JP5929748B2 - Manufacturing method of all solid state battery - Google Patents

Description

  The present invention relates to a method for manufacturing an all-solid battery.

  In recent years, a secondary battery has become an indispensable component as a power source for personal computers, video cameras, mobile phones, and the like, or as a power source for automobiles and power storage.

  Among secondary batteries, a lithium ion secondary battery has a feature that it has a higher capacity density than other secondary batteries and can operate at a high voltage. Therefore, it is used in information-related equipment and communication equipment as secondary batteries that are easy to reduce in size and weight. In recent years, high-output and high-capacity lithium-ion secondary batteries for electric vehicles and hybrid vehicles as low-pollution vehicles have been used. Development is underway.

  A lithium ion secondary battery or a lithium secondary battery includes a positive electrode layer and a negative electrode layer, and an electrolyte containing a lithium salt disposed between the positive electrode layer and the negative electrode layer, and the electrolyte is constituted by a non-aqueous liquid or solid. . When a non-aqueous liquid electrolyte is used for the electrolyte, the electrolyte solution penetrates into the positive electrode layer, so that an interface between the positive electrode active material constituting the positive electrode layer and the electrolyte is easily formed, and performance is easily improved. . However, since widely used electrolytes are flammable, it is necessary to install a system for ensuring safety such as attachment of a safety device that suppresses temperature rise at the time of short circuit and prevention of short circuit. In contrast, an all-solid battery in which the liquid electrolyte is changed to a solid electrolyte to make the battery all solid does not use a flammable organic solvent in the battery, so the safety device can be simplified, and manufacturing costs and productivity can be reduced. It is considered excellent and is being developed.

  In an all-solid-state battery in which the solid electrolyte layer is disposed between the positive electrode layer and the negative electrode layer, the positive electrode layer, the solid electrolyte layer, and the negative electrode layer are combined for the purpose of reducing ion conduction resistance and the like are compared. May press at high pressure.

  In order to prevent a short circuit between the positive electrode layer and the negative electrode layer as a technique related to such an all solid state battery, a solid electrolyte layer is laminated on a positive electrode layer made of a positive electrode active material and a solid electrolyte, or on a positive electrode layer made of a positive electrode active material. Then, a step of obtaining a positive electrode member by pressure forming, a negative electrode layer made of a negative electrode active material and a solid electrolyte, or a solid electrolyte layer laminated on a negative electrode layer made of a negative electrode active material, followed by pressure forming and forming a negative electrode A method for producing an all-solid-state battery comprising a step of obtaining a member and a step of press-molding the positive electrode member and the negative electrode member obtained in each of the above steps together with the respective solid electrolytes is disclosed ( Patent Document 1).

JP 2012-69248 A

  According to Patent Document 1, it is possible to prevent a short circuit between the positive electrode layer and the negative electrode layer penetrating the solid electrolyte, but when the positive electrode layer, the solid electrolyte layer, and the negative electrode layer are stacked and pressed, the electrode layer In some cases, the outer periphery of the crumbled. If the outer peripheral portion of the electrode layer collapses, the broken electrode layer cannot be used sufficiently, and the utilization rate of the electrode layer may decrease, leading to a decrease in battery capacity. In particular, stress tends to concentrate at the end of the electrode layer having a small area among the positive electrode layer and the negative electrode layer, and the outer peripheral portion tends to collapse greatly. In addition, if the electrode layer is pressed and densified in advance to prevent collapse of the outer periphery of the electrode layer during pressing of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer, There is also a possibility that a short circuit occurs between the breakthrough positive electrode layer and the negative electrode layer.

  Therefore, there is a demand for a method for manufacturing an all-solid-state battery that can increase the utilization factor of the electrode layer as compared with the conventional one while preventing a short circuit between the positive electrode layer and the negative electrode layer.

The present invention is a method for producing an all-solid battery including an electrode body including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer,
(A) A step of providing a positive electrode layer and a negative electrode layer having different areas, wherein the electrode layer having a smaller area of the positive electrode layer and the negative electrode layer has a shape in which the outer peripheral portion is thicker than the central portion;
(B) A step of providing a solid electrolyte layer having a larger area than an electrode layer having a smaller area among the positive electrode layer and the negative electrode layer;
(C) A lamination step of laminating a solid electrolyte layer on an electrode layer having a larger area among the positive electrode layer and the negative electrode layer to form a laminate C of the solid electrolyte layer and an electrode layer having a larger area;
(D) Pressing the laminate C to form a laminate D in which a solid electrolyte layer is pressure-bonded to an electrode layer having a larger area;
(E) A step of laminating the laminate D and an electrode layer having a smaller area, wherein the solid electrolyte layer and the electrode layer having a smaller area are adjacent to each other, and a positive electrode layer, a solid electrolyte layer, and A laminating step of forming a laminate E including a negative electrode layer; and (F) a pressing step of pressing the laminate E to form an electrode body;
Is a method for producing an all-solid battery.

  ADVANTAGE OF THE INVENTION According to this invention, the all-solid-state battery which raised the utilization factor of the electrode layer rather than before can be obtained, preventing the short circuit of a positive electrode layer and a negative electrode layer.

FIG. 1 is a schematic cross-sectional view showing a general method for manufacturing an all-solid battery. FIG. 2 is a schematic cross-sectional view showing the positive electrode layer portion pushed outward by the press. FIG. 3 is a schematic cross-sectional view showing an example of the providing step (A) of the positive electrode layer and the negative electrode layer included in the method according to the present invention. FIG. 4 is a schematic top view for explaining the shapes of the positive electrode layer and the negative electrode layer having different areas in the present application. FIG. 5 is a schematic cross-sectional view illustrating an example of an electrode layer having a smaller area. FIG. 6 is a schematic cross-sectional view illustrating an example of an electrode layer having a smaller area. FIG. 7 is a schematic cross-sectional view illustrating an example of an electrode layer having a smaller area. FIG. 8 is a schematic cross-sectional view showing an example of a solid electrolyte layer providing step (B) included in the method according to the present invention. FIG. 9 is a schematic cross-sectional view showing an example of a lamination step (C) included in the method according to the present invention. FIG. 10 is a schematic cross-sectional view showing an example of the pressing step (D) included in the method according to the present invention. FIG. 11 is a schematic cross-sectional view illustrating an example of a laminate D obtained in the pressing step (D). FIG. 12 is a schematic cross-sectional view showing an example of a stacking step (E) included in the method according to the present invention. FIG. 13 is a schematic cross-sectional view showing an example of the pressing step (F) included in the method according to the present invention. FIG. 14 is a schematic cross-sectional view illustrating an example of an electrode body obtained in the pressing step (F). FIG. 15 is a schematic cross-sectional view illustrating an example of the configuration of the all solid state battery according to the present invention. FIG. 16 is a schematic cross-sectional view illustrating a method of applying a positive electrode (electrode) composite material on a current collector having a shape in which the central portion is raised from the outer peripheral portion. FIG. 17 is a schematic cross-sectional view of a positive electrode (electrode) layer including a (positive electrode) current collector and having an outer peripheral portion thicker than the central portion. FIG. 18 is a schematic cross-sectional view of a negative electrode (electrode) layer including a (negative electrode) current collector. FIG. 19 shows a negative electrode current collector 5, a negative electrode layer 3, a solid electrolyte layer 2 formed using a positive electrode layer including a positive electrode current collector and a negative electrode layer including a negative electrode current collector and having a larger area than the positive electrode layer. 2 is a schematic cross-sectional view of an all-solid battery including a positive electrode layer 1 and a positive electrode current collector 4. FIG. FIG. 20 is a schematic cross-sectional view of an electrode layer having a shape in which the outer peripheral portion with the PET film is thicker than the central portion.

  FIG. 1 shows a general method for manufacturing an all-solid battery. A negative electrode current collector 5, a negative electrode layer 3, a solid electrolyte layer 2, a positive electrode layer 1, and a positive electrode current collector 4 are laminated, and these are put in a battery case 6 such as a laminate and cold isostatic press (CIP) or the like. The press molding is performed using the press method. A white arrow indicates that pressure is applied isotropically. In the following drawings, the positive electrode current collector 4 and the negative electrode current collector 5 are not shown, but unless otherwise specified, the positive electrode current collector 4 and the negative electrode current collector 5 are included even if included. It does not have to be.

  As described above, when the positive electrode layer, the negative electrode layer, and the solid electrolyte layer are overlaid and pressed, the positive electrode layer bites into the solid electrolyte layer by pressing the negative electrode layer and the solid electrolyte layer in advance to increase the density. Preventing a short circuit between the positive electrode layer and the negative electrode layer due to this has been performed. However, when a negative electrode layer and a solid electrolyte layer with high density are stacked and pressed with a positive electrode layer with low density, the outer periphery of the positive electrode layer 1 collapses as shown in FIG. End up.

  FIG. 2 schematically shows a positive electrode layer portion 24 extruded to the outside when the positive electrode layer 1, the solid electrolyte layer 2, and the negative electrode layer 3 are pressed together with the positive electrode current collector 4 and the negative electrode current collector 5 in the pressing step. (Battery case is not shown).

  The positive electrode layer portion 24 extruded to the outside has a low density, and becomes restraint-free when the all-solid battery 100 is restrained using the restraining jig 9 as shown in FIG. A path is difficult to form and cannot function sufficiently as an electrode layer, and the utilization factor of the electrode layer is lowered, leading to a reduction in capacity of the all-solid-state battery.

  In FIGS. 1 and 2, the positive electrode layer, the solid electrolyte layer, and the negative electrode layer are pressed together with the current collector and then pressed. After forming the positive electrode layer, the solid electrolyte layer, and the negative electrode layer press-molded body, When the current collector is stacked and pressed, the contact area between the positive electrode layer portion 24 pushed out to the outside and the current collector is reduced, or the current collector is brought into contact with the positive electrode layer portion 24 pushed out to the outside. Even when formed in this way, the restraint-free portion cannot be reduced.

  Further, in the above method, even if the pressing method is a uniaxial rigid press instead of the cold isostatic press (CIP), the outer peripheral portion of the positive electrode layer may collapse so as to be pushed outward. Is inevitable.

  In view of such circumstances, the present inventor has found a method for producing an all-solid-state battery using a positive electrode layer in which an outer peripheral part is formed thicker than a central part.

  The present invention presses a laminate of either a positive electrode layer or a negative electrode layer and a solid electrolyte layer, presses the positive electrode layer or the negative electrode layer to the solid electrolyte layer, and then presses the positive electrode layer or the negative electrode layer. In addition, the above-described conventional problems can be solved by using a method including pressure bonding a negative electrode layer or a positive electrode layer having an outer peripheral portion thicker than the central portion.

  According to the present invention, an electrode layer whose outer peripheral portion is thicker than the central portion is formed in consideration of the amount that the electrode layer is pushed outward by pressing, and the electrode layer is thicker than the central portion. By pressing the layer and the other electrode layer, the area ratio of the electrode layer having a substantially uniform density and thickness can be increased. Thereby, it is possible to form an all-solid-state battery in which the utilization rate of the electrode layer is higher than that of the conventional one while preventing a short circuit between the positive electrode layer and the negative electrode layer. By increasing the utilization rate of the electrode layer, it is possible to obtain an all-solid-state battery having a capacity and an output that are higher than those of conventional ones.

  Hereinafter, a method according to the present invention will be described with reference to the drawings.

  In FIG. 3, the cross-sectional schematic diagram showing an example of the provision process (A) included in the method which concerns on this invention is shown. As shown in FIG. 3, the method according to the present invention includes a step (A) of providing a positive electrode layer 1 and a negative electrode layer 3 having different areas, and the positive electrode layer having a smaller area among the positive electrode layer and the negative electrode layer, The outer peripheral portion has a thicker shape than the central portion. The negative electrode layer having a larger area preferably has a flat surface as shown in FIG. Although not shown in each drawing, the positive electrode layer 1, the solid electrolyte layer 2, and the negative electrode layer 3 may have a base material.

  FIG. 3 illustrates the case where the area of the positive electrode layer 1 is smaller than the area of the negative electrode layer 3, and the area of the positive electrode layer 1 may be larger than the area of the negative electrode layer 3, and in this case, the area is smaller. The negative electrode layer 3 preferably has a shape in which the outer peripheral portion is thicker than the central portion, and the positive electrode layer having a larger area has a flat surface.

  In the present application, “the area is smaller” means, for example, as shown in FIG. 4, when the disc-shaped positive electrode layer and the negative electrode layer are arranged so as to contact each other and viewed from the upper surface, The area is smaller than the area of the other layer, and the size is such that the entire outer periphery of one layer falls within the plane of the other layer. “The area is larger” means a size in which the area of one layer is larger than the area of the other layer and the outer periphery of the other layer is entirely within the plane of the one layer. “The same area” means that both layers have substantially the same area and the same shape.

  As shown in FIG. 4, the positive electrode layer 1 and the negative electrode layer 3 are preferably similar in projected shape when viewed from above, and more preferably each has a disk shape or a quadrangular shape.

  The difference in area between the positive electrode layer and the negative electrode layer is such that no short circuit occurs between the positive electrode layer 1 and the negative electrode layer 3 when the positive electrode layer 1, the solid electrolyte layer 2, and the negative electrode layer 3 are stacked and pressed. For example, the area of the positive electrode layer 1 or the negative electrode layer 3 is 75 to 99.9% or 90 to 99.9% of the area of the solid electrolyte layer 2.

  The electrode layer having a smaller area is not limited to the shape whose thickness increases toward the outer peripheral portion shown in FIG. 3 as long as the outer peripheral portion has a thicker shape than the central portion. For example, the electrode layer has a rectangular shape on the outer peripheral portion as shown in FIG. A shape having a protruding portion, a thickness increasing toward the outer peripheral portion as shown in FIG. 6, and a shape having a rectangular protruding portion on the outer peripheral portion, or a substantially protruding portion on the outer peripheral portion as shown in FIG. If it is, a shape having rounded corners may be used.

  The electrode layer having a smaller area preferably has a shape in which the outer peripheral part is thicker than the central part and the angle of the boundary between the central part and the outer peripheral part is larger than 90 ° as shown in FIG. When the electrode layer having a smaller area has such a shape, it becomes easier to obtain an electrode layer having a substantially uniform density after pressing.

  The electrode layer having a smaller area may be self-supporting or non-supporting, but is preferably a self-supporting film. When the area is a self-supporting film, the substrate may or may not be present, and the presence or absence of the substrate can be selected according to other purposes. In the case where the electrode layer having a smaller area is not a self-supporting film, the electrode layer having a smaller area can be handled together with the substrate until at least the layers are laminated or pressed.

  In FIG. 8, the schematic diagram showing an example of the provision process (B) included in the method which concerns on this invention is shown. As shown in FIG. 8, the method according to the present invention includes a step (B) of providing a solid electrolyte layer 2 having a larger area than an electrode layer having a smaller area among the positive electrode layer 1 and the negative electrode layer 3. When the solid electrolyte layer 2 has such an area, a short circuit between the positive electrode layer 1 and the negative electrode layer 3 in the electrode body can be prevented.

  FIG. 8 illustrates the case where the area of the solid electrolyte layer 2 has a larger area than that of the positive electrode layer 1, which is smaller than the positive electrode layer 1 and the negative electrode layer 3, and the same area as the negative electrode layer 3. It is. When the area of the positive electrode layer 1 is larger than the area of the negative electrode layer 3, the area of the solid electrolyte layer 2 has a larger area than that of the negative electrode layer 3.

  The solid electrolyte layer 2 preferably has an area that is equal to or larger than the area of the electrode layer having a larger area, more preferably substantially the same area as that of the electrode layer having a larger area. Have. When the solid electrolyte layer 2 has such an area, all of the outer peripheral portions of the electrode layer having a larger area are pressed in contact with the solid electrolyte layer 2, so that the positive electrode layer 1 and the negative electrode layer 3 in the electrode body are pressed. It becomes easier to prevent a short circuit between them.

  In FIG. 9, the schematic diagram showing an example of the lamination process (C) included in the method which concerns on this invention is shown. As shown in FIG. 9, the method according to the present invention has a larger area than the solid electrolyte layer 2 by laminating the solid electrolyte layer 2 on the electrode layer having a larger area among the positive electrode layer 1 and the negative electrode layer 3. A lamination step (C) for forming a laminate C with the electrode layer is included.

  FIG. 9 illustrates the case where the solid electrolyte layer 2 is laminated on the negative electrode layer 3 having a larger area among the positive electrode layer 1 and the negative electrode layer 3. When the area of the positive electrode layer 1 is larger than the area of the negative electrode layer 3, the solid electrolyte layer 2 and the positive electrode layer having a larger area are laminated.

  In FIG. 10, the schematic diagram showing an example of the press process (D) included in the method which concerns on this invention is shown. The method according to the present invention is a step of pressing the laminate C. As shown in FIG. 10, the laminate C is pressed using, for example, the lower mold 7 and the upper mold 8, and the process shown in FIG. A pressing step (D) for forming a laminate D in which a solid electrolyte layer is pressure-bonded to an electrode layer having a larger area as shown.

  The pressing pressure in the pressing step (D) can be performed at a pressure at which the solid electrolyte layer can be pressure bonded to the electrode layer having a larger area, for example, 90 to 780 MPa or 290 to 780 MPa.

  The pressing method in the pressing step (D) is not particularly limited, and can be performed using a commercially available pressure molding apparatus, and examples thereof include a uniaxial press, an isostatic press, or a hot press. For example, it can be pressure-molded by uniaxially pressing the laminate C using a mold of a predetermined size, or by performing isostatic pressing with the laminate C placed in a vacuum pack.

  10 and 11 illustrate the case where the solid electrolyte layer 2 is pressure-bonded on the negative electrode layer 3 having a larger area among the positive electrode layer 1 and the negative electrode layer 3. When the area of the positive electrode layer 1 is larger than the area of the negative electrode layer 3, the solid electrolyte layer 2 and the positive electrode layer having a larger area are pressure bonded.

  FIG. 12 is a schematic diagram showing an example of the stacking step (E) included in the method according to the present invention. As shown in FIG. 12, the method according to the present invention is a step of laminating a laminate D and an electrode layer having a smaller area so that the solid electrolyte layer 2 and the electrode layer 1 having a smaller area are adjacent to each other. And laminating step (E) for forming a laminate E including the positive electrode layer 1, the solid electrolyte layer 2, and the negative electrode layer 3.

  In FIG. 12, the positive electrode layer 1 having a smaller area is laminated on the laminate D including the negative electrode layer 3 and the solid electrolyte layer 2 having a larger area among the positive electrode layer 1 and the negative electrode layer 3. The case is illustrated. When the area of the positive electrode layer 1 is larger than the area of the negative electrode layer 3, the laminate D including the positive electrode layer 1 having a larger area and the solid electrolyte layer 2 and the negative electrode layer 3 having a smaller area are laminated.

  FIG. 13: shows the cross-sectional schematic diagram showing an example of the press process (F) included in the method which concerns on this invention. The method according to the present invention includes a pressing step (F) of pressing the laminate E as shown in FIG. 13 to form the electrode body 10 as shown in FIG.

  The pressing pressure in the pressing step (F) can be performed at a desired pressure that can increase the density by reducing voids contained in the positive electrode layer, the solid electrolyte layer, and the negative electrode layer, and can enhance the performance as a battery. For example, it can be performed at 290 to 780 MPa. The time and temperature at which the pressure is applied are not particularly limited, and can be set so as to obtain a desired density.

  The pressing method in the pressing step (F) is not particularly limited, and can be performed using a commercially available pressure molding apparatus, and examples thereof include a uniaxial press, a hydrostatic press, and a hot press. For example, pressure molding can be performed by performing uniaxial pressing using a mold having a predetermined size, or by performing isostatic pressing by placing the laminate E in a vacuum pack.

  In the electrode body 10 shown in FIG. 14, when the electrode layer having a smaller area is viewed from the upper surface, the area ratio of the constant density and thickness region 26 with respect to the entire projected area is preferably 95% or more, more preferably 99% or more. It is. Thus, by increasing the area ratio of the region where the density and thickness are constant in the electrode layer, it is possible to obtain an all solid state battery with a high utilization rate of the electrode layer. Variations in the density and thickness of the constant density and thickness region 26 are each preferably 10% or less, more preferably 5% or less, and even more preferably substantially 0%.

  In the method according to the present invention, the steps (A) to (F) may be performed in separate steps, or may be performed continuously or simultaneously.

  For example, the providing steps (A) and (B) are simultaneously performed to provide a positive electrode layer and a negative electrode layer having different areas, and at the same time, a solid having a larger area than the electrode layer having a smaller area among the positive electrode layer and the negative electrode layer. An electrolyte layer may be provided.

  In addition, for example, the stacking step (C) and the pressing step (D) are performed simultaneously, and the solid electrolyte layer is stacked on the electrode layer having a larger area among the positive electrode layer and the negative electrode layer. At the same time as forming the laminated body C with the large electrode layer, the laminated body C may be pressed to form the laminated body D in which the solid electrolyte layer is pressure-bonded to the electrode layer having a larger area.

  Further, for example, the stacking step (E) and the pressing step (F) are performed at the same time so that the solid electrolyte layer side of the laminate D and the electrode layer having a smaller area are adjacent to each other, and the positive electrode layer, the solid electrolyte layer At the same time as forming the laminated body E including the negative electrode layer, the laminated body E may be pressed to form an electrode body.

In the present invention, as the solid electrolyte material contained in the solid electrolyte layer, a material that can be used as a solid electrolyte of an all-solid battery can be used. For example, 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, or Sulfide-based amorphous solid electrolyte such as Li ₂ S—P ₂ S ₅ , Li ₂ O—B ₂ O ₃ —P ₂ O ₅ , Li ₂ O—SiO ₂ , Li ₂ O—B ₂ O ₃ , or Oxide-based amorphous solid electrolyte such as Li ₂ O—B ₂ O ₃ —ZnO, Li _1.3 Al _0.3 Ti _0.7 (PO ₄ ) ₃ , Li _{1 + x + y} A _x Ti _2−x Si _y P _{3− y} O ₁₂ (A is Al or Ga, 0 ≦ x ≦ 0.4, 0 <y ≦ 0.6), [(B _1/2 Li _1/2 ) _1−z C _z ] TiO ₃ (B is , La, Pr, Nd, or m, 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 6 BaLa 2 Ta 2 O 12, or Li _3.6 Si _0.6 P Crystalline oxide such as _0.4 O ₄ , crystalline oxynitride such as Li ₃ PO _{(4-3 / 2w)} N _w (w <1), or LiI, LiI—Al ₂ O ₃ , Li ₃ N, or Li ₃ N—LiI—LiOH or the like can be used. A sulfide-based amorphous solid electrolyte is preferably used in that it has excellent lithium ion conductivity. Further, as the solid electrolyte of the present invention, a semi-solid polymer electrolyte such as polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, or polyacrylonitrile containing a lithium salt can also be used.

In the present invention, as an active material contained in the positive electrode layer and the negative electrode layer, a material that can be used as an electrode active material of an all-solid battery can be used. Examples of the active material include lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , Li _{1 + x Mn 2-xy M y} O 4 (M is, Al, Mg, Co, Fe, Ni, and one or more metal elements selected from Zn) different element substituted Li-Mn spinel composition represented by, Transition metal oxidation such as lithium titanate (Li _x TiO _y ), lithium metal phosphate (LiMPO ₄ , M is Fe, Mn, Co, or Ni), vanadium oxide (V ₂ O ₅ ), and molybdenum oxide (MoO ₃ ) things, titanium sulfide (TiS _2), carbon materials such as graphite and hard carbon, lithium-cobalt nitride (LiCoN), lithium silicon oxide _{(Li x Si y O z)} , lithium metal (L ), Lithium alloy (LiM, M is, Sn, Si, Al, Ge, Sb, or P), lithium storage intermetallic compound (Mg _x M or NySb, M is Sn, Ge or Sb, N is an In,,, Cu, or Mn) and the like, and derivatives thereof.

  In the present invention, there is no clear distinction between the positive electrode active material and the negative electrode active material, and the two types of charge / discharge potentials are compared. A battery having an arbitrary voltage can be formed using the negative electrode for the negative electrode layer.

  The positive electrode layer can contain a known solid electrolyte that can be used in an all-solid battery, if desired. As such a solid electrolyte, the said solid electrolyte which can be contained in a solid electrolyte layer can be illustrated. When the solid electrolyte is contained in the positive electrode layer, the mixing ratio of the positive electrode active material and the solid electrolyte is not particularly limited, but the positive electrode active material: solid electrolyte volume ratio is preferably 40:60 to 90:10.

In the case where the positive electrode layer contains a sulfide solid electrolyte, the positive electrode is formed from the viewpoint of making it easy to prevent an increase in battery resistance by making it difficult to form a high resistance layer at the interface between the positive electrode active material and the sulfide solid electrolyte. The active material is preferably coated with an ion conductive oxide. As the lithium ion conductive oxide covering the positive electrode active material, for example, the general formula LixAOy (A is B, C, Al, Si, P, S, Ti, Zr, Nb, Mo, Ta or W, x and y are positive numbers)). Specifically, Li ₃ BO ₃ , Li _B O 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 Examples thereof include Ti ₅ O ₁₂ , Li ₂ Ti ₂ O ₅ , Li ₂ ZrO ₃ , LiNbO ₃ , Li ₂ MoO ₄ , Li ₂ WO _{4 and the} like. The lithium ion conductive oxide may be a complex oxide.

As the composite oxide covering the positive electrode active material, any combination of the above lithium ion conductive oxides can be employed. For example, Li ₄ SiO ₄ —Li ₃ BO ₃ , Li ₄ SiO ₄ —Li ₃ PO ₄ etc. can be mentioned.

  Further, when the surface of the positive electrode active material is coated with an ion conductive oxide, the ion conductive oxide only needs to cover at least part of the positive electrode active material, and covers the entire surface of the positive electrode active material. Also good. In addition, the thickness of the ion conductive oxide covering the positive electrode active material is, for example, preferably from 0.1 nm to 100 nm, and more preferably from 1 nm to 20 nm. The thickness of the ion conductive oxide can be measured using, for example, a transmission electron microscope (TEM).

  Each of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer may contain a binder. As binder materials, polytetrafluoroethylene, polytrifluoroethylene, polyethylene, nitrile rubber, polybutadiene rubber, butyl rubber, hydrogenated butylene rubber, polystyrene, styrene butadiene rubber, styrene butadiene latex, polysulfide rubber, nitrocellulose, acrylonitrile butadiene rubber Polyvinyl fluoride, polyvinylidene fluoride, fluororubber and the like are desirable, but not particularly limited.

  Each of the positive electrode layer and the negative electrode layer may contain conductive aid particles as desired. The conductive aid particles are not particularly limited, and graphite, carbon black and the like can be used. Examples of binders include polytetrafluoroethylene, polytrifluoroethylene, polyethylene, nitrile rubber, polybutadiene rubber, butyl rubber, polystyrene, styrene butadiene rubber, styrene butadiene latex, polysulfide rubber, nitrocellulose, acrylonitrile butadiene rubber, polyvinyl fluoride, polyvinyl fluoride. Vinylidene chloride, fluororubber and the like are desirable, but not particularly limited.

  The thickness of the solid electrolyte layer before pressing is preferably 15 to 250 μm, and more preferably 30 to 100 μm. When the thickness of the solid electrolyte layer before pressing is in the above range, the thickness of the solid electrolyte layer after pressing can be preferably 5 μm to 50 μm, more preferably 10 to 20 μm, and penetrates the solid electrolyte layer. A short circuit between the positive electrode layer and the negative electrode layer can be prevented.

  The thickness of the central portion of the positive electrode layer before pressing is preferably 1.5 to 3000 μm, and more preferably 7.5 to 300 μm. When the thickness of the positive electrode layer before pressing is in the above range, the thickness of the positive electrode layer after pressing can be preferably 1 to 1000 μm, more preferably 5 to 100 μm.

  The thickness of the negative electrode layer before pressing is preferably 1.5 to 3000 μm, and more preferably 7.5 to 300 μm. When the thickness of the negative electrode layer before pressing is in the above range, the thickness of the negative electrode layer after pressing can be preferably 1 to 1000 μm, more preferably 5 to 100 μm.

  The thickness 21 of the outer peripheral portion of the electrode layer before pressing shown in FIGS. 3 to 6 is preferably 5 to 30 μm at the thickest portion, and more preferably 10 to 20 μm. Moreover, 10-300 micrometers is preferable and, as for the width | variety 22 of the outer peripheral part of the electrode layer before a press, 50-100 micrometers is more preferable. When the thickness and width of the outer peripheral portion of the electrode layer before pressing are in the above range, the region 26 in which the density and thickness of the electrode layer are constant can be obtained by pressing.

The electrode body 10 having the positive electrode layer 1, the negative electrode layer 3, and the solid electrolyte layer 2 disposed therebetween has an arbitrary structure of 1 to 300 cm ² , for example, depending on the required characteristics and size of the battery. It can have any thickness such as area and 20-250 μm thickness.

  FIG. 15 is a schematic cross-sectional view illustrating an example of the configuration of the all solid state battery 100 according to the present invention. As shown in FIG. 15, an all-solid battery 100 produced by the method according to the present invention includes an electrode body 10 having a positive electrode layer 1, a negative electrode layer 3, and a solid electrolyte layer 2 disposed therebetween. A positive electrode current collector 4 can be electrically connected to the positive electrode layer 1, and a negative electrode current collector 5 can be electrically connected to the negative electrode layer 3. The all-solid battery 100 can be configured by covering the electrode body 10, the positive electrode current collector 4, and the negative electrode current collector 5 with a battery case 6 from which a current collector or a lead electrode connected to the current collector is drawn.

  The material of the positive electrode current collector 4 is not particularly limited as long as it has conductivity and functions as a positive electrode current collector. For example, SUS, aluminum, copper, nickel, iron, titanium, and Carbon etc. can be mentioned, SUS and aluminum are preferable. Furthermore, examples of the shape of the positive electrode current collector 4 include a foil shape, a plate shape, and a mesh shape. Among these, a foil shape is preferable.

  The material of the negative electrode current collector 5 is not particularly limited as long as it has conductivity and functions as a negative electrode current collector. Examples thereof include SUS, copper, nickel, and carbon. SUS and copper are preferred. Furthermore, examples of the shape of the negative electrode current collector 5 include a foil shape, a plate shape, and a mesh shape. Among these, a foil shape is preferable.

  The thickness of the positive electrode current collector 4 and the negative electrode current collector 5 is not particularly limited, and for example, a metal foil having a thickness of about 10 to 500 μm can be used.

  As the battery case 6 that encloses the all-solid battery, a known case that can be used in the all-solid battery can be used. For example, a laminated film, a case with a jig that can be restrained, or the like can be used. Examples of the laminate film include a resin laminate film, a film obtained by vapor-depositing a metal on a resin laminate film, and the like.

  The all-solid-state battery 100 can have a desired shape such as a cylindrical shape, a rectangular shape, a button shape, a coin shape, or a flat shape, but is not limited thereto.

  The positive electrode layer, the solid electrolyte layer, and the negative electrode layer provided in steps (A) and (B) can be formed and provided on a substrate, respectively. The positive electrode layer, solid electrolyte layer, and negative electrode layer are formed on the substrate using a slurry coating process, a blast method, an aerosol deposition method, a cold spray method, a sputtering method, a vapor deposition method, or a thermal spray method. The positive electrode layer, the solid electrolyte layer, and the negative electrode layer can be obtained by a process that is simple in the slurry coating process and is preferably used.

  The substrate is not particularly limited as long as the electrode layer or the solid electrolyte layer can be formed thereon, and a substrate having a film-like flexibility or a hard substrate can be used. For example, a foil-like positive electrode current collector 4 and / or a negative electrode current collector 5 can be used as a base material, or a base material such as Teflon (registered trademark) or polyethylene terephthalate (PET) film can be used. it can.

  Examples of the slurry coating process include a dam type slurry coater, a doctor blade method, a gravure transfer method, screen printing, a reverse roll coater, and the like, and a slurry or paste of a positive electrode material, a solid electrolyte material, and a negative electrode material is used.

  When forming a positive electrode layer, a solid electrolyte layer, and a negative electrode layer by applying and drying a slurry or paste of a positive electrode material, a solid electrolyte material, and a negative electrode material on a substrate, respectively, by a slurry coating process, the positive electrode material The solvent used for preparing the slurry or paste for each of the solid electrolyte material and the negative electrode material is not particularly limited as long as it does not adversely affect the performance of the positive electrode active material, the solid electrolyte, and the negative electrode active material. Examples include hydrocarbon organic solvents such as heptane, toluene, and hexane. Preferably, hydrocarbon organic solvents that have been dehydrated to reduce the water content are used.

  In the method according to the present invention, a positive electrode layer, a solid electrolyte layer, and a negative electrode layer from which the substrate has been removed in steps (A) and (B) may be provided, and steps (A) to (F) may be provided. You may remove a base material in any process of these.

  The electrode layer provided in the step (A) and having an outer peripheral part thicker than the central part and having a smaller area can be formed by any method, and is not limited, for example, by the method described below. Can be formed.

  The step (A) includes a step of providing a first base material having a shape in which a central portion is raised more than an outer peripheral portion; and an electrode mixture is applied on the first base material, Forming an electrode layer that includes a material and has a shape in which the outer peripheral portion is thicker than the central portion and has a smaller area.

  In the present application, an electrode mixture means a positive electrode mixture or a negative electrode mixture, and the above-mentioned active material, solid electrolyte material, binder, conductive additive particles, solvent, other dispersing agents, thixotropic agents, and the like are mixed. Means a slurry or paste to be prepared.

  For example, the electrode mixture is applied on the first substrate, the coating film is dried as necessary, and then the electrode mixture is further applied only to the outer peripheral portion, and the coating film is applied as necessary. Drying can be performed to form an electrode layer with a smaller area having a thicker outer peripheral portion than the central portion. The electrode mixture may be applied repeatedly in accordance with the desired thickness of the outer peripheral portion. The coating method can be performed using the above-described screen printing or the like.

  In another method, the electrode mixture is applied onto the first substrate, the coating film is dried as necessary, the electrode mixture is applied onto another substrate, and the coating film is applied as necessary. Then, the electrode mixture coated on another substrate is transferred only to the outer peripheral portion of the electrode layer coated on the first substrate, and the outer peripheral portion is thicker than the central portion. An electrode layer having a smaller area can be formed. The electrode mixture may be applied and transferred repeatedly in accordance with the desired thickness of the outer peripheral portion.

Still alternatively, the first substrate can be a first current collector layer;
The step of providing the first substrate in the step (A) includes:
Providing a first current collector layer; and raising a central portion of the first current collector layer to form a first current collector layer having a shape in which the central portion is raised from the outer peripheral portion. The process of
And forming an electrode layer with a smaller area,
A step of applying an electrode mixture on the first current collector layer having a shape in which the central portion is raised more than the outer peripheral portion; and the first current collector layer except for raising the first current collector. Forming an electrode layer having a smaller area having a shape in which the outer peripheral portion including the electric body layer is thicker than the central portion;
Can be included.

  An example in which the area of the positive electrode layer is smaller than the area of the negative electrode layer will be described below. When the area of the positive electrode layer is smaller than the area of the negative electrode layer, a positive electrode current collector using a positive electrode current collector such as an Al foil having a shape in which the central part is raised from the outer peripheral part and the positive electrode current collector as a base material is used. A positive electrode mixture can be applied on the body.

  FIG. 16 is a cross-sectional view schematically showing a method of coating the electrode mixture on the current collector having a shape in which the central portion is raised from the outer peripheral portion.

  In order to make the central part of the positive electrode current collector such as an Al foil used as a base material a shape higher than the outer peripheral part, when coating is performed, for example, as shown in FIG. The raised portion 15 is arranged, and the positive electrode current collector 4 can be arranged so that the raised portion 15 is located on the lower surface of the central portion of the positive electrode current collector 4.

  The raising portion 15 can be arranged by an arbitrary method, for example, a member having a thickness necessary for raising the height may be separately arranged, or the coating machine is disposed at the central portion of the coating table 14. Examples of the method include a raising portion 15 that may be driven up and down, and arranging the raising portion 15 so as to protrude from the coating table surface.

  An arbitrary member can be used for the raised portion 15, for example, the same Al foil as the positive electrode current collector, or the same metal material as the coating table may be used.

  As shown in FIG. 16, the positive electrode mixture 16 can be applied using a coating blade 17 on a positive electrode current collector having a shape in which the central portion is raised from the outer peripheral portion by the raised portion.

  The coated positive electrode mixture 16 is dried as necessary, taken out from the coating machine together with the positive electrode current collector 4 as a base material, and includes the positive electrode current collector 4 as shown in FIG. The positive electrode layer 1 having a shape thicker than the central portion can be obtained.

In addition, the step (A)
Providing a second substrate;
Applying an electrode mixture on the second substrate to form an electrode layer having a larger area including the substrate;
Can be included.

  The second substrate can be a second current collector layer.

  If the area of the positive electrode layer is smaller than the area of the negative electrode layer, apply a negative electrode mixture on the negative electrode current collector using a negative electrode current collector such as a Cu foil, and perform drying as necessary. The negative electrode current collector as a base material is taken out from the coating machine, and the negative electrode layer 3 including the negative electrode current collector 5 as shown in FIG. 18 can be obtained.

As described above, in the step (A) included in the method according to the present invention, a positive electrode layer including a positive electrode current collector and a negative electrode layer including a negative electrode current collector and having a larger area than the positive electrode layer can be provided. Using the positive electrode layer and the negative electrode layer thus obtained, a solid electrolyte layer having a larger area than the positive electrode layer is provided,
Laminating the negative electrode layer and the solid electrolyte layer so as to be adjacent to each other to form a laminate C including the negative electrode current collector 5, the negative electrode layer 3, and the solid electrolyte layer 2,
The laminate C is pressed to form a laminate D in which the solid electrolyte layer is pressure-bonded to the negative electrode layer including the negative electrode current collector,
A laminated body E including a negative electrode current collector 5, a negative electrode layer 3, a solid electrolyte layer 2, a positive electrode layer 1, and a positive electrode current collector 4, wherein the solid electrolyte layer and the positive electrode layer of the laminated body D are laminated so as to be adjacent to each other. Form the
The laminate E can be pressed to form an all-solid battery including the negative electrode current collector 5, the negative electrode layer 3, the solid electrolyte layer 2, the positive electrode layer 1, and the positive electrode current collector 4 as shown in FIG. .

  When a current collector is used as the base material, a step of arranging the current collector separately is unnecessary, and when the positive electrode layer and / or the negative electrode layer is not a self-supporting film, it can be handled together with the current collector. Is advantageous.

  Materials other than the current collector can also be used for the base material. For example, an electrode mixture is coated on a PET film, and similarly, the outer peripheral portion with the PET film as shown in FIG. 20 is thicker than the central portion. An electrode layer having a shape can be obtained.

  Thus, when using a base material such as a PET film other than the current collector, in the same manner as when using the current collector as the base material, the negative electrode layer in which the pet film is arranged up and down, the solid electrolyte layer, and An electrode body including a positive electrode layer can be obtained. In this case, the PET film can be peeled, and the positive electrode current collector and the negative electrode current collector can be disposed above and below the electrode body.

  Further, when the solid electrolyte layer is formed on a substrate such as a PET film, a laminate C is formed by laminating a solid electrolyte layer with a PET film on a negative electrode layer having a larger area, and the laminate C is pressed. After forming the laminated body D, the PET film on the solid electrolyte layer side is peeled off, and the solid electrolyte layer and the positive electrode layer having a smaller area are laminated so as to be adjacent to each other, and the positive electrode layer, the solid electrolyte layer, and the negative electrode layer The electrode body can be obtained by forming the laminate body E including the material and pressing the laminate body E. When the positive electrode layer and the negative electrode layer are provided with a PET film, the PET film on the negative electrode layer side and the PET film on the positive electrode layer side may be peeled after the laminate E is pressed.

  When the positive electrode current collector and the negative electrode current collector are arranged after the electrode body is formed, the arrangement can be performed by an arbitrary method. For example, the carbon spray may be coated on the surfaces of the positive electrode layer and the negative electrode layer before the current collector is arranged to improve the contact between the current collector and the electrode layer, and / or after the current collector is arranged. You may press in the direction perpendicular | vertical to a collector surface. Further, for example, in the pressing step (F), the positive electrode current collector, the laminate E, and the negative electrode current collector may be pressed simultaneously.

DESCRIPTION OF SYMBOLS 1 Positive electrode layer 2 Solid electrolyte layer 3 Negative electrode layer 4 Positive electrode collector 5 Negative electrode collector 6 Battery case 7 Lower mold 8 Upper mold 9 Restraint jig 10 Electrode body 11 Laminate C
12 Laminate D
13 Laminate E
DESCRIPTION OF SYMBOLS 14 Coating table 15 Raised part 16 Positive electrode (electrode) compound material 17 Coating blade 18 PET film 21 Thickness of outer peripheral part of electrode layer 22 Width of outer peripheral part of electrode layer 24 Extruded positive electrode layer part 26 Density and thickness Fixed area 100 All solid state battery

Claims (7)

A method for producing an all-solid battery including an electrode body including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer,
(A) A step of providing a positive electrode layer and a negative electrode layer having different areas, wherein the electrode layer having a smaller area of the positive electrode layer and the negative electrode layer has a shape in which an outer peripheral part is thicker than a central part. ;
(B) providing a solid electrolyte layer having an area larger than the electrode layer having a smaller area among the positive electrode layer and the negative electrode layer;
(C) Of the positive electrode layer and the negative electrode layer, the solid electrolyte layer is laminated on an electrode layer having a larger area to form a laminate C of the solid electrolyte layer and the electrode layer having a larger area. Laminating process;
(D) pressing the laminate C to form a laminate D in which the solid electrolyte layer is pressure-bonded to an electrode layer having a larger area;
(E) A step of laminating the laminate D and an electrode layer having a smaller area, the positive electrode layer being laminated so that the solid electrolyte layer and the electrode layer having a smaller area are adjacent to each other, A laminating step of forming a laminated body E including the solid electrolyte layer and the negative electrode layer; and (F) a pressing step of pressing the laminated body E to form an electrode body;
Only including,
After the pressing in the step (F), the area of the electrode layer having a smaller area is not more than the area of the solid electrolyte layer.
Manufacturing method of all solid state battery. 2. The method for producing an all-solid-state battery according to claim 1, wherein, in the step (B), the solid electrolyte layer has an area having a size equal to or larger than an area of the electrode layer having the larger area. The step (A)
A step of providing a first base material having a shape in which a central portion is raised more than an outer peripheral portion; and the outer periphery including the first base material by coating an electrode mixture on the first base material. Forming an electrode layer having a smaller area with a portion having a shape thicker than the central portion;
The manufacturing method of the all-solid-state battery of Claim 1 or 2 containing this. Providing the first substrate comprises:
A step of providing a first current collector layer; and a first current collector layer having a shape in which the central portion of the first current collector layer is raised and the central portion is raised from the outer peripheral portion. Forming step,
And forming an electrode layer having a smaller area,
Coating the electrode mixture on the first current collector layer having a shape in which the central portion is raised from the outer peripheral portion; and excluding raising the first current collector layer, Forming an electrode layer having a smaller area in which the outer peripheral portion including one current collector layer has a thicker shape than the central portion;
The manufacturing method of the all-solid-state battery of Claim 3 containing this. The step (A)
Providing a second substrate;
Applying an electrode mixture on the second base material to form an electrode layer having a larger area including the second base material;
The manufacturing method of the all-solid-state battery as described in any one of Claims 1-4 containing this.   The manufacturing method of the all-solid-state battery of Claim 5 whose said 2nd base material is a 2nd electrical power collector layer. Providing a positive electrode current collector and a negative electrode current collector,
Disposing the positive electrode current collector in contact with the positive electrode layer of the electrode body, and disposing the negative electrode current collector in contact with the negative electrode layer of the electrode body;
The manufacturing method of the all-solid-state battery of Claim 1 or 2 containing this.

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