Electrode for solid-state battery and method for manufacturing the same, solid-state battery and method for manufacturing the same, battery package

Abstract

Provided is a solid-state battery electrode for use in solid-state batteries that has better performance. The solid-state battery electrode comprises: a plurality of active material particles; a resin containing at least one of the group consisting of polyimides, polyamides and polyamide-imides, and containing a carbide in a part thereof; and an inorganic solid-state electrolyte comprising a lithium salt containing at least one element selected from the group consisting of B (boron), C (carbon), S (sulfur), and Cl (chlorine).

Description

[Technical Field]

[0001] The present technology relates to an electrode for a solid-state battery having a solid electrolyte and a manufacturing method thereof, a solid-state battery and a manufacturing method thereof, and a battery package. [Background technology]

[0002] Due to the widespread use of various electronic devices such as mobile phones, secondary batteries have been developed as power sources that are small, lightweight, and capable of achieving high energy density. These secondary batteries include a positive electrode, a negative electrode, and an electrolyte housed inside an exterior member. In recent years, solid-state batteries, which are secondary batteries that include a solid electrolyte instead of a liquid or gel electrolyte containing an organic solvent, have been developed (see, for example, Patent Documents 1 and 2 and Non-Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 092370 [Patent Document 2] Special Publication No. 2019-537221 [Non-patent literature]

[0004] [Non-Patent Document 1] “All-solid-state lithium ion battery using garnet-type oxide and Li3BO3 solid electrolytes fabricated by screen-printing”, Shingo Ohta et al., Journal of Power Sources 238 (2013) 53-56 [Non-patent document 2] “Formation of interfacial contact with ductile Li3BO3-based electrolytes for improving cyclability in all-solid-state batteries” Kenji Nagao et al., Journal of Power Sources 424 (2019) 215-219 Summary of the Invention

[0005] As described in the above-mentioned prior art documents, various studies have been conducted to improve the performance of solid-state batteries, but there is still room for improvement in the performance of solid-state batteries.

[0006] Therefore, there is a demand for solid-state battery electrodes that can be used in solid-state batteries with better performance.

[0007] An electrode for a solid state battery according to one embodiment of the present disclosure includes a plurality of active material particles, a resin containing at least one selected from the group consisting of polyimide, polyamide, and polyamideimide, and also containing a carbide in part, and an inorganic solid electrolyte containing a lithium salt containing at least one element selected from the group consisting of B (boron), C (carbon), S (sulfur), and Cl (chlorine).

[0008] According to an embodiment of the solid-state battery electrode of the present disclosure, active material particles are firmly connected to each other by a highly adhesive resin such as polyimide. Furthermore, since the resin contains a carbide in part, a good conductive network is formed while maintaining elasticity (flexibility). Therefore, when applied to a solid-state battery, superior performance such as high capacity and high output can be achieved.

[0009] Note that the effects of the present disclosure are not necessarily limited to the effects described here, but may be any of a series of effects related to the present disclosure described below. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating a configuration example of an electrode for a solid state battery according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a flow chart showing an example of a manufacturing process for the electrode for the solid state battery shown in FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the configuration of a battery package according to a second embodiment of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view illustrating the configuration of the solid-state battery shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing a structural example of the solid electrolyte layer shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order. 0. Overview of this Disclosure 1. First embodiment 1.1 Structure of electrodes for solid-state batteries 1.2 Manufacturing method for electrodes for solid-state batteries 1.3 Functions and effects of electrodes for solid-state batteries 2. Second embodiment 2.1 Battery package 2.2 Solid state batteries 2.3 Covering 2.4 Battery package manufacturing method 2.5 Action and effect 3. Battery package applications 4. Working Example The "solid-state battery" of the present disclosure refers to a battery whose components are solid. For example, the "solid-state battery" of the present disclosure is a stacked solid-state battery formed by stacking multiple layers. The multiple layers are made of, for example, a sintered body. The "solid-state battery" of the present disclosure encompasses not only secondary batteries that can be repeatedly charged and discharged, but also primary batteries that can only be discharged. Furthermore, the "electrode for a solid-state battery" of the present disclosure can also be applied to wound-type batteries (for example, coin-type, cylindrical-type, or pouch-type).

[0012] [0. Summary of this Disclosure] First, an overview of the present disclosure will be described. Various studies have been conducted to improve the performance of solid-state batteries. For example, Patent Document 1 discloses a solid-state battery in which a solid electrolyte layer or the like contains a material with a glass transition temperature of 500°C or lower at a predetermined volume ratio, thereby ensuring stable operation. Non-Patent Document 1 also discloses a technique for forming a positive electrode having a good interface between the active material and the solid electrolyte by applying a mixed slurry containing Li3BO3, which melts at 700°C, to a solid electrolyte and a positive electrode active material, and then heating the mixture to 700°C to melt and impregnate the material. Non-Patent Document 2 also discloses a technique for forming a high-density solid electrolyte-containing positive electrode by using a composite glass body (solid electrolyte) of Li3BO3 and Li2SO4, which has a lower hardness than Li3BO3, and pressing it under an ultra-high pressure of 720 MPa at room temperature.

[0013] However, the techniques described in the above-mentioned prior art documents are not considered to have high conductivity, and therefore are not suitable for thickening the positive electrode (e.g., a thickness of 20 μm or more). For example, in the technique described in Non-Patent Document 1, the conductive additive particles are also impregnated with the insulator Li3BO3, which is expected to result in insufficient conductivity of the positive electrode when the positive electrode is made thicker. In addition, in the technique described in Non-Patent Document 2, the composite glass body inhibits contact formation of the conductive additive, which is expected to result in insufficient conductivity of the positive electrode when the positive electrode is made thicker. It should be noted that the technique described in Patent Document 1 can also be improved by adding a conductive additive. However, increasing the amount of conductive additive added can lead to embrittlement of the electrode, raising concerns about issues such as electrode cracking during the battery formation process.

[0014] Furthermore, Patent Document 2 discloses a technique for forming a positive and negative electrode containing a solid electrolyte by embedding a solid electrolyte and an active material in an electrospun nonwoven fabric. However, the method of Patent Document 2 involves complicated steps such as forming an electrospun nonwoven fabric and embedding an electrode material slurry. Furthermore, the nonwoven fabric is filled with a solid electrolyte at a concentration of 1 mg / cm.2 Embedding the electrode material uniformly with the accuracy below this level is difficult in manufacturing and is not suitable for mass production. Furthermore, because a powdered solid electrolyte is embedded, it is difficult to form a good interface between the active material and the solid electrolyte.

[0015] In view of the above circumstances, the present applicant proposes an electrode for a solid state battery having higher conductivity, and a solid state battery using the electrode, as described below.

[0016] 1. First Embodiment 1.1 Structure of electrodes for solid-state batteries A solid state battery electrode 1 according to a first embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view illustrating a configuration example of the solid state battery electrode 1. The solid state battery electrode 1 includes a plurality of active material particles 2, a resin 3, and a solid electrolyte 4.

[0017] The active material particles 2 are not particularly limited, but include a positive electrode material or a negative electrode material that can occlude and release an electrode reactant such as lithium ions.

[0018] The resin 3 is provided so as to connect the plurality of active material particles 2 together. The resin 3 is a partially carbonized polymer compound containing at least one selected from the group consisting of polyimide, polyamide, and polyamideimide. That is, the resin 3 contains a carbonized imide. The partially carbonized polymer compound forms a conductive path connecting the plurality of active material particles 2 together. Here, "partially carbonized polymer compound" means that not all of the polymer compound constituting the resin 3 is carbonized to form C-C bonds, but imide bonds remain in the resin 3. Furthermore, voids may be formed within the resin 3. The voids within the resin 3 may be distributed, for example, throughout the solid battery electrode 1 and filled with the solid electrolyte 4. Note that "voids within the resin 3 are filled with the solid electrolyte 4" does not necessarily mean that the voids within the resin 3 are completely filled with the solid electrolyte 4, but also includes the case where some of the voids within the resin 3 are occupied by the solid electrolyte 4. The partial carbonization of the resin 3 can be detected, for example, by Raman spectroscopy. When resin 3 contains carbonized imide, the Raman spectrum shows a peak at 1350 cm -1 A peak appears around 1520 cm (carbon D band) and a peak appears around 1600 cm (carbon G band). The imide bonds contained in the resin 3 can be detected by, for example, a fluorescence method using a fluorometer or an infrared spectroscopy (FT-IR) method. In the fluorescence method, if imide bonds remain, fluorescence (emission) is detected in the visible light region. In the infrared spectroscopy, a peak appears around 1520 cm -1 Around 1775cm -1 A peak derived from the imide group can be detected near . In this way, in the solid state battery electrode 1, imide bonds remain in the resin 3, so the solid state battery electrode 1 exhibits high flexibility compared to a case where all of the polymer compounds constituting the resin 3 are carbonized to form C-C bonds. This flexibility can be evaluated by, for example, a bending test.

[0019] The solid electrolyte 4 contains a lithium salt containing at least one element selected from the group consisting of B (boron), C (carbon), S (sulfur), and Cl (chlorine). Specifically, the solid electrolyte 4 preferably contains at least one of Li2CO3, Li2SO4, Li3BO3, Li3OCl, and Li2OHCl as its main constituent material. The solid electrolyte 4 is provided in the gaps between the active material particles 2 so as to fill the gaps between the active material particles 2. The solid electrolyte 4 may also be present in voids present in the partially carbonized resin 3 or in the gaps between the resin 3 and the active material particles 2. However, the solid electrolyte 4 may contain voids within itself. Also, gaps may be formed between the solid electrolyte 4 and some of the active material particles 2. The solid electrolyte 4 preferably does not have a particle interface within itself. This is to achieve better conductivity as a solid-state battery electrode 1. The solid electrolyte 4 is formed by, for example, allowing a molten lithium salt obtained by melting the lithium salt described above to penetrate into the gaps between the active material particles 2 and then crystallizing the molten lithium salt.

[0020] <1.2 Manufacturing method of solid state battery electrode 1> Next, an example of a method for manufacturing the electrode 1 for a solid battery will be described with reference to FIG. 2. FIG. 2 is a flow chart showing an example of a manufacturing process of the electrode 1 for a solid battery. The electrode 1 for a solid battery can be formed, for example, by a green sheet method using a green sheet. One manufacturing method will be described below as an example, but the present technology is not limited to the manufacturing method described below. Furthermore, the chronological matters such as the order of description below are merely for the convenience of explanation, and the present technology is not limited to those matters.

[0021] First, active material particles, a resin, and a solvent are mixed to form a slurry (step S101). When forming the slurry, optional additives such as a conductive additive may be added. The resin is a polymer compound containing at least one selected from the group consisting of polyimide, polyamide, and polyamideimide. For example, when polyimide is used as the resin, a polyimide solution is prepared by dissolving the polyimide in NMP (N-methyl-2-pyrrolidone) as a solvent at a solid content of 18.6%. Next, the polyimide solution is added to the active material particles at a mixing ratio of approximately 10 to 30% by weight to form a mixed liquid. The mixed liquid is then stirred for a predetermined time using a hybrid mixer or the like to form a slurry. Alternatively, a mixture of active material particles and solid electrolyte powder may be added to the polyimide solution to form a mixed liquid.

[0022] Next, the slurry is applied onto the film, and then the applied slurry is dried in an oven or the like to form a green sheet (step S102). The film onto which the slurry is applied can be a release film made of polyethylene terephthalate (PET), a metal foil, or the like.

[0023] Next, the prepared green sheet is heated at a temperature of 800°C or less to partially carbonize the resin (step S103). This heating treatment can be performed by placing the green sheet in a vacuum furnace and performing it at a temperature of 700°C under a pressure of 10-2 Pa or less for one hour. This heating treatment forms a conductive network in which multiple active material particles 2 are bonded by a partially carbonized resin 3 such as polyimide. Partial carbonization of the resin through the heating treatment reduces the volume of the resin, creating voids within the resin 3. It is desirable that the voids formed within the resin 3 at this time become continuous pores that penetrate the entire green sheet in a tortuous path. This is because the molten solid electrolyte can more easily be impregnated in the next step S104. Furthermore, in step S103, the green sheet is preferably heated at a temperature of 550°C or more and 700°C or less. This is because the flexibility and conductivity of the green sheet after heating are further improved. If a release film is coated with the slurry in step S102, the release film is peeled off from the green sheet before the heating treatment.

[0024] Thereafter, the heated green sheet is impregnated with a molten solid electrolyte, for example, by dripping it (step S104). This allows the molten solid electrolyte to penetrate into the gaps between the active material particles 2 and the gaps between the active material particles 2 and the partially carbonized resin 3. As the molten solid electrolyte, a lithium molten salt containing at least one of Li2CO3, Li2SO4, Li3BO3, Li3OCl, and Li2OHCl is preferably used. Finally, a drying process is performed to crystallize the molten solid electrolyte.

[0025] This completes the manufacture of the solid-state battery electrode 1. The solid-state battery electrode 1 may have a laminated structure in which an active material layer containing an active material is provided on a current collector such as a metal foil. In such a laminated structure, for example, in step S102, a slurry is applied to a metal foil serving as a current collector and dried, and then in step S103, a heat treatment is performed on the laminate of the metal foil and the dried slurry. The heat treatment temperature may be adjusted depending on the type (melting point) of the metal foil. For example, if the metal foil is an aluminum foil, the heat treatment temperature is preferably 550°C or higher and 600°C or lower. Furthermore, if the metal foil is a stainless steel foil or copper foil, the heat treatment temperature is preferably 550°C or higher and 700°C or lower. In addition, when a green sheet is prepared in the form of a film rather than by applying a slurry to a metal foil, the green sheet prepared through steps S101 to S104 may be superimposed on a metal foil serving as a current collector and then integrated by press bonding to form a laminated structure.

[0026] <1.3 Functions and effects of electrodes for solid-state batteries> The solid-state battery electrode 1 of this embodiment includes a plurality of active material particles 2, a resin 3 containing at least one selected from the group consisting of polyimide, polyamide, and polyamideimide, and a partially carbonized resin, and a solid electrolyte 4 containing a lithium salt containing at least one element selected from the group consisting of B, C, S, and Cl. Therefore, the solid-state battery electrode 1 allows the active material particles 2 to be firmly connected to each other by the highly adhesive resin 3, such as polyimide. Furthermore, because the resin 3 is partially carbonized, the resin 3 has both elasticity and good conductivity. Therefore, the solid-state battery electrode 1 can form a good conductive network while maintaining elasticity. Therefore, when applied to a solid-state battery, the electrode can be made thicker, achieving better performance, such as high capacity and high output.

[0027] For example, when polyimide is baked at a temperature exceeding 800°C, a larger amount of imide is decomposed, increasing the proportion of C-C bonds, and there is a high possibility that the elasticity of the solid state battery electrode 1 will decrease and the electrode 1 will become brittle. In the method for manufacturing the solid state battery electrode 1 of this embodiment, only a portion of the resin 3 is carbonized at a treatment temperature of 800°C or less, so that the flexibility of the solid state battery electrode 1 can be obtained.

[0028] Furthermore, in the solid state battery electrode 1 of this embodiment, the voids inside the resin 3 are filled with the solid electrolyte 4, so that better conductivity can be obtained.

[0029] Furthermore, in the solid state battery electrode 1 of this embodiment, the lithium salt contained in the solid electrolyte 4 can be melted and impregnated into the active material particles 2, and then crystallized. This makes it difficult for interfaces between particles to occur in the solid electrolyte 4. By reducing the interfaces between particles of the solid electrolyte 4 that reduce ion conductivity, good conductivity can be ensured.

[0030] Furthermore, in the manufacturing method of the solid state battery electrode 1 of this embodiment, before the green sheet is impregnated with the molten solid electrolyte, a heat treatment is performed to form a strong conductive network by bonding the partially carbonized resin 3 with the active material particles 2. Therefore, even when the green sheet is impregnated with the solid electrolyte, the conductive network is maintained. Furthermore, because the partially carbonized resin 3 has elasticity, the green sheet heated during the manufacturing process is less likely to crack and is easy to handle.

[0031] A polymer compound containing at least one selected from the group consisting of partially carbonized polyimide, polyamide, and polyamideimide is chemically stable in an inert atmosphere at 800°C or less. Therefore, if the molten solid electrolyte is heated to less than 800°C in a vacuum or inert atmosphere, the conductive network can be prevented from being broken down by the impregnation process. A solid electrolyte 4 containing at least one of Li2CO3, Li2SO4, Li3BO3, Li3OCl, and Li2OHCl melts at temperatures below 800°C. Therefore, when these lithium salts are melted and impregnated, a strong conductive network formed by the bond between the partially carbonized resin 3 and the active material particles 2 can be stably maintained.

[0032] 2. Second Embodiment <2.1 Battery package 100> Next, a battery package 100 according to a second embodiment of the present disclosure will be described. FIG. 3 is a schematic cross-sectional view illustrating the overall configuration of the battery package 100. The battery package 100 includes a solid-state battery 101 and a covering 102 that covers the solid-state battery 101. The covering 102 protects the solid-state battery 101 from the external environment. The covering 102 prevents, for example, water vapor from penetrating into the solid-state battery 101. The solid-state battery 101 will be described below, followed by the covering 102. "Water vapor" here refers to moisture, such as water vapor in the atmosphere, and in a preferred embodiment, refers to moisture that includes not only water vapor in gas form but also liquid water. Preferably, such a moisture-impermeable solid-state battery 101 is packaged to be suitable for substrate mounting, particularly for surface mounting.

[0033] <2.2 Solid state battery 101> FIG. 4 is a schematic cross-sectional view illustrating the configuration of a solid-state battery 101. As illustrated in FIGS. 3 and 4 , the solid-state battery 101 includes a laminate 5, a positive electrode terminal 6, and a negative electrode terminal 7. The positive electrode terminal 6 and the negative electrode terminal 7 are disposed opposite each other with the laminate 5 interposed therebetween. As illustrated in FIG. 4 , the laminate 5 includes a positive electrode layer 10, a negative electrode layer 20, and a solid electrolyte layer 30 stacked in the Z-axis direction. The solid electrolyte layer 30 is interposed between the positive electrode layer 10 and the negative electrode layer 20 in the Z-axis direction, which is the stacking direction. Specifically, the solid-state battery 101 has a structure in which a unit U, which includes a negative electrode layer 20, a solid electrolyte layer 30, a positive electrode layer 10, and a solid electrolyte layer 30 stacked in this order, is repeatedly stacked in the Z-axis direction. Note that FIG. 4 illustrates the solid-state battery 101 including two units U, but the solid-state battery 101 is not limited to this embodiment and may include three or more units U. The solid-state battery 101 may further include blank layers 41 and 42, which are electronic insulating layers. The blank layer 41 is provided in the same layer as a part of the positive electrode layer 10. The blank layer 42 is provided in the same layer as a part of the negative electrode layer 20.

[0034] The positive electrode layer 10 and the negative electrode layer 20 may contain a conductive additive. Examples of the conductive additive that may be contained in the positive electrode layer 10 and the negative electrode layer 20 include at least one of metal materials such as silver, palladium, gold, platinum, copper, and nickel, and carbon. The conductive additive contained in the positive electrode layer 10 and the conductive additive contained in the negative electrode layer 20 may be the same or different.

[0035] Furthermore, the positive electrode layer 10 and the negative electrode layer 20 may contain a sintering aid. The sintering aid may be at least one selected from the group consisting of lithium oxide, sodium oxide, potassium oxide, boron oxide, silicon oxide, bismuth oxide, and phosphorus oxide. The sintering aid contained in the positive electrode layer 10 and the sintering aid contained in the negative electrode layer 20 may be the same or different.

[0036] (Positive electrode layer 10) The positive electrode layer 10 is an electrode layer containing at least a positive electrode active material. In the solid state battery 101 shown in FIG. 4, the positive electrode layer 10 has a laminated structure including a positive electrode current collector 11 and a pair of positive electrode active material layers 12 and 13.

[0037] The positive electrode current collector 11 is a metal foil such as an aluminum foil. The positive electrode current collector 11 may be a sintered body to reduce the internal resistance of the positive electrode current collector 11. When the positive electrode current collector 11 is a sintered body, the positive electrode current collector 11 may contain a conductive additive and a sintering additive. The conductive additive contained in the positive electrode current collector 11 may be the same as the conductive additive contained in the positive electrode active material layers 12 and 13. The sintering additive contained in the positive electrode current collector 11 may be the same as the sintering additive contained in the positive electrode active material layers 12 and 13. While FIG. 4 illustrates an example in which the positive electrode layer 10 includes the positive electrode current collector 11, the positive electrode current collector 11 is not an essential component. The positive electrode layer 10 may include either the positive electrode active material layer 12 or the positive electrode active material layer 13 without including the positive electrode current collector 11.

[0038] (Cathode active material layer 12, 13) The positive electrode active material layers 12 and 13 contain a positive electrode active material as a main component. The positive electrode active material layer 12 is provided on the upper surface of the positive electrode current collector 11, and the positive electrode active material layer 13 is provided on the lower surface of the positive electrode current collector 11. The positive electrode active material layers 12 and 13 may have the configuration of the solid state battery electrode 1 that does not include a metal foil, as described in the first embodiment.

[0039] The positive electrode active material contained in the positive electrode active material layers 12, 13 is a material that participates in the absorption and release of ions in the solid-state battery 101 and in the transfer of electrons to and from the external circuit. Ions move between the positive electrode layer 10 and the negative electrode layer 20 via the solid electrolyte (i.e., ion conduction). The absorption and release of ions in the positive electrode active material is accompanied by oxidation or reduction of the positive electrode active material. Electrons or holes for such an oxidation-reduction reaction are transferred from the external circuit to the positive electrode terminal 6 or the negative electrode terminal 7, and then to the positive electrode layer 10 or the negative electrode layer 20, thereby allowing charging and discharging to proceed. The positive electrode active material layers 12, 13 contain, for example, lithium ions, sodium ions, protons (H + ), potassium ions (K + ), magnesium ions (Mg 2+ ), aluminum ions (Al 3+ ), silver ions (Ag + ), fluoride ion (F - ) or chloride ions (Cl - In other words, the solid-state battery 101 is preferably an all-solid-state secondary battery in which charging and discharging are performed by the ions moving between the positive electrode layer 10 and the negative electrode layer 20 via the solid electrolyte.

[0040] (Cathode active material) The positive electrode active material contained in the positive electrode layer 10 may be at least one selected from the group consisting of a lithium-containing phosphate compound having a Nasicon structure, a lithium-containing phosphate compound having an olivine structure, a lithium-containing layered oxide, and a lithium-containing oxide having a spinel structure. An example of a lithium-containing phosphate compound having a Nasicon structure is Li3V2(PO4)3. An example of a lithium-containing phosphate compound having an olivine structure is Li3Fe2(PO4)3, LiFePO4, LiMnPO4, LiFe 0.6 Mn 0.4 Examples of lithium-containing layered oxides include LiCoO2, LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, LiCo 0.8 Ni0.15 Al 0.05 Examples of lithium-containing oxides having a spinel structure include LiMn2O4, LiNi 0.5 Mn 1.5 Examples include O4.

[0041] In addition, the positive electrode active material capable of absorbing and releasing sodium ions may be at least one selected from the group consisting of sodium-containing phosphate compounds having a Nasicon structure, sodium-containing phosphate compounds having an olivine structure, sodium-containing layered oxides, and sodium-containing oxides having a spinel structure.

[0042] (negative electrode layer 20) The negative electrode layer 20 is an electrode layer containing at least a negative electrode active material. The negative electrode layer 20 may have the configuration of the solid state battery electrode 1 not containing a metal foil as described in the first embodiment. The negative electrode layer 20 may have a negative electrode current collector. The negative electrode current collector is, for example, a metal foil such as copper foil. The negative electrode current collector may also be a sintered body. This is to reduce the internal resistance of the negative electrode current collector. When the negative electrode current collector is a sintered body, the negative electrode current collector may contain a conductive additive and a sintering additive.

[0043] (Negative electrode active material) The anode active material contained in the anode layer 20, like the cathode active material contained in the cathode layer 10, is a material that participates in the absorption and release of ions in the solid-state battery 101 and in the transfer of electrons to and from the external circuit. Ions move between the cathode layer 10 and the anode layer 20 via the solid electrolyte layer 30 (i.e., ion conduction). The absorption and release of ions in the anode active material is accompanied by oxidation or reduction of the anode active material. Electrons or holes for such oxidation-reduction reactions are transferred from the external circuit to the cathode terminal 6 or the anode terminal 7, and then to the cathode layer 10 or the anode layer 20, thereby allowing charging and discharging to proceed. The anode active material may contain, for example, lithium ions, sodium ions, protons (H + ), potassium ions (K + ), magnesium ions (Mg2+ ), aluminum ions (Al 3+ ), silver ions (Ag + ), fluoride ion (F - ) or chloride ions (Cl - ) can be absorbed and released. Examples of the negative electrode active material contained in the negative electrode layer 20 include at least one selected from the group consisting of an oxide containing at least one element selected from the group consisting of Ti, Si, Sn, Cr, Fe, Nb, and Mo, a graphite-lithium compound, a lithium alloy, a lithium-containing phosphate compound having a Nasicon structure, a lithium-containing phosphate compound having an olivine structure, and a lithium-containing oxide having a spinel structure. An example of a lithium alloy is Li-Al. Examples of lithium-containing phosphate compounds having a Nasicon structure are Li3V2(PO4)3 and LiTi2(PO4)3. Examples of lithium-containing phosphate compounds having an olivine structure are Li3Fe2(PO4)3 and LiCuPO4. An example of a lithium-containing oxide having a spinel structure is Li4Ti5O 12 etc.

[0044] In addition, the negative electrode active material capable of absorbing and releasing sodium ions may be at least one selected from the group consisting of sodium-containing phosphate compounds having a Nasicon structure, sodium-containing phosphate compounds having an olivine structure, and sodium-containing oxides having a spinel structure.

[0045] (Solid electrolyte layer 30) The solid electrolyte contained in the solid electrolyte layer 30 is a material capable of conducting ions such as lithium ions or sodium ions. In particular, the solid electrolyte constituting the battery constituent unit in a solid-state battery forms a layer capable of conducting, for example, lithium ions between the positive electrode layer 10 and the negative electrode layer 20. Specific examples of the solid electrolyte include lithium-containing phosphate compounds having a Nasicon structure, oxides having a perovskite structure, and oxides having a garnet or garnet-like structure. Examples of lithium-containing phosphate compounds having a Nasicon structure include Lix M y (PO4)3 (1≦x≦2, 1≦y≦2, M is at least one selected from the group consisting of Ti, Ge, Al, Ga and Zr). An example of a lithium-containing phosphate compound having a Nasicon structure is, for example, Li 1.2 Al 0.2 Ti 1.8 (PO4)3, etc. An example of an oxide having a perovskite structure is La 0.55 Li 0.35 Examples of oxides with garnet or garnet-like structures include Li7La3Zr2O 12 Examples of the solid electrolyte capable of conducting sodium ions include sodium-containing phosphate compounds having a Nasicon structure, oxides having a perovskite structure, and oxides having a garnet or garnet-like structure. Examples of the sodium-containing phosphate compounds having a Nasicon structure include Na x M y (PO4)3 (1≦x≦2, 1≦y≦2, M is at least one selected from the group consisting of Ti, Ge, Al, Ga, and Zr). The solid electrolyte contained in the solid electrolyte layer 30 may further include sulfides (Li7PS6 with an argyrodite structure, or materials obtained by substituting a part of it (e.g., Li6PS5Cl, Li6PS5Br, etc.)), Li with a lithiated structure, 10 GeP2S 12 and materials that have been partially substituted (e.g., Li 10 SiP2S 12 and Li 9.54 Si 1.74 P 1.44 S 11.7 C l0.3 ) or halides (Li2MCl4 with an inverse spinel structure (M is at least one of Mg, Fe, Ni, Zn, Al, In, and Sc), Li3MCl6 with a monoclinic structure (M is at least one of Al, Ga, In, Sc, and Y)) can also be used.

[0046] Alternatively, the solid electrolyte layer 30 may be a mixture containing a first solid electrolyte 31 having a perovskite structure and a second solid electrolyte 32 having an inverse perovskite structure, as shown in FIG. 5 . FIG. 5 is a schematic cross-sectional view illustrating an example of a configuration of the solid electrolyte layer 30. By combining the first solid electrolyte 31 having a perovskite structure with the second solid electrolyte 32 having an inverse perovskite structure, a good lattice matching state can be obtained in the solid electrolyte layer 30. Specifically, the first solid electrolyte 31 is a plurality of electrolyte particles, and the second solid electrolyte 32 fills the gaps between the plurality of first solid electrolyte particles 31. In the solid electrolyte layer 30, for example, the first solid electrolyte 31 is dispersed and incorporated into the second solid electrolyte 32, and almost no grain boundaries are formed in the second solid electrolyte 32. By suppressing the formation of grain boundaries in the second solid electrolyte 32, high ionic conductivity can be obtained in the solid electrolyte layer 30, and the solid battery 101 can be rapidly charged and have a high output.

[0047] It is desirable that the lattice constant of the crystal of the first solid electrolyte 31 having a perovskite structure and the lattice constant of the crystal of the second solid electrolyte 32 having an inverse perovskite structure are similar to each other. In the perovskite structure and the inverse perovskite structure, the positively charged cations and the negatively charged anions are arranged in opposite directions. Therefore, if the lattice constants of the perovskite structure and the inverse perovskite structure are similar, the positive and negative charges will be adjacent when the two structures come into contact. Therefore, ionic bonds are formed in a lattice-matched state with little misalignment of ions, resulting in a very clean interface between the first solid electrolyte 31 and the second solid electrolyte 32. A clean interface here refers to an interface in an epitaxial state (lattice-matched state) with very few structural defects. Furthermore, the lattice-matched state refers to a state in which the ratio of the lattice constant of the anti-perovskite structure to the lattice constant of the perovskite structure is 0.9 or more and 1.1 or less. It is particularly desirable that the ratio of the lattice constant of the anti-perovskite structure to the lattice constant of the perovskite structure be 0.95 or more and 1.05 or less.

[0048] The first solid electrolyte 31 and the second solid electrolyte 32 may each have a lattice constant that is an integer multiple of, for example, 3.8 Å or more and 4.1 Å or less. Specifically, the first solid electrolyte 31 is Li 0.33 La 0.56 The second solid electrolyte 32 may be Li3OCl or Li2(OH)Cl. 0.33 La 0.56 The lattice constant of TiO3 is 3.92 Å, and the lattice constants of Li3OCl and Li2(OH)Cl are both 3.91 Å.

[0049] The solid electrolyte layer 30 may contain a sintering aid. The sintering aid that can be contained in the solid electrolyte layer 30 may be selected from, for example, the same materials as the sintering aids that can be contained in the positive electrode layer 10 and the negative electrode layer 20. Furthermore, if sintering is not performed in the process of forming the solid electrolyte layer 30, a binder may be contained instead of a sintering aid.

[0050] (Positive terminal 6 and negative terminal 7) The positive electrode terminal 6 and the negative electrode terminal 7 are external connection terminals for connecting the laminate 5 to an external device. The positive electrode terminal 6 and the negative electrode terminal 7 are preferably provided as end surface electrodes on the side surfaces of the laminate 5. That is, the positive electrode terminal 6 and the negative electrode terminal 7 extend along the Z-axis direction, which is the stacking direction of the laminate 5. In FIG. 4, the positive electrode terminal 6 and the negative electrode terminal 7 are arranged to face each other in the X-axis direction. As shown in FIG. 4, the positive electrode terminal 6 is electrically connected to the end surface of the positive electrode current collector 11 of the positive electrode layer 10. The negative electrode terminal 7 is electrically connected to the end surface of the negative electrode layer 20. The positive electrode terminal 6 and the negative electrode terminal 7 are preferably made of a material having high conductivity. Examples of materials for the positive electrode terminal 6 and the negative electrode terminal 7 include at least one selected from the group consisting of gold, silver, platinum, aluminum, tin, nickel, copper, manganese, cobalt, iron, titanium, and chromium. However, the constituent materials of the positive electrode terminal 6 and the negative electrode terminal 7 are not limited to those mentioned above.

[0051] (Margin layers 41, 42) The marginal layer 41 has marginal portions 411 to 413. The marginal portion 411 is in the same layer as the positive electrode current collector 11 and is provided between the positive electrode current collector 11 and the negative electrode terminal 7. The marginal portion 412 is in the same layer as the positive electrode active material layer 12 and is provided between the positive electrode active material layer 12 and the positive electrode terminal 6 and between the positive electrode active material layer 12 and the negative electrode terminal 7. The marginal portion 413 is in the same layer as the positive electrode active material layer 13 and is provided between the positive electrode active material layer 13 and the positive electrode terminal 6 and between the positive electrode active material layer 13 and the negative electrode terminal 7. The marginal layer 42 is in the same layer as the negative electrode layer 20 and is provided between the negative electrode layer 20 and the positive electrode terminal 6.

[0052] Examples of materials constituting the marginal portions 411 to 413 of the marginal layer 41 and the marginal layer 42 include materials having electronic insulation properties (hereinafter simply referred to as insulating materials).

[0053] Examples of insulating materials include glass and ceramic. Examples of glass materials include, but are not limited to, at least one selected from the group consisting of soda-lime glass, potash glass, borate glass, borosilicate glass, barium borosilicate glass, zinc borate glass, barium borate glass, bismuth borosilicate glass, bismuth zinc borate glass, bismuth silicate glass, phosphate glass, aluminophosphate glass, and zinc phosphate glass. Examples of ceramic materials include, but are not limited to, at least one selected from the group consisting of aluminum oxide (Al2O3), boron nitride (BN), silicon dioxide (SiO2), silicon nitride (Si3N4), zirconium oxide (ZrO2), aluminum nitride (AlN), silicon carbide (SiC), and barium titanate (BaTiO3). The insulating material may also be an organic material with excellent mechanical properties, such as polyimide, polyamide, polyamideimide, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or polyether ether ketone resin (PEEK).

[0054] The insulating material constituting the blank layers 41, 42 may contain a solid electrolyte. In this case, the solid electrolyte contained in the insulating material is preferably the same material as the solid electrolyte contained in the solid electrolyte layer 30. This is because such a configuration can further improve the bonding between the blank layers 41, 42 and the solid electrolyte layer 30.

[0055] <2.3 Covering portion 102> 3, the covering portion 102 of the battery package 100 has a support substrate 102A, a covering insulating film 102B, and a covering inorganic film 102C. In the battery package 100, the solid-state battery 101 is entirely surrounded by the covering portion 102. In other words, the covering portion 102 is provided so that the solid-state battery 101 is not exposed to the outside.

[0056] (Support board 102A) The support substrate 102A is a plate-shaped member that supports the solid-state battery 101. The support substrate 102A has a surface 102S that faces the bottom surface 101B, which is the main surface of the solid-state battery 101. The support substrate 102A may be a resin substrate or a ceramic substrate. In a preferred embodiment, the support substrate 102A is a ceramic substrate. The support substrate 102A contains ceramic as a main component. A ceramic substrate is preferable because it has excellent water vapor prevention properties and excellent heat resistance. A ceramic substrate can be obtained, for example, by firing a green sheet laminate. Specifically, the ceramic substrate may be, for example, an LTCC (Low Temperature Co-fired Ceramics) substrate or an HTCC (High Temperature Co-fired Ceramic) substrate. By way of example only, the thickness of the support substrate 102A is 20 μm to 1000 μm, for example, 100 μm to 300 μm.

[0057] (Coating insulation film 102B) The coated insulating film 102B is a layer provided so as to cover at least the top surface 101A and the side surface 101C of the solid-state battery 101. As shown in FIG. 3, the solid-state battery 101 provided on the support substrate 102A is entirely enclosed by the coated insulating film 102B. In a preferred embodiment, the coated insulating film 102B is provided so as to cover the entire top surface 101A and the side surface 101C of the solid-state battery 101. Of the two main surfaces constituting the solid-state battery 101, the one positioned relatively lower is the bottom surface 101B. Therefore, the top surface 101A is the main surface located opposite the support substrate 102A. Therefore, the coated insulating film 102B may cover all surfaces of the solid-state battery 101 except for the bottom surface 101B. The coated insulating film 102B is made of, for example, a resin material capable of blocking water vapor. The coated insulating film 102B, in combination with the coated inorganic film 102C, forms a suitable water vapor barrier. Examples of materials used for the coated insulating film 102B include epoxy resins, silicone resins, and liquid crystal polymers. By way of example only, the thickness of the coated insulating film 102B is 30 μm or more and 1000 μm or less, and may be, for example, 50 μm or more and 300 μm or less.

[0058] (Coated inorganic film 102C) The coated inorganic film 102C is provided to cover the coated insulating film 102B. Since the coated inorganic film 102C is positioned on the coated insulating film 102B, together with the coated insulating film 102B, it has a shape that largely envelops the solid-state battery 101 on the support substrate 102A as a whole. The material of the coated inorganic film 102C is not particularly limited as long as it is an inorganic material. The coated inorganic film 102C may be metal, glass, oxide ceramic, or a mixture thereof. In a preferred embodiment, the coated inorganic film 102C contains a metal component. That is, the coated inorganic film 102C may be a metal thin film. By way of example only, the thickness of the coated inorganic film 102C is 0.1 μm or more and 100 μm or less, for example, 1 μm or more and 50 μm or less. The coated inorganic film 102C may be a dry-plated film. The dry-plated film referred to here is a film obtained by a vapor-phase method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD), and is a thin film having an extremely thin thickness on the order of nanometers or micrometers. A thin dry-plated film contributes to the miniaturization and thinning of the battery package 100. The dry-plated film may contain at least one metal selected from the group consisting of aluminum (Al), nickel (Ni), palladium (Pd), silver (Ag), tin (Sn), gold (Au), copper (Cu), titanium (Ti), platinum (Pt), silicon (Si), and stainless steel. A dry-plated film made of such components is chemically and thermally stable, resulting in a solid-state battery 101 with excellent chemical resistance, weather resistance, and heat resistance, and thus improved long-term reliability.

[0059] In the battery package 100 shown in FIG. 3, the support substrate 102A is a terminal substrate provided with substrate wiring 8 including external terminals for connecting the solid-state battery 101 to an external device. The substrate wiring 8 in the support substrate 102A serving as a terminal substrate is not particularly limited as long as it allows electrical connection between the upper and lower surfaces of the support substrate 102A. In FIG. 3, the support substrate 102A is provided with substrate wiring 8 including a via 8A and a pair of lands 8B and 8C. The land 8B is exposed on the upper surface of the support substrate 102A and is electrically connected to the positive electrode terminal 6 or the negative electrode terminal 7. The land 8C is exposed on the lower surface of the support substrate 102A. The via 8A penetrates the support substrate 102A to connect the land 8B and the land 8C.

[0060] <2.4 Manufacturing method> Next, a brief description will be given of a method for manufacturing the battery package 100 of the present disclosure. The battery package 100 can be produced, for example, by a step of manufacturing the solid-state battery 101 and a step of packaging the solid-state battery 101.

[0061] (Process for manufacturing the solid-state battery 101) In manufacturing the laminate 5 of the solid-state battery 101, a printing method such as a screen printing method, a green sheet method using a green sheet, or a combination of these methods can be used.

[0062] The following description will be given using one manufacturing method as an example, but the present disclosure is not limited to the manufacturing method described below. Furthermore, the chronological order of the following descriptions is merely for the convenience of explanation, and the present disclosure is not limited to these details.

[0063] First, the positive electrode layer 10 is fabricated according to the procedure described in the first embodiment. Specifically, after preparing the positive electrode current collector 11, positive electrode active material particles, a resin, and a solvent are mixed to form a positive electrode slurry. Next, the positive electrode slurry is applied to both sides of the positive electrode current collector 11, and the applied positive electrode slurry is dried to form positive electrode green sheets on both sides of the positive electrode current collector 11. Furthermore, the fabricated positive electrode green sheets are heated at a temperature below 800°C to partially carbonize the resin and obtain heat-treated positive electrode green sheets. Finally, the heated positive electrode green sheets are impregnated with a molten positive electrode solid electrolyte, for example, by dropping it onto the sheets. The molten positive electrode solid electrolyte may be a lithium molten salt containing at least one of Li2CO3, Li2SO4, Li3BO3, Li3OCl, and Li2OHCl. As a result of the above, a positive electrode layer 10 is obtained in which positive electrode active material layers 12 and 13 are formed on a positive electrode current collector 11. Note that instead of applying the positive electrode slurry to the positive electrode current collector 11, the positive electrode slurry may be applied to a release film. In this case, the release film is removed from the positive electrode green sheet, and then a heat treatment is performed to produce two heat-treated positive electrode green sheets. Next, the heat-treated positive electrode green sheets are superimposed on both sides of the positive electrode current collector 11 and then press-bonded to obtain a positive electrode layer 10 in which the positive electrode current collector 11 and the positive electrode active material layers 12 and 13 are integrated.

[0064] Next, the anode layer 20 is fabricated according to the procedure of the manufacturing method for the solid-state battery electrode 1 described in the first embodiment. Specifically, anode active material particles, a resin, and a solvent are mixed to form an anode slurry. Next, the anode slurry is applied to a film, and the applied anode slurry is dried to form an anode green sheet. The fabricated anode green sheet is then heated at a temperature below 800°C to carbonize a portion of the resin, thereby obtaining a heat-treated anode green sheet. Finally, the heated anode green sheet is impregnated with a molten anode solid electrolyte, for example, by dropping it onto the sheet. The molten anode solid electrolyte may be a lithium molten salt containing at least one of Li2CO3, Li2SO4, Li3BO3, Li3OCl, and Li2OHCl. This process yields the anode layer 20.

[0065] Next, the solid electrolyte sintered body is produced as follows. Specifically, first, an oxide solid electrolyte powder and an organic binder are kneaded to produce a kneaded powder. The oxide solid electrolyte powder is Li 0.33 La 0.56 TiO3 can be used. Polybutyral binder can be used as the organic binder. Next, the kneaded powder is compression molded using a method such as cold isostatic pressing (CIP) to produce a compression molded body. The compression molded body is then fired in an air atmosphere at a predetermined temperature for a predetermined time to obtain a solid electrolyte sintered body. The firing conditions are, for example, 1300°C for 10 hours.

[0066] Furthermore, an insulating material, a binder, an organic binder, a solvent, and optional additives are mixed together to prepare an insulating paste.

[0067] Next, a positive electrode layer 10, a solid electrolyte sintered body, a negative electrode layer 20, and a solid electrolyte sintered body are stacked in this order to form a laminated structure. This laminated structure corresponds to one unit U shown in FIG. 4. When fabricating this laminated structure, an insulating paste is applied to the areas where blank layers 41 and 42 will be formed. The laminated structure is impregnated with a molten solid electrolyte for the solid electrolyte layer by, for example, dropping it, and then dried. This impregnates the solid electrolyte sintered body with the solid electrolyte, resulting in a solid electrolyte layer 30. The molten solid electrolyte for the solid electrolyte layer may be a lithium molten salt containing at least one of Li2CO3, Li2SO4, Li3BO3, Li3OCl, and Li2OHCl. The dried laminated structure is compressed by cold isostatic pressing (CIP) or the like to pressure-bond the positive electrode layer 10, the solid electrolyte layer 30, the negative electrode layer 20, and the solid electrolyte layer 30. Finally, the laminate 5 is obtained by heating at a temperature of less than 800° C. in a nitrogen atmosphere.

[0068] Next, a conductive paste is applied to the side surface of the heated laminate 5 where a portion of the positive electrode layer 10 is exposed. This allows the positive electrode terminal 6 to be formed. Similarly, a conductive paste is applied to the side surface of the heated laminate 5 where a portion of the negative electrode layer 20 is exposed. This allows the negative electrode terminal 7 to be formed. Note that the positive electrode terminal 6 and the negative electrode terminal 7 are not limited to being formed on the heated laminate 5, but may be formed on the laminate structure before heating and then heat-treated simultaneously with the laminate structure.

[0069] In this way, the solid state battery 101 can be obtained.

[0070] (Process of packaging the solid-state battery 101) First, the support substrate 102A is prepared. The support substrate 102A can be obtained, for example, by stacking and firing multiple green sheets. The preparation of the support substrate 102A can be performed, for example, in accordance with the preparation of an LTCC substrate. The support substrate 102A has substrate wiring 8 formed thereon, including vias 8A and lands 8B, 8C. Specifically, for example, holes are formed in the green sheets using a punch press or a carbon dioxide laser, and the vias 8A and lands 8B, 8C are formed by filling the holes with a conductive paste material or by using a printing method. Next, a predetermined number of such green sheets are stacked and thermocompression-bonded to form a green sheet laminate, and the green sheet laminate is then fired to obtain the support substrate 102A on which the substrate wiring 8 is formed. The substrate wiring 8 can also be formed after firing the green sheet laminate.

[0071] After preparing the support substrate 102A as described above, the solid-state battery 101 is placed on the support substrate 102A. At this time, the solid-state battery 101 is placed on the support substrate 102A so that the board wiring 8 of the support substrate 102A and the positive electrode terminal 6 and negative electrode terminal 7 of the solid-state battery 101 are electrically connected to each other. Note that a conductive paste containing silver or the like may be applied onto the board wiring 8 of the support substrate 102A, and the conductive paste may be electrically connected to the positive electrode terminal 6 and negative electrode terminal 7, respectively.

[0072] Next, the insulating coating film 102B is formed so as to entirely cover the solid-state battery 101 on the support substrate 102A. When the insulating coating film 102B is made of a resin material, the resin material is applied so as to cover the side surface 101C and the top surface 101A of the solid-state battery 101, and then the resin material is cured to form the insulating coating film 102B. For example, the insulating coating film 102B may be molded by applying pressure to the resin material using a mold of a predetermined shape. Note that the molding of the insulating coating film 102B is not limited to mold molding, and may also be performed using polishing, laser processing, chemical treatment, or the like.

[0073] Next, the inorganic coated film 102C is formed so as to entirely cover the insulating coated film 102B. Specifically, for example, the inorganic coated film 102C may be formed by dry plating.

[0074] By going through the steps described above, a battery package 100 can be obtained in which the solid state battery 101 mounted on the support substrate 102A is entirely covered with the insulating coating film 102B and the inorganic coating film 102C.

[0075] <2.5 Effects> According to the battery package 100 including the solid-state battery 101 of this embodiment, the laminate 5 of the solid-state battery 101 has the positive electrode layer 10 and the negative electrode layer 20 that adopt the configuration of the solid-state battery electrode 1 described in the first embodiment. Therefore, the positive electrode layer 10 and the negative electrode layer 20 can have a good conductive network while being elastic. Therefore, in the solid-state battery 101, the positive electrode layer 10 and the negative electrode layer 20 have high conductivity, so that the thicknesses of the positive electrode layer 10 and the negative electrode layer 20 can be made larger, and better performance such as high capacity and high output can be achieved.

[0076] [3. Battery package applications] Next, uses (application examples) of the battery package including the above-described solid-state battery will be described.

[0077] The use of the battery package is not particularly limited as long as it is used mainly in machines, devices, instruments, apparatuses, and systems (assemblies of multiple devices, etc.) that can use solid-state batteries as a driving power source or a power storage source for power accumulation. The battery package used as a power source may be a main power source or an auxiliary power source. A main power source is a power source that is used preferentially regardless of the presence or absence of other power sources. An auxiliary power source may be a power source used in place of the main power source, or a power source that can be switched from the main power source as needed. When the battery package is used as an auxiliary power source, the type of main power source is not limited to one equipped with a solid-state battery.

[0078] Specific examples of uses for battery packages are as follows: Electronic devices (including portable electronic devices) such as video cameras, digital still cameras, mobile phones, notebook computers, cordless phones, headphone stereos, portable radios, portable televisions, and portable information terminals. Portable household appliances such as electric shavers. Storage devices such as backup power supplies and memory cards. Power tools such as power drills and power saws. Battery packs installed in notebook computers and the like as removable power sources. Medical electronic devices such as pacemakers and hearing aids. Electric vehicles such as electric cars (including hybrid cars). Power storage systems such as home battery systems that store power in preparation for emergencies. It is also possible to use multiple battery packages as a battery module.

[0079] The battery module is effectively applied to relatively large equipment such as electric vehicles, power storage systems, and power tools. An electric vehicle is a vehicle that operates (runs) using a battery module as its driving power source, and may also be an automobile (such as a hybrid automobile) that also has a driving source other than a battery package equipped with solid-state batteries. A power storage system is a system that uses a battery package as a power storage source. In a home power storage system, power is stored in a secondary battery, which is the power storage source, and this power can be used to power household electrical appliances, etc.

[0080] 4. Working Example An embodiment of the present disclosure will now be described.

[0081] Example 1 As will be described below, the solid state battery 101 shown in FIG. 4 was fabricated, and then its battery characteristics were evaluated.

[0082] (Fabrication of Positive Electrode Layer 10) First, a 15 μm thick aluminum foil was prepared as the positive electrode current collector 11. Next, lithium nickel cobalt aluminum oxide (NCA) as the positive electrode active material and polyimide as the positive electrode binder were mixed to obtain a positive electrode mixture. The mixture ratio of the positive electrode active material to the positive electrode binder was 80:20. Next, the positive electrode mixture was added to NMP (N-methyl-2-pyrrolidone) as an organic solvent, and the organic solvent containing the positive electrode mixture was stirred to prepare a paste-like positive electrode slurry. The stirring was performed using a hybrid mixer at a rotation speed of 2000 rpm for 3 minutes. Next, the positive electrode slurry was applied to predetermined areas on both sides of the positive electrode current collector 11 using a coating device, and the positive electrode slurry was then dried to form positive electrode green sheets on both sides of the positive electrode current collector 11. The prepared positive electrode green sheet was then heated at 800°C for 1 hour to carbonize a portion of the resin, thereby obtaining a heat-treated positive electrode green sheet. Finally, Li2OHCl dissolved in pure water was added dropwise to the heated positive electrode green sheet as a lithium molten salt, and the positive electrode layer 10 was thus obtained.

[0083] (Fabrication of negative electrode layer 20) A negative electrode mixture was obtained by mixing a carbon material made of natural graphite as the negative electrode active material and polyimide as the negative electrode binder. The mixing ratio of the negative electrode active material to the negative electrode binder was 80:20. Next, the negative electrode mixture was added to NMP (N-methyl-2-pyrrolidone) as an organic solvent, and the organic solvent containing the negative electrode mixture was stirred to prepare a paste-like negative electrode slurry. The mixture was stirred for 3 minutes at a rotation speed of 2000 rpm using a hybrid mixer. Next, the negative electrode slurry was applied to a release film made of polyethylene terephthalate (PET) using a coating device, and the negative electrode slurry was dried to form a negative electrode green sheet on the release film. The prepared negative electrode green sheet was then heated at 700°C for 1 hour to carbonize a portion of the resin, yielding a heat-treated negative electrode green sheet. Finally, Li2OHCl dissolved in pure water was dropped onto the heated negative electrode green sheet as a lithium molten salt to impregnate the sheet. In this way, a negative electrode layer 20 was obtained.

[0084] (Production of sintered solid electrolyte) Li as oxide solid electrolyte powder 0.33 La 0.56 A mixed powder was prepared by mixing TiO3, a polyacrylic binder as an organic binder, and butyl acetate. 0.33 La 0.56 The mixing ratio of TiO3, polyacrylic binder, and butyl acetate was 50:10:40. Next, the kneaded powder was compression molded at a pressure of 200 MPa using the cold isostatic pressing (CIP) method to produce a compression molded body. Furthermore, the compression molded body was sintered in the air at a temperature of 1300°C for 10 hours. This resulted in a solid electrolyte sintered body.

[0085] (Production of laminate 5) Next, the positive electrode layer 10, the solid electrolyte sintered body, the negative electrode layer 20, and the solid electrolyte sintered body prepared as described above were sequentially stacked to prepare a laminated structure. Li2OHCl dissolved in pure water was added dropwise to the laminated structure as a lithium molten salt, and the laminated structure was then dried. The dried laminated structure was compressed by cold isostatic pressing (CIP) to pressure-bond the positive electrode layer 10, the solid electrolyte layer 30, the negative electrode layer 20, and the solid electrolyte layer 30. Finally, the laminated structure was heated at 270°C for 1 hour in a nitrogen atmosphere to obtain a laminated body 5.

[0086] Next, a conductive paste was applied to the side surface of the sintered laminate 5 where a portion of the positive electrode layer 10 was exposed, thereby forming a positive electrode terminal 6. A conductive paste was applied to the side surface of the sintered laminate 5 where a portion of the negative electrode layer 20 was exposed, thereby forming a negative electrode terminal 7.

[0087] In this way, a solid-state battery 101 was obtained. The mixture ratio of the positive electrode active material to the positive electrode binder in the positive electrode layer 10 after the heat treatment was 95:5 by weight. This is because the carbonization causes some of the organic components contained in the positive electrode binder to decompose and volatilize. For the same reason, the mixture ratio of the negative electrode active material to the negative electrode binder in the negative electrode layer 20 after the heat treatment was also 95:5 by weight.

[0088] (Evaluation of battery characteristics) The battery characteristics of the solid-state battery 101 were evaluated, and the results shown in Table 1 were obtained. Here, the charge capacity [mAh / g] and the initial charge / discharge efficiency [%] were evaluated in an environment at a temperature of 90°C. The solid-state battery 101 of Example 1 was charged and discharged as follows. First, constant-current charging was performed at a constant current of 0.5 mA until the battery voltage reached 4.2 V, and constant-voltage charging was performed at a constant voltage of 4.2 V until the battery voltage reached 0.05 mA. Subsequently, constant-current discharging was performed at a constant current of 0.5 mA until the voltage reached 2.0 V. This combination of charging and discharging constituted one cycle. The initial charge / discharge efficiency was calculated as the ratio of the discharge capacity at the first cycle to the charge capacity at the first cycle, i.e., (discharge capacity at the first cycle / charge capacity at the first cycle) × 100 (%). Regarding the charge capacity, the electric capacity of the solid state battery 101 charged at a constant current as described above was measured, and then the charge capacity per gram of the positive electrode active material layers 12, 13 (charge capacity of the positive electrode) was calculated.

[0089] <Examples 2 to 4> Except for varying the heating temperature of the positive electrode layer 10 within the range of 700°C to 500°C as shown in Table 1, each solid state battery 101 was fabricated in the same manner as in Example 1, and then the battery characteristics of each battery were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0090] <Example 5> Except for using lithium cobalt dioxide (LCO:LiCoO) instead of NCA as the positive electrode active material, a solid-state battery 101 was fabricated in the same manner as in Example 1, and then its battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0091] Example 6 Except for using lithium titanate (LTO: Li2TiO3) instead of NCA as the positive electrode active material, a solid state battery 101 was fabricated in the same manner as in Example 1, and then its battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0092] Example 7 A solid state battery 101 was fabricated in the same manner as in Example 1, except that Li3BO3 was used instead of Li2OHCl as the lithium molten salt, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0093] Example 8 A solid state battery 101 was fabricated in the same manner as in Example 1, except that Li2CO3 was used instead of Li2OHCl as the lithium molten salt, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0094] Example 9 A solid state battery 101 was fabricated in the same manner as in Example 1, except that LiSO was used instead of LiOHCl as the lithium molten salt, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0095] Example 10 A solid state battery 101 was fabricated in the same manner as in Example 1, except that Li3OCl was used instead of Li2OHCl as the lithium molten salt, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0096] Example 11 Li2(OH)Cl0.9F instead of Li2OHCl as the lithium molten salt 0.1 A solid state battery 101 was fabricated in the same manner as in Example 1, except that the above-mentioned was used, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 1.

[0097] <Comparative Example 1> Except for changing the heating temperature of the positive electrode layer 10 to 900° C., solid state batteries 101 were fabricated in the same manner as in Example 1, and then the battery characteristics of each battery were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0098] <Comparative Example 2> A solid state battery 101 was fabricated in the same manner as in Example 1, except that no heat treatment was performed when fabricating the positive electrode layer 10 and the negative electrode layer 20, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0099] <Comparative Example 3> Except for using polyvinylidene fluoride (PVDF) instead of polyimide as the positive electrode binder, a solid state battery 101 was fabricated in the same manner as in Example 1, and then its battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 2.

[0100] <Comparative Example 4> Except for the fact that no heat treatment was performed when the positive electrode layer 10 and the negative electrode layer 20 were produced and that polyvinylidene fluoride (PVDF) was used as the positive electrode binder instead of polyimide, a solid state battery 101 was produced in the same manner as in Example 1, and then its battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 2.

[0101] <Comparative Example 5> Except for using polyacrylic acid instead of polyimide as the positive electrode binder, a solid state battery 101 was fabricated in the same manner as in Example 1, and then its battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 2.

[0102] <Comparative Example 6> Except for the fact that no heat treatment was performed when the positive electrode layer 10 and the negative electrode layer 20 were produced and that polyacrylic acid was used instead of polyimide as the positive electrode binder, a solid state battery 101 was produced in the same manner as in Example 1, and then its battery characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 2.

[0103] [Table 1]

[0104] [Table 2]

[0105] [Consideration] As shown in Tables 1 and 2, a comparison of Examples 1 to 11 and Comparative Examples 1 to 6 reveals that the charge capacity can be improved by heat treating the positive electrode layer 10 and the negative electrode layer 20. This is thought to be because the heat treatment carbonizes part of the polyimide contained in the positive electrode layer 10 and the negative electrode layer 20, forming a good conductive network while maintaining elasticity and thereby achieving good conductivity.

[0106] The present disclosure has been described above with reference to several embodiments, modifications, and examples, but the configuration of the present disclosure is not limited to the configuration described above and can be modified in various ways.

[0107] Specifically, for example, in the first embodiment, the battery package 100 is described in which the solid-state battery 101 is placed on the support substrate 102A and packaged, but the battery package of the present disclosure is not limited to this form. For example, the battery package may not have a support substrate and may be sealed only by a covering insulating film or a covering inorganic film.

[0108] Furthermore, in the first embodiment, the electrode reactant is lithium, but the electrode reactant is not particularly limited. Therefore, as described above, the electrode reactant may be other alkali metals such as sodium and potassium, or alkaline earth metals such as beryllium, magnesium, and calcium. In addition, the electrode reactant may be other light metals such as aluminum.

[0109] The effects described in this specification are merely examples, and the effects of the present disclosure are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present disclosure.

Claims

1. a plurality of active material particles; a resin provided so as to connect the plurality of active material particles together, the resin being formed by partially carbonizing a polymer compound containing at least one selected from the group consisting of polyimide, polyamide, and polyamideimide, with C-C bonds and imide bonds remaining; an inorganic solid electrolyte containing a lithium salt containing at least one element selected from the group consisting of B (boron), C (carbon), S (sulfur), and Cl (chlorine); An electrode for a solid-state battery comprising:

2. The inorganic solid electrolyte is provided in the gaps between the plurality of active material particles. The electrode for a solid state battery according to claim 1 .

3. The inorganic solid electrolyte contains Li as the lithium salt. ２ CO ３ , Li ２ SO ４ , Li ３ BO ３ , Li ３ OCl, Li ２ OHCl, Li ７ P.S. ６ , Li ６ P.S. ５ Cl, Li ６ P.S. ５ Br, Li １０ GeP ２ S １２ , Li １０ SiP ２ S １２ , Li ９．５４ Si １．７４ P １．４４ S １１．７ C ｌ０．３ , Li ２ MCl ４ (M is at least one of Mg, Fe, Ni, Zn, Al, In, and Sc), and Li ３ MCl ６ (M is at least one of Al, Ga, In, Sc, and Y) The electrode for a solid state battery according to claim 1 or 2.

4. mixing active material particles, a resin containing at least one selected from the group consisting of polyimide, polyamide, and polyamideimide, and a solvent to form a slurry; applying the slurry onto a film and then drying the applied slurry to form a green sheet; carbonizing a portion of the resin in the green sheet by heating at a temperature of 500°C or higher and 800°C or lower; impregnating the green sheet in which the resin has been partially carbonized with a molten inorganic solid electrolyte; Contains A method for manufacturing electrodes for solid-state batteries.

5. A positive electrode and a negative electrode; a solid electrolyte layer interposed between the positive electrode and the negative electrode; Equipped with At least one of the positive electrode and the negative electrode is a plurality of active material particles; a resin provided so as to connect the plurality of active material particles together, the resin being formed by partially carbonizing a polymer compound containing at least one selected from the group consisting of polyimide, polyamide, and polyamideimide, with C-C bonds and imide bonds remaining; an inorganic solid electrolyte containing a lithium salt containing at least one element selected from the group consisting of B (boron), C (carbon), S (sulfur), and Cl (chlorine); have solid state battery.

6. The inorganic solid electrolyte is provided in the gaps between the plurality of active material particles. The solid-state battery according to claim 5 .

7. The inorganic solid electrolyte contains Li as the lithium salt. ２ CO ３ , Li ２ SO ４ , Li ３ BO ３ , Li ３ OCl, and Li ２ OHCl, Li ７ P.S. ６ , Li ６ P.S. ５ Cl, Li ６ P.S. ５ Br, Li １０ GeP ２ S １２ , Li １０ SiP ２ S １２ , Li ９．５４ Si １．７４ P １．４４ S １１．７ C ｌ０．３ , Li ２ MCl ４ (M is at least one of Mg, Fe, Ni, Zn, Al, In, and Sc), and Li ３ MCl ６ (M is at least one of Al, Ga, In, Sc, and Y) The solid state battery according to claim 5 or 6.

8. The solid electrolyte layer is a first solid electrolyte having a perovskite structure and a lattice constant that is an integer multiple of 3.8 Å or more and 4.1 Å or less; a second solid electrolyte having an antiperovskite structure with a lattice constant that is an integer multiple of 3.8 Å or more and 4.1 Å or less; have The solid state battery according to claim 5 or 6.

9. the first solid electrolyte has a plurality of electrolyte particles; The second solid electrolyte is provided between the plurality of electrolyte particles. The solid-state battery according to claim 8.

10. The first solid electrolyte is Li ０．３３ La ０．５６ TiO ３ and The second solid electrolyte is Li ３ OCl or Li ２ OHCl The solid-state battery according to claim 8.

11. forming a positive electrode, a negative electrode, and a solid electrolyte layer; forming a laminated structure having the positive electrode, the negative electrode, and the solid electrolyte layer; Including, The step of forming the positive electrode includes: mixing positive electrode active material particles, a first resin including at least one selected from the group consisting of polyimide, polyamide, and polyamideimide, and a first solvent to form a positive electrode slurry; forming a first green sheet by applying the positive electrode slurry onto a first film and then drying the applied positive electrode slurry; carbonizing a portion of the first resin in the first green sheet by heating at a temperature of 500° C. or higher and 800° C. or lower; impregnating the first green sheet in which a portion of the first resin has been carbonized with a molten first inorganic solid electrolyte; Including, The step of forming the negative electrode includes: mixing negative electrode active material particles, a second resin including at least one selected from the group consisting of polyimide, polyamide, and polyamideimide, and a second solvent to form a negative electrode slurry; applying the negative electrode slurry onto a second film, and then drying the applied negative electrode slurry to form a second green sheet; carbonizing a portion of the second resin in the second green sheet by heating at a temperature of 500° C. or higher and 800° C. or lower; impregnating the second green sheet in which a portion of the second resin has been carbonized with a molten second inorganic solid electrolyte; Including, The step of forming the laminated structure includes: forming a laminate by sequentially stacking the positive electrode, the solid electrolyte layer, and the negative electrode, and then impregnating the laminate with a molten third inorganic solid electrolyte; applying pressure to the laminate to bond the positive electrode, the solid electrolyte layer, and the negative electrode together, and then heating the laminate at a temperature of less than 800°C; Contains How solid-state batteries are manufactured.

12. A solid-state battery; a covering portion that covers the solid-state battery; Equipped with The solid-state battery comprises: A positive electrode and a negative electrode; a solid electrolyte layer interposed between the positive electrode and the negative electrode; Equipped with At least one of the positive electrode and the negative electrode is a plurality of active material particles; a resin provided so as to connect the plurality of active material particles together, the resin being formed by partially carbonizing a polymer compound containing at least one selected from the group consisting of polyimide, polyamide, and polyamideimide, with C-C bonds and imide bonds remaining; an inorganic solid electrolyte containing a lithium salt containing at least one element selected from the group consisting of B (boron), C (carbon), S (sulfur), and Cl (chlorine); have Battery package.

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