer. At 140°C, a load of 5 MPa was applied to adhere the positive electrode current collector layer having a recess to the surface of the positive electrode active material layer. Thus, an electrode laminate was obtained. Similarly, nine electrode laminates were produced. Then, 10 sheets of the obtained electrode stacks were stacked and cut to have a length in the y direction of 40 mm. Thus, an electrode stack having a recessed portion with a depth of 1 mm in the positive electrode current collector layer was obtained.

[0136] (Configuration of fixed components)

[0137] The fixing member is arranged by bonding an acrylate-based ultraviolet curing resin to the side surface portion extending in the x-direction of the electrode stack. The amount of application and the amount of ultraviolet irradiation are controlled to adjust the Young's modulus.

[0138] (Battery production)

[0139] Current collector terminals were welded to the positive and negative electrode current collector layers extending from the side surfaces extending in the y direction of the obtained electrode stack, and the electrode stack and a portion of the current collector terminals were vacuum sealed in the laminate film.

[0140] "evaluate"

[0141] Check if the fixing parts have peeled off

[0142] During vacuum sealing in the battery production process, it was visually checked whether the fixing member had peeled off.

[0143] <Resistance measurement>

[0144] The resistance value of the obtained battery was measured by a general method in the field of batteries.

[0145] Examples 2 to 7

[0146] Batteries of Examples 2 to 7 were prepared and evaluated in the same manner as in Example 1, except that the Young's modulus and thickness and the lengths Lp, Lr, and Ln of the fixing member were changed as described in Table 1.

[0147] Example 8

[0148] A battery of Example 8 was prepared and evaluated in the same manner as in Example 1, except that similar recesses were provided in the positive electrode active material layer at positions where the recesses in the positive electrode current collector layer were formed.

[0149] Comparative Example 1

[0150] A battery of Comparative Example 1 was prepared and evaluated in the same manner as in Example 1, except that no recessed portion was formed in the positive electrode current collector layer.

[0151] "result"

[0152] The presence or absence of peeling of the fixing member and the results of the resistance value measurement are shown in Table 1. The resistance value is shown as a relative value with the value of Comparative Example 1 being 1.00.

[0153]

Table 1

[0154]

[0155] As shown in Table 1, in the battery of the Example having the recessed portion in the positive electrode current collector layer, peeling of the fixing member did not occur.

[0156] In addition, the batteries of Examples 1 to 6, in which the recesses were present only in the positive electrode current collector layer and the depth of the recesses was 1 to 3 mm, had small resistance values.

Claims

1. An electrode stack, wherein: The positive electrode current collector layer, the positive electrode active material layer, the electrolyte layer, the negative electrode active material layer and the negative electrode current collector layer are sequentially stacked. in, A fixing member containing a curable resin is arranged on the side surface. The positive electrode current collector layer and / or the negative electrode current collector layer in each layer of the electrode stack has a recessed portion at an end portion where the fixing member is arranged, and a portion of the fixing member intrudes into the recessed portion.

2. The electrode stack according to claim 1, wherein Only the positive electrode current collector layer and / or the negative electrode current collector layer has the recessed portion.

3. The electrode stack according to claim 2, wherein: The positive electrode current collector layer has the recessed portion.

4. The electrode stack according to claim 3, wherein The outermost positive electrode current collector layer has the recessed portion. The electrode stack according to claim 1 , wherein: The depth of the recess is not less than 1 mm and not more than 3 mm.

6. A battery, wherein: The battery has: One or more electrode stacks according to any one of claims 1 to 5; and A laminate film seals the electrode stack.

Images