JP2019140024A - Method for laminating solid electrolyte laminate on transfer target - Google Patents

Abstract

To provide a method for laminating a solid electrolyte laminate on a transfer target, which can suppress the decrease in production yield while increasing the strength of a solid electrolyte layer.SOLUTION: A method for laminating a solid electrolyte laminate on a transfer target comprises the steps of: (a) forming a solid electrolyte laminate on a base to be peeled, the laminate having a first solid electrolyte layer containing a first solid electrolyte and a first binder, and a second solid electrolyte layer containing a second solid electrolyte and a second binder in this order; and (b) transferring the solid electrolyte laminate from the base to be peeled to the transfer target containing a third binder. A proportion of a volume of the first binder to a volume of solid contents in the first solid electrolyte layer is smaller than a proportion of a volume of the second binder to a volume of solid contents in the second solid electrolyte layer, and it is smaller than a proportion of a volume of the third binder to a volume of solid contents in the transfer target.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a method of laminating a solid electrolyte laminate on a transfer object.

  In recent years, all-solid-state batteries in which the electrolytic solution is replaced with a solid electrolyte have attracted attention. Many reports have been made in which a binder is added to the solid electrolyte layer.

  For example, Patent Document 1 discloses a wound all-solid battery including solid electrolyte layers having different binder concentrations in the winding direction. Patent Document 2 discloses an electrolyte having a multilayer structure including a gel polymer electrolyte on both sides of a ceramic solid electrolyte, and a binder (0.1 per 100 parts by weight of ceramic solid electrolyte) is disclosed in the ceramic solid electrolyte. ~ 50 parts by weight).

  In addition, the solid electrolyte layer for an all-solid-state battery depends on the proportion of the binder contained therein (for example, the proportion of volume, etc.), and the greater the proportion of the binder, the higher the strength of the solid electrolyte layer. It is known to do.

Japanese Patent Laying-Open No. 2015-103433 JP2013-214494A

  However, when the solid electrolyte layer slurry is applied onto the release substrate to form a solid electrolyte layer, and this solid electrolyte layer is transferred to an object to be transferred such as an active material layer, the volume of the binder in the solid electrolyte layer If the ratio is high, the solid electrolyte layer cannot be successfully transferred from the release substrate, and thus the production yield of the all-solid battery may be lowered.

  Therefore, the present disclosure has been made in view of the above circumstances, and is a method of laminating a solid electrolyte laminate on a transfer object, and reducing the manufacturing yield while improving the strength of the solid electrolyte layer laminate. It aims at providing the method which can suppress.

  Further, it is also possible to provide a method for producing an all-solid battery by using the method for laminating the solid electrolyte laminate of the present disclosure, and capable of suppressing a decrease in production yield while improving the strength of the solid electrolyte layer. Objective.

The inventor of the present disclosure has found that the above problems can be solved by the following means.
(A) On the release substrate, the first solid electrolyte layer containing the first solid electrolyte and the first binder, and the second solid electrolyte layer containing the second solid electrolyte and the second binder, Forming a solid electrolyte laminate having in order; and (b) transferring the solid electrolyte laminate from the release substrate to a transfer object including a third binder;
Including
The ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer is smaller than the ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer, And smaller than the ratio of the volume of the third binder to the volume of the solid content in the transferred object,
A method of laminating a solid electrolyte laminate on a transfer object.

  According to the present disclosure, it is possible to suppress a decrease in manufacturing yield while improving the strength of the solid electrolyte layer.

FIG. 1 is an image diagram schematically illustrating features of the present disclosure. FIG. 2 is a diagram schematically illustrating one mode of the step (a) according to the present disclosure. FIG. 3 is a diagram schematically illustrating one mode of the step (b) according to the present disclosure. FIG. 4 is a diagram schematically illustrating one mode of the step (c) according to the present disclosure.

  Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present disclosure. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

≪Method of laminating a solid electrolyte laminate on a transfer object≫
(A) On the release substrate, the first solid electrolyte layer containing the first solid electrolyte and the first binder, and the second solid electrolyte layer containing the second solid electrolyte and the second binder, Forming a solid electrolyte laminate having in order; and (b) transferring the solid electrolyte laminate from a release substrate to a transfer object including a third binder;
Including
The ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer is smaller than the ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer. Is smaller than the ratio of the volume of the third binder to the volume of the solid content.

  As described above, in order to improve the strength of the solid electrolyte layer, it is necessary to increase the volume ratio of the binder in the solid electrolyte layer. However, when the volume ratio of the binder in the solid electrolyte layer is increased, the solid electrolyte layer cannot be successfully transferred from the release substrate, and the production yield of the all-solid battery is reduced. This is because the binder has binding properties, and therefore, when the volume ratio in the solid electrolyte layer is high, the solid electrolyte layer is firmly bonded to the release substrate. For this reason, in the conventional manufacturing method of an all-solid battery, it is difficult to suppress a decrease in the manufacturing yield of the all-solid battery while improving the strength of the solid electrolyte layer.

  On the other hand, the method of the present disclosure for laminating the solid electrolyte laminate on the transfer object pays attention to the structure of the solid electrolyte layer (also referred to as “solid electrolyte laminate” in the present disclosure), and at least the first Designed to be a multilayer structure including a solid electrolyte layer and a second solid electrolyte layer, and included in the solid electrolyte layer (ie, the first solid electrolyte layer) in direct contact with the release substrate. The volume ratio of one binder is controlled to be smaller than both the volume ratio of the second binder contained in the second solid electrolyte layer and the volume ratio of the third binder contained in the transferred material. Has characteristics. As a result, when the first solid electrolyte layer and the second solid electrolyte layer formed on the release substrate are transferred to the transfer object, only between the first solid electrolyte layer and the release substrate. Separation can occur. In addition, the volume ratio of the binder in the second solid electrolyte layer can be freely set according to the desired strength of the solid electrolyte layer.

  In particular, when the release substrate is peeled by controlling the volume ratio of the first binder contained in the first solid electrolyte layer to be smaller than the volume ratio of the third binder contained in the transfer object. In addition, the transfer object can be prevented from being damaged and / or the transfer object from being peeled off from the underlying substrate.

Specifically, as shown in FIG. 1, when the first solid electrolyte layer and the second solid electrolyte layer formed on the release substrate are transferred to the transfer target, The ratio of the volume of the first binder to the volume of the solid content in the solid electrolyte layer (X ₁ ), the ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer (X ₂ ), and By making it smaller than the ratio (X ₃ ) of the volume of the third binder to the volume of the solid content in the transfer object, it is possible to suppress peeling from B between the transfer object and the substrate, and the first It can peel only from A between a solid electrolyte layer and a peeling base material.

  Note that the ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer, the ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer, and the solid in the transfer object The specific value of the ratio of the volume of the third binder to the volume of the minute is based on the type of release substrate used, the type of binder used, or the compatibility between the release substrate and the binder. These can be set as appropriate within the scope of the present disclosure.

  Below, each process concerning the method of this indication is explained in detail.

<Process (a)>
In the step (a), a first solid electrolyte layer containing a first solid electrolyte and a first binder, and a second solid electrolyte layer containing a second solid electrolyte and a second binder on the release substrate. Are formed in this order.

  In the present disclosure, the ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer is the ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer. If it is smaller than the ratio of the volume of the 3rd binder with respect to the volume of solid content in a thing, it will not specifically limit, According to the compatibility of a peeling base material, the kind of binder, a peeling base material, and a binder, etc., a peeling base material Can be set within a range that can be reliably peeled off. For example, the ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer may be 0.1% by volume or more, or 5% by volume or less.

  The ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer is not particularly limited as long as it is within the scope of the present disclosure, and is set according to the desired strength, function, etc. of the solid electrolyte layer. can do. For example, this ratio may be 5% by volume or more, or 70% by volume or less.

  In the present disclosure, the “solid content in the solid electrolyte layer” means a component in the solid electrolyte layer excluding the solvent (or solvent) and air (or bubbles). Further, the “solid content in the transferred material” refers to a component of the transferred material excluding the solvent (or solvent) and air (or bubbles).

  In the present disclosure, the thickness of the first solid electrolyte layer is not particularly limited, and may be, for example, 1 μm or more, 100 μm or less, or 50 μm or less. In addition, it is preferable to set the thickness of the first solid electrolyte layer to be thin from the viewpoint of improving the energy density, ionic conductivity, and the like of the all-solid battery manufactured according to the present disclosure.

  The thickness of the second solid electrolyte layer is not particularly limited, and may be, for example, 1 μm or more, 100 μm or less, or 50 μm or less. In addition, it is preferable to set the thickness of the second solid electrolyte layer to be thin from the viewpoint of improving the energy density, ion conductivity, and the like of the all-solid battery manufactured according to the present disclosure. From the viewpoint of improving the strength of the solid electrolyte laminate, the thickness of the second solid electrolyte layer is preferably set to be greater than the thickness of the first solid electrolyte layer.

((Formation of solid electrolyte layer using slurry for solid electrolyte layer))
The method for forming the solid electrolyte laminate having the first solid electrolyte layer and the second solid electrolyte layer in this order on the release substrate is not particularly limited. For example, the first solid electrolyte layer slurry And a second slurry for the solid electrolyte layer can be prepared, applied, and optionally dried and pressed.

  More specifically, for example, a first solid electrolyte layer slurry containing a first solid electrolyte and a first binder is applied onto a release substrate, and then a second solid electrolyte and a second solid electrolyte are applied thereon. The solid electrolyte which has the 1st solid electrolyte layer and the 2nd solid electrolyte layer in this order on the peeling base material by apply | coating the slurry for 2nd solid electrolyte layers containing the binder of this, and optionally drying and pressing A laminate can be formed.

  FIG. 2 is a diagram schematically illustrating one mode of the step (a) according to the present disclosure. As shown in FIG. 2, a first solid electrolyte layer slurry 1 a containing a first solid electrolyte and a first binder is applied on a release substrate 11, and the first solid electrolyte layer 1 is applied. Form. Then, on the first solid electrolyte layer 1, the second solid electrolyte layer slurry 2 a containing the second solid electrolyte and the second binder is applied to form the second solid electrolyte layer 2. Thus, the solid electrolyte laminate 3 having the first solid electrolyte layer 1 and the second solid electrolyte layer 2 in this order can be formed on the peeling substrate 11.

(Preparation of slurry for solid electrolyte layer)
The first solid electrolyte layer slurry is prepared to include the first solid electrolyte and the first binder, and the second solid electrolyte layer slurry includes the second solid electrolyte and the second binder. Can be prepared. The first solid electrolyte and the second solid electrolyte may be the same or different. Moreover, the 1st binder, the 2nd binder, and the 3rd binder mentioned later may be the same, and may differ. Specific examples of the solid electrolyte and the binder will be described later.

  In the present disclosure, the ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer is higher than the ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer. It is necessary to make it smaller and smaller than the ratio of the volume of the third binder to the volume of the solid content in the transfer object. For this reason, the ratio of the volume of the 1st binder with respect to the volume of solid content in the slurry for 1st solid electrolyte layers is from the ratio of the volume of 2nd binder with respect to the volume of solid contents in the slurry for 2nd solid electrolyte layers. And smaller than the ratio of the volume of the third binder to the volume of the solid content in the slurry for transferred material.

  In the present disclosure, a solvent (or solvent) can be used when preparing the first and second solid electrolyte layer slurries. Specific examples of the solvent will be described later.

(Slurry application)
The application of each slurry is not particularly limited, and can be performed by a known method or means. For example, a known coating method such as a blade coater, a gravure coater, a dip coater, a reverse coater, a roll knife coater, a wire bar coater, a slot die coater, an air knife coater, a curtain coater, an extrusion coater, or a combination thereof is adopted. can do.

(Dry)
After apply | coating each slurry mentioned above, the process of drying can be performed. For example, by applying a first solid electrolyte layer slurry on a release substrate to form a first solid electrolyte layer slurry layer, and drying the first solid electrolyte layer slurry layer A first solid electrolyte layer is formed. The second solid electrolyte layer slurry is applied on the first solid electrolyte layer to form a second solid electrolyte layer slurry layer, and the second solid electrolyte layer slurry layer is dried. By doing so, the second solid electrolyte layer can be formed. Or after forming the slurry layer for 1st solid electrolyte layers mentioned above, after forming the slurry layer for 2nd solid electrolyte layers on it, the slurry layer for 1st and 2nd solid electrolyte layers is formed simultaneously. By drying, a solid electrolyte laminate having the first solid electrolyte layer and the second solid electrolyte layer in this order can be formed.

  The drying is not particularly limited, and can be performed by a known method or means such as natural drying, hot air, low-humidity air, vacuum, infrared, far-infrared, and / or electron beam.

(press)
After applying each of the above-described slurries, pressing (crimping) can be included. Moreover, it is preferable to perform a press after apply | coating each slurry mentioned above and drying. By pressing, it becomes easy to improve the adhesiveness between the first solid electrolyte layer and the release substrate and the adhesiveness between the first solid electrolyte layer and the second solid electrolyte layer.

  The press is not particularly limited, and can be performed using, for example, a commercially available pressure molding apparatus, such as a uniaxial press, a cold isostatic press (CIP), a hot isostatic press (WIP), a roll press, or It can implement by well-known methods or means, such as a hot press. The pressure for pressing is not particularly limited. For example, in the case of a uniaxial press or an isotropic pressure press, the pressure may be the above, or may be 1000 MPa or less, or 400 MPa or less. Moreover, the holding time of a press is not specifically limited, For example, 1 second or more may be sufficient and 10 minutes or less may be sufficient. For example, in the case of a roll press, it may be 1 kN / cm or more, or 10 kN / cm or more, or 1000 kN / cm or less, or 100 kN / cm or less.

<Process (b)>
In the step (b), the solid electrolyte laminate is transferred from the release substrate to a transfer object including a third binder.

  More specifically, in step (b), the surface on the second solid electrolyte layer side of the solid electrolyte laminate with the release substrate formed in step (a) is aligned with the surface of the transfer object. Then, the solid electrolyte laminate can be transferred to the transfer object by peeling off the peeling substrate.

  Moreover, it is preferable that a process (b) contains a press, in order to make a solid electrolyte laminated body and a to-be-transferred material adhere more. The method or means for pressing, the pressure, and the holding time are not particularly limited as long as the solid electrolyte laminate can be reliably transferred. For example, the press conditions described above can be appropriately employed.

  In the present disclosure, the material to be transferred only needs to include the third binder and the solid electrolyte laminate can be transferred thereon. For example, when an all-solid battery is manufactured, the transferred object may be a positive electrode active material layer or a negative electrode active material layer.

  Moreover, the base material may be laminated | stacked on the surface on the opposite side to the side to which a solid electrolyte laminated body transcribe | transfers of to-be-transferred objects. That is, the solid electrolyte laminate with a release substrate can be transferred to the surface of the transfer object with the substrate on the transfer object side. In this case, as described above, the ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer is smaller than the ratio of the volume of the third binder to the volume of the solid content in the transfer object. If it peels, when peeling a peeling base material, peeling from between a to-be-transferred object and the base material can be suppressed. In addition, the ratio of the volume of the 3rd binder with respect to the volume of solid content in a transcription | transfer material will not be specifically limited if it is in the range of this indication, It can set suitably according to a use and the objective.

  The substrate of the material to be transferred is not particularly limited. For example, when producing an all-solid battery, if the transfer object is a positive electrode active material layer, the substrate can be a positive electrode current collector layer, and if the transfer object is a negative electrode active material layer, The substrate can be a negative electrode current collector layer.

  For example, FIG. 3 is a diagram schematically illustrating one form of the step (b) according to the present disclosure. As shown in FIG. 3, the surface on the second solid electrolyte layer 2 side of the solid electrolyte laminate 3 with the peeling substrate 11 and the first current collector layer 5 (covered) prepared in advance. As the base material of the transfer material) and the surface of the first active material layer 4 (transfer object) on the first active material layer 4 side of the laminate 6, the release base material is brought into close contact with each other. The solid electrolyte laminate 3 is transferred to the first active material layer 4 side of the laminate 6 of the first current collector layer 4 and the first active material layer 5 by peeling 11. In this way, the solid electrolyte layer laminate 3 can be laminated on the first active material layer 4 (transfer object).

  By applying the method of the present disclosure described above, an all-solid battery can be manufactured. Hereinafter, a method for manufacturing an all-solid battery will be described.

≪All-solid battery manufacturing method≫
The manufacturing method of the all-solid-state battery of the present disclosure includes:
(A) On the release substrate, the first solid electrolyte layer containing the first solid electrolyte and the first binder, and the second solid electrolyte layer containing the second solid electrolyte and the second binder, Forming a solid electrolyte laminate having in order;
(B) transferring the solid electrolyte laminate from the release substrate to the first active material layer of the first active material layer laminate comprising the first current collector layer and the third binder; and (C) laminating the second active material layer and the second current collector layer in this order on the solid electrolyte laminate;
Including
The ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer is smaller than the ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer, and the first It is smaller than the ratio of the volume of the 3rd binder with respect to the volume of solid content in an active material layer.

  According to the manufacturing method of the present disclosure, it is possible to suppress a decrease in manufacturing yield of the all-solid battery while improving the strength of the solid electrolyte layer.

  Steps (a) and (b) according to the method for producing an all-solid-state battery of the present disclosure include steps (a) and (b) according to the method of the present disclosure for laminating a solid electrolyte laminate on the transfer target described above. The description is omitted here because it can be referred to.

<Process (c)>
In the step (c), the second active material layer and the second current collector layer are laminated in this order on the solid electrolyte laminate.

  More specifically, in the step (c), the second active material layer is formed on the first solid electrolyte layer side surface of the solid electrolyte laminate from which the release substrate has been peeled after the step (b) described above. And an all-solid-state battery can be manufactured by laminating | stacking a 2nd electrical power collector layer in this order.

  This “stacking the second active material layer and the second current collector layer in this order” means (i) the second active material layer and the second current collector layer one by one in order, The second active material may be laminated on the solid electrolyte laminate, or (ii) a second active material layer and a second current collector layer laminate prepared in advance by a known method. You may laminate | stack the said laminated body on a solid electrolyte laminated body from the layer side.

  Moreover, it is preferable that a process (c) includes a press after laminating | stacking a 2nd active material layer and a 2nd electrical power collector layer in this order on a solid electrolyte laminated body. By pressing, it becomes easy to improve the adhesiveness between the layers of the unit all solid state battery. In addition, it does not specifically limit about the method and conditions at the time of pressing, A well-known method and conditions can be employ | adopted suitably, and the method and conditions concerning description of the process (a) mentioned above can also be employ | adopted suitably.

  FIG. 4 is a diagram schematically illustrating one mode of the step (c) according to the present disclosure. As shown in FIG. 4, the second active material layer 7 and the second current collector layer 8 are formed on the surface of the first solid electrolyte layer 1 side from which the release substrate 11 has been peeled. The laminated body 9 is laminated from the side of the second active material layer, and then pressed, whereby the first current collector layer 5, the first active material layer 4, the solid electrolyte layer laminated body 3 (second electrolyte layer 2) Producing an all-solid battery 10 in which the solid electrolyte layer 2, the first solid electrolyte layer 1), the second active material layer 7, and the second current collector layer 8 are laminated in this order. it can.

  In the present disclosure, the “first current collector layer” and the “second current collector layer”, and the “first active material layer” and the “second active material layer” are as follows. To interpret. That is, when the first current collector layer and the first active material layer are the positive electrode current collector layer and the positive electrode active material layer, respectively, the second current collector layer and the second active material layer are And negative electrode current collector layer and negative electrode active material layer, respectively. When the first current collector layer and the first active material layer are a negative electrode current collector layer and a negative electrode active material layer, respectively, the second current collector layer and the second active material layer are Respectively, a positive electrode current collector layer and a positive electrode active material layer.

≪Constituent material of each member according to the method of the present disclosure≫
Below, the example of the constituent material of the member used for each process concerning the method of this indication is explained in detail. Note that, in order to easily understand the present disclosure, a material for producing an all-solid-state lithium battery will be described as an example. However, the method of the present disclosure includes, for example, an all-solid sodium battery, an all-solid magnesium battery, and an all-solid-state battery. The present invention can be widely applied to the production of all-solid batteries such as calcium batteries.

<Peeling substrate>
In the present disclosure, the release substrate supports the slurry for the solid electrolyte layer when the solid electrolyte layer is formed, and peels from the solid electrolyte layer when the solid electrolyte layer is transferred. The material used as a peeling base material is not specifically limited, For example, a resin film or a metal sheet is mentioned.

(Resin film)
Examples of the resin film include polyethylene (PE), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), syndiotactic polystyrene (SPS), poly Examples include resin films such as methyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS), cycloolefin polymer (COP), polyamide (PA), polyimide (PI), polycarbonate (PC), and fluororesin. However, it is not limited to these.

(Metal sheet)
Examples of the metal sheet include, but are not limited to, metal sheets such as aluminum, nickel, copper, stainless steel (SUS), and titanium.

<Solid electrolyte>
The solid electrolyte is not particularly limited, and a material that can be used as a solid electrolyte of an all-solid battery can be used. For example, a known sulfide solid electrolyte or a known oxide solid electrolyte can be used. The solid electrolyte may be glass or crystallized glass (glass ceramic).

(Sulfide solid electrolyte)
Examples of the sulfide solid electrolyte include, for example, Li ₂ S—P ₂ S ₅ system (Li ₇ P ₃ S ₁₁ , Li ₃ PS ₄ , Li ₈ P ₂ S _9, etc.), Li ₂ S—SiS ₂ , LiI— _{Li 2 S-SiS 2, LiI} -Li 2 S-P 2 S 5, LiI-LiBr-Li 2 S-P 2 S 5, Li 2 S-P 2 S 5 -GeS 2 (Li 13 GeP 3 S 16, Li ₁₀ GeP ₂ S _{12, etc.), LiI-Li 2 S-} P 2 O 5, LiI-Li 3 PO 4 -P 2 S 5, and _{Li 7-x PS 6-x} Cl x , and the like; and combinations thereof It can mention, but it is not limited to these.

(Oxide solid electrolyte)
Examples of oxide solid electrolytes include Li ₇ La ₃ Zr ₂ O _12, Li _7-x La ₃ Zr _1-x Nb _x O _12, Li _7-3x La ₃ Zr ₂ Al _x O ₁₂ , Li _3x La _{2 / 3-x} TiO ₃ , Li _{1 + x} Al _x Ti _{2 -x} (PO ₄ ) ₃ , Li _{1 + x} Al _x Ge _{2 -x} (PO ₄ ) ₃ , Li ₃ PO ₄ , Li _{3 + x} PO _4−x N _x (LiPON) , Polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof, but are not limited thereto.

<binder>
Examples of the binder include, but are not limited to, rubber-based binders such as polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), butadiene rubber (BR), and styrene butadiene rubber (SBR).

<Current collector layer>
The current collector layer is laminated on the surface of the active material layer opposite to the surface of the active material layer on which the solid electrolyte layer is laminated. When the active material layer is a positive electrode active material layer, the current collector layer laminated thereon is a positive electrode current collector layer, and when the active material layer is a negative electrode active material layer, the current collector layer is laminated thereon. The current collector layer is a negative electrode current collector layer. Further, when the all-solid battery stack is of a bipolar type, a positive electrode / negative electrode current collector layer can be used. Here, the “positive electrode / negative electrode current collector layer” means what can play a role as any electrode (positive electrode or negative electrode), that is, in the case of a bipolar all-solid battery laminate, a positive electrode active material It means a current collector layer that can be shared by the layer and the negative electrode active material layer.

  Examples of the material constituting the positive electrode current collector layer, the negative electrode current collector layer, or the positive electrode / negative electrode current collector layer are not particularly limited, and various metals such as silver, copper, gold, aluminum, nickel, and iron , Stainless steel (SUS), titanium, and the like, and alloys thereof. From the viewpoint of chemical stability and the like, the positive electrode current collector layer is preferably an aluminum current collector layer, and the negative electrode current collector layer is preferably a copper current collector layer, and the positive electrode / negative electrode current collector layer. As, SUS is preferable.

  Moreover, it does not specifically limit as a shape of each collector layer, For example, foil shape, plate shape, mesh shape, etc. can be mentioned.

<Positive electrode active material>
The positive electrode active material is not particularly limited, and known materials are used. For example, lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , Li _{1 + x} Mn _{2−x− Examples} include a heteroelement-substituted Li—Mn spinel having a composition represented by _y MyO ₄ (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn), It is not limited to these.

<Negative electrode active material>
The negative electrode active material is not particularly limited as long as it can occlude and release metal ions such as lithium ions. Examples include, but are not limited to, metals such as Li, Sn, Si or In, oxides such as Li ₄ Ti ₅ O ₁₂ , or carbon materials such as hard carbon, soft carbon, or graphite.

<Other materials>
(Conductive aid)
The conductive auxiliary agent is not particularly limited, and known ones are used. Examples include, but are not limited to, acetylene black, ketjen black, graphite, carbon fiber, and metal material.

(solvent)
It does not specifically limit as a solvent, The well-known solvent used when manufacturing an all-solid-state battery may be sufficient. Examples of the solvent include, but are not limited to, heptane, pentane, octane, propane, butane, xylene, toluene, triethylamine, cyclopentyl methyl ether, ethane mercaptan, butyl butyrate and the like.

  Hereinafter, examples of the present disclosure will be described. It should be noted that the following examples are for illustrative purposes only and do not limit the present disclosure.

<Examples 1 to 5 and Comparative Example 1>
An aluminum casting film was used as the peeling substrate.

  Solid electrolyte laminate having the first and second solid electrolyte layer slurries on the release substrate, the first solid electrolyte layer (thickness: 5 μm) and the second solid electrolyte layer (thickness 20 μm) in this order. Formed body.

Note that the slurry for the first and second solid electrolyte layer, respectively as a solid electrolyte, a solid electrolyte mainly composed of Li ₇ P ₃ S _11, and using a rubber-based binder. Moreover, the ratio of the volume of the 1st binder with respect to the volume of solid content in the slurry for 1st solid electrolyte layers, and the ratio of the volume of 2nd binder with respect to the volume of solid content in the slurry for 2nd solid electrolyte layers, respectively. Is shown in Table 1 below.

  As the first current collector layer, an aluminum current collector foil (thickness: 15 μm) was used.

As the first active material layer, a positive electrode active material layer containing a positive electrode active material (LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ), a sulfide solid electrolyte, a conductive additive and a binder was used. Under the present circumstances, the ratio of the volume of the binder with respect to the volume of solid content in the slurry for positive electrode active material layers was 2 volume%.

  Based on the schematic diagram shown in FIG. 3, the solid electrolyte laminate with the release substrate and the laminate of the positive electrode current collector layer and the positive electrode active material layer were superimposed using the above-described materials. Then, pressing was performed at a pressure of 50 MPa. This produced the sample for each Example and a comparative example.

  The test (each 5 times) which peeled a peeling base material was done with respect to the sample for each Example and comparative example produced above. The test results are shown in Table 1 below.

  As can be seen from the results in Table 1, in any of the examples of the present disclosure, the release substrate could be reliably peeled off. On the other hand, in Comparative Example 1, the positive electrode active material layer and the positive electrode current collector layer were separated. This is because the ratio of the volume of the first binder to the volume of the solid content in the electrolyte layer slurry for the first solid electrolyte layer (5% by volume) is the first binder with respect to the volume of the solid content in the positive electrode active material layer slurry. Therefore, the adhesive force between the first solid electrolyte layer and the release substrate is relatively stronger than the adhesive force between the positive electrode active material layer and the positive electrode current collector layer. This is considered to be the result.

<Comparative Examples 2-7>
In the production of the above-described examples, samples for each comparative example were produced in the same manner as in the examples except that a solid electrolyte layer having a single layer structure was formed. The ratio of the volume of the binder in the solid electrolyte layer slurry to the solid volume in the solid electrolyte layer slurry is shown in Table 2.

  Each sample for Comparative Example was subjected to a test (5 times each) for peeling the peeling substrate. The test results are shown in Table 2 below.

  As can be seen from the results in Table 2, none of Comparative Examples 3 to 7 was able to successfully peel the release substrate. In particular, there were many results of peeling from between the positive electrode current collector layer and the positive electrode active material layer. In Comparative Example 2, the release substrate was successfully peeled, but the ratio of the volume of the binder to the volume of the solid content in the solid electrolyte layer was only 1% by volume, and the desired strength of the solid electrolyte layer It was difficult to satisfy the function and the like.

DESCRIPTION OF SYMBOLS 1 1st solid electrolyte layer 1a 1st slurry for 1st solid electrolyte layers 2 2nd solid electrolyte layer 2a 2nd slurry for solid electrolyte layers 3 Solid electrolyte layer laminated body 4 1st active material layer 5 1st collection Electric current layer 6 Stack of first current collector layer and first active material layer 7 Second active material layer 8 Second current collector layer 9 Second current collector layer and second active material Laminated body 10 All-solid-state battery 11 Peeling substrate

Claims (1)

(A) On the release substrate, the first solid electrolyte layer containing the first solid electrolyte and the first binder, and the second solid electrolyte layer containing the second solid electrolyte and the second binder, Forming a solid electrolyte laminate having in order; and (b) transferring the solid electrolyte laminate from the release substrate to a transfer object including a third binder;
Including
The ratio of the volume of the first binder to the volume of the solid content in the first solid electrolyte layer is smaller than the ratio of the volume of the second binder to the volume of the solid content in the second solid electrolyte layer, And smaller than the ratio of the volume of the third binder to the volume of the solid content in the transferred object,
A method of laminating a solid electrolyte laminate on a transfer object.

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