JP2011165410A - All solid lithium ion secondary battery and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture an electrode layer with low internal resistance and high lithium ion conductivity, and to provide an all solid lithium ion secondary battery with high capacity with its electrode layer thickened, and a method for manufacturing the all solid lithium ion secondary battery with high productivity even though the electrode layer is thickened. <P>SOLUTION: The all solid lithium ion secondary battery includes a battery element which is made by pinching a solid electrolyte layer containing crystal of lithium ion conductivity, laminating a cathode layer and an anode layer, and laminating a collector layer on at least either the cathode layer or the anode layer. Further, in the all solid lithium ion secondary battery, at least either the cathode layer or the anode layer contains a conductive assistant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an all solid lithium ion secondary battery. More specifically, the present invention relates to an all-solid lithium ion secondary battery in which a positive electrode layer and a negative electrode layer are stacked with a solid electrolyte interposed therebetween, and a current collector layer is further stacked, and a method for manufacturing the same. Particularly preferably, the present invention relates to an all solid lithium ion secondary battery in which a solid electrolyte, a positive electrode layer, a negative electrode layer, and a current collector layer are sinter-bonded, and a method for manufacturing the same.

In recent years, with higher performance and smaller size of portable electronic devices such as mobile phones, it is desired to increase the energy density and size of batteries used in these portable electronic devices. In general, since a high voltage is obtained and a high energy density is obtained in a lithium battery, it is expected as a power source for these portable electronic devices. Usually, in such a lithium battery, lithium transition metal composite oxides such as lithium cobaltate (LiCoO ₂ ), lithium manganate (LiMn ₂ O ₄ ), and lithium nickelate (LiNiO ₂ ) are used as the positive electrode active material. Yes. Moreover, carbon materials, such as graphite and fibrous carbon, are used as a negative electrode active material. An organic electrolyte is used for such a lithium battery, but a polymer electrolyte obtained by mixing a polymer electrolyte and an organic electrolyte is also being studied. Since these lithium batteries or polymer electrolyte batteries use liquid as the electrolyte, they have low reliability such as liquid leakage or fire. In addition, freezing of the electrolytic solution at a low temperature and vaporization of the electrolytic solution at a high temperature may significantly impair the performance of the battery, so that the use temperature of such a battery is limited. Therefore, it is desired to develop a lithium battery using a solid electrolyte having lithium ion conductivity instead of an organic electrolyte as a highly reliable lithium battery. Capacitance is desired.

Since such a solid battery does not use a flammable organic solvent, there is no risk of liquid leakage or ignition, and it is excellent in safety. Further, in general, in the solid state battery, the capacity of the battery depends on the amount of the active material contained in the electrode layer, but even if the electrode layer is simply thickened to increase the amount of the active material, Electron conductivity and ionic conductivity are lowered. If the electron conductivity and ion conductivity in the electrode layer are low, when the charge / discharge current is large, the movement of electrons and ions accompanying the battery reaction does not catch up, and the capacity of the active material is not used effectively. There is a problem that the discharge ends. Such a problem is particularly remarkable in a solid battery. For example, Patent Document 1 uses a crystalline active material (first substance) capable of releasing and occluding lithium ions in the electrode layer, and does not mention any other electron conductive material. As the active material, a crystalline first phosphoric acid compound is used, and a material represented by the general formula: LiMPO ₄ is considered preferable. The thickness of the electrode layer that is directly related to the amount of the active material is preferably 10 μm or less, and is made thin to facilitate charge / discharge. This is considered to consider the ionic conductivity and electronic conductivity in the layer (Patent Document 1).
JP 2007-5279 A

  As described above, in order to increase the electric capacity, it is necessary to increase the molar amount of the active material (the first material in Patent Document 1), but since the density is substantially constant, It is necessary to increase the thickness of the electrode layer. On the other hand, when the thickness of the electrode layer becomes too large, there arises a problem that the internal resistance of the electrode increases due to the lithium ion conductivity and electronic conductivity of the active material. However, if the electrode layer is made thin in order to increase lithium ion conductivity and electron conductivity, there is a possibility that the electric capacity may be reduced, and there is a mutually contradictory relationship.

  In order to increase the effective electric capacity while increasing the charge / discharge current, it is strongly desired to improve the electron conductivity of the electrode. However, in a solid battery in which a solid electrolyte layer is sinter-bonded, it is difficult to say that the structure of an electrode having good electron conductivity has been sufficiently elucidated. Therefore, an electrode layer having a predetermined configuration with low internal resistance and high electron conductivity is manufactured, and a battery including such a battery layer (including each battery element including a positive electrode, a negative electrode, and an electrolyte) is manufactured. Thus, an object is to provide a large-capacity all-solid-state lithium ion secondary battery.

  In view of such circumstances, the present invention provides an all-solid-state lithium ion secondary battery that solves the above problems by clarifying an electrode layer having a predetermined configuration and a structure of a battery including such an electrode layer. To do.

More specifically, the following can be provided.
(1) A battery element in which a positive electrode layer and a negative electrode layer are stacked with a solid electrolyte layer containing a lithium ion conductive crystal in between, and a current collector layer is stacked on at least one of the positive electrode layer or the negative electrode layer. It is possible to provide an all-solid-state lithium ion secondary battery including the same.

  The solid electrolyte layer, the positive electrode layer, the negative electrode layer, and the current collector layer constituting the battery element can include a structure in which a plurality of each are stacked.

(2) The all-solid-state lithium ion secondary battery as described in said (1) which contains a conductive support agent in at least one of the said positive electrode layer or the said negative electrode layer can be provided.

(3) The all-solid-state lithium ion secondary battery according to (1) or (2) above, wherein the conductive additive contains carbon, metal, or metal oxide.

(4) The conductive assistant is one selected from carbon or aluminum, copper, titanium, molybdenum, tungsten, nickel, zinc, magnesium, tantalum, iron, chromium, palladium, platinum, rhodium, indium, and tin. The all-solid-state lithium ion secondary battery according to any one of the above (1) to (3), comprising the above metal and alloy or metal oxide can be provided.

Here, a conductive support agent refers to the additive mix | blended in order to improve the electroconductivity of an electrode layer, and what has an electronic conductivity of 1 * 10 ^<-2 > Scm ^{< -1} > or more can be included. As an example of the conductive aid, tungsten can be used for the positive electrode and nickel can be used for the negative electrode, and these can include particles (powder), fibers, and the like. When the conductive additive is in the form of particles, the particle size is preferably smaller than the particles of the active material contained in the positive electrode layer and the negative electrode layer. Further, when the conductive additive is fibrous, it is preferable that the fineness (fiber thickness) is smaller than the particle diameter of the active material. Carbon as a conductive aid preferably has a chemical structure consisting of a long carbon chain. Any material having electronic conductivity may be used. Accordingly, the capacity of lithium storage and release is not limited. For example, acetylene black or carbon nanofibers can be used. When carbon is used as a conductive additive, the amount can be grasped by performing TG-DTA analysis. Note that graphite and hard carbon (phenol resin fired body) have an occlusion capacity of about 370 mAh / g and 800 mAh / g, and function not only as a negative electrode active material but also as a conductive aid.

(5) The all-solid-state lithium ion secondary battery according to any one of (1) to (4), wherein an ion conduction assistant is included in at least one of the positive electrode layer or the negative electrode layer. be able to.

Here, the ion conduction assistant refers to an additive blended to improve the ion conductivity of the electrode layer, and can include those having an ion conductivity of 1 × 10 ⁻⁶ Scm ⁻¹ or more. A solid electrolyte powder may be included as an example of the ion conduction aid.

(6) The all-solid-state lithium ion secondary battery according to any one of (1) to (5) above, wherein a thickness of the positive electrode layer or the negative electrode layer exceeds 1 μm.

  As the electrode layer is thicker, the amount of active material increases and the capacity of the battery can be increased. Therefore, the lower limit of the thickness of the positive electrode layer is preferably more than 1 μm, more preferably more than 5 μm, most preferably 10 μm. The value exceeds. However, if the electrode layer is too thick, lithium ions are difficult to move and the capacity and charge / discharge cycle are deteriorated. Therefore, the upper limit of the thickness of the positive electrode layer is preferably 300 μm or less, more preferably 250 μm or less, and most preferably 200 μm or less. It is. For the same reason as the positive electrode layer, the lower limit of the thickness of the negative electrode layer is preferably more than 1 μm, more preferably more than 5 μm, and most preferably more than 10 μm. Further, the upper limit value of the thickness of the negative electrode layer is preferably 300 μm or less, more preferably 250 μm or less, and most preferably 200 μm or less.

(7) The all-solid-state lithium ion secondary battery according to any one of (1) to (6) above, wherein the thickness of the solid electrolyte layer is 0.2 μm to 150 μm.

  In order to suppress deformation due to stress generated during bonding with the electrode and prevent short circuit, the lower limit value of the thickness of the solid electrolyte layer is preferably 0.2 μm or more, more preferably 0.3 μm or more, and most preferably 0.4 μm or more. In addition, as the thickness of the solid electrolyte decreases, the lithium ion transfer distance between the electrodes decreases and a high output battery is obtained, and the electrode area per unit volume can be secured widely and a high capacity battery can be obtained. The upper limit of the thickness is preferably 150 μm or less, more preferably 140 μm or less, and most preferably 130 μm or less.

(8) The all-solid-state lithium ion secondary battery according to any one of (1) to (7) above, wherein the current collector layer has a thickness of 0.05 μm to 20 μm. .

  Since the current collector may break during charging / discharging or bonding with the electrode, the lower limit of the thickness of the current collector layer is preferably 0.05 μm or more, more preferably 0.1 μm or more, and most preferably 0.5 μm or more. Further, since the electrode layer may peel off without being able to disperse the stress generated during charge / discharge, the upper limit value of the thickness of the current collector layer is preferably 20 μm or less, more preferably 19 μm or less, most preferably Preferably it is 18 micrometers or less.

(9) The lithium ion conductive crystal is Li _{1 + x + z} M _x (Ge _1−y Ti _y ) _2−x Si _z P _3−z O ₁₂ (however, 0 ≦ x ≦ 0.8, 0 ≦ y ≦ 1) 0.0, 0 ≦ z ≦ 0.6, M = one or more selected from Al and Ga), the all solid lithium ion secondary according to any one of (1) to (8) above A battery can be provided.

(10) The above-mentioned comprising a compound containing any component of O, P, or F between the solid electrolyte layer and the positive electrode layer or between the solid electrolyte layer and the negative electrode layer. The all-solid-state lithium ion secondary battery in any one of (1)-(9) can be provided.

  Here, the electrode-electrolyte boundary layer is a layer that can be clearly distinguished from other layers by abruptly changing the concentration of at least one of the components of O, P, or F. Alternatively, it may be a layer constituted by a slow change in the component concentration. That is, such a layer can be recognized by increasing and decreasing the concentration of these components in a cross section by a plane crossing the boundary between the electrode and the electrolyte. Here, as the compound containing oxygen (O) or phosphorus (P), a metal oxide, particularly an oxide of a group IV element such as titanium, zirconium, hafnium, or the like can be included. In addition, various allotropes of phosphorus (P) can be used alone or in combination to be applied to the surface of a solid electrolyte or the like before firing, and a phosphorus oxide such as diphosphorus pentoxide can be generated at the electrode electrolyte boundary by firing.

The compound contained in the electrode-electrolyte boundary layer may include any one or more of La, Ta, and O components. Such compounds may include, for example, Li ₆ CaLa ₂ Ta ₂ O ₁₂ and those in which the Ca is substituted. The compound provided in the electrode-electrolyte boundary layer may include P. Compound or amorphous material with as aspect of the _{P 2 O 5, Li 2 O} -P 2 O 5 or the like of Li component, red _phosphorus, Cu ₅ P 2, TiP like metal - phosphorus compounds. When the OPF compound contains P, it can be used for low-temperature firing, generation of a stable electrode, and an electrolyte interface.

(11) The all-solid-state lithium ion secondary battery according to any one of (1) to (10), wherein an insulating layer is stacked on at least one of the current collector layers. it can.

  The current collector layer may be composed of a single layer or may be composed of a plurality of layers. The current collector may contain a metal element having electronic conductivity, and the positive electrode and the negative electrode may contain the same metal element. As the metal element, an alloy having a heat resistant temperature as high as that of the solid electrolyte layer, the positive electrode layer, and the negative electrode layer, and having oxidation resistance if it is a positive electrode current collector and reducing resistance if it is a negative electrode current collector. Can be included. As the alloy, a heat-resistant iron-based alloy, for example, an alloy containing chromium and / or nickel can be used. More specifically, stainless steel such as SUS304 or 600 can be used.

(12) The all-solid-state lithium ion secondary battery according to any one of (1) to (11) above, including a stacked portion in which a plurality of the battery elements are stacked.

  Here, a laminated part is formed by combining different types of battery elements (consisting of one or a plurality of solid electrolyte layers, positive electrode layers, negative electrode layers, and current collector layers, and the number of stacked layers is not the same). Also good.

  FIG. 4 is a schematic cross-sectional view illustrating a cross-section of a part of the stacked portion. As shown in FIG. 4A, in the stacked portion 30, the positive electrode current collector layer 22a of one battery element 28a and the negative electrode current collector layer 24b of the other battery element 28b are provided with an insulating layer 62. And a stacked structure (hereinafter referred to as “order product”). Also, as shown in FIG. 4B, one battery element 28a and the other battery element 28b are made of the same current collector layers (positive electrode collector layer 24a and positive electrode collector layer 24b, Alternatively, although not shown, a structure in which the negative electrode current collector layer 22 and the negative electrode current collector layer 22) are stacked with the insulating layer 62 interposed therebetween (hereinafter referred to as a reverse product) can be included. Further, when the reverse product is performed, a structure in which the insulating layers 62 are not interposed can be included, and at this time, as shown in FIG. The current collector layers 24a and 24b may be shared. Further, as shown in FIGS. 4D and 4E, a structure in which a forward product and a reverse product are appropriately combined can be included. In addition, the lamination | stacking part can contain what is sintered.

  By making such battery elements multi-layered, a stable battery that is compact and has a large battery capacity can be obtained. Furthermore, as shown in FIGS. 4F and 4G, a structure in which a plurality of battery elements are stacked without the electronic current insulating layer being directly overlapped with the negative electrode current collector layer 24 and the positive electrode current collector layer 22 The negative electrode current collector layer 24 and the positive electrode current collector layer 22 can be shared as the same layer without using an electronic insulating layer, and a plurality of battery elements can be stacked. 4 (f) and 4 (g) is a state in which a plurality of battery elements are connected in series, and the positive electrode lead and the negative electrode lead of the entire stacked battery may be provided one by one, and connection between the battery elements is a lead. There is no need to connect with a wire or the like, and the manufacturing can be simplified. This configuration is preferable in that the voltage of the battery can be increased. Since the all solid state battery does not contain the organic electrolyte solution, there is no problem that the organic electrolyte solution is decomposed by a high voltage, and this configuration is advantageous for the all solid state battery. In addition, the lamination | stacking part can contain what is sintered.

(13) The all-solid-state lithium ion secondary battery according to (12) above, wherein the stacked portion has the flat battery elements stacked.

(14) The all-solid-state lithium ion secondary battery according to the above (12), wherein the stacked unit is wound with the battery element.

  The laminated portion is not limited to the battery element being wound, but includes a plurality of stacked battery elements as illustrated in FIG. The wound laminated portion includes that the band-shaped battery element is wound in a spiral shape. Further, the laminated portion may include that the wound appearance is a cylindrical shape, an elliptical cylindrical shape, a rectangular parallelepiped shape, or a flat shape thereof. When the laminated part is formed in a cylindrical shape, it is easy to manufacture, and when it is flattened, there is an advantage that no dead space is generated when stored in a rectangular container, both improving volumetric efficiency. Can be made.

(15) The all-solid-state lithium ion secondary battery according to (12), wherein the battery unit is folded in the stacked portion.

  The stacked portion is not limited to one battery element being folded, but may include a plurality of stacked battery elements as illustrated in FIG. 4 being folded.

(16) The all-solid-state lithium ion secondary battery according to the above (15), wherein the stacked portion has the battery element folded in an even number.

  By even-folding the battery element, the positive electrode and the negative electrode appear on the upper surface and the lower surface of the stacked portion, respectively, so that current collection in the stacked portion can be facilitated.

(17) A step of preparing an electrolyte green sheet, a positive electrode green sheet, and a negative electrode green sheet containing lithium ion conductive inorganic powder or oxide glass powder that exhibits lithium ion conductivity by heat treatment, and sandwiching the electrolyte green sheet The positive electrode green sheet and the negative electrode green sheet are laminated, and a current collector green sheet is laminated on at least one of the positive electrode green sheet or the negative electrode green sheet to produce a battery element green sheet; and the battery element green sheet The manufacturing method of the all-solid-state lithium ion secondary battery characterized by including the process of producing a laminated body by laminating | stacking, and the process of baking the said laminated body can be provided.

  Here, the green sheet is an unfired body obtained by mixing an organic binder, a plasticizer, a solvent, and the like into powder such as glass before firing or ceramics of inorganic oxide, and mixing the mixture into a thin slurry. Can mean This molding can be performed by a doctor blade, calendar method, spin coating, dip coating or other coating method, ink jet, bubble jet (registered trademark), offset printing method, die coater method, spray method, etc., mixed slurry From this, a thin plate-like green sheet can be made. In general, the mixed slurry is formed on a film such as PET that has been subjected to a mold release treatment, and is prepared by peeling after drying. However, the slurry is directly formed on the green sheet or ceramics to be laminated. In addition, the layer produced by this method may be included in the concept of the green sheet. The green sheet before firing is flexible, and can be cut into an arbitrary shape or laminated.

In addition, examples of the lithium ion conductive inorganic powder include a crystal having a perovskite structure having lithium ion conductivity such as LiN, LISICON, La _0.55 Li _0.35 TiO _3, and LiTi ₂ P having a NASICON type structure. ₃ O ₁₂ or glass ceramics on which these crystals are precipitated can be used. As a preferable lithium ion conductive crystal, Li _{1 + x + z} M _x (Ge _1−y Ti _y ) _2−x Si _z P _3−z O ₁₂ (where 0 ≦ x ≦ 0.8, 0 ≦ y ≦ 1. 0, 0 ≦ z ≦ 0.6, one or more selected from M = Al, Ga). A crystal that does not include a grain boundary that inhibits ionic conduction is advantageous in terms of ionic conduction. In particular, glass ceramics are more preferable because they have almost no vacancies or crystal grain boundaries that hinder ion conduction, and therefore have high ion conductivity and excellent chemical stability. In addition to glass ceramics, examples of a material that has almost no vacancies or crystal grain boundaries that hinder ion conduction include single crystals of the above crystals, which are difficult to manufacture and expensive. Lithium ion conductive glass ceramics are also advantageous from the viewpoint of ease of production and cost.

  Here, the vacancies and grain boundaries that hinder ion conduction refer to the conductivity of the entire inorganic substance including lithium ion conductive crystals with respect to the conductivity of the lithium ion conductive crystal itself in the inorganic substance. Ion conductivity-inhibiting substances such as vacancies and grain boundaries that decrease to 10 or less. In addition to glass ceramics, examples of materials that have almost no vacancies or crystal grain boundaries that impede ion conduction include single crystals of the above crystals, but they are difficult to manufacture and expensive, so lithium ion conductive glass ceramics can be used. Most preferably it is used.

Examples of the lithium ion conductive glass ceramics include those in which the mother glass has a composition of Li ₂ O—Al ₂ O ₃ / Ga ₂ O ₃ —TiO ₂ / GeO ₂ —SiO ₂ —P ₂ O ₅ system. . This glass is crystallized by heat treatment, and the main crystal phase at that time is Li _{1 + x + z} M _x (Ge _1-y Ti _y ) _2−x Si _z P _3−z O ₁₂ (where 0 ≦ x ≦ 0.8 , 0 ≦ y ≦ 1.0, 0 ≦ z ≦ 0.6, M = one or more selected from Al and Ga). The ratio of the lithium ion conductive glass ceramics to the mother glass can be appropriately changed depending on the required ion conductivity, firing conditions, and the like. Such lithium ion conductive glass ceramics may have the following composition with the mother glass mol% based on oxide.
Li ₂ O 10-25%, and Al ₂ O ₃ and / or Ga ₂ O ₃ 0-15%, and TiO ₂ and / or GeO ₂ 25-50%, and SiO ₂ 0-15%, and P ₂ O ₅ 26-40%
The mother glass powder having the above composition is an example of an oxide glass powder that exhibits lithium ion conductivity by heat treatment.

  Here, the glass ceramics can include a material obtained by precipitating a crystal phase in a glass phase by heat-treating the glass. A material composed of an amorphous solid and a crystal may be included. The crystal precipitation can be detected by, for example, an X-ray diffraction method or the like when a crystal layer is formed by sufficient growth after generation of crystal nuclei. Furthermore, the glass ceramics can include those in which the entire glass phase is phase-transitioned into the crystal phase, that is, those having a crystal amount of 100 mass% (crystallinity of 100%). In general, in ceramics, vacancies and grain boundaries between crystal grains tend to remain even after sintering. However, since the glass ceramic referred to here precipitates crystals from the glass phase during the production process, no vacancies or crystal grain boundaries occur. Since ionic conduction is remarkably suppressed by vacancies and grain boundaries between crystal grains, in the case of ceramics, the ionic conductivity is considered to be considerably lower than the conductivity of the crystal grains themselves. Since glass ceramics can suppress a decrease in ionic conductivity between crystals by controlling the crystallization process, the ionic conductivity of the same degree as that of crystal particles can be maintained as a whole. Even when the glass ceramic powder or the mother glass powder is sintered, the glass matrix is fused, so that voids and crystal grain boundaries can be prevented from remaining.

  The current collector green sheet can be produced from, for example, a mixed powder of copper oxide and carbon or an iron-based alloy powder, a binder having binding properties, and an organic solvent capable of dissolving the binder.

  The step of producing the battery element green sheet may include a step of laminating an insulator green sheet on at least one of the current collector green sheets.

  The firing process includes a degreasing process and a sintering process. A degreasing process is a process which processes a green sheet at high temperature, gasifies components, such as organic binders other than the inorganic substance, and discharges it from the green sheet. A sintering process is a process of joining the particle | grains of the inorganic substance which comprises a green sheet by processing a green sheet at higher temperature than a degreasing process. In any of the degreasing step and the sintering step, it is preferable to perform exhaust in order to keep the atmosphere in the furnace constant. Although a known firing furnace such as a gas furnace or a microwave furnace can be used for the firing step, it is preferable to use an electric furnace for reasons such as environment, temperature distribution in the furnace, and cost.

  The atmosphere in firing may include an oxidizing atmosphere and a non-oxidizing atmosphere. The oxidizing atmosphere can mean an atmosphere containing at least a component that causes an oxidation reaction. For example, the atmosphere containing oxygen can be an oxidizing atmosphere. On the other hand, the non-oxidizing atmosphere may mean an atmosphere that does not contain a component that causes an oxidation reaction. For example, an oxygen-free atmosphere can be included. In addition, an atmosphere composed of at least one of nitrogen and an inert gas can also be a non-oxidizing atmosphere. Even in an atmosphere containing oxygen, an atmosphere in which the degree of oxidation of a substance to be fired is reduced can be handled as a non-oxidizing atmosphere.

  The firing temperature can be, for example, higher than the temperature at which the oxide glass powder exhibits lithium ion conductivity by heat treatment and lower than the melting point of the alloy contained in the current collector layer. In addition, when it can bak at a temperature lower than the temperature which expresses the lithium ion conductivity by mixing a low melting point material in the electrolyte green sheet, it is not limited to the above.

(18) The method for producing an all-solid-state lithium ion secondary battery according to the above (17), comprising a step of containing a conductive additive in at least one of the positive electrode green sheet or the negative electrode green sheet. be able to.

(19) The all-solid-state lithium ion secondary battery according to (17) or (18) above, comprising a step of containing an ion conduction aid in at least one of the positive electrode green sheet or the negative electrode green sheet. A manufacturing method can be provided.

(20) The all-solid-state lithium ion secondary according to any one of (17) to (19), wherein the step of manufacturing the laminate includes a step of laminating a plurality of the battery element green sheets. A method for manufacturing a battery can be provided.

  The step of producing the laminate can include a step of laminating a flat battery element green sheet. The stacking step includes a step in which the positive electrode current collector green sheet and the negative electrode current collector green sheet of the battery element green sheet are overlapped and stacked, and the same polarity current collector green sheets are stacked and stacked. be able to. At this time, a step of sharing a current collector green sheet of the same polarity may be included.

(21) The step of producing the laminate includes a step of winding and laminating the battery element green sheet, and the all-solid lithium ion secondary electrode according to any one of (17) to (20), A method for manufacturing a secondary battery can be provided.

  The step of producing the laminate may include a step of winding the electric element green sheet, and a step of winding a plurality of stacked battery element green sheets. The step of winding and laminating includes a step of winding a band-shaped battery element green sheet in a spiral shape, and the appearance of the wound laminated portion is cylindrical, oval, rectangular, or The process which becomes these flat shapes can be included.

(22) The step of producing the laminate includes a step of folding and laminating the battery element green sheet, and the all solid lithium ion secondary according to any one of (17) to (20) above A method for manufacturing a battery can be provided.

  The step of folding and stacking may include a step of folding the electric element green sheet, and a step of folding a plurality of stacked battery element green sheets. Moreover, the process of folding these battery element green sheets by an even number can be included.

(23) The lithium ion conductive inorganic powder is Li _{1 + x + z} M _x (Ge _1−y Ti _y ) _2−x Si _z P _3−z O ₁₂ (where 0 ≦ x ≦ 0.8, 0 ≦ y ≦ 1.0, 0 ≦ z ≦ 0.6, M = one or more selected from Al and Ga), the all solid according to any one of (17) to (22) above A method for manufacturing a lithium ion secondary battery can be provided.

(24) The oxide glass powder is mol% based on oxide,
Li ₂ O 10-25%, and Al ₂ O ₃ and / or Ga ₂ O ₃ 0-15%, and TiO ₂ and / or GeO ₂ 25-50%, and SiO ₂ 0-15%, and P ₂ O ₅ 26-40%
The manufacturing method of the lithium ion secondary battery in any one of said (17)-(23) containing each component of these can be provided.

The Li ₂ O component is an essential component for providing Li ⁺ ion carriers and providing lithium ion conductivity. In order to obtain good conductivity, the lower limit of the content is preferably 10 mol%, more preferably 11 mol%, still more preferably 12 mol%. Further, if the Li ₂ O component is too much, the thermal stability of the glass tends to deteriorate, and the conductivity of the glass ceramics tends to decrease, so the upper limit of the content is preferably 25 mol%, and is 24 mol%. It is more preferable, and it is still more preferable that it is 23 mol%.

The Al ₂ O ₃ component and / or the Ga ₂ O ₃ component can enhance the thermal stability of the mother glass, and at the same time, Al ³⁺ ions and / or Ga ³⁺ ions are dissolved in the crystal phase to form lithium ions. It is also effective in improving conductivity. The Al ₂ O ₃ component and / or Ga ₂ O ₃ component may not be contained in the glass, but in order to obtain this effect, the lower limit of the content is more preferably 1 mol%, and 2 mol%. More preferably. However, if the content exceeds 15 mol%, the thermal stability of the glass tends to deteriorate and the conductivity of the glass ceramic tends to decrease. Therefore, the upper limit of the content is preferably 15 mol%. In addition, the upper limit of more preferable content is 14 mol%, and the upper limit of more preferable content is 13 mol%.

The TiO ₂ component and / or GeO ₂ component contributes to the formation of glass and is also a constituent component of the crystal phase, and is a useful component in both the glass and the crystal. In order to vitrify and to obtain a high conductivity by the crystal phase being precipitated from glass as a main phase, the lower limit of the content is preferably 25 mol%, more preferably 26 mol%, and 27 mol % Is more preferable. In addition, if the TiO ₂ component and / or GeO ₂ component is too much, the thermal stability of the glass tends to deteriorate and the conductivity of the glass ceramic tends to decrease, so the upper limit of the content is preferably 50 mol%. 49 mol% is more preferable, and 48 mol% is still more preferable.

The SiO ₂ component can improve the meltability and thermal stability of the mother glass, and at the same time, Si ⁴⁺ ions are dissolved in the crystal phase, contributing to an improvement in lithium ion conductivity. In order to sufficiently obtain this effect, the lower limit of the content is preferably 0 mol%, more preferably 1 mol%, still more preferably 2 mol%. However, if the content exceeds 15 mol%, the conductivity tends to decrease. Therefore, the upper limit of the content is preferably 15 mol%, more preferably 14 mol%, and more preferably 13 mol%. Is more preferable.

The P ₂ O ₅ component is an essential component for the formation of glass and is also a constituent component of the crystal phase. If the content is less than 26 mol%, vitrification is difficult, so the lower limit of the content is preferably 26 mol%, more preferably 27 mol%, and even more preferably 28 mol%. Further, if the content exceeds 40 mol%, the crystal phase is difficult to precipitate from the glass, and it becomes difficult to obtain desired characteristics. Therefore, the upper limit of the content is preferably 40 mol%, more preferably 39 mol%. 38 mol% is more preferable.

In the case of the above-mentioned composition, glass can be easily obtained by casting molten glass, and glass ceramics having the crystal phase obtained by heat-treating this glass have high lithium ion conductivity. In addition to the composition of the well, as long as the glass-ceramics having a crystal structure similar to, it is also possible to replace part or all of _Al 2 _{O 3} and _{Ga 2 O} 3, TiO 2 into GeO _2. Furthermore, in the production of glass ceramics, it is possible to add other raw materials within a range that does not greatly deteriorate the ion conductivity in order to lower the melting point or increase the stability of the glass.

It is desirable that the glass ceramic composition does not contain alkali metals such as Na ₂ O and K ₂ O other than Li ₂ O as much as possible. When these components are present in the glass ceramic, the conductivity of Li ⁺ ions is inhibited by the effect of mixing alkali ions, and the conductivity is easily lowered. Further, when sulfur is added to the composition of the glass ceramic, the lithium ion conductivity is slightly improved, but the chemical durability and stability are deteriorated. It is desirable that the glass ceramic composition does not contain as much as possible components such as Pb, As, Cd, and Hg that may cause harm to the environment and the human body.

  A battery element in which a positive electrode layer and a negative electrode layer are stacked with a solid electrolyte layer including a lithium ion conductive crystal interposed therebetween, and a current collector layer is stacked on at least one of the positive electrode layer and the negative electrode layer is included. In addition, at least one of the positive electrode layer or the negative electrode layer includes a conductive additive. Therefore, the positive electrode layer and / or the negative electrode layer can reduce the internal resistance and improve the electron conductivity, so that the electrode can be thickened while having high electron conductivity, and a battery having a large capacity is manufactured. can do.

  In addition, the current collector layer includes an iron-based alloy powder containing chromium and / or nickel, so that a metal material having the same heat resistance is used for the positive electrode current collector and the negative electrode current collector. Therefore, the firing temperature and firing atmosphere of the positive electrode current collector and the negative electrode current collector can be made the same. In addition, according to the present invention, a laminate composed of a solid electrolyte, a positive electrode, a negative electrode, a positive electrode current collector, and a negative electrode current collector can be sintered together, so that the manufacturing process can be simplified and productivity can be improved. It can also contribute to increase.

It is a schematic cross section of the all-solid-state lithium ion secondary battery of the Example of this invention. It is a schematic cross section of the all-solid-state lithium ion secondary battery of the Example of this invention. It is a figure which shows the example of a process which manufactures the all-solid-state lithium ion secondary battery assembly of a present Example. It is the schematic cross section which illustrated the cross section of a part of the laminated part of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the following description is made for explaining the embodiments of the present invention, and the present invention is limited to these embodiments. It is not a thing. The same or the same type of elements are denoted by the same or related symbols, and redundant description is omitted.

  FIG. 1 schematically shows a cross section of an all-solid-state lithium ion secondary battery 10 according to one embodiment of the present invention. A positive electrode 14 is disposed on the upper side and a negative electrode 16 is disposed on the lower side with a layer made of the solid electrolyte 12 interposed therebetween. Also, a positive electrode current collector 22 and a negative electrode current collector 24 are disposed on the upper side of the positive electrode and the lower side of the negative electrode, respectively.

[Solid electrolyte]
The thickness of the solid electrolyte 12 sandwiched between the positive electrode 14 and the negative electrode 16 is preferably smaller because the lithium ion moving distance becomes shorter and a high output battery can be obtained, and a large electrode area per unit volume can be secured. . For example, the thickness of the layered solid electrolyte 12 is preferably 200 μm or less, more preferably 180 μm or less, and most preferably 150 μm or less.

  The performance of the solid state battery of this example depends on the lithium ion conductivity and lithium ion transport number of the electrolyte. Therefore, it is preferable to use a substance having high lithium ion conductivity for the solid electrolyte of the present invention.

The ion conductivity of the lithium ion conductive crystal is preferably 1 × 10 ⁻⁴ S · cm ⁻¹ or more, more preferably 5 × 10 ⁻⁴ S · cm ⁻¹ or more, and 1 × 10. Most preferably, it is ⁻³ S · cm ⁻¹ or more.

  Examples of the lithium ion conductive inorganic powder that can be used for the green sheet for producing the solid electrolyte in this embodiment or the oxide glass powder that exhibits lithium ion conductivity by heat treatment include, for example, lithium ion conductive crystallized glass. It may be an inorganic substance powder containing a mother glass powder, a lithium ion conductive crystal (ceramic or glass ceramic) powder, or a mixture thereof. In order to obtain high lithium ion conductivity, the lithium ion conductive inorganic powder preferably contains lithium, silicon, phosphorus, and titanium as main components.

  Since a higher conductivity can be obtained by including many of these crystals in the solid electrolyte, it is preferable that 50 wt% or more of lithium ion conductive crystals be included in the solid electrolyte. More preferably, it is 55 wt% or more, and most preferably 60 wt% or more.

  In addition, the lower limit of the content of the lithium ion conductive inorganic powder contained in the green sheet for obtaining the solid electrolyte or the oxide glass powder that exhibits lithium ion conductivity by heat treatment in the green sheet reduces the voids after firing. Therefore, it is preferably 60 wt% or more, more preferably 65 wt% or more, and most preferably 70 wt% or more.

In addition, the upper limit of the content of the lithium ion conductive inorganic powder or the oxide glass powder that exhibits lithium ion conductivity by heat treatment is preferably 97 wt% or less, and 94 wt% or less in order to maintain the sheet shape. More preferably, it is most preferably 90 wt% or less. Here, lithium ion conductivity means that lithium ion conductivity shows a value of 1 × 10 ⁻⁸ S · cm ⁻¹ or more at 25 ° C.

  Since a high conductivity can be obtained by including a large amount of lithium ion conductive glass ceramics in the solid electrolyte, it is preferable that 80 wt% or more of the lithium ion conductive glass ceramics be included in the solid electrolyte. More preferably, it is 85 wt% or more, and most preferably 90 wt% or more.

  As the lithium ion conductive inorganic powder having high ionic conductivity to be contained in the solid electrolyte layer of the present invention, it is preferable to use a pulverized lithium ion conductive glass ceramic. It is preferable that the lithium ion conductive inorganic powder is uniformly dispersed in the solid electrolyte in terms of the ionic conductivity and mechanical strength of the solid electrolyte. In order to improve the dispersibility and to obtain a desired thickness of the solid electrolyte, the average particle size of the lithium ion conductive inorganic powder is preferably 20 μm or less, more preferably 15 μm or less, and more preferably 10 μm or less. Is most preferred.

  The lithium ion conductive inorganic powder or the oxide glass powder that exhibits lithium ion conductivity by heat treatment can be produced by pulverizing the above lithium ion conductive inorganic substance or oxide glass with a ball mill, a jet mill or the like. The average particle diameter of the lithium ion conductive inorganic powder or the oxide glass powder that exhibits lithium ion conductivity by heat treatment when included in the mixed slurry for producing the solid electrolyte green sheet is 5 μm or less in order to increase the filling rate. Preferably, the thickness is 3 μm or less, more preferably 1 μm or less. The lower limit of the average particle size of the lithium ion conductive inorganic powder is preferably 0.01 μm or more, more preferably 0.05 μm or more, and more preferably 0.1 μm or more in order to disperse uniformly. Most preferred.

Here, the average particle diameter is a value of D ₅₀ (cumulative volume fraction 50% diameter) when measured by a laser diffraction method, and the measuring apparatus used is specifically a particle size analyzer manufactured by Nikkiso Co., Ltd. A value measured by Microtrac MT3300EXII or Beckman Coulter Submicron Particle Analyzer N5 can be used. The average particle diameter is a value expressed on a volume basis. The above-described measuring apparatus is properly used depending on the particle size of the object to be measured. When the maximum particle size of the object to be measured is less than 3 μm, measurement is performed using only the submicron particle analyzer N5. When the minimum particle size of the object to be measured is 0.4 μm or more, the measurement is performed using Microtrack MT3300EXII.

[Conductive aid for positive electrode or negative electrode]
By including a conductive additive in at least one of the positive electrode and the negative electrode, the electron conductivity in the electrode is improved, so that the thickness of the electrode can be increased and the battery capacity can be improved. In the case where an electrode is produced by sintering, the conductive assistant is carbon, or aluminum, copper, titanium, molybdenum, tungsten, nickel, zinc, magnesium, tantalum, iron, chromium, palladium, platinum, rhodium, One or more metals and alloys or metal oxides selected from indium and tin are preferable. In order to include these conductive additives in the electrode, it is preferable to include the powder of the material in a green sheet for producing the electrode. As the carbon, acetylene black and carbon nanofiber (VGCF (registered trademark) manufactured by Showa Denko KK) are preferably used. The carbon referred to here may include carbon that becomes carbon after firing.
The active material for the negative electrode may have electronic conductivity that can be used as a battery. In this case, a conductive aid is not necessarily required for the negative electrode. It is more important that at least the positive electrode contains a conductive additive.

  The average particle size of the conductive auxiliary agent powder contained in the electrode green sheet is preferably 5 μm or less, preferably 3 μm or less in order to improve the mixing with the active material powder in the electrode green sheet. Most preferably, it is 1 μm or less. The lower limit of the average particle diameter is not particularly limited, but is preferably 1 nm or more from the viewpoint of industrial availability and easy dispersion.

  Further, the amount of the conductive auxiliary agent contained in the green sheet is preferably 30% by mass or less, more preferably 25% by mass, most preferably 20% by mass or less with respect to the amount of the active material in order not to reduce the capacity. . The lower limit is preferably 0.1% by mass or more, more preferably 0.5% by mass, and most preferably 1% by mass or more in order to impart good electron conductivity.

[Positive electrode]
As an active material used for the positive electrode, a metal compound capable of occluding and releasing Li ions can be used, and a metal oxide or transition metal oxide containing Li is preferable, for example, manganese, cobalt, nickel, vanadium, A metal oxide containing at least one selected from niobium, molybdenum, titanium, iron, phosphorus, aluminum, and chromium can be used. The green sheet for producing the positive electrode can contain the above-mentioned active material powder in the green sheet. These active materials are not necessarily required to have high conductivity, but it is preferable to occlude and release a large amount of lithium. For example, a structure such as Li _x M _y O _z can be taken (M means manganese, cobalt, nickel, vanadium, niobium, molybdenum, titanium, iron, aluminum, chromium, and O means oxygen, phosphorus, Meaning acid, silicic acid, boric acid). On the other hand, the conductive assistant has the ability to conduct electrons, but does not necessarily have a high ability to occlude or release lithium. As for the electronic conductivity of a conductive support agent, 10 ^<-2 > Scm ^{< -1} > or more is preferable.

  The lower limit value of the content of the active material contained in the positive electrode green sheet is preferably 40 wt% or more, more preferably 50 wt% or more, because if the amount is small, the battery capacity per unit volume decreases after firing. Preferably, it is most preferably 60 wt% or more. Further, the content of the active material contained in the positive electrode green sheet is preferably 97 wt% or less, more preferably 94 wt% or less, and more preferably 90 wt%, because if the content is too large, flexibility is lost and handling becomes difficult. Most preferably:

  In order to obtain a positive electrode green sheet having the active material content and to prepare a slurry that can be satisfactorily applied, a mixture comprising positive electrode active material powder, inorganic powder, organic binder, plasticizer, solvent, etc. The amount of the positive electrode active material is preferably 10 wt% or more, more preferably 15 wt% or more, and most preferably 20 wt% or more with respect to the amount of slurry. In order to prepare a slurry that can be satisfactorily applied, the upper limit value of the content of the active material is preferably 90 wt% or less, more preferably 80 wt% or less, based on the amount of the mixed slurry. 75 wt% or less is most preferable.

[Negative electrode]
Active materials used for the negative electrode include alloys capable of occluding and releasing Li ions such as aluminum, silicon and tin, metal oxides or transition metal oxides containing Li, such as titanium, vanadium, chromium, niobium and silicon. An oxide or a material such as graphitizable carbon such as graphite or coke can be used. The green sheet for producing the negative electrode can contain the above-mentioned active material powder in the green sheet. Further, a furfuryl alcohol resin, a phenol resin, or the like that becomes graphite or graphitizable carbon after firing may be included in the green sheet. These metals, their compounds, graphite, and the like function as active materials, but there is a possibility that physical contact is lost due to expansion and contraction due to charge and discharge, and resistance increases. In order to avoid this, it is preferable to add a metal having high bonding property, VGCF (registered trademark) having a long chain, or the like as a conductive assistant because it is considered that the formation of a network becomes easier.

  The lower limit value of the content of the active material contained in the negative electrode green sheet is preferably 40 wt% or more, more preferably 50 wt% or more, since the battery capacity per unit volume decreases if the amount is small. Most preferably, it is 60 wt% or more. Further, the content of the active material contained in the negative electrode green sheet is preferably 97 wt% or less, more preferably 94 wt% or less, and more preferably 90 wt%, because if the content is too large, flexibility is lost and handling becomes difficult. Most preferably:

  In order to obtain a negative electrode green sheet having the above-mentioned active material content and to prepare a slurry that can be applied satisfactorily, a mixture comprising negative electrode active material powder, inorganic powder, organic binder, plasticizer, solvent, etc. The amount of the negative electrode active material is preferably 10 wt% or more, more preferably 15 wt% or more, and most preferably 20 wt% or more with respect to the amount of slurry. The upper limit of the content of the active material needs to be slurried using a binder or a solvent, and is preferably 90 wt% or less, and preferably 80 wt% or less with respect to the amount of the mixed slurry. More preferably, it is most preferable to set it as 75 wt% or less.

  Here, the positive electrode active material and the negative electrode active material are not absolute. That is, a battery having an arbitrary voltage can be configured by using the positive and negative electrodes that show a more noble potential by comparing the charge and discharge potentials of two types of metal oxides, respectively. it can. When a transition metal oxide is used for the positive electrode active material and the negative electrode active material, metal lithium does not precipitate even when the battery is overcharged, and the reliability of the battery is improved.

  For the positive electrode or negative electrode, (i) the active material powder and the binder component are mixed and dispersed in water or a solvent in which the molding aid is dissolved, and if necessary, a plasticizer and a dispersing agent are mixed to form a slurry. A method of adjusting and applying this slurry onto a substrate film and drying, (ii) adding a molding aid to a premixed mixture in the same manner as described above, and granulating it with a press machine A method of pressure forming, (iii) a method of pressure forming with a roll press machine and processing into a sheet shape, or the like is used.

  FIG. 2 schematically shows a cross section of the all-solid-state lithium ion secondary battery 10 according to one embodiment of the present invention. A positive electrode 14 is disposed on the upper side and a negative electrode 16 is disposed on the lower side with a layer made of the solid electrolyte 12 interposed therebetween. Oxides 18 and 20 are arranged in layers at each electrode electrolyte boundary, and ions such as lithium ions 26 can be passed during charging or discharging. In addition, a positive electrode current collector 22 and a negative electrode current collector 24 are disposed above the positive electrode 14 and below the negative electrode 16, respectively. Except that the oxides 18 and 20 are arranged, the process is the same as in the case of FIG.

[Compound containing oxygen or P]
The compound 18 containing oxygen or P provided at the electrode electrolyte boundary between the positive electrode 14 and the solid electrolyte 12 hardly reacts with the electrode material (including the active material) and the solid electrolyte 12 of the positive electrode 14 and has ion conductivity or ion permeability. You may have. The compound containing oxygen can contain an oxide, for example, and can contain glass ceramics as described above. The compound containing P may include phosphoric acid, a phosphoric acid compound, and the like. Here, it is difficult to react, and even if it is a pressure range of 0.1 MPa to 1000 MPa for 1 minute to 10 hours in a temperature range of 300 ° C. to 1000 ° C., almost no reaction layer is seen. Alternatively, it may mean that the thickness of the reaction layer is 1 μm or less. Moreover, since this compound needs to permeate | transmit lithium ion, it is preferable that an ion conductivity is 1 * 10 < ^-4 > S * cm < ^-1 > or more, and it is 5 * 10 < ^-4 > S * cm < ^-1 > or more. More preferably, it is more preferably 1 × 10 ⁻³ S · cm ⁻¹ or more.

  The compound 20 containing oxygen or P provided at the electrode electrolyte boundary between the negative electrode 16 and the solid electrolyte 12 hardly reacts with the electrode material (including the active material) or the solid electrolyte 12 of the negative electrode 16 and has ion conductivity or ion permeability. You may have. Such a compound 20 can have the same or substantially the same composition and properties as the above-described compound 18, and therefore, details are omitted here.

  For convenience, in FIG. 2, these compounds 18 and 20 are expressed in a flat layer shape. However, the compound is not limited to a flat shape, and a free curve may be drawn in a cross section. Further, such layers of the compounds 18 and 20 may be perforated. However, since predetermined ion conductivity or ion permeability is required between the positive electrode 14 or the negative electrode 16 and the solid electrolyte 12, a shape (average and / or maximum) thickness, porosity, or It is preferable to have an aperture ratio. For example, the average thickness between the positive electrode 14 or the negative electrode 16 and the solid electrolyte 12 is preferably 10 μm or less, more preferably 5 μm or less, and still more preferably 1 μm or less.

  Although an example in which a layer is sandwiched between an electrode and an electrolyte has been described here, the present invention is not limited to this. For example, when the surface of the active material of the positive electrode or the negative electrode is coated, the reaction with the contacted solid electrolyte is suppressed. Accordingly, if the surface of the positive or negative electrode active material is coated with a compound containing oxygen or phosphorus and collected at the electrode electrolyte boundary, the same effect can be expected.

FIG. 3 is a diagram illustrating an example of a process for manufacturing an all-solid lithium ion secondary battery. Hereinafter, a method for manufacturing the all-solid-state lithium ion secondary battery assembly will be briefly described. First,
A solid electrolyte green sheet 52, a positive electrode green sheet 54, a negative electrode green sheet 56, a positive electrode current collector green sheet 58, and a negative electrode current collector green sheet 60 are prepared. Next, the solid electrolyte green sheet 52 is sandwiched between the positive electrode green sheet 54 and the negative electrode green sheet 56, and further, on the upper side of the positive electrode green sheet 54 and the lower side of the negative electrode green sheet 56, respectively, The negative electrode current collector green sheet 60 is arranged and laminated to produce the battery element 28. The battery element 28 is prepared by stacking a plurality of appropriate solid electrolyte green sheets 52, positive electrode green sheets 54, negative electrode green sheets 56, positive electrode current collector green sheets 58, and negative electrode current collector green sheets 60. Including doing. Here, a plurality of battery elements 28 are stacked so that the positive electrode current collector green sheet 58 or the negative electrode current collector green sheet 60 is shared, and this is pressed to produce the stacked portion 30. When this laminated part 30 is baked, the all-solid-state lithium ion secondary battery 10 can be manufactured.

[Experimental Example 1]
A battery was fabricated by applying the above steps. Hereinafter, experimental examples will be described more specifically.

[Production of oxide glass powder green sheet]
An oxide glass powder green sheet was prepared as a solid electrolyte green sheet.

H ₃ PO ₄ , Al (PO ₃ ) ₃ , Li ₂ CO ₃ , SiO ₂ , and TiO ₂ are used as raw materials, and these are mol% in terms of oxide, 33.9% of P ₂ O ₅ , Al ₂ O ₃ is 7.5%, Li ₂ O is 14.5%, TiO ₂ is 41.3%, and SiO ₂ is 2.8%. The glass melt was heated and melted for 3 hours at 1450 ° C. in an electric furnace while stirring. Thereafter, the glass melt was dropped into running water to obtain flaky glass. The glass flakes were pulverized with a jet mill to obtain glass fine particles having an average particle diameter of 1.9 μm. Further, the mixture was finely pulverized using a wet ball mill with ethanol, and the slurry was further dried by spray drying to obtain glass microparticles having an average particle size of 0.3 μm.

  A dispersant was added to the acrylic resin dispersed in the glass fine particles and water, and stirred for 48 hours with a ball mill to prepare a slurry. The glass fine particles contained in the slurry at this time were 65.5 wt%, and the acrylic resin was 18.5 wt%. This slurry was applied at a speed of 0.3 m / min by the doctor blade method, formed to a thickness of 12 μm on a PET film that had been subjected to a release treatment, and primary dried at 80 ° C. and then secondary dried at 95 ° C. The oxide glass powder green sheet was obtained.

[Preparation of positive electrode green sheet]
The flaky glass was heat-treated at 950 ° C. for 12 hours, and the main crystal phase was Li _{1 + x + z} Al _x Ti _2−x Si _z P _3−z O ₁₂ (0 ≦ x ≦ 0.4, y = 0, 0 <z ≦ 0.6), a flaky solid electrolyte having an ionic conductivity of 1.0 × 10 ⁻³ Scm ⁻¹ was obtained. Using this flaky solid electrolyte, a powdery solid electrolyte having an average particle size of 0.4 μm was obtained using a jet mill and a wet ball mill. Here, a commercially available LiCoO ₂ having an average particle size of 3.0 μm is used as a positive electrode active material, the powdered solid electrolyte is used as an ion conduction aid, and a commercially available tungsten particle having an average particle size of 1.1 μm is used as a conduction aid. The powder solid electrolyte: LiCoO ₂ : tungsten particles = 20: 70: 10 were mixed until uniform by a ball mill. A dispersant was added to the composite obtained here and the acrylic resin dispersed in water, and the mixture was stirred for 48 hours with a ball mill to prepare a slurry. The composite contained in the slurry at this time was 64.5 wt%, and the acrylic resin was 17.7 wt%. This slurry was applied at a speed of 0.3 m / min by the doctor blade method, formed to a thickness of 45 μm on a PET film that had been subjected to a release treatment, and primary dried at 80 ° C., and then secondary dried at 95 ° C. A positive green sheet was obtained. Here, the lithium storage capacity of LiCoO ₂ was about 130 mAh / g (the same applies to the following experiments), and the electronic conductivity of tungsten was about 2 × 10 ⁹ S · cm ⁻¹ .

[Production of negative electrode green sheet]
A commercially available Li _4/3 Ti _5/3 O ₄ having an average particle diameter of 7.5 μm, which is pulverized to an average particle diameter of 2.5 μm using a ball mill, is used as the negative electrode active material, and the powdered solid electrolyte is assisted by ion conduction. And a commercially available nickel fiber having an average diameter of 2.0 μm as a conductive additive, so that the weight ratio of powdered solid electrolyte: Li _4/3 Ti _5/3 O ₄ : nickel fiber = 20: 75: 5 Was mixed with a ball mill until uniform. The composite obtained here, an acrylic resin dispersed in water, and a dispersant were stirred for 48 hours by a ball mill to prepare a slurry. The composite contained in the slurry at this time was 60.8 wt%, and the acrylic resin was 16.8 wt%. This slurry was applied by a doctor blade method at a speed of 0.3 m / min, formed to a thickness of 43 μm on a PET film that had been subjected to a release treatment, and primary dried at 80 ° C., and then secondary at 95 ° C. Drying was performed to obtain a negative electrode green sheet. Here, the lithium storage capacity of Li _4/3 Ti _5/3 O ₄ was about 175 mAh / g (the same applies to the following experiment), and the electronic conductivity of nickel was about 20 S · cm ⁻¹ .

[Preparation of positive electrode current collector green sheet and negative electrode current collector green sheet]
Polyvinylidene fluoride (Pvdf) is added to N-methylpyrrolidone (NMP), dissolved and stirred for 8 hours with a biaxial mixer, and copper oxide (Wako Pure Chemical, average particle size 2 μm) and graphite (SEC carbon, average particle size 3 μm) After stirring for 12 hours, it was coated at a speed of 0.3 m / min by the doctor blade method, formed to a thickness of 15 μm on the PET film subjected to the release treatment, and primary dried at 80 ° C., and further 90 ° C. Secondary drying was performed to obtain a positive electrode current collector green sheet and a negative electrode current collector green sheet. Here, the added copper oxide and graphite react at the time of firing, and copper is generated to become a current collector. If there is excess graphite, it can function as a current collector.

[Production of green sheet laminate]
Each green sheet obtained above was cut into 50 mm squares, and a negative electrode current collector green sheet / negative electrode green sheet / oxide glass powder green sheet (solid electrolyte green sheet) / positive electrode green sheet / positive electrode current collector green sheet. In this order, the upper and lower surfaces are sandwiched between PET films that have been subjected to a release treatment, placed on a 1 mm SUS plate, vacuum packed, and pressurized at 196.1 MPa for 10 minutes using a CIP (cold isotropic pressure device). To obtain a green sheet laminate. At this time, each green sheet is composed of one negative current collector green sheet, two negative green sheets, one oxide glass powder green sheet, two positive green sheets, and positive current collector green. One sheet was used.

[Heat treatment of green sheet laminate and production of all solid lithium ion battery]
The green sheet laminate obtained above was heated from room temperature to 480 ° C. and held for 2 hours, and then rapidly heated to 900 ° C. After maintaining at 900 ° C. for 3 minutes, the temperature was rapidly lowered to 600 ° C., and then gradually cooled to room temperature to obtain a laminated sintered body including a current collector, an electrode, and a solid electrolyte. At this time, the thickness of each layer was 72 μm for the positive electrode, 9 μm for the solid electrolyte, 67.5 μm for the negative electrode, and 9 μm for the positive electrode current collector and the negative electrode current collector. Further, a SUS foil was connected as a positive electrode lead on the positive electrode side, a SUS foil was connected as a negative electrode lead on the negative electrode side, and the inside was sealed in an aluminum laminate film with an insulation coating, to prepare a lithium ion battery. The produced battery had an average driving voltage of 2.5 V and a capacity of 2.2 mAh / cm ² .

[Experiment 2]
[Preparation of positive electrode green sheet]
The flaky glass was heat-treated at 950 ° C. for 12 hours, and the main crystal phase was Li _{1 + x + z} Al _x Ti _2−x Si _z P _3−z O ₁₂ (0 ≦ x ≦ 0.4, y = 0, 0 <z ≦ 0.6), a flaky solid electrolyte having an ionic conductivity of 1.0 × 10 ⁻³ Scm ⁻¹ was obtained. Using this flaky solid electrolyte, a powdery solid electrolyte having an average particle size of 0.4 μm was obtained using a jet mill and a wet ball mill. Here, a commercially available LiCoO ₂ having an average particle size of 3.0 μm is used as a positive electrode active material, the powdered solid electrolyte is used as an ion conduction aid, and a commercially available zinc oxide particle having an average particle size of 0.5 μm is used as a conduction aid. by weight, powdered solid electrolyte: LiCoO _2: zinc oxide particles = 20: 70: mixed until uniform using a ball mill so as to be 10. A dispersant was added to the acrylic resin in which the composite and water thus obtained were dispersed, and the mixture was stirred for 48 hours with a ball mill to prepare a slurry. The composite contained in the slurry at this time was 64.5 wt%, and the acrylic resin was 18.3 wt%. This slurry was applied at a speed of 0.3 m / min by the doctor blade method, formed to a thickness of 48 μm on a PET film subjected to a release treatment, and primary dried at 80 ° C., and then secondary dried at 95 ° C. A positive green sheet was obtained. Here, the electronic conductivity of zinc oxide was about 5 × 10 ³ S · cm ⁻¹ .

[Production of negative electrode green sheet]
A commercially available Li _4/3 Ti _5/3 O ₄ having an average particle diameter of 7.5 μm, which is pulverized to an average particle diameter of 2.5 μm using a ball mill, is used as the negative electrode active material, and the powdered solid electrolyte is assisted by ion conduction. A commercially available indium oxide particle having an average diameter of 0.1 μm was used as a conductive aid. By weight, powdered solid _electrolyte: Li _{4/3 Ti} 5/3 _{O 4:} indium oxide powder = 17: 75: was mixed to uniformity in a ball mill so that 8. The composite obtained here, an acrylic resin dispersed in water, and a dispersant were stirred for 48 hours by a ball mill to prepare a slurry. The composite contained in the slurry at this time was 61.0 wt%, and the acrylic resin was 17.5 wt%. This slurry was applied by a doctor blade method at a speed of 0.3 m / min, formed to a thickness of 45 μm on a PET film that had been subjected to a release treatment, and primary dried at 80 ° C., and then secondary dried at 95 ° C. To obtain a negative electrode green sheet. Here, the electronic conductivity of indium oxide was about 1 × 10 ² S · cm ⁻¹ .

[Preparation of positive electrode current collector green sheet and negative electrode current collector green sheet]
After adding polyvinylidene fluoride (Pvdf) to N-methylpyrrolidone (NMP), dissolving and stirring for 8 hours with a biaxial mixer, adding commercially available SUS powder (SUS430 powder) with an average particle size of 1.0 μm, and stirring for 12 hours, It is coated at a speed of 0.3 m / min by the doctor blade method, molded to a thickness of 15 μm on a PET film that has been subjected to a release treatment, primary dried at 80 ° C., and then secondary dried at 90 ° C. A current collector green sheet and a negative electrode current collector green sheet were obtained.

[Production of green sheet laminate]
The positive electrode green sheet, the negative electrode green sheet, the positive electrode current collector green sheet, the negative electrode current collector green sheet, and the oxide glass powder green sheet prepared in Experimental Example 1 were cut into 50 mm squares to obtain a negative electrode current collector. Stacked in the order of electrical green sheet / negative electrode green sheet / oxide glass powder green sheet (solid electrolyte green sheet) / positive electrode green sheet / positive electrode current collector green sheet, and sandwiched between upper and lower PET films with release treatment A green sheet laminate was obtained by placing on a 1 mm SUS plate and vacuum-packing, and pressurizing at 196.1 MPa for 10 min using a CIP (cold isostatic press). At this time, each green sheet is composed of one negative current collector green sheet, two negative green sheets, one oxide glass powder green sheet, two positive green sheets, and positive current collector green. One sheet was used.

[Heat treatment of green sheet laminate and production of all solid lithium ion battery]
Heat treatment was performed under the same conditions as in Experimental Example 1 to obtain a laminated sintered body. At this time, the thickness of each layer was 74 μm for the positive electrode, 9 μm for the solid electrolyte, 70 μm for the negative electrode, and 9 μm for the positive electrode current collector and the negative electrode current collector. Further, a SUS foil was connected as a positive electrode lead on the positive electrode side, a SUS foil was connected as a negative electrode lead on the negative electrode side, and the inside was sealed in an aluminum laminate film with an insulation coating, to prepare a lithium ion battery. The produced battery had an average driving voltage of 2.5 V and a capacity of 1.6 mAh / cm ² .

[Experiment 3]
[Preparation of positive electrode green sheet]
The flaky glass was heat-treated at 950 ° C. for 12 hours, and the main crystal phase was Li _{1 + x + z} Al _x Ti _2−x Si _z P _3−z O ₁₂ (0 ≦ x ≦ 0.4, y = 0, 0 <z ≦ 0.6), a flaky solid electrolyte having an ionic conductivity of 1.0 × 10 ⁻³ Scm ⁻¹ was obtained. Using this flaky solid electrolyte, a powdery solid electrolyte having an average particle size of 0.4 μm was obtained using a jet mill and a wet ball mill. Here, commercially available LiCoO ₂ having an average particle size of 3.0 μm is used as a positive electrode active material, the powdered solid electrolyte is used as an ion conduction aid, and acetylene black (Denka Black, average particle size of 35 nm) manufactured by Denki Kagaku Kogyo is electrically conductive. As an auxiliary agent, the mixture was mixed by a ball mill so that the powdered solid electrolyte: LiCoO ₂ : acetylene black = 25: 70: 5 by weight ratio. A dispersant was added to the acrylic resin in which the composite and water thus obtained were dispersed, and the mixture was stirred for 48 hours with a ball mill to prepare a slurry. The composite contained in the slurry at this time was 64.5 wt%, and the acrylic resin was 18.3 wt%. This slurry was applied at a speed of 0.3 m / min by the doctor blade method, formed to a thickness of 48 μm on a PET film subjected to a release treatment, and primary dried at 80 ° C., and then secondary dried at 95 ° C. A positive green sheet was obtained. Here, the electronic conductivity of carbon produced from acetylene black is estimated to be about 1 × 10 ² S · cm ⁻¹ (the same applies to the following experiments).

[Production of negative electrode green sheet]
A commercially available Li _4/3 Ti _5/3 O ₄ having an average particle diameter of 7.5 μm, which is pulverized to an average particle diameter of 2.5 μm using a ball mill, is used as the negative electrode active material, and the powdered solid electrolyte is assisted by ion conduction. An acetylene black (Denka Black, average particle size 35 nm) manufactured by Denki Kagaku Kogyo was used as a conductive aid. By weight, powdered solid _electrolyte: Li _{4/3 Ti} 5/3 _{O 4:} acetylene black = 20: 75: was mixed to uniformity in a ball mill to be 5. The composite obtained here, an acrylic resin dispersed in water, and a dispersant were stirred for 48 hours by a ball mill to prepare a slurry. The composite contained in the slurry at this time was 61.0 wt%, and the acrylic resin was 17.5 wt%. This slurry was applied by a doctor blade method at a speed of 0.3 m / min, formed to a thickness of 45 μm on a PET film that had been subjected to a release treatment, and primary dried at 80 ° C., and then secondary dried at 95 ° C. To obtain a negative electrode green sheet.

[Preparation of positive electrode current collector green sheet and negative electrode current collector green sheet]
Polyvinylidene fluoride (Pvdf) was added to N-methylpyrrolidone (NMP), dissolved and stirred for 8 hours with a biaxial mixer, scale-like graphite powder (SGP3) with an average particle size of 3.0 μm made of SEC carbon was added and stirred for 12 hours. After that, it was coated at a speed of 0.3 m / min by the doctor blade method, molded to a thickness of 15 μm on the PET film subjected to the release treatment, and primary dried at 80 ° C., and then secondary dried at 90 ° C. The positive electrode current collector green sheet and the negative electrode current collector green sheet were obtained.

[Production of green sheet laminate]
The positive electrode green sheet, the negative electrode green sheet, the positive electrode current collector green sheet, the negative electrode current collector green sheet, and the oxide glass powder green sheet prepared in Experimental Example 1 were cut into 50 mm squares to obtain a negative electrode current collector. Stacked in the order of electrical green sheet / negative electrode green sheet / oxide glass powder green sheet (solid electrolyte green sheet) / positive electrode green sheet / positive electrode current collector green sheet, and sandwiched between upper and lower PET films with release treatment A green sheet laminate was obtained by placing on a 1 mm SUS plate and vacuum-packing, and pressurizing at 196.1 MPa for 10 min using a CIP (cold isostatic press). At this time, each green sheet is composed of one negative current collector green sheet, two negative green sheets, one oxide glass powder green sheet, two positive green sheets, and positive current collector green. One sheet was used.

[Heat treatment of green sheet laminate and production of all solid lithium ion battery]
Heat treatment was performed under the same conditions as in Experimental Example 1 to obtain a laminated sintered body. At this time, the thickness of each layer was 50 μm for the positive electrode, 20 μm for the solid electrolyte, 50 μm for the negative electrode, and 50 μm for the positive electrode current collector and the negative electrode current collector. Further, a SUS foil was connected as a positive electrode lead on the positive electrode side, a SUS foil was connected as a negative electrode lead on the negative electrode side, and the inside was sealed in an aluminum laminate film with an insulation coating, to prepare a lithium ion battery. The produced battery had an average driving voltage of 2.8 V and a capacity of 2.0 mAh / cm ² .

[Experimental Example 4]
[Production of green sheet laminate]
The various green sheets obtained in Experimental Example 1 were cut into 50 mm squares, and one positive electrode current collector green sheet / two positive electrode green sheets / one oxide glass powder green sheet / two negative electrode green sheets / negative electrode current collector. 1 green body sheet (shared with positive electrode current collector green sheet) / 2 positive electrode green sheets / 1 oxide glass powder green sheet / 2 negative electrode green sheets / 1 negative electrode collector green sheet in this order Green sheet laminate by sandwiching the upper and lower surfaces with a release-treated PET film, placing it on a 1 mm SUS plate, vacuum-packing, and pressurizing at 196.1 MPa for 10 min using a CIP (cold isostatic press) Got.

[Heat treatment of green sheet laminate and production of all solid lithium ion battery]
Heat treatment was performed under the same conditions as in Experimental Example 1 to obtain a laminated sintered body. At this time, the thickness of each layer was 74 μm for the positive electrode, 9 μm for the solid electrolyte, 70 μm for the negative electrode, and 9 μm for the positive electrode current collector and the negative electrode current collector. Further, a SUS foil was connected as a positive electrode lead on the positive electrode side, a SUS foil was connected as a negative electrode lead on the negative electrode side, and the inside was sealed in an aluminum laminate film with an insulation coating, to prepare a lithium ion battery. The produced battery had an average driving voltage of 2.5 V and a capacity of 1.5 mAh / cm ² .

[Comparative Example 1]
[Production of oxide glass powder green sheet]
The glass flakes obtained during the production of the glass fine particles of Experimental Example 1 were pulverized with a jet mill to obtain glass fine particles having an average particle diameter of 1.9 μm. Further, the mixture was finely pulverized using a wet ball mill with ethanol, and the slurry was further dried by spray drying to obtain glass fine particles having an average particle diameter of 0.17 μm.

  A dispersant was added to the glass fine particles and acrylic resin dispersed in water, and the mixture was stirred with a ball mill for 48 hours to prepare a slurry. The glass fine particles contained in the slurry at this time were 63.4 wt%, and the acrylic resin was 21.5 wt%. The slurry is applied by gravure printing at a speed of 0.5 m / min, formed on a PET film that has been subjected to a mold release treatment to a thickness of 6 μm, primarily dried at 80 ° C., and further dried at 95 ° C. A green sheet was obtained.

[Preparation of positive electrode green sheet]
The flaky glass was heat-treated at 950 ° C. for 12 hours, and the main crystal phase was Li _{1 + x + z} Al _x Ti _2−x Si _z P _3−z O ₁₂ (0 ≦ x ≦ 0.4, y = 0, 0 <z ≦ 0.6), a flaky solid electrolyte having an ionic conductivity of 1.0 × 10 ⁻³ Scm ⁻¹ was obtained. Using this flaky solid electrolyte, a powdery solid electrolyte having an average particle size of 0.4 μm was obtained using a jet mill and a wet ball mill. Here, a commercially available LiCoO ₂ having an average particle diameter of 3.0 μm was finely pulverized using a wet ball mill and further dried by spray drying to obtain a positive electrode active material having an average particle diameter of 0.4 μm. Here, the mixture was mixed by a ball mill so that the powdered solid electrolyte: LiCoO ₂ = 30: 70 by weight ratio. A dispersant was added to the composite obtained here and the acrylic resin dispersed in water, and a slurry was prepared by stirring for 48 hours with a ball mill. The composite contained in the slurry at this time was 63.5 wt%, and the acrylic resin was 19.5 wt%. This slurry was applied by gravure printing at a speed of 0.5 m / min, formed to a thickness of 6 μm on a PET film that had been subjected to a mold release treatment, primary dried at 80 ° C., and then secondary dried at 95 ° C. To obtain a positive electrode green sheet.

[Production of negative electrode green sheet]
Commercially available Li _4/3 Ti _5/3 O ₄ having an average particle diameter of 7.5 μm is finely pulverized using a jet mill and a wet ball mill, and the slurry is further dried by spray drying. A powder obtained by pulverizing to 2 μm is used as a negative electrode active material, and the powdered solid electrolyte is used as an ion conduction aid, so that the powdered solid electrolyte: Li _4/3 Ti _5/3 O ₄ = 30: 70 by weight ratio. Mix until uniform with a ball mill. The composite obtained here, an acrylic resin dispersed in water, and a dispersant were stirred for 48 hours with a ball mill to prepare a slurry. The composite contained in the slurry at this time was 61.7 wt%, and the acrylic resin was 18.5 wt%. This slurry was applied at a speed of 0.6 m / min by gravure printing, formed to a thickness of 7 μm on a PET film that had been subjected to a release treatment, and primary dried at 80 ° C. and then secondary dried at 95 ° C. To obtain a negative electrode green sheet.

[Production of green sheet laminate]
The oxide glass powder green sheet, positive electrode green sheet, and negative electrode green sheet obtained above were cut into 50 mm squares, and in the order of negative electrode green sheet / oxide glass powder green sheet (solid electrolyte green sheet) / positive electrode green sheet Piled up. At this time, since the green sheet group is low in strength and difficult to peel off from the PET film as a carrier, the surfaces of the green sheets are aligned in accordance with the above order in the film-formed state on a 1 mm SUS plate. Then, it was vacuum-packed and pressured at 196.1 MPa for 10 min using a CIP (cold isotropic pressure device). This process was repeated to obtain a green sheet laminate having a peelable strength from the PET film. At this time, the number of constituents of each green sheet was one negative green sheet, one oxide glass powder green sheet, and one positive green sheet.

[Heat treatment of green sheet laminate and production of all solid lithium ion battery]
The green sheet laminate obtained above was heat-treated under the conditions of Experimental Example 1 to obtain a laminated sintered body. At this time, the thickness of each layer was 4.8 μm for the positive electrode, 3.2 μm for the solid electrolyte, and 4.1 μm for the negative electrode. Here, aluminum was sputtered on the positive electrode side, copper on the negative electrode side, and a current collector was formed by sputtering with a thickness of 0.05 μm or more. Furthermore, an aluminum foil was connected as a positive electrode lead on the positive electrode side, a copper foil was connected as a negative electrode lead on the negative electrode side, and the lithium ion battery was fabricated by enclosing it in a laminate film that was insulated and coated on the inside. The produced battery had an average driving voltage of 2.5 V and a capacity of 0.2 mAh / cm ² .

[Comparative Example 2]
[Preparation of positive electrode green sheet]
The slurry containing the positive electrode active material obtained in the preparation of the positive electrode green sheet of Comparative Example 1 was applied at a speed of 0.3 m / min by the doctor blade method, and 14 μm on the PET film subjected to the release treatment. Molded to a thickness, primary dried at 80 ° C., and further secondary dried at 95 ° C. to obtain a positive electrode green sheet.

[Production of negative electrode green sheet]
The slurry containing the negative electrode active material obtained in the preparation of the negative electrode green sheet of Comparative Example 1 was applied at a speed of 0.3 m / min by the doctor blade method, and 15 μm on the PET film subjected to the release treatment. Molded to a thickness, primary dried at 80 ° C., and further secondary dried at 95 ° C. to obtain a negative electrode green sheet.

[Production of green sheet laminate]
The positive electrode green sheet and the negative electrode green sheet obtained above were cut into 50 mm squares, and the oxide glass powder green sheet, the positive electrode current collector green sheet, and the negative electrode current collector green sheet prepared in Experimental Example 1 were used as the negative electrode current collector. Body green sheet / negative electrode green sheet / oxide glass powder green sheet (solid electrolyte green sheet) / positive electrode green sheet / positive electrode current collector green sheet are stacked in this order, and the upper and lower surfaces are sandwiched between the PET films subjected to the release treatment, It was placed on a 1 mm SUS plate, vacuum packed, and pressed at 196.1 MPa for 10 min using a CIP (cold isostatic press) to obtain a green sheet laminate. At this time, each green sheet is composed of one negative electrode current collector green sheet, six negative electrode green sheets, one oxide glass powder green sheet, six positive electrode green sheets, and positive electrode current collector green. One sheet was used.

[Heat treatment of green sheet laminate and production of all solid lithium ion battery]
The green sheet laminate obtained above was heat-treated under the conditions of Experimental Examples 1 and 2 to obtain a laminated sintered body. At this time, the thickness of each layer was 69.5 μm for the positive electrode, 9 μm for the solid electrolyte, 72 μm for the negative electrode, and 9 μm for the positive electrode current collector and the negative electrode current collector. Further, a SUS foil was connected as a positive electrode lead on the positive electrode side, a SUS foil was connected as a negative electrode lead on the negative electrode side, and the inside was sealed in an aluminum laminate film with an insulation coating, to prepare a lithium ion battery. When the manufactured battery was charged under the same conditions as in Experimental Examples 1 and 2, it immediately reached the set potential and could not be charged, and no discharge was confirmed.

  As described above, in Experimental Examples 1 to 3, by including a metal, metal oxide, carbon, or the like as a conductive auxiliary agent, the internal resistance can be lowered, and operation is possible even when the electrode is thick. A large battery could be produced. On the other hand, in Comparative Example 1 in which no conductive assistant was used, the battery could be produced by thinning the positive electrode green sheet and the negative electrode green sheet, but the capacity could not be increased. Similarly, in Comparative Example 2 in which the positive electrode green sheet and the negative electrode green sheet were made to have the same thickness as Experimental Examples 1 and 2 without using a conductive additive, a battery could not be produced.

  In Experimental Example 1, since the positive electrode current collector green sheet and the negative electrode current collector green sheet contain copper powder having high heat resistance, the green sheet laminate can be sintered in the same atmosphere and the same temperature history. A battery could be produced.

DESCRIPTION OF SYMBOLS 10 All-solid-state lithium ion secondary battery 12 Solid electrolyte 14 Positive electrode 16 Negative electrode 18, 20 Oxide 22, 22a, 22b Positive electrode collector 24, 24a, 24b Negative electrode collector 26 Lithium ion 28, 28a, 28b Battery element 30 Stacking Part 52 Solid electrolyte green sheet 54 Positive electrode green sheet 56 Negative electrode green sheet 58 Positive electrode current collector green sheet 60 Negative electrode current collector green sheet 62 Insulating part

Claims (24)

  Including a battery element in which a positive electrode layer and a negative electrode layer are stacked with a solid electrolyte layer including a lithium ion conductive crystal in between, and a current collector layer is stacked on at least one of the positive electrode layer and the negative electrode layer. An all-solid lithium ion secondary battery.   The all-solid-state lithium ion secondary battery according to claim 1, wherein a conductive additive is contained in at least one of the positive electrode layer or the negative electrode layer.   The all-solid-state lithium ion secondary battery according to claim 2, wherein the conductive auxiliary agent contains carbon, metal, or metal oxide.   The conductive assistant is carbon or one or more metals selected from aluminum, copper, titanium, molybdenum, tungsten, nickel, zinc, magnesium, tantalum, iron, chromium, palladium, platinum, rhodium, indium, tin, and The all solid lithium ion secondary battery according to claim 2, comprising an alloy or a metal oxide.   The all-solid-state lithium ion secondary battery according to any one of claims 1 to 4, wherein an ion conduction assistant is included in at least one of the positive electrode layer or the negative electrode layer.   The all-solid-state lithium ion secondary battery according to claim 1, wherein a thickness of the positive electrode layer or the negative electrode layer exceeds 1 μm.   The all-solid-state lithium ion secondary battery according to claim 1, wherein the solid electrolyte layer has a thickness of 0.2 μm to 150 μm.   8. The all-solid-state lithium ion secondary battery according to claim 1, wherein the current collector layer has a thickness of 0.05 μm to 20 μm. The lithium ion conductive crystalline is _{Li 1 + x + z M x} (Ge 1-y Ti y) 2-x Si z P 3-z O 12 ( where, 0 ≦ x ≦ 0.8,0 ≦ y ≦ 1.0, The solid-state lithium ion secondary battery according to claim 1, wherein 0 ≦ z ≦ 0.6, M = one or more selected from Al and Ga).   A compound containing any component of O, P, or F between the solid electrolyte layer and the positive electrode layer or between the solid electrolyte layer and the negative electrode layer (hereinafter referred to as “electrode-electrolyte boundary layer”) The all-solid-state lithium ion secondary battery in any one of Claims 1-9 characterized by the above-mentioned.   The all-solid-state lithium ion secondary battery according to claim 1, wherein an insulating layer is laminated on at least one of the current collector layers.   The all-solid-state lithium ion secondary battery according to any one of claims 1 to 11, further comprising a stacked portion in which a plurality of the battery elements are stacked.   The all-solid-state lithium ion secondary battery according to claim 12, wherein the stacked portion is formed by stacking the flat battery elements.   The all-solid-state lithium ion secondary battery according to claim 12, wherein the battery element is wound in the stacked portion.   The all-solid-state lithium ion secondary battery according to claim 12, wherein the battery element is folded in the stacked portion.   The all-solid-state lithium ion secondary battery according to claim 15, wherein the laminated portion has the battery element folded evenly. A step of producing an electrolyte green sheet, a positive electrode green sheet, and a negative electrode green sheet containing lithium ion conductive inorganic powder or oxide glass powder expressing lithium ion conductivity by heat treatment;
Sandwiching the electrolyte green sheet, the positive green sheet and the negative green sheet are laminated,
A step of producing a battery element green sheet by laminating a collector green sheet on at least one of a positive electrode green sheet or a negative electrode green sheet;
Laminating the battery element green sheets to produce a laminate;
And a step of firing the laminate. A method for producing an all-solid-state lithium ion secondary battery.   The method for producing an all-solid-state lithium ion secondary battery according to claim 17, further comprising a step of incorporating a conductive additive into at least one of the positive electrode green sheet or the negative electrode green sheet.   The method for producing an all-solid-state lithium ion secondary battery according to claim 17 or 18, wherein an ion conduction assistant is contained in at least one of the positive electrode green sheet or the negative electrode green sheet.   The method for producing an all-solid-state lithium ion secondary battery according to any one of claims 17 to 19, wherein the step of producing the laminate includes a step of laminating a plurality of the battery element green sheets.   21. The method for producing an all-solid-state lithium ion secondary battery according to any one of claims 17 to 20, wherein the step of manufacturing the laminate includes a step of winding and laminating the battery element green sheets.   21. The method for producing an all-solid-state lithium ion secondary battery according to claim 17, wherein the step of producing the laminate includes a step of folding and laminating the battery element green sheets. The lithium ion conductive inorganic powder is Li _{1 + x + z} M _x (Ge _1−y Ti _y ) _2−x Si _z P _3−z O ₁₂ (where 0 ≦ x ≦ 0.8, 0 ≦ y ≦ 1. The crystal of an all-solid-state lithium ion secondary battery according to any one of claims 17 to 22, comprising a crystal of 0, 0≤z≤0.6, one or more selected from M = Al, Ga). Production method. The oxide glass powder is expressed in mol% based on oxide,
Li ₂ O 10-25%, and Al ₂ O ₃ and / or Ga ₂ O ₃ 0-15%, and TiO ₂ and / or GeO ₂ 25-50%, and SiO ₂ 0-15%, and P ₂ O ₅ 26-40%
Each of these components is included, The manufacturing method of the lithium ion secondary battery in any one of Claims 17-23 characterized by the above-mentioned.

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