JPWO2019103008A1 - Electrode body for all-solid-state battery and its manufacturing method - Google Patents

Abstract

Provided are a method for producing an electrode body for an all-solid-state battery capable of suppressing cracking of a solid electrolyte layer even when the electrode body is pressed with a higher pressure, and an electrode body manufactured by the method. The method for manufacturing an all-solid-state battery electrode body disclosed herein manufactures an all-solid-state battery electrode body including a solid electrolyte layer and a first active material layer bonded to the first surface of the solid electrolyte layer. In the method, when there is a difference between the solid electrolyte layer area and the first active material layer area at the joint surface between the solid electrolyte layer and the first active material layer, the solid electrolyte layer and the first active material layer are separated. Overlapping, providing an insulating layer in the area that is in contact with the edge of the smaller area solid electrolyte layer or primary active material layer and fills the gap, solid electrolyte layer, primary active material layer and insulating layer Includes pressurizing in the stacking direction of the solid electrolyte layer and the primary active material layer.

Description

The present invention relates to an electrode body for an all-solid-state battery and a method for manufacturing the same.
This application claims priority based on Japanese Patent Application No. 2017-223700 filed on November 21, 2017 and US Patent Application No. 16 / 184,109 filed on November 8, 2018. The entire contents of that application are incorporated herein by reference.

In recent years, secondary batteries are indispensable as portable power sources for personal computers, mobile terminals, etc., vehicle drive power sources for electric vehicles (EV), hybrid vehicles (HV), plug-in hybrid vehicles (PHV), and power storage power sources. Has become an existence. Among them, lithium-ion batteries have a high energy density and can output at a high rate, and therefore, with their widespread use, further improvement in performance and reliability are desired.

Regarding this secondary battery, in order to improve safety, the practical application of an all-solid-state battery using a solid electrolyte made of ceramics, an ionic conductive polymer, etc., without using a flammable electrolyte as an electrolyte, has been promoted. There is. The all-solid-state battery constitutes an electrode body by arranging a layered solid electrolyte between the positive electrode active material layer and the negative electrode active material layer. These solid electrolyte layers and positive / negative active material layers can be formed as dense thin films by the CVD method or the like, but are generally in the form of powder (particulates) in consideration of cost and productivity. It is constructed by binding the electrode constituent materials of (shape) with a binder.

Japanese Unexamined Patent Publication No. 2015-050149 Japanese Unexamined Patent Publication No. 2012-08425 Japanese Unexamined Patent Publication No. 2014-203740 Japanese Unexamined Patent Publication No. 09-153354

Since there is no electrolytic solution in the all-solid-state battery, the interfacial resistance between the solid electrolyte layer and the positive and negative active material layers is high. In addition to this, in an all-solid-state battery manufactured using a powdery material, interfacial resistance is generated between particles even in the solid electrolyte layer and the positive and negative active material layers. Therefore, for the purpose of reducing the interfacial resistance, the electrode body in which the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are laminated is placed at a higher pressure than in a liquid battery (for example, about 100 to 200 MPa in surface pressure). ) Pressing is performed to increase the packing density of each layer. When pressing the electrode body, tensile stress may act in a direction orthogonal to the pressing direction, so that the end of the positive electrode active material layer and the end of the negative electrode active material layer facing each other via the solid electrolyte layer come into contact with each other. A short circuit may occur. Therefore, in order to prevent this short circuit, for example, it has been proposed to design the width of one active material layer (for example, the positive electrode active material layer) to be small. In addition, a configuration has been proposed in which the ends of the solid electrolyte layer or the positive / negative active material layer are covered with an insulator (for example, Patent Documents 1 to 3). Then, the present inventors have stated that the electrode body is pressed at a pressure higher than the conventional one (for example, the surface pressure exceeds 200 MPa) for the purpose of further increasing the density of each layer of the electrode body to improve the performance of the battery. Are considering. However, it has become clear that when pressing at a higher pressure, a new problem arises in which a short circuit is likely to occur in the electrode body.

Therefore, the present invention provides a method for manufacturing an electrode body for an all-solid-state battery, which can suppress a short circuit of the electrode body even when the electrode body is pressed with a higher pressure. In another aspect, it is an object of the present invention to provide an electrode body for an all-solid-state battery manufactured by such a method.

The present inventors have investigated in detail the pressing process in the production of a conventional all-solid-state battery and found the following events. That is, in the conventional configuration in which the size of the active material layer is reduced, there are places where the active material layer is present and where there is no active material layer on the surface of the solid electrolyte layer, and a step is formed in the electrode body. Further, also in the configurations disclosed in Patent Documents 1 to 3, a step is formed at the end of the solid electrolyte layer or the active material layer by a portion coated with an insulator and a portion not covered with the insulator. Further, even when such a step is not formed at first glance, it is generated in the plane direction with respect to the solid electrolyte layer when the electrode body is pressed or when pressure is applied to the electrode body when using a battery. It has been found that the tensile stress may be uneven or a local stress may be applied to the solid electrolyte layer due to the stepped portion. The stress unevenness of the solid electrolyte layer and the application of local stress did not adversely affect the electrode body in the battery manufactured by the conventional press pressure (for example, about 100 to 200 MPa in surface pressure). .. However, when pressing at a higher pressure than before, it has been found that stress unevenness of the solid electrolyte layer and application of local stress induce cracks and chips of the solid electrolyte layer, leading to a short circuit of the electrode body.

In the method for manufacturing an electrode body of an all-solid-state battery disclosed herein, an electrode body of an all-solid-state battery including a solid electrolyte layer and a first active material layer bonded to the first surface of the solid electrolyte layer is manufactured. To do. In this production method, when there is a difference between the area of the solid electrolyte layer and the area of the first active material layer at the joint surface between the solid electrolyte layer and the first active material layer, the solid electrolyte layer and the first active material layer are used. Overlapping with the active material layer, providing an insulating layer in a region that is in contact with the end of the solid electrolyte layer or the first active material layer having a smaller area and fills the difference, and the solid electrolyte layer. This includes pressing the first active material layer and the insulating layer in the stacking direction of the solid electrolyte layer and the first active material layer.

In an all-solid-state battery, the solid electrolyte layer is formed larger than at least one of the first active material layer and the second active material layer for the purpose of preventing a short circuit between the first active material layer and the second active material layer. I often do it. In such a configuration, an insulating layer is provided so as to fill the area difference at the joint surface between the solid electrolyte layer and the first active material layer. As a result, when the electrode body is pressed, stress unevenness and application of local stress due to the difference in the bonding area of each layer are reduced, and cracking and betting of the solid electrolyte layer and eventually short circuit of the electrode body are suppressed. be able to.

In a preferred embodiment of the method for producing an electrode body of an all-solid-state battery disclosed herein, a solid electrolyte layer, a first active material layer provided on the first surface of the solid electrolyte layer, and the above-mentioned solid electrolyte layer. An electrode body including a second active material layer provided on the second surface opposite to the first surface is manufactured. This manufacturing method includes the following steps (a) to (e). (A) Prepare the first active material layer. (B) The solid electrolyte layer is prepared so that the first surface of the first active material layer and the first surface of the solid electrolyte layer are in contact with each other. Here, the second surface of the solid electrolyte layer includes a peripheral edge portion which is at least a part of the peripheral edge, and a laminated portion excluding the peripheral edge portion. (C) Prepare the second active material layer so as to be in contact with the laminated portion of the solid electrolyte layer. (D) An insulating layer shall be prepared so as to be in contact with the peripheral portion of the solid electrolyte layer. (E) A laminate containing the first active material layer, the solid electrolyte layer, the second active material layer and the insulating layer until at least the surfaces of the second active material layer and the insulating layer are flush with each other. Pressurize in the stacking direction to obtain the above electrode body.

According to such a configuration, the first active material layer, the solid electrolyte layer, and the second active material layer can be pressurized at once in a laminated state, and the laminated body can be easily compacted. Further, in the laminated body, the second active material layer is formed smaller than the solid electrolyte layer. An insulating layer is provided on the peripheral edge of the solid electrolyte layer. Therefore, even when the laminate is pressurized, it is possible to prevent the end portion of the first active material layer and the end portion of the second active material layer from coming into contact with each other to cause a short circuit. Further, the pressurization of the laminate is carried out until at least the thicknesses of the second active material layer and the insulating layer are the same. In other words, the step formed between the solid electrolyte layer and the secondary active material layer is filled with the insulating layer. As a result, the pressing pressure due to the pressurization is applied to the second active material layer and the insulating layer not only when rolling at the same pressure as the conventional one but also when the pressure is increased higher than the conventional one. It can be more uniformly transmitted through the solid electrolyte layer. As a result, unevenness of tensile stress generated in the solid electrolyte layer can be suppressed, and cracking of the solid electrolyte layer can be suppressed both during the production of the electrode body and during the subsequent use.

In a preferred embodiment of the method for producing an electrode body for an all-solid-state battery disclosed herein, the first active material layer, the solid electrolyte layer, and the second active material layer contain a powder material and a binder, respectively. .. The layer formed by the powder material and the binder tends to have a low packing density and a low strength. Therefore, it is preferable to apply the present technique to an electrode body formed by using such a material because the above effect can be remarkably exhibited.

In a preferred embodiment of the method for producing an all-solid-state battery electrode body disclosed herein, the first active material layer, the solid electrolyte layer, and the second active material layer are formed of a powder material, a binder, and a dispersion medium, respectively. After supplying a slurry (including paste, suspension, etc., the same applies hereinafter) containing the above-mentioned dispersion medium, the mixture is prepared.
According to such a configuration, the electrode body can be manufactured with high productivity and low cost, which is suitable.

A preferred embodiment of the method for producing an all-solid-state battery electrode body disclosed herein includes (b) a drying step of drying the first active material layer and the solid electrolyte layer, following the step (b).
According to such a configuration, for example, it is possible to prevent the slurry forming the solid electrolyte layer and the slurry forming the second active material layer from being mixed with each other. Further, the second active material layer can be laminated and pressurized on the first active material layer and the solid electrolyte layer which have become relatively hard due to drying. As a result, the press pressure due to pressurization can be sufficiently transmitted to the second active material layer. Here, since the positive electrode active material generally has a higher hardness than other materials, the positive electrode active material layer is difficult to be compacted. Therefore, for example, it is preferable to use the second active material layer as the positive electrode active material layer because the positive electrode active material layer, which is relatively difficult to be compacted, can be sufficiently compacted.

In a preferred embodiment of the method for manufacturing an all-solid-state battery electrode body disclosed herein, the pressurization is performed while heating to a temperature equal to or higher than the softening point of the binder.
According to such a configuration, the packing density of the electrode body can be further increased, which is preferable. For example, the packing density of the electrode body can be increased to 85% by volume or more (preferably 90% by volume or more), and the interfacial resistance can be further reduced, which is preferable. For this packing density, for example, a value measured by a pycnometer method can be adopted. In addition, it can be measured by an image analysis method.
Further, by applying pressure while heating the layers in a laminated state, the binder contained in each layer can bond the layers. As a result, even when the volume of the electrode layer changes due to charging / discharging, the adhesion of each layer can be maintained, and an increase in internal resistance can be suppressed.

In a preferred embodiment of the method for manufacturing an all-solid-state battery electrode body disclosed herein, the pressurization is performed by a flat press having a surface pressure of 200 MPa or more. Alternatively, the pressurization is performed by roll rolling with a linear pressure of 10 kN / cm or more.
According to the above configuration, since the unevenness of the tensile stress generated in the solid electrolyte layer can be reduced, cracking of the solid electrolyte layer can be suppressed even when the electrode body is pressurized with a pressure higher than the conventional one. This is preferable because the packing density of the electrode body can be further increased.

In a preferred embodiment of the method for manufacturing an all-solid-state battery electrode body disclosed herein, the Young's modulus of the insulating layer prepared in the step (d) is 1 / of the compressive deformation resistivity of the second active material layer. It is 10 or more.
According to such a configuration, the deformation behavior of the insulating layer due to pressurization preferably follows the deformation behavior of the second active material layer, and the press pressure due to pressurization can be more uniformly transmitted to the solid electrolyte layer, which is preferable.

In a preferred embodiment of the method for producing an all-solid-state battery electrode body disclosed herein, in the step (d), an insulating composition containing at least a photocurable resin composition is supplied to the peripheral portion to emit curing light. By irradiating, the above insulating layer containing a photocurable resin is prepared.
Such a configuration is preferable because the time required for preparing the insulating layer can be shortened.

In a preferred embodiment of the method for producing an all-solid-state battery electrode body disclosed herein, the insulating composition comprises porous ceramic powder, ceramic hollow particles, hollow aggregates of ceramic particles, porous resin particles, and hollow resin. Includes at least one selected from the group consisting of particles, insulating fibrous fillers.
According to such a configuration, the compression behavior of the insulating layer made of the ultraviolet curable resin can be adjusted to a desired value, which is preferable.

In a preferred embodiment of the method for producing an all-solid-state battery electrode body disclosed herein, the insulating layer supplies a slurry containing the insulating ceramic particles, the binder and the dispersion medium, and then removes the dispersion medium. Prepare by. For example, the insulating layer preferably contains at least one of alumina and a solid electrolyte material.
According to such a configuration, the deformation behavior due to pressurization is preferable because an insulating layer similar to the second active material layer can be formed.

In a preferred embodiment of the method for manufacturing an all-solid-state battery electrode body disclosed herein, the first active material layer is prepared on both sides of the current collector in the step (a).
According to the above configuration, one set of laminates including the first active material layer, the solid electrolyte layer and the second active material layer can be formed on both surfaces of the current collector. This is preferable because two sets of laminated bodies can be pressurized together with the current collector at one time to easily obtain a higher capacity electrode body.

In another aspect, the techniques disclosed herein provide electrodes for all-solid-state batteries. This electrode body includes a solid electrolyte layer, a first active material layer, a second active material layer, and an insulating layer. Here, the solid electrolyte layer has a first surface and a second surface opposite to the first surface, and the second surface is a peripheral edge that is at least a part of the peripheral edge of the solid electrolyte layer. A portion and a laminated portion excluding the peripheral portion are included. Further, the first active material layer is provided on the first surface, the second active material layer is provided on the laminated portion, and the insulating layer is provided on the peripheral portion. The surfaces of the second active material layer and the insulating layer on the opposite side of the second surface are flush with each other.
According to such a configuration, even when the packing density of the electrode body is increased, it is preferable because the solid electrolyte layer is less likely to be cracked from the time of manufacture to the time of use.

FIG. 1 is a flow chart of a manufacturing process of an electrode body of an all-solid-state battery according to an embodiment of the present invention. FIG. 2 is a plan view (A) and a side view (B) schematically showing a manufacturing process of an electrode body of an all-solid-state battery according to an embodiment of the present invention. 3 (a) to 3 (e) are schematic cross-sectional views taken along the lines IIIa to IIIe of FIG. 2 (A). FIG. 4 is a cross-sectional view of the electrode body after rolling by the conventional method. FIG. 5 is a schematic cross-sectional view of (A) an electrode body before rolling and (B) an electrode body after rolling, which describes another embodiment. FIG. 6 is a graph showing an example of the results of CAE analysis regarding the thickness and elastic modulus of the insulating layer with respect to the positive electrode active material layer with respect to the rolled state of the positive electrode active material layer and the insulating layer when rolling under predetermined conditions. ..

Hereinafter, embodiments according to the present invention will be described. It should be noted that matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention (for example, general configurations of electrode bodies for all-solid-state batteries that do not characterize the present invention) are described. It can be grasped as a design matter of a person skilled in the art based on the prior art in the field. The present invention can be carried out based on the contents disclosed in the present specification and common general technical knowledge in the art. Further, in the following drawings, members / parts having the same action are described with the same reference numerals. In addition, the dimensional relationships (length, width, thickness, etc.) in each figure do not reflect the actual dimensional relationships. The numerical range represented by "A to B" in the present specification means "A or more and B or less".

[First Embodiment]
FIG. 1 is a flow chart showing a method of manufacturing the electrode body 1 of the all-solid-state battery according to the embodiment. The method for manufacturing the electrode body 1 includes steps (a) to (e) and steps (b'). Further, FIG. 2 is a schematic view showing a manufacturing process of the electrode body 1 in the present embodiment. FIG. 2 (A) shows a plan view of the manufacturing of the electrode body as viewed from above, and FIG. 2 (B) shows a side view of the electrode body as viewed from the side. In the figure, arrows X, Y, and Z indicate three directions orthogonal to each other, X indicates a longitudinal direction (transportation direction), Y indicates a width direction, and Z indicates a thickness direction (vertical direction). FIG. 3 is a schematic cross-sectional view of the electrode body 1 in the process of being manufactured prepared in steps (a) to (e).

S1, S2, S3, and S4 in FIG. 2 all indicate a slurry coating apparatus. The slurry coating devices S1, S2, S3, and S4 are provided in the order of the slurry coating device S1, the slurry coating device S2, the slurry coating device S3, and the slurry coating device S4 in this order from the upstream side in the transport direction X. There is. The configuration of the slurry coating device is not particularly limited, and may be, for example, various known coating devices such as a gravure coater, a slit coater, a die coater, a comma coater, a dip coater, and a blade coater. The slurry coating devices S1, S2, S3, and S4 of the present embodiment are die coaters. D in the figure indicates a dryer. The configuration of the dryer is also not particularly limited, and may be, for example, a heat dryer, a blower dryer, an infrared dryer, a freeze dryer, or the like. Further, P in the figure indicates a rolling apparatus, and the rolling apparatus P of the present embodiment is a hot roll rolling mill. C in the figure indicates a cutting device such as a cutter and a laser cutting machine.

The electrode body 1 manufactured in the present embodiment includes, as a typical configuration, a solid electrolyte layer 10, a first active material layer 20, and a second active material layer 30. The first active material layer 20 is provided on the first surface 11 of the solid electrolyte layer 10. The second active material layer 30 is provided on the second surface 12 of the solid electrolyte layer 10 opposite to the first surface 11. The first active material layer 20, the solid electrolyte layer 10, and the second active material layer 30 are provided on both surfaces of the current collector 24. Therefore, first, the constituent materials of each component will be briefly described below.

The solid electrolyte layer 10 mainly contains a solid electrolyte material. The solid electrolyte layer 10 typically contains a powdered solid electrolyte material and a binder. The powdered solid electrolyte material is bound to each other by a binder and is fixed to another layer by a binder. As the solid electrolyte material, various materials that can be used as the solid electrolyte of the all-solid-state battery can be used.
In the present specification, "mainly" means that the component is contained in an amount of 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more (for example, 80% by mass or more, 90). Mass% or more, 95% by mass or more).

As the solid electrolyte material, for example, various compounds having lithium ion conductivity can be preferably used. Such solid electrolyte material, specifically, for _{example, Li 2 S-SiS 2,} LiI-Li 2 S-SiS 2, LiI-Li 2 S-P 2 S 5, LiI-Li 2 S-B _{2 S 3, Li 3 PO 4} -Li 2 S-Si 2 S, Li 3 PO 4 -Li 2 S-SiS 2, LiPO 4 -Li 2 S-SiS, LiI-Li 2 S-P 2 O 5, LiI -Li ₃ PO ₄ -P ₂ S ₅ , LiI-Li ₃ PS _4- LiBr, Li ₂ SP ₂ S ₅ , Li ₂ SP ₂ S ₅ -Li I-Li Br and Li ₂ SP ₂ S ₅ Amorphous sulfides such as −GeS ₂ , Li ₂ O−B ₂ O ₃ −P ₂ O ₅ , Li ₂ O−SiO ₂ , Li ₂ O−B ₂ O ₃ , and Li ₂ O−B ₂ O ₃ Amorphous oxides such as −ZnO, crystalline sulfides such as Li ₁₀ GeP ₂ S ₁₂ , Li _1.3 Al _0.3 Ti _0.7 (PO ₄ ) ₃ , Li _{1 + x + y} A ¹ _x Ti _2-x Si _y P _3-y O ₁₂ (A ¹ is Al or Ga, 0 ≦ x ≦ 0.4, 0 <y ≦ 0.6), [(A ² _1/2 Li _1/2 ) _1-z C _z ] TiO ₃ (A ² is La, Pr, Nd, or Sm, C is Sr or Ba, 0 ≦ z ≦ 0.5), Li ₅ La ₃ Ta ₂ O ₁₂ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li Crystalline oxides such as ₆ BaLa ₂ Ta ₂ O ₁₂ and Li _3.6 Si _0.6 P _0.4 O ₄ , crystalline acid nitrides such as Li ₃ PO _{(4-3 / 2w)} N _w (w <1), Li crystalline nitride such as ₃ N, _{and, LiI, LiI-Al 2 O} 3, and Li ₃ crystalline iodide such as N-LiI-LiOH and the like. Among them, amorphous sulfide can be preferably used because it has excellent lithium ion conductivity. The average particle size of the solid electrolyte powder is not particularly limited, but for example, an average particle size (D ₅₀ ) of about 0.1 μm or more is appropriate, and 0.4 μm or more is preferable. The volume average particle size of the solid electrolyte powder is, for example, 50 μm or less, preferably 5 μm or less. As the solid electrolyte, a semi-solid polymer electrolyte such as polyethylene oxide containing a lithium salt, polypropylene oxide, polyvinylidene fluoride, or polyacrylonitrile can also be used.
The average particle size in the present specification is a particle size corresponding to a cumulative total of 50% in a volume-based particle size distribution measured using a laser diffraction / light scattering type particle size distribution meter. In addition, values measured using an electron microscope (for example, a scanning electron microscope: SEM) or the like can also be adopted.

The first active material layer 20 and the second active material layer 30 can be composed of, for example, one of the positive electrode active material layer and the other of the negative electrode active material layer. The positive electrode active material layer mainly contains the positive electrode active material. The negative electrode active material layer mainly contains the negative electrode active material. The positive and negative active material layers typically include powdered active material particles and a binder. In the positive and negative active material layers, the active material particles are bound to each other by a binder, and the active material particles are fixed to the current collector 24 or another layer by the binder.

As the positive electrode active material and the negative electrode active material, various materials that can be used as the electrode active material of the all-solid-state battery can be used. For example, various compounds capable of occluding and releasing lithium ions can be preferably used. There is no clear limitation on these positive electrode active materials and negative electrode active materials, and the charge / discharge potentials of the two types of active material are compared, and the one whose charge / discharge potential shows a relatively noble potential is used as the positive electrode. Those showing an electric potential can be used for the negative electrode. Examples of such active material materials include lithium cobaltate (for example, LiCoO ₂ ), lithium nickelate (for example, LiNiO ₂ ), and Li _{1 + x} Co _1/3 Ni _1/3 Mn _1/3 O ₂ (for example, LiCoO ₂ ). Layered rock salt type lithium transition metal oxide such as x satisfies 0 ≦ x <1, lithium manganate (for example, LiMn ₂ O ₄ ), Li _{1 + x} Mn _2-xy M ¹ _y O ₄ (M ¹ is , Al, Mg, Ti, Co, Fe, Ni, and Zn, which are one or more metal elements, and x and y independently satisfy 0 ≦ x, y ≦ 1). Spinel-type lithium transition metal oxides such as dissimilar element-substituted Li-Mn spinels, lithium titanates (for example, Li _x TiO _y and x, y independently satisfy 0 ≦ x, y ≦ 1), lithium metal phosphates. Oxides such as (eg, LiM ² PO ₄ , M ² is Fe, Mn, Co, or Ni), vanadium oxide (eg V ₂ O ₅ ) and molybdenum oxide (eg MoO ₃ ), titanium sulfide (eg MoO ₃ ). TiS ₂ ), carbon materials such as graphite and hard carbon, lithium cobalt nitride (eg LiCoN), lithium silicon oxide (eg Li _{x S y} O _z , x, y, z are independently 0 ≦ x, Lithium metal (Li), silicon (Si) and tin (Sn) and their oxides (eg, SiO, SnO ₂ ), lithium alloys (eg, LiM ³ , M ³⁾ C, Sn, Si, Al, Ge, Sb, or P), lithium-storing metal-to-metal compounds (eg, Mg _x M ⁴ and M ⁵ _y Sb, M ⁴ are Sn, Ge, or Sb, M ⁵ are In, Cu or Mn), as well as derivatives and complexes thereof. The average particle size of the active material particles is not particularly limited, but may be, for example, 0.1 μm or more, and may be 0.5 μm or more. On the other hand, the volume average particle diameter is, for example, 50 μm or less, and may be 5 μm or less. When the active material particles are processed into the form of granulated powder and used, it is preferable that the average particle size of the active material particles as the primary particles is in the above range.

Further, in the first active material layer 20 and the second active material layer 30, a part of the active material material may be replaced with the above-mentioned solid electrolyte material in order to enhance the lithium ion conductivity in the layer. In this case, the ratio of the solid electrolyte material contained in the active material layers 20 and 30 can be, for example, 60% by mass or less, and 50% by mass, when the total of the active material and the solid electrolyte material is 100% by mass. % Or less is preferable, and 40% by mass or less is more preferable. The proportion of the solid electrolyte material is preferably 10% by mass or more, preferably 20% by mass or more, and more preferably 30% by mass or more. The first active material layer 20 and the second active material layer 30 are mainly composed of an active material material and a solid electrolyte material.

When a solid electrolyte composed of sulfide is contained in the positive electrode active material layer having a higher potential, a high resistance reaction layer may be formed at the interface between the positive electrode active material and the solid electrolyte, and the interface resistance may increase. .. Therefore, in order to suppress such an event, it is preferable that the positive electrode active material particles are coated with a crystalline oxide having lithium ion conductivity. Examples of the lithium-ion conductive oxide covering the positive electrode active material, for example, the general formula LixA ³ Oy ^{(A 3} is, B, C, Al, Si , P, S, Ti, Zr, Nb, Mo, Ta or W And x and y are positive numbers.). Specifically, Li ₃ BO ₃ , Li BO ₂ , Li ₂ CO ₃ , LiAlO ₂ , Li ₄ SiO ₄ , Li ₂ SiO ₃ , Li ₃ PO ₄ , Li ₂ SO ₄ , Li ₂ TiO ₃ , Li ₄ Ti ₅ Examples thereof include O ₁₂ , Li ₂ Ti ₂ O ₅ , Li ₂ ZrO ₃ , LiNbO ₃ , Li ₂ MoO ₄ , and Li ₂ WO ₄ . Further, the lithium ion conductive oxide include _{Li 4 SiO 4 -Li 3 BO 3} , Li 4 SiO 4 -Li 3 as PO ₄ or the like, a composite oxide composed of any combination of the lithium-ion conductive oxide It may be a thing.

When the surface of the positive electrode active material particles is coated with the ionic conductive oxide, the ionic conductive oxide need only cover at least a part of the positive electrode active material, and covers the entire surface of the positive electrode active material particles. You may be. The thickness of the ionic conductive oxide that coats the positive electrode active material particles is, for example, preferably 0.1 nm or more, and more preferably 1 nm or more. The thickness of the ionic conductive oxide is, for example, preferably 100 nm or less, more preferably 20 nm or less. The thickness of the ionic conductive oxide can be measured using, for example, an electron microscope such as a transmission electron microscope (TEM).

The first active material layer 20 and the second active material layer 30 may contain a conductive material for enhancing electron conductivity, if necessary. The conductive material is not particularly limited, and for example, graphite, carbon black such as acetylene black (AB) and Ketjen black (KB), vapor-grown carbon fiber (VGCF), carbon nanotube, carbon nanofiber, and the like. Carbon material can be preferably used. When the total amount of the electrode active material layer is 100% by mass, such a conductive material may be, for example, 1% by mass or more, and may be in the range of 1% by mass to 12% by mass, and 2% by mass to It may be in the range of 10% by mass.

The binder is not particularly limited, and various organic compounds having binding properties can be used. Examples of such a binder include polytetrafluoroethylene, polytrifluoroethylene, polyethylene, cellulose resin, acrylic resin, vinyl resin, nitrile rubber, polybutadiene rubber, butyl rubber, polystyrene, styrene butadiene rubber, styrene butadiene latex, and polysulfide. Examples thereof include rubber, acrylonitrile butadiene rubber, polyvinyl fluoride, polyvinylidene fluoride (PVDF), and fluororubber. Any one of these can be used alone or in combination of two or more.

Further, as the current collector 24, various materials having excellent electron conductivity and which are hard to change in quality at the charge / discharge potential of the active material to be used can be used. Examples of such a material include aluminum, copper, nickel, iron, titanium, alloys thereof (for example, aluminum alloy and stainless steel), carbon and the like. The shape of the current collector 24 can be, for example, a foil shape, a plate shape, a mesh shape, or the like. The thickness of the current collector 24 is not particularly limited because it depends on the dimensions of the electrode body and the like, but is preferably 5 μm or more and 500 μm or less, and more preferably 10 μm or more and 100 μm or less.

Next, each step will be described.
a. Preparation of the first active material layer In the step (a), the first active material layer 20 is prepared. The first active material layer 20 is prepared on one side or both sides of the current collector 24. In the present embodiment, as shown in FIG. 3A, the first active material layer 20 is formed on both sides of the current collector 24. As a method for producing the first active material layer, a coating method can be preferably adopted from the viewpoint of relatively low cost and excellent productivity. In the coating method, a slurry for the first active material layer is prepared, and this slurry is supplied to the current collector 24 to form the first active material layer 20. The slurry for the first active material layer can be prepared by dispersing at least powdery active material particles and a binder in a dispersion medium. Here, as the dispersion medium, an aqueous solvent or a non-aqueous solvent (organic solvent) capable of suitably dissolving or dispersing the binder to be used can be used. Examples of such an aqueous dispersion medium include water and a mixed solvent of a lower alcohol mainly composed of water. Examples of the non-aqueous dispersion medium include ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl butyrate, ethyl butyrate and butyl butyrate, hydrocarbon solvents such as toluene, xylene, cyclohexane and heptane, acetone and methyl ethyl ketone. Preferable examples include a ketone solvent, N-methyl-2-pyrrolidone (NMP), telepineol and the like. The dispersion medium may be used in the form of, for example, a binder solution in which a binder is dissolved, a binder dispersion solution in which a binder is dispersed, or the like. Further, the slurry used in the coating method may contain a viscosity adjusting agent or the like for adjusting the viscosity of the slurry, if necessary. The viscosity modifier is not particularly limited, and for example, an organic compound such as carboxymethyl cellulose (CMC) can be preferably used. The solid content concentration in the slurry is not particularly limited, and for example, 50% by mass or more is appropriate, 60% by mass or more is preferable, and 70% by mass or more is more preferable. From the viewpoint of slurry supply, the solid content concentration of the slurry may be, for example, 80% by mass or less.

The first active material layer 20 in the present embodiment is, for example, a negative electrode active material layer. Silicon (Si) powder with an average particle size of 4 μm is used as the negative electrode active material, LiI-Li ₃ PS _4- LiBr with an average particle size of 1 μm is used as the solid electrolyte, and AB is used as the conductive material. A slurry for a negative electrode can be prepared by dispersing the particles in a solution using a fill mix disperser. The binder solution was prepared by dissolving PVDF as a binder in butyl butyrate at a concentration of 5% by mass. The softening point of the PVDF used is in the range of 134 to 169 ° C. Further, as the current collector 24, a copper foil having a thickness of about 15 μm and a tensile strength of 500 N / mm ² or more at 25 ° C. was used.

As shown in FIG. 2, the current collector 24 is prepared, for example, in the form of a current collector roll 100 in which a long foil-shaped current collector 24 is wound around a roll. The current collector 24 is unwound from the current collector roll 100 by a transport means (not shown), and is continuously transported along the transport direction X. Then, the slurry for the first active material layer is applied to both surfaces of the current collector 24 being transported by the slurry coating device S1 provided on the transport path. Both ends of the width direction Y orthogonal to the longitudinal direction X of the current collector 24 are provided with active material layer non-forming portions 24a in which the current collector 24 is exposed without supplying the slurry for the first active material layer. ing. The current collector 24 is continuously transported by utilizing the active material layer non-forming portion 24a. Further, the slurry coating device S1 can intermittently coat the current collector 24 with the slurry for the first active material layer according to the desired dimensions of the electrode body 1. As a result, between the two first active material layers 20 adjacent to each other in the longitudinal direction X, an active material layer non-forming portion 24b in which the current collector 24 is exposed is provided over the width direction Y (FIG. 2 (A). )reference). Thereby, the first active material layer 20 having desired dimensions in the longitudinal direction X and the width direction Y can be prepared on the surface of the current collector 24. Here, of the surfaces of the first active material layer 20, the surface on the side not in contact with the current collector 24 is referred to as the first surface 21.

b. Preparation of Solid Electrolyte Layer In step (b), the solid electrolyte layer 10 is prepared so that the first surface 21 of the first active material layer 20 and the first surface 11 of the solid electrolyte layer 10 are in contact with each other. Here, among the surfaces of the solid electrolyte layer 10, the surface on the side in contact with the first active material layer 20 is referred to as the first surface 11, and the surface on the side not in contact with the first active material layer 20 is referred to as the second surface 12. .. In the present embodiment, the solid electrolyte layer 10 is formed on the first surface 21 of the two first active material layers 20 formed on both sides of the current collector 24. The solid electrolyte layer 10 in the present embodiment is formed by a coating method in the same manner as the first active material layer 20.

The solid electrolyte slurry used in the coating method can be prepared by dispersing the powdery solid electrolyte in the binder solution. In this embodiment, LiI-Li ₃ PS _4- LiBr having the same average particle size of 1 μm as that used for the first active material layer 20 was used as the solid electrolyte. As the binder solution, the same 5% by mass PVDF butyl butyrate solution used for the first active material layer 20 was used. Then, these were mixed and dispersed using a fill mix dispersion device to prepare a slurry for a solid electrolyte.
The slurry for solid electrolyte is housed in the slurry coating device S2 provided on the transport path, and is applied to the first surface 21 of the first active material layer 20 formed in the step (a). As shown in FIG. 3B, the solid electrolyte slurry is supplied to the entire surface of the first surface 21 of the first active material layer 20. As a result, the solid electrolyte layer 10 can be prepared so as to cover the entire first surface 21 of the first active material layer 20.

b'. Drying of the First Active Material Layer and the Solid Electrolyte Layer In the step (b'), the first active material layer 20 and the solid electrolyte layer 10 prepared in the steps (a) and (b) are dried. Although this step (b') is not essential, it is preferable to carry out the step (b') because a high-quality electrode body 1 can be manufactured in a short time. In the step (b'), the first active material layer 20 and the solid electrolyte layer 10 formed on the current collector 24 are conveyed along the transfer path together with the current collector 24 as shown in FIG. Introduced in D. While the first active material layer 20 and the solid electrolyte layer 10 pass through the dryer D, the dispersion medium (here, butyl butyrate) in the slurry is removed. The drying conditions in this embodiment are 120 ° C. for 20 minutes. As a result, a laminate of the first active material layer 20 and the solid electrolyte layer 10 as a dried product can be obtained. The thickness of the first active material layer 20 formed in this manner is about 50 μm, and the packing density (bulk density) is about 50% by volume. The thickness of the solid electrolyte layer 10 is about 55 μm, and the packing density (bulk density) is about 50% by volume. In addition, in this specification, "thickness" for each layer means the average thickness. Further, the dimensions of the first active material layer 20 and the solid electrolyte layer 10 in the width direction Y in the present embodiment are substantially the same.

c. Preparation of the second active material layer In the step (c), the second active material layer 30 is prepared so as to be in contact with the second surface 12 of the solid electrolyte layer 10. Here, as shown in FIG. 3C, the second surface 12 of the solid electrolyte layer 10 is divided into a peripheral edge portion 12a which is at least a part of the peripheral edge and a laminated portion 12b excluding the peripheral edge portion 12a. .. Then, the second active material layer 30 is prepared so as to be in contact with the laminated portion 12b. In other words, the second active material layer 30 is prepared so as not to come into contact with the peripheral edge portion 12a. The size of the second active material layer 30 in the plane direction is smaller than that of the first active material layer 20 and the solid electrolyte layer 10 by the amount of the peripheral portion 12a. In the present embodiment, the second active material layer 30 is formed by the coating method in the same manner as the first active material layer 20.

The second active material layer 30 in the present embodiment is, for example, a positive electrode active material layer. Lithium transition metal oxide (LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ ) powder with an average particle size of 4 μm is used as the positive electrode active material, and LiI with an average particle size of 0.8 μm is used as the solid electrolyte. Li ₂ SP ₂ S ₅ amorphous sulfide containing Li ₂ SP ₂ S ₅ amorphous sulfide was prepared, and VGCF was prepared as a conductive material. Then, these were dispersed in a 5% by mass butyl butyrate solution of PVDF as a binder solution using a Philmix disperser to prepare a slurry for a positive electrode.

Then, the slurry for the positive electrode is applied to the laminated portion 12b of the solid electrolyte layer 10 dried in the step (b') by the slurry coating apparatus S3 provided on the transport path. As shown in FIG. 2A, in the present embodiment, the peripheral edge portion 12a of the second surface 12 of the solid electrolyte layer 10 is set so as to be along both ends in the width direction Y. Further, the laminated portion 12b was set at the central portion in the width direction Y excluding the peripheral portion 12a on the second surface 12 of the solid electrolyte layer 10. As a result, the area of the second active material layer 30 in a plan view is smaller than the area of the solid electrolyte layer 10 and the first active material layer 20. Therefore, in order to match the volume ratios of the first active material layer 20 and the second active material layer 30, the dimension (thickness) of the second active material layer 30 in the vertical direction Z is the said of the first active material layer 20. It is formed so as to be thicker than the size (see FIG. 3C). Thereby, the second active material layer 30 can be prepared. The thickness of the second active material layer 30 formed in this manner is, for example, about 70 μm, and the packing density is about 50% by volume.

d. In the step (d) of preparing the insulating layer, the insulating layer 32 is prepared so as to be in contact with the peripheral edge portion 12a of the solid electrolyte layer 10. The insulating layer 32 has a function of insulating so that the end portion of the first active material layer 20 and the end portion of the second active material layer 30 that are crushed by rolling in the next step (e) do not come into contact with each other. The insulating layer 32 can be made of an insulating material having no electron conductivity. The insulating layer 32 can be made of, for example, an insulating material that does not have electron conductivity and lithium ion conductivity. The insulating layer 32 can be mainly composed of an insulating material. As the insulating layer 32, an insulating layer member formed in a predetermined shape corresponding to the peripheral edge portion 12a may be prepared in advance and arranged on the peripheral edge portion 12a of the solid electrolyte layer 10. Alternatively, the insulating layer 32 may be prepared by supplying a precursor material of the insulating material constituting the insulating layer 32 to the peripheral edge portion 12a of the solid electrolyte layer 10 and curing the insulating layer 32.

The insulating material is not particularly limited, and for example, thermoplastic resins such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN), epoxy resins, phenol resins, and unsaturated polyester resins. , Urea resin, melamine resin, urethane resin, imide resin and other thermosetting resins, polyamide, polyimide, polyacetal, polycarbonate, modified polyphenylene oxide and other engineering plastics, polyphenylene sulfide (PPS), polyether sulfone (PES), poly Super engineering plastics such as ether ether ketone (PEEK), polyetherimide (PEI), modified polyamide, photocurable resin polymerized and cured by supplying light energy, alumina, silica, titania, ceria, zirconia, boehmite, water It can be composed of an insulating ceramic such as aluminum oxide or magnesium hydroxide, a solid electrolyte material, or the like. Among them, the insulating material is an inorganic material such as an insulating ceramic or a solid electrolyte material from the viewpoint of adjusting the compressive resistivity of the insulating layer 32 and the positive electrode active material before rolling to an appropriate relationship, which will be described later. It is preferable, and the use of alumina, the above-mentioned sulfide-based solid electrolyte and the like is more preferable.

The "engineering plastic" referred to here has a heat resistance of 100 ° C. or higher (typically, at least one of a deflection temperature under load and a continuous use temperature), a tensile strength of 49 MPa or higher, and 2.5 GPa or higher. A material having a flexural modulus of. Further, the "super engineering plastic" refers to an engineering plastic having a heat resistance of 150 ° C. or higher.
The deflection temperature under load is a temperature at which the amount of deflection when the temperature is raised while applying a constant load to the resin material exceeds a certain value according to the method specified in ASTM D648 or JIS K7191-1: 2015. Is. In addition, the continuous use temperature is based on the method defined by UL746B of the US UL standard, and can be used continuously in a no-load environment defined as the Relative Thermal Index (RTI). Temperature.

When the insulating material is the above resin (cured product), the precursor material can be, for example, a resin composition containing a monomer, an oligomer, a prepolymer, or the like of the resin. When the resin is a photocurable resin, the photocurable resin composition as an uncured photocurable resin can contain additives such as a photopolymerization initiator. When the insulating material is the insulating ceramic, the precursor material can be, for example, a powder containing particles made of the insulating ceramic and a binder, or a slurry in which the powder is dispersed in a dispersion medium. .. When the insulating material contains a solid electrolyte material, the solid electrolyte material may be the same as or different from the solid electrolyte material constituting the solid electrolyte layer 10. As these materials, for example, two or more different materials may be used in combination in order to adjust the compressive deformation resistivity described later.

The insulating material in this embodiment is an alumina powder molded product. Then, this alumina powder molded product can be prepared by applying an alumina slurry as a precursor material to the peripheral portion 12a of the solid electrolyte layer 10 and removing the dispersion medium, similarly to the first active material layer 20. it can. The alumina slurry can be prepared by dispersing alumina powder having an average particle diameter of 4 μm in a PVDF 5% by mass NMP solution as a binder solution using a fill mix dispersion device.
The alumina slurry is applied to the peripheral edge portion 12a of the solid electrolyte layer 10 by the slurry coating device S4 provided on the transport path. As shown in FIG. 3D, in the present embodiment, the alumina slurry is supplied so as to be in contact with the end portion of the second active material layer 30 in the width direction Y. In other words, the alumina slurry is supplied so as to fill the stepped portion formed by the surfaces of the solid electrolyte layer 10 and the second active material layer 30. Then, the dispersion medium in the alumina slurry is removed by volatilization to form the insulating layer 32. As a result, a laminated body in which the first active material layer 20, the solid electrolyte layer 10, the second active material layer 30 and the insulating layer 32 are laminated can be formed.

As shown in FIG. 3D, in this laminated body, insulating layers 32 are provided at both ends of the second active material layer 30 in the width direction Y. In the laminated body, the first active material layer 20 formed on both sides of the current collector 24, the second solid electrolyte layer 10, the second active material layer 30 and the insulating layer 32 of the third layer are , The ends in the width direction Y are almost aligned. Further, in the present embodiment, the coating amount of the alumina slurry is adjusted so that the thickness of the insulating layer 32 is substantially the same as the thickness of the second active material layer 30. The surfaces of the insulating layer 32 and the second active material layer 30 in the present embodiment are formed so as to be substantially flush with each other. The thickness of the insulating layer 32 formed in this way is, for example, about 70 μm, and the packing density is about 50% by volume. The thickness of the laminated body is, for example, about 400 μm.

e. In the rolling step (e) of the laminated body of each layer, the laminated body prepared in the above step (d) is pressed in the laminating direction (that is, the thickness direction Z). As shown in FIG. 2, the laminated body is conveyed along the conveying direction X and sent to the rolling apparatus P. As the laminate passes through the rolling apparatus P, the laminate is densely rolled. As a result, as shown in FIG. 3 (e), it is possible to obtain the electrode body 1 in which the dimensions in the thickness direction are compressed and the packing density is increased.

In this embodiment, a hot roll press is used as the rolling apparatus P. Among the rolling mills, the roll rolling apparatus is advantageous in that the laminated body during transportation can be smoothly compressed. The rolling conditions by the rolling apparatus P are preferably, for example, large rolling with a linear pressure of 10 kN / cm or more. The linear pressure is more preferably 30 kN / cm or more, further preferably 40 kN / cm or more, and particularly preferably 50 kN / cm or more. The upper limit of the linear pressure is not particularly limited, and can be appropriately set according to the rolling capacity of the rolling apparatus P and the shape maintaining characteristics of the laminated body. This makes it possible to compress the laminate more densely by rolling once. Further, this rolling is preferably carried out while heating from the viewpoint of obtaining a more dense electrode body 1. The heating temperature during rolling is not particularly limited, but is, for example, a temperature equal to or higher than the softening point of the binder contained in the first active material layer 20, the solid electrolyte layer 10, the second active material layer 30, and the insulating layer 32 (170 in this case). ℃ or higher) is preferable. The thickness of the electrode body 1 thus obtained is, for example, approximately 225 μm (compression rate: about 44%). Needless to say, the heating temperature of rolling can be lower than the temperature that causes unintended deterioration of the material used. For example, the heating temperature can be a temperature lower than the thermal decomposition start temperature of the binder.

A plurality of electrode bodies 1 thus obtained are formed on both sides of the long current collector 24 with the active material layer non-forming portion 24b interposed therebetween. Therefore, as shown in FIG. 2, for example, by using the cutting device C to cut the current collector 24 at the active material layer non-forming portion 24b along the width direction Y, the plurality of electrode bodies 1 are individually cut. Can be obtained.

As described above, the manufacturing method disclosed herein employs rolling at a higher pressure than before, so that the electrode body 1 can be manufactured by rolling (pressurizing) only once. Further, in the rolling, for example, the compression rate (rolling rate) in the thickness direction is 20% or more, more preferably 30% or more, further preferably 40% or more, for example 45% or more, and particularly preferably 50% or more. It can be realized. According to the conventional rolling, the packing density of each layer of the electrode body could be increased only to about 70% by volume. On the other hand, according to the technique disclosed herein, the packing density of each layer of the obtained electrode body 1 was, for example, about 50% by volume before rolling, but about 80% by volume or more, more preferably about. It is increased to 85% by volume or more, more preferably to about 90% by volume or more. As a result, the interfacial resistance in each layer is suppressed to be low, and the electrode body 1 having a low internal resistance can be easily manufactured.

The linear pressure produced by the roll rolling acts on the laminated body in the thickness direction Z and also in the width direction Y relatively large. Tensile stress in the width direction Y acts on the laminated body by rolling. Here, since the second active material layer 30 is formed to have a small dimension in the width direction Y, the dimension in the thickness direction Z is relatively larger than, for example, the first active material layer 20. As a result, the amount of deformation in the width direction Y by rolling tends to increase. In particular, when the second active material layer 30 is a positive electrode active material layer containing a lithium transition metal oxide commonly used as a positive electrode active material, the metal oxide is an active material material (typically) often used as a solid electrolyte or a negative electrode active material. In terms of hardness, it can be higher than that of carbon materials and metal materials. As a result, the second active material layer 30 is more likely to undergo compressive deformation than densification due to rolling. However, according to the above configuration, insulating layers 32 are provided at both ends of the second active material layer 30 in the width direction Y. As a result, it is possible to prevent the second active material layer 30 from being significantly deformed in the width direction Y and short-circuiting with the first active material layer 20.

Further, as shown in FIG. 3D, the step on the surface between the solid electrolyte layer 10 and the second active material layer 30 is filled with the insulating layer 32. As a result, the pressure can be uniformly transmitted to the second surface 12 of the solid electrolyte layer 10 even when large rolling is performed with a large pressure. In other words, the difference in pressure transmitted to the laminated portion 12b and the peripheral portion 12a of the solid electrolyte layer 10 is alleviated. In particular, when the insulating layer 32 is a ceramic powder molded product, the compression deformation behavior of the insulating layer 32 and the second active material layer 30 can be approximated, so that the pressure can be uniformly transmitted to the solid electrolyte layer 10. it can. As a result, for example, as shown in FIG. 4, it is possible to suppress the occurrence of rolling cracks at the boundary between the peripheral edge portion 112a and the laminated portion 112b of the solid electrolyte layer 110, which has been seen in the conventional electrode body 101. Thereby, the electrode body 1 in which the first active material layer 20, the solid electrolyte layer 10 and the second active material layer 30 are uniformly rolled to a high packing density can be obtained.

Further, as shown in FIG. 3E, in the electrode body 1 obtained after rolling, the surface heights of the second active material layer 30 and the insulating layer 32 are equal and flush with each other. Further, the physical properties such as the deformation behavior of the second active material layer 30 and the insulating layer 32 with respect to pressure are similar. As a result, even when the electrode body 1 receives stress or the like due to vibration caused by the use of the all-solid-state battery, for example, stress is applied to the boundary between the peripheral portion 12a and the laminated portion 12b of the solid electrolyte layer 10. It is possible to suppress concentration. Therefore, it is possible to manufacture the electrode body 1 in which fatigue cracking and the like of the solid electrolyte layer 10 are suppressed not only during manufacturing but also during use. This is preferable because it exerts a particularly remarkable effect on the electrode body 1 in which the packing density of each layer is further increased. Further, this is especially true when the electrode body 1 having a structure containing a material having a large volume change with charging / discharging (for example, a carbon material or a Si-based material, particularly a Si-based material) as an electrode active material is repeatedly charged / discharged. It is preferable in that the above action is more effectively exhibited.

In the above embodiment, the first active material layer 20, the solid electrolyte layer 10, the second active material layer 30, and the insulating layer 32 are all prepared by a coating method. Further, the first active material layer 20, the solid electrolyte layer 10, the second active material layer 30, and the insulating layer 32 were integrally formed in this order in this order. However, the techniques disclosed herein are not limited to this. For example, the first active material layer 20, the solid electrolyte layer 10, the second active material layer 30, and the insulating layer 32 are independently of each other, such as a powder compression molding method, a granulated powder compression molding method, and a thin film forming method. It can be prepared by a known method. Further, each layer may be formed integrally in sequence, or each layer may be formed as an independent body. When each layer is prepared independently, each layer is formed in advance on the current collector 24 or an arbitrary carrier sheet, and these are overlapped in steps (a) to (d), and the rolling step (e) is performed. It is good to join and integrate with.

Further, in the above embodiment, the steps (c) and (d) are independently carried out in this order. However, the techniques disclosed herein are not limited to this. For example, in the step (c) and the step (d), the step (d) may be carried out before the step (c), or the step (c) and the step (d) may be carried out at the same time. Good. When the step (c) and the step (d) are carried out at the same time, the case is not limited to this, but for example, as a slurry coating device, the slurry for the second active material and the alumina slurry are simultaneously striped in a stripe shape. A multi-row coating device that can be coated can be preferably used.

Further, in the above embodiment, the drying step (b') was carried out after the steps (a) and (b) by the slurry coating. However, the techniques disclosed herein are not limited to this. For example, when each layer is prepared by a method such as a powder compression molding method, a granulated powder compression molding method, or a thin film forming method, the step (b') can be omitted.
On the other hand, in the above embodiment, in the step (d) by slurry coating, the dispersion medium is removed by volatilization. However, the technique disclosed herein is not limited to this, and for example, a drying step (d') may be carried out after the step (d).

Further, in the above embodiment, the rolling step (e) was carried out after the step (d) by the slurry coating. However, the technique disclosed herein is not limited to this, and for example, prior to step (e), a step of preparing a second current collector on the second active material layer 30 and the insulating layer 32 is carried out. You may. Further, a step of preparing a laminated body in which a plurality of laminated bodies as shown in FIG. 3D may be stacked may be carried out via the second current collector. As the second current collector, various materials which are the same as the above current collector 24, have excellent electron conductivity, and are not easily altered in the charge / discharge potential of the electrode active material contained in the second active material layer 30 are used. be able to. For example, an aluminum foil can be preferably used. As a result, the electrode having a configuration in which the first active material layer 20, the solid electrolyte layer 10, the second active material layer 30, and the insulating layer 32 are sandwiched between two current collectors and integrated with one or more storage units. Body 1 can be obtained.

Further, in the above embodiment, after the rolling step (e), the current collector 24 is cut to separate the electrode body 1. However, the timing of cutting the current collector 24 is not limited after the rolling step (e). The current collector 24 may be cut, for example, before the rolling step (e).

Further, in the above embodiment, the rolling step (e) was carried out by roll rolling using a hot roll rolling mill. However, the technique disclosed herein is not limited to this, and for example, the rolling step (e) may be carried out by a flat press using a flat plate rolling mill. Although not limited to this, as described above, when the current collector 24 is cut before the rolling step (e), it is also preferable to perform the rolling step (e) by a flat press. The surface pressure when performing a flat press is, for example, preferably 200 MPa or more, more preferably 400 MPa or more, further preferably 600 MPa or more, particularly preferably 800 MPa or more, for example, about 1000 MPa. The upper limit of the surface pressure can be appropriately set depending on the performance of the flat plate rolling mill used and the like.

In the case of flat pressing, in addition to the tensile stress in the width direction Y, the tensile stress in the longitudinal direction X is likely to be generated in each layer as compared with the case of roll rolling. Therefore, on the second surface 12 of the solid electrolyte layer 10, in addition to providing the peripheral edge portion 12a along both ends in the width direction Y, it may be provided along both ends in the longitudinal direction X. In other words, the peripheral edge portion 12a may be provided over the entire peripheral edge of the second surface 12 of the solid electrolyte layer 10. Further, in accordance with this, the insulating layer 32 may be provided over the entire peripheral edge of the second surface 12 of the solid electrolyte layer 10. As a result, even when the second active material layer 30 is significantly deformed not only in the width direction Y but also in the longitudinal direction X by rolling, the short circuit between the first active material layer 20 and the second active material layer 30 is preferably performed. Can be prevented.

Further, in the above embodiment, before the rolling step (e), the dimensions of the second active material layer 30 and the insulating layer 32 in the thickness direction Z are such that the surfaces of both are substantially surface as shown in FIG. 3D. It was formed to be one. Further, the position of the end portion of the insulating layer 32 in the width direction Y opposite to that of the second active material layer 30 was substantially aligned with the position of the end portion of the solid electrolyte layer 10 in the width direction Y. However, the technique disclosed herein is not limited to this, and the form of the insulating layer 32 may be changed in various ways. For example, in the example shown in FIG. 5A, before the rolling step (e), both sides of the current collector 24 and both ends of the solid electrolyte layer 10 in the width direction Y are insulated in four different cross-sectional forms. Layers 32a, 32b, 32c, 32d are formed. As described above, for example, the insulating layer 32a may be thicker than the second active material layer 30. Further, the insulating layer 32b may be thinner than the second active material layer 30. Further, the end portion of the insulating layer 32c may protrude in the width direction Y from the solid electrolyte layer 10. Further, the size of the insulating layer 32d in the width direction Y may change along the thickness direction Z. These insulating layers 32a, 32b, 32c, and 32d are rolled in the rolling step (e) until at least the surfaces of the second active material layer 30 and the insulating layer 32 are flush with each other, as shown in FIG. 5 (B). Will be done. Therefore, if the structure is such that rolling is possible, the effect of the present technology can be realized as in the above embodiment.

However, if the thicknesses of the insulating layers 32a and 32b are too different from those of the second active material layer 30, the pressure applied to the solid electrolyte layer 10 in the rolling step (e) may be uneven, which is not preferable. Therefore, although it cannot be said unconditionally because it depends on the constituent materials of the second active material layer 30 and the insulating layer 32, for example, the thickness T1 of the insulating layer 32b before rolling is the thickness of the second active material layer 30 before rolling. It is desirable to satisfy the relationship of 0.6 × T2 ≦ T1 with respect to T2, more preferably 0.75 × T2 ≦ T1, and for example, 0.8 × T2 ≦ T1 may be satisfied. Further, it is desirable that the thicknesses T1 and T2 satisfy the relationship of T1 ≦ 1.8 × T2, and T1 ≦ 1.6 × T2, T1 ≦ 1.4 × T2, and further T1 ≦ 1.25 × T2. It is more desirable to satisfy the relationship of T1 ≦ 1.2 × T2. As a result, the solid electrolyte layer 10 can be rolled more uniformly even when the thicknesses of the second active material layer 30 and the insulating layer 32 are different.

Further, from the viewpoint of transmitting a uniform pressure to the solid electrolyte layer 10, it is preferable that the second active material layer 30 and the insulating layer 32 have similar deformation resistance at the time of compression. According to the study by the present inventors, for example, the compressive deformation resistivity (compressive elastic modulus, also simply referred to as "elastic modulus") of the insulating layer 32b prepared in the step (d) (in other words, before rolling) E1. It is preferable that E1 ≧ 0.1 × E2 is satisfied with respect to the compressive deformation resistivity E2 of the second active material layer 30 before rolling, and E1 ≧ 0.2 × E2 is more preferable. As a result, the pressure can be satisfactorily transmitted to the solid electrolyte layer 10. The compressive deformation resistivity E1 is preferably 0.5 × E2 or more, more preferably 0.8 × E2 or more, further preferably 0.9 × E2 or more, and particularly preferably E2 or more. Further, according to the study by the present inventors, it is permissible that the insulating layer 32 is not excessive and is relatively difficult to stretch and deform as compared with the second active material layer 30. Therefore, the compressive deformation resistivity E1 is preferably about 2 × E2 or less, more preferably 1.5 × E2 or less, further preferably 1.3 × E2 or less, and particularly preferably 1.2 × E2 or less. As a result, even when the materials of the second active material layer 30 and the insulating layer 32 are different, the effect of the present technology can be exhibited as in the above embodiment. In addition, a guideline for designing the insulating layer 32 is provided.

In order to sufficiently densify the second active material layer 30 and suppress cracking of the solid electrolyte layer 10 at a high level in a well-balanced manner, the second active material layer 30 and the insulating layer 32 to be subjected to rolling are used. It is preferable that the thickness of the material and the compressive deformation resistivity satisfy the following relationship. That is, first, it is preferable that E1 ≧ 0.2 × E2. Then, in the case of (1) 0.2 × E2 ≦ E1 ≦ 0.5 × E2, it is preferable that 0.75 × T2 ≦ T1 ≦ 1.6 × T2. Further, in the case of (2) 0.5 × E2 <E1, it is preferable that 0.75 × T2 ≦ T1 ≦ 1.25 × T2.

In this specification, the compressive deformation resistivity means the transmission efficiency of the compressive stress when it is subjected to the compressive stress. For this compressive deformation resistance, for example, a compression test is performed on a sample corresponding to the insulating layer 32b before rolling and the second active material layer 30 before rolling at the same temperature and compressive load as in the rolling step (e). It can be grasped as the slope of the stress-strain curve obtained. When calculating the slope of the stress-strain curve, since the sample thickness is extremely thin, the stress-strain curve may be linearly complemented to obtain the slope. Further, when the insulating layer is made of a composite material like the second active material layer, a yield point or a fracture point may be seen in the stress-strain curve. In that case, the slope may be calculated based on the compound law, or may be obtained by linearly complementing the curve in the initial strain region up to the yield point (or fracture point). The compression test can be appropriately performed according to, for example, JIS K7181, K7056, R1608, and the like. In practice, stress-strain when a compressive load exceeding 500 MPa is applied to a thin-film (typically 100 to 200 μm thick) sample such as an insulating layer or a second active material layer before rolling. It can be difficult to measure the properties. In that case, for the compressive deformation resistivity, for example, 500 MPa (representative value) may be adopted as the compressive load in the rolling step (e). The relationship between the compressive deformation resistivity E1 of the insulating layer and the compressive deformation resistivity E2 of the second active material layer is various, for example, using a precision universal testing machine and a specially prepared jig. For the insulating layer sample and the second active material layer sample, the compressive deformation resistivityes E1 and E2 when a compressive force of 500 MPa is applied under the temperature conditions of room temperature (25 ° C.) to 200 ° C. (typically 170 ° C.) It was derived based on this.

[Second Embodiment]
(CAE analysis)
In manufacturing an electrode body of an all-solid-state battery, the response curved surface method is used to determine the rolled state of the solid electrolyte layer when a predetermined rolling is performed on the laminated body in which the solid electrolyte layer, the positive electrode active material layer and the insulating layer are laminated. The results predicted by CAE (computer aided engineering) analysis based on the above are shown in FIG. In FIG. 6, the vertical axis shows the ratio of the thickness of the insulating layer to the positive electrode active material layer before rolling, and the horizontal axis shows the ratio of the elastic modulus (compressive deformation resistivity) of the insulating layer to the positive electrode active material layer. FIG. 6 shows that the combined region of region II and region III is a region in which the relationship between the positive electrode active material layer and the insulating layer is a region in which compressive stress of a predetermined value or more is applied to the positive electrode active material layer by pressing. .. On the other hand, when the relationship between the positive electrode active material layer and the insulating layer is in region I, the insulating layer is too hard or too thick, so that the pressing pressure is applied only to the insulating layer and the solid electrolyte layer portion in contact with the insulating layer. It is shown that it is loaded and the required compressive load is not applied to the positive electrode active material layer. Further, when the relationship between the positive electrode active material layer and the insulating layer is in the region where the regions I and II are combined, compressive stress is applied to the solid electrolyte layer in contact with the region I via the insulating layer, but the solid electrolyte layer is conveyed during roll pressing. Indicates that no tensile stress is applied in the direction. On the other hand, when the relationship between the positive electrode active material layer and the insulating layer is in the other region III (the region from the left side to the lower half), the insulating layer is too soft or too thin and is in contact with the insulating layer. It is shown that the electrolyte layer cannot be compressed, tensile stress is applied to the solid electrolyte layer in contact with the insulating layer, and cracks or the like occur in the insulating layer or the solid electrolyte layer. Therefore, when the relationship between the positive electrode active material layer and the insulating layer is in region II, the solid electrolyte layer is not cracked or the like, and the positive electrode active material layer can be firmly densified.

[Electrode body fabrication test]
In addition, it was confirmed by the following electrode body fabrication test whether or not the prediction by the CAE analysis in FIG. 6 was appropriate. FIG. 6 also shows the results of this electrode body fabrication test.
(Examples 1 and 2)
Lithium transition metal oxide (LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ ) powder with an average particle size of 4 μm as a positive electrode active material and LiI-containing Li with an average particle size of 0.8 μm as a sulfide solid electrolyte ₂ SP ₂ S ₅ series glass ceramic, VGCF as a conductive material, 5% by mass butyl butyrate solution of PVdF as a binder solution, and butyl butyrate solution as a dispersion medium are stirred by a fill mix disperser. A positive electrode paste was obtained.
Silicon powder with an average particle size of 5 μm as a negative electrode active material, Li ₂ SP ₂ S ₅ system glass ceramic with an average particle size of 2.5 μm as a sulfide solid electrolyte, and 5 masses of PVdF as a binder solution. The% butyl butyrate solution and the butyl butyrate solution as a dispersion medium were stirred with an ultrasonic disperser for 30 seconds to obtain a negative electrode paste.

Li ₂ SP ₂ S ₅ glass ceramic containing LiI with an average particle size of 2.5 μm as a sulfide solid electrolyte, a 5 mass% heptane solution of a butadiene rubber (BR) binder, and heptane as a dispersion medium. The mixture was stirred with an ultrasonic disperser for 30 seconds to obtain a paste for the SE layer.
Alumina powder with an average particle size of 5 μm as an insulating layer material, a 10 mass% mesitylene solution of a butadiene rubber (BR) binder, and mesityylene as a dispersion medium are stirred for 30 seconds with an ultrasonic disperser, and a paste for the insulating layer is used. Got

A positive electrode active material layer and an SE layer were prepared by applying a positive electrode paste and an SE layer paste on an aluminum foil by a blade method and drying them on a hot plate at 100 ° C. for 30 minutes. The thickness of the positive electrode active material layer was set to 60 μm. Next, the negative electrode paste is applied to one side of the copper foil by the blade method, dried on a hot plate at 100 ° C. for 30 minutes, and then the negative electrode paste is applied to the other side of the copper foil by the blade method. The work was carried out and dried on a hot plate at 100 ° C. for 30 minutes to obtain a negative electrode having negative electrode active material layers on both sides of the copper foil. The dimensions of the negative electrode active material layer and the SE layer in a plan view are the same, and the positive electrode active material layer is formed to have a narrower dimension in the width direction than the SE layer.

The prepared SE layers are laminated on the negative electrode active material layers on both sides of the prepared negative electrode, roll-pressed at room temperature (25 ° C.), and then the aluminum foil is peeled off to form the SE layer on the negative electrode by the transfer method. Membrane. Further, in the same manner, the positive electrode active material layer was transferred onto the SE layer. As a result, the SE layer and the negative electrode active material layer protrude at both ends in the width direction from the positive electrode active material layer, and there are a total of four steps on both sides between the SE layer and the positive electrode active material layer at both ends in the width direction. Been formed. The width of these stepped portions was about 2 mm, and the height of these stepped portions was 60 μm, which coincided with the thickness of the positive electrode active material layer.

Therefore, the insulating layer paste was supplied to the stepped portion by a dispenser and dried on a hot plate at 100 ° C. for 30 minutes to form an insulating layer. However, in Example 1, it was formed so that the thickness of the insulating layer was 60 μm, and in Example 2, it was formed so that the thickness of the insulating layer was 55 μm. Two insulating layers were provided on each side, and a total of four insulating layers were provided on both sides to prepare a laminated body. Then, this laminated body is sandwiched between two SUS plates having a thickness of 0.1 mm, rolled at a linear pressure of 50 kN / cm with a roll press machine at 170 ° C., and each layer is densified to form Examples 1 and 2. An electrode body for an all-solid-state battery was obtained.

(Example 3)
An electrode body of Example 3 was obtained in the same manner as in Example 1 except that a Li I-containing Li ₂ SP ₂ S ₅ series glass ceramic having an average particle diameter of 2.5 μm was used as the insulating layer material.
(Example 4)
The electrode body of Example 4 was obtained in the same manner as in Example 1 except that the insulating layer was not formed.

(Examples 5 to 6)
An acrylic resin-based UV curable resin was supplied to the stepped portion by a screen printing method, and an insulating layer was formed by irradiating the step portion with UV. Here, in Example 5, the thickness of the insulating layer was formed to be 60 μm, and in Example 6, the thickness of the insulating layer was formed to be 52 μm. Except for these, the electrode bodies of Examples 5 and 6 were obtained in the same manner as in Example 1.

[Elastic modulus of insulating layer]
By producing the insulating layer portion of the electrode body of each example under the same conditions and performing a compression test in an environment of 170 ° C., the compressive deformation resistivity of the insulating layer of each example (hereinafter, simply referred to as “elastic modulus”) is shown. .) Was measured. The results are shown in Table 1 below. For reference, the elastic modulus of the positive electrode active material layer before the roll press was about 8000 MPa.
[Evaluation of solid electrolyte layer]
The insulating layer of the electrode body of each example and the solid electrolyte layer in contact with the insulating layer were observed, and the presence or absence of defects such as cracks is shown in Table 1 below.

It was confirmed that in the electrode bodies of Examples 1 and 2 in which alumina was used as the insulating layer material, the solid electrolyte layer could be rolled uniformly and uniformly by one roll rolling without causing cracks in the solid electrolyte layer. By using a material (about + 15%) having an elastic modulus close to that of the positive electrode active material such as alumina as the insulating layer material, the thickness of the positive electrode active material layer and the insulating layer may differ by about 5 μm (about -8%). However, it was found that good rolling can be performed. It was also confirmed that the electrode body of Example 3 can be rolled uniformly and uniformly by using a solid electrolyte material (about -24%) having an elastic modulus close to that of the positive electrode active material as the insulating layer material. ..
On the other hand, in the electrode body of Example 4 in which the insulating layer was not provided, it was confirmed that the solid electrolyte layer was damaged during roll rolling (at a linear pressure of 20 kN / cm or more). Further, for the electrode bodies of Examples 5 and 6 in which an acrylic resin (about -99%) having a elastic modulus significantly different from that of the positive electrode active material is used as the insulating layer material, the thickness of the positive electrode active material layer and the insulating layer are the same. It was confirmed that the insulating layer and the solid electrolyte layer were damaged during roll rolling even when (Example 5) was different by about 8 μm (about -13%) (Example 6). In Example 5, it is considered that the insulating layer was broken because the insulating layer was so low in elasticity that it could not withstand the compressive stress. In Example 6, the thickness of the insulating layer is thin, rolling stress acts on the positive electrode active material layer and the solid electrolyte layer in contact with the positive electrode active material layer, and the insulating layer and the solid electrolyte layer in contact with the insulating layer come into contact with the insulating layer before receiving the rolling stress. It is probable that tensile stress was applied to the solid electrolyte layer, and such a difference in tensile stress damaged the insulating layer and the solid electrolyte layer in contact with the insulating layer.

As shown in FIG. 6, it was confirmed that the relationship between the thickness and elastic modulus of the insulating layer of the above examples 1, 3, 5 and 6 and the positive electrode active material layer was in good agreement with the analysis result by CAE. From this, it was confirmed that the insulating layer and the insulating layer material suitable for the positive electrode active material layer can be selected in consideration of the rolling conditions. The region II in which the solid electrolyte layer can be rolled evenly is approximately the following (1) or (2) based on the thickness T1 and elastic modulus E1 of the insulating layer before rolling and the thickness T2 and elastic modulus E2 of the positive electrode active material layer. ) Indicates. From this, it can be seen that the insulating layer before rolling and the positive electrode active material layer may be designed so as to satisfy the following (1) or (2).
(1) 0.2 × E2 ≦ E1 ≦ 0.5 × E2 and 0.75 × T2 ≦ T1 ≦ 1.6 × T2
(2) 0.5 × E2 <E1 and 0.75 × T2 ≦ T1 ≦ 1.25 × T2

[Third Embodiment]
In the first embodiment, in the step (d), an alumina slurry was used to prepare an insulating layer 32 made of an alumina powder molded product. In the second embodiment, the case where the insulating layer 32 is prepared by the ultraviolet curable resin in the step (d) will be described. Along with this, the step (d) of preparing the insulating layer 32 was carried out before the step (c) of preparing the second active material layer. Since the other parts are the same as those in the first embodiment described above, duplicate description will be omitted.

In the present embodiment, as a material constituting the insulating layer 32, an ultraviolet curable acrylic resin composition containing an acrylic monomer as a base polymer and a photopolymerization initiator was prepared. Further, a shirasu balloon was prepared as an adjusting material for adjusting the compression characteristics of the insulating layer 32. The shirasu balloon is a fine hollow glass sphere produced from shirasu, which is a volcanic ejecta, and is an inorganic powder having properties of being lightweight, having a low bulk density, and having a relatively low uniaxial compressive strength. Then, Shirasu balloon was blended with this ultraviolet curable acrylic resin composition at a volume ratio of 50:50 to prepare a material (precursor material) for an insulating layer.

In the production of the electrode body 1 in the present embodiment, the step (d) of preparing the insulating layer 32 is carried out following the drying step (b'). Therefore, instead of the slurry coating device S3 shown in FIG. 2, a resin applicator and an ultraviolet lamp were prepared. Then, the above-mentioned material for the insulating layer was supplied to the peripheral edge portion 12a of the solid electrolyte layer 10 by an applicator provided on the transport path, and the material for the insulating layer was cured by irradiating with an ultraviolet lamp. As a result, the two insulating layers 32 were formed so as to stand on the peripheral edges 12a set at both ends of the solid electrolyte layer 10 in the width direction Y.

Next, the step (c) of preparing the second active material layer 30 was carried out. That is, using the slurry coating device S4, the same positive electrode slurry as in the first embodiment was supplied between the insulating layers 32 formed along both ends of the solid electrolyte layer 10. Then, the second active material layer 30 was formed by volatilizing the dispersion medium in the positive electrode slurry. Then, subsequently, the rolling step (e) and the cutting of the current collector 24 were carried out in the same manner as in the first embodiment to obtain the electrode body 1 having a predetermined size. In the obtained electrode body 1, an insulating layer 32 is filled between the peripheral edge portion 12a of the solid electrolyte layer 10 and the second active material layer 30. The insulating layer 32 is a pseudo-porous material in which shirasu balloons are dispersed and exist in a cured acrylic resin.

According to the above configuration, the time required for preparing the insulating layer 32 can be significantly shortened, and the time required for manufacturing the electrode body 1 can be reduced. Further, by performing the step (c) after the step (d), the thick secondary active material layer 30 can be easily formed by suppressing sagging at both ends. Further, the acrylic resin has a relatively high compressive strength after curing, and if the insulating layer 32 is formed only by the ultraviolet curable acrylic resin, there may be a problem that it is difficult to roll in the next step (e). Alternatively, since the compression behavior of the insulating layer 32 and the second active material layer 30 are significantly different, the pressure transmitted to the second surface 12 of the solid electrolyte layer 10 becomes uneven due to rolling, causing cracks in the solid electrolyte layer 10. There is a risk of On the other hand, in the above embodiment, the compression characteristics of the insulation layer 32 are adjusted to match the compression characteristics of the second active material layer 30 by blending the adjusting material with the ultraviolet curable acrylic resin constituting the insulation layer 32. doing. As a result, pressure unevenness applied to the solid electrolyte layer 10 can be suppressed not only in the rolling step (e) but also when the all-solid-state battery is used. As a result, a high-quality electrode body 1 in which cracking of the solid electrolyte layer 10 is suppressed can be manufactured.

In the above embodiment, a shirasu balloon was used as the adjusting material. However, the adjusting material is not limited to this. For example, as the adjusting material, one or more of porous ceramic powder, ceramic hollow particles, hollow aggregates of ceramic particles, porous resin particles, hollow resin particles, insulating fibrous filler, etc., alone or 2 More than seeds can be used in combination. Further, the existence of these adjusting materials is confirmed by being contained in the insulating layer 32 of the manufactured electrode body 1 as, for example, crushed matter, crushed matter, compressed matter, agglomerate, etc. at a high packing density. be able to.

It should be noted that Patent Document 4 discloses that after obtaining the battery structure, the unsealed portion of the battery structure is sealed with an insulating resin such as a polyolefin resin or an epoxy resin, if necessary. Has been done. However, this sealing material differs from the manufacturing method provided by the present technology in that it is filled after obtaining the structure for battery construction. Further, the structure for battery construction of Patent Document 4 does not include an electrode active material layer having a size smaller in the plane direction than the solid electrolyte layer, and due to the difference in dimensions between the solid electrolyte layer and the electrode active material layer. It differs from the electrode body provided by the present technology in that the sealing material does not form a step to be generated.

[Use]
In the electrode body 1 disclosed here, a current collector 24 is connected to the first active material layer 20, and a second current collector (not shown) is electrically connected to the second active material layer 30. Can be done. Then, the all-solid-state battery can be constructed by housing the current collector or the extraction electrode electrically connected to the current collector in the battery case while drawing the extraction electrode to the outside. The form of the battery case is not limited, and may be a rectangular parallelepiped type, a cylindrical type, or a laminated pack type. The electrode body 1 may be housed in one battery case in a state where a plurality of electrodes (for example, 2 to 10, preferably 2 to 5) are laminated. The all-solid-state battery may be used by uniformly pressurizing, for example, the central portion of the electrode body 1 in the surface direction, preferably the entire surface direction of the electrode body 1. The all-solid-state battery can also be used in the form of an assembled battery in which a plurality of batteries are electrically connected. Such an all-solid-state battery can be used for various purposes. Suitable applications include drive power supplies mounted on vehicles such as plug-in hybrid vehicles (PHVs), hybrid vehicles (HVs), and electric vehicles (EVs).

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples illustrated above.

1 Electrode body 10 Solid electrolyte layer 20 First active material layer 24 Current collector 30 Second active material layer 32 Insulation layer

Claims (15)

A solid electrolyte layer, a first active material layer provided on the first surface of the solid electrolyte layer, and a second active material layer provided on the second surface of the solid electrolyte layer opposite to the first surface. Is a method of manufacturing an electrode body of an all-solid-state battery including
(A) Preparing the first active material layer,
(B) The solid electrolyte layer is prepared so that the first surface of the first active material layer and the first surface of the solid electrolyte layer are in contact with each other.
Here, the second surface of the solid electrolyte layer includes a peripheral edge portion which is at least a part of the peripheral edge, and a laminated portion excluding the peripheral edge portion.
(C) The second active material layer is prepared so as to be in contact with the laminated portion of the solid electrolyte layer.
(D) An insulating layer is prepared so as to be in contact with the peripheral portion of the solid electrolyte layer, and
(E) A laminate containing the first active material layer, the solid electrolyte layer, the second active material layer and the insulating layer until at least the surfaces of the second active material layer and the insulating layer are flush with each other. Pressurizing in the stacking direction to obtain the electrode body,
Manufacturing method, including. The production method according to claim 1, wherein the first active material layer, the solid electrolyte layer, and the second active material layer each include a powder material and a binder. The first active material layer, the solid electrolyte layer, and the second active material layer are each prepared by supplying a slurry containing a powder material, a binder, and a dispersion medium, and then removing the dispersion medium. The manufacturing method according to claim 1 or 2. The production method according to claim 3, further comprising (b) a drying step of drying the first active material layer and the solid electrolyte layer following the step (b). The production method according to any one of claims 2 to 4, wherein the pressurization is performed while heating to a temperature equal to or higher than the softening point of the binder. The production method according to any one of claims 1 to 5, wherein the pressurization is performed by a flat press having a surface pressure of 200 MPa or more. The production method according to any one of claims 1 to 5, wherein the pressurization is performed by roll rolling with a linear pressure of 10 kN / cm or more. The method according to any one of claims 1 to 7, wherein the compressive deformation resistivity of the insulating layer prepared in the step (d) is 1/10 or more of the compressive deformation resistivity of the second active material layer. Manufacturing method. In the step (d), the insulating layer containing at least the photocurable resin composition is supplied to the peripheral portion and irradiated with the curing light to prepare the insulating layer containing the photocurable resin. Item 8. The production method according to any one of Items 1 to 8. The insulating composition contains at least one selected from the group consisting of porous ceramic powder, ceramic hollow particles, hollow aggregates of ceramic particles, porous resin particles, hollow resin particles, and insulating fibrous filler. , The manufacturing method according to claim 9. The production method according to any one of claims 1 to 10, wherein the insulating layer is prepared by supplying a slurry containing insulating ceramic particles, a binder and a dispersion medium, and then removing the dispersion medium. In the step (a), the first active material layer is prepared on both sides of the current collector.
, The manufacturing method according to any one of claims 1 to 11. A method for manufacturing an electrode body of an all-solid-state battery including a solid electrolyte layer and a first active material layer bonded to the first surface of the solid electrolyte layer.
When there is a difference between the area of the solid electrolyte layer and the area of the first active material layer at the joint surface between the solid electrolyte layer and the first active material layer,
Overlapping the solid electrolyte layer and the first active material layer,
An insulating layer is provided in a region that is in contact with the end of the solid electrolyte layer or the first active material layer having a smaller area and that fills the difference.
Pressurizing the solid electrolyte layer, the first active material layer, and the insulating layer in the stacking direction of the solid electrolyte layer and the first active material layer.
Manufacturing method, including. The production method according to any one of claims 1 to 13, wherein the insulating layer contains at least one of alumina and a solid electrolyte material. Includes a solid electrolyte layer, a first active material layer, a second active material layer, and an insulating layer.
The solid electrolyte layer has a first surface and a second surface opposite to the first surface.
The second surface includes a peripheral edge portion that is at least a part of the peripheral edge of the solid electrolyte layer, and a laminated portion excluding the peripheral edge portion.
The first active material layer is provided on the first surface.
The second active material layer is provided in the laminated portion and is provided.
The insulating layer is provided on the peripheral portion and is provided.
An electrode body of an all-solid-state battery in which the surfaces of the second active material layer and the insulating layer opposite to the second surface are flush with each other.

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