Electrochemical cell and manufacturing method for the same

Abstract

To provide an electrochemical cell and a manufacturing method for the same.SOLUTION: An electrochemical cell has an electrode body where a positive electrode body provided with a positive electrode layer containing a positive electrode active material on a positive current collector and a negative electrode body provided with a negative electrode layer containing a negative electrode active material on a negative current collector are laid over each other via a solid electrolyte layer between the positive electrode layer and the negative electrode layer. The solid electrolyte layer is a pseudo-solid electrolyte layer containing a non-aqueous electrolyte: 65 to 85 mass% containing lithium salt, oxide particles: 10 to 30 mass%, and binder: 1 to 5 mass%.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an electrochemical cell and a method for manufacturing the same.

Background Art

[0002] As an example of a method for manufacturing an all-solid-state battery, a manufacturing method applying the technology of a multilayer ceramic capacitor (MLCC) is known. In this manufacturing method, for example, a required number of layers such as a positive electrode layer, a negative electrode layer, and an electrolyte layer are stacked and fired all at once to form a laminate. Next, a conductive paste is applied to the side surface of the laminate and fired at the curing temperature of the conductive paste to connect the layers and collect current.

[0003] Patent Document 1 below discloses an all-solid-state battery including a positive electrode body having a positive electrode active material layer on a plurality of connected positive electrode current collectors, and a negative electrode body having a negative electrode active material layer on a plurality of connected negative electrode current collectors, with the positive electrode body and the negative electrode body folded over each other via a solid electrolyte layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the all-solid-state battery described above, even combinations of materials that cannot be fired all at once can be fired individually and provided as a battery combining a positive electrode layer, a negative electrode layer, and a solid electrolyte layer. However, since the materials that have undergone firing are hard and brittle, there is a risk of breakage if the battery is subjected to impact during manufacturing or use.

[0006] Therefore, an object of the present invention is to provide an electrochemical cell that is excellent in impact resistance and has a low risk of breakage by constructing an electrochemical cell using a soft solid electrolyte layer that does not require sintering.

Means for Solving the Problems

[0007] (1) The electrochemical cell according to the present invention has an electrode body in which a positive electrode body including a positive electrode layer containing a positive electrode active material and a negative electrode body including a negative electrode layer containing a negative electrode active material are stacked with a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, and the solid electrolyte layer is a pseudo solid electrolyte layer containing 65 to 85% by mass of a non-aqueous electrolyte containing a lithium salt, 10 to 30% by mass of oxide particles, and 1 to 5% by mass of a binder.

[0008] The electrolyte layer containing a non-aqueous electrolyte containing a lithium salt, oxide particles, and a binder in the above-mentioned ratio is a pseudo solid electrolyte layer obtained by drying a slurry and is not a fired body, so it is soft. Therefore, since it has a structure in which a soft solid electrolyte layer is disposed between the positive electrode body and the negative electrode body, it is possible to provide an electrochemical cell with a low risk of breakage even when a load such as an impact acts. In addition, since an appropriate amount of non-aqueous electrolyte as a supporting salt electrolyte exists around the oxide particles, good ionic conductivity can be obtained, contributing to the improvement of battery performance. Since the solid electrolyte layer contains an appropriate amount of oxide particles, it has an appropriate density as a partition between the positive electrode body and the negative electrode body, and exhibits good ionic conductivity while preventing short circuit between the positive and negative electrodes.

[0009] (2) In the electrochemical cell according to one embodiment of the present invention, it is preferable that the average particle diameter of the oxide particles is 5 nm or more and 50 nm or less.

[0010] For the oxide particles with the aforementioned particle size, an appropriate amount of supporting salt electrolyte can be carried on the surface of the particles, which contributes to the improvement of ionic conductivity. When the particle size of the oxide particles is smaller, the surface area for carrying the non-aqueous electrolyte as the supporting salt electrolyte becomes larger. However, particles that are too small have high aggregability, resulting in a decrease in the uniform dispersibility of the particles. If it is within the aforementioned particle size range, a solid electrolyte layer having high ionic conductivity and excellent uniform dispersibility of the oxide particles can be provided.

[0011] (3) In the electrochemical cell according to one embodiment of the present invention, it is preferable that the pseudo solid electrolyte layer contains 14 to 19% by mass of oxide particles. (4) In the electrochemical cell according to one embodiment of the present invention, it is preferable that the pseudo solid electrolyte layer contains 15 to 19% by mass of oxide particles.

[0012] By setting the oxide particles contained in the pseudo solid electrolyte to 14 to 19% by mass, an electrochemical cell with excellent rate characteristics can be provided. By setting the oxide particles to 15 to 19% by mass, an electrochemical cell with further excellent rate characteristics can be provided.

[0013] (5) In the electrochemical cell according to one embodiment of the present invention, a negative electrode body having a negative electrode layer containing a negative electrode active material on a plurality of negative electrode current collectors connected at the negative electrode connection part, a positive electrode body having a positive electrode layer containing a positive electrode active material on a plurality of positive electrode current collectors connected at the positive electrode connection part, and a solid electrolyte layer provided between the negative electrode layer and the positive electrode layer, and it is preferable to have an electrode body in which the negative electrode body and the positive electrode body are folded so that the negative electrode layer and the positive electrode layer overlap with each other via the solid electrolyte layer.

[0014] According to the aforementioned electrochemical cell, for the separately formed negative electrode body and positive electrode body, an electrochemical cell can be fabricated by folding them so that the negative electrode layer and the positive electrode layer overlap with each other via the solid electrolyte layer.

[0015] (6) In the electrochemical cell according to one embodiment of the present invention, it is preferable that the electrode body is housed in a container-shaped exterior body.

[0016] By housing the electrode body in an exterior body, an electro-chemical cell having a robust structure that can withstand external forces, loads, etc. can be provided.

[0017] (7) In the method for manufacturing an electro-chemical cell according to one embodiment of the present invention, a non-aqueous electrolyte containing a lithium salt, oxide particles, and a binder are put into a solvent at a predetermined ratio and mixed, and then the solvent is volatilized by heat treatment to prepare a slurry of a pseudo solid electrolyte containing 65 to 85% by mass of the non-aqueous electrolyte containing a lithium salt, 10 to 30% by mass of oxide particles, and 1 to 5% by mass of the binder. A pseudo solid electrolyte sheet can be prepared using the slurry, and an electrode body can be prepared by stacking a positive electrode body and a negative electrode body via a solid electrolyte layer obtained from the pseudo solid electrolyte sheet.

[0018] The solid electrolyte layer containing a non-aqueous electrolyte containing a lithium salt, oxide particles, and a binder in the aforementioned ratio is a pseudo solid electrolyte obtained by drying the slurry and is not a fired body, so it is soft. For this reason, since it has a structure in which a soft solid electrolyte layer is disposed between the positive electrode body and the negative electrode body, an electro-chemical cell with a low risk of breakage can be provided even when a load such as an impact acts. In addition, since an appropriate amount of non-aqueous electrolyte serving as a supporting salt exists around the oxide particles, good ion conductivity can be obtained, contributing to an improvement in battery performance. Since the solid electrolyte layer contains an appropriate amount of oxide particles, it has an appropriate density for partitioning the positive electrode body and the negative electrode body, and exhibits good ion conductivity while preventing short-circuiting between the positive and negative electrodes.

[0019] (8) In the method for manufacturing an electro-chemical cell according to one embodiment of the present invention, it is preferable to include 14 to 19% by mass of oxide particles in the slurry. (9) In the method for manufacturing an electro-chemical cell according to one embodiment of the present invention, it is preferable to include 15 to 19% by mass of oxide particles in the slurry.

[0020] By setting the oxide particles contained in the pseudo solid electrolyte to 14 to 19% by mass, an electro-chemical cell having excellent rate characteristics can be manufactured. By setting the oxide particles contained in the suspected solid electrolyte to 15 to 19% by mass, an electrochemical cell with further excellent rate characteristics can be manufactured.

[0021] (10) In the method for manufacturing an electrochemical cell according to one embodiment of the present invention, a negative electrode body including a negative electrode layer containing a negative electrode active material and a solid electrolyte layer covering the surface of the negative electrode layer on a plurality of negative electrode current collectors connected at the negative electrode connection portion, and a positive electrode body including a positive electrode layer containing a positive electrode active material on a plurality of positive electrode current collectors connected at the positive electrode connection portion are used, and the negative electrode body and the positive electrode body are overlapped with each other so as to overlap the negative electrode layer and the positive electrode layer via the solid electrolyte layer to form an electrode body, and it is preferable to accommodate the electrode body in an exterior body.

[0022] The target electrode body can be formed by overlapping a negative electrode body having a solid electrolyte layer on a negative electrode layer and a positive electrode body having a positive electrode layer. By accommodating the electrode body in an exterior body, an electrochemical cell having a robust structure that can withstand external forces and loads can be provided.

[0023] (11) In the method for manufacturing an electrochemical cell according to the present invention, it is preferable that the exterior body is an exterior body composed of a positive electrode side laminate film and a negative electrode side laminate film.

[0024] By configuring the exterior body from a laminate film, a lightweight electrochemical cell can be provided. By configuring the exterior body from a positive electrode side container and a negative electrode side container, when a positive electrode side electrode plate is provided in the positive electrode side container and a negative electrode side electrode plate is provided in the negative electrode side container, the positive electrode body and the negative electrode body of the electrode body can be easily connected. The positive electrode side container and the negative electrode side container made of a laminate film can be easily integrated by heat-sealing their peripheral wall portions, and an electrochemical cell having a lightweight and highly airtight exterior body can be provided.

[0025] (12) In the method for manufacturing an electrochemical cell according to the present invention, it is preferable to overlap and heat-seal the peripheral wall of the positive electrode side container and the peripheral wall portion of the negative electrode side container.

[0026] The positive electrode side container and the negative electrode side container made of a laminated film can be easily integrated by heat-sealing their peripheral wall portions, and an electrochemical cell provided with a lightweight and highly airtight exterior body can be provided.

[0027] (13) In the method for manufacturing an electrochemical cell according to the present invention, the electrode body in which the positive electrode body and the negative electrode body are stacked via the solid electrolyte layer can be housed inside a metal exterior body.

[0028] An electrochemical cell can be configured by housing a positive electrode body and a negative electrode body stacked via a solid electrolyte layer in a metal exterior body.

[0029] (14) In the method for manufacturing an electrochemical cell according to the present invention, the electrode body in which the positive electrode body and the negative electrode body are stacked via the solid electrolyte layer can be housed inside a metal exterior body together with an electrolytic solution.

[0030] An electrochemical cell can be configured by housing a positive electrode body and a negative electrode body stacked via a solid electrolyte layer in a metal exterior body together with an electrolytic solution.

Advantages of the Invention

[0031] In the electrochemical cell according to the present invention, the solid electrolyte layer containing a non-aqueous electrolyte containing a lithium salt, oxide particles, and a binder in an appropriate ratio is a pseudo solid electrolyte obtained by drying a slurry and is not a fired body, and thus is soft. For this reason, since it has a structure in which a soft pseudo solid electrolyte layer is disposed between the positive electrode body and the negative electrode body, an electrochemical cell with a low risk of breakage can be provided even when a load such as an impact acts. Further, since a non-aqueous electrolyte serving as an appropriate amount of supporting salt exists around the oxide particles, good ion conductivity can be obtained, contributing to an improvement in battery performance. Since the solid electrolyte layer contains an appropriate amount of oxide particles, an electrochemical cell having an appropriate density as a partition between the positive electrode body and the negative electrode body and exhibiting good ion conductivity while preventing short circuit between the positive and negative electrodes can be provided.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Embodiments for Carrying Out the Invention

[0033] Hereinafter, embodiments of the electrochemical cell according to the present invention will be described with reference to the drawings. In the following embodiments, as an example of the electrochemical cell, a coin-type all-solid-state battery (hereinafter simply referred to as "battery") will be cited, and the configuration of this battery will be described. In the drawings used in the following description, in order to make each member recognizable in size, the scale of each member is appropriately changed and displayed.

[0034] <First Embodiment> Figs. 1 to 4 are drawings showing a first embodiment in which the electrochemical cell according to the present invention is applied to an all-solid-state battery. The battery (electrochemical cell) 1 of this embodiment is a button-type battery having a circular shape in plan view. This battery 1 includes a container-shaped exterior body 2 and an electrode body 3 housed inside the exterior body 2.

[0035] (Exterior body) As shown in Fig. 4, the exterior body 2 includes a housing portion 4 that houses the electrode body 3, and a sealing portion 5 that is bent along the outer periphery of the housing portion 4. The sealing portion 5 is bent along the outer periphery of the housing portion 4 by, for example, drawing molding. The exterior body 2 includes a first container (outer container) 7 and a second container (inner container) 8 that sandwich the electrode body 3 therebetween. The first container 7 and the second container 8 are each formed of a laminate film (laminate structure). The laminate film has a metal foil (metal layer), a fusion layer (resin layer) provided on the overlapping surface (inner surface) that covers the metal foil, and a protective layer (resin layer) provided on the outer surface that covers the metal foil. The metal layer is formed of a metal foil that blocks outside air and water vapor, and is made of, for example, aluminum or stainless steel. The fusion layer on the overlapping surface is formed of, for example, a single body or copolymer of a thermoplastic resin such as polyethylene or polypropylene of polyolefin. The protective layer on the outer surface is formed of, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, nylon, etc. For example, the first container 7 is made of a negative electrode side laminate film, and the second container 8 is made of a positive electrode side laminate film.

[0036] The first container (negative electrode side container; outer container) 7 includes a circular first bottom wall portion 6 and a first peripheral wall portion 9 extending cylindrically from the outer periphery of the first bottom wall portion 6. A first through hole 23 having an inner diameter about one fraction of the inner diameter of the first bottom wall portion 6 is formed at the center of the first bottom wall portion 6. On the inner surface side of the first bottom wall portion 6, a negative electrode side electrode plate 26 such as a nickel plate or a metal plate nickel-plated on a copper plate is heat-sealed via a ring-shaped first seal film (negative electrode side seal film) 24. The first seal film 24 is formed by molding a seal film made of a thermoplastic resin such as polyethylene or polypropylene of polyolefin into a ring shape. One side of the first seal film 24 is heat-sealed to the first bottom wall portion 6 of the first container 7, and the other side of the first seal film 24 is heat-sealed to the negative electrode side electrode plate 26.

[0037] The negative electrode side electrode plate 26 is exposed to the outside of the battery 1 through the first through hole 23 and functions as the negative electrode terminal of the battery 1. The negative electrode tab 13 of the electrode body 3 described later is connected to the negative electrode side electrode plate 26 by a joining means such as ultrasonic welding.

[0038] The second container (positive electrode side container: inner container) 8 includes a disk-shaped second bottom wall portion 31, a second peripheral wall portion 32 extending cylindrically from the outer peripheral edge of the second bottom wall portion 31, and a bent peripheral wall portion 33 bent in a U-shaped cross section from the opening edge of the second peripheral wall portion 32 toward the outside of the second peripheral wall portion 32 and extending toward the second bottom wall portion 31 side. The second bottom wall portion 31 is disposed on the opposite side of the first bottom wall portion 6 of the first container 7 with the electrode body 3 interposed therebetween. The second bottom wall portion 31 is formed to have the same outer diameter as the first bottom wall portion 6 of the first container 7. A second through hole 35 having an inner diameter about one fraction of the inner diameter of the second bottom wall portion 31 is formed at the center of the second bottom wall portion 31.

[0039] On the inner surface side of the second bottom wall portion 31, a positive electrode side electrode plate 38 is thermally fused via a ring-shaped second seal film (seal film on the positive electrode side) 37. It is preferable that a protective plate made of a nickel plate, an Au-plated plate, etc. is welded to the center of the outer surface of the positive electrode side electrode plate 38. If a plating layer such as nickel or a nickel alloy is formed on the outer surface of the positive electrode side electrode plate 38, the protective plate may be omitted. The second seal film 37 is formed of a thermoplastic resin, similar to the first seal film 24.

[0040] The central portion of the positive electrode side electrode plate 38 is connected to a positive electrode tab 21 (see FIGS. 8 and 13) of the electrode body 3 described later. In FIG. 3, since the internal structure is complex, the tab connection portion is not shown. The positive electrode side electrode plate 38 is made of a stainless steel plate having excellent corrosion resistance such as SUS316 and functions as a positive electrode terminal of the battery 1.

[0041] As shown in FIG. 4, the second peripheral wall portion 32 extends in a cylindrical shape from the outer periphery of the second bottom wall portion 31 toward the first bottom wall portion 6 of the first container 7. The second peripheral wall portion 32 forms the outer periphery of the accommodating portion 4. The bent peripheral wall portion 33 is bent from the end portion on the first bottom wall portion 6 side of the second peripheral wall portion 32 along the second peripheral wall portion 32 so as to be cylindrical toward the second bottom wall portion 31 side. The bent peripheral wall portion 33 is arranged at a distance outside the second peripheral wall portion 32. The second peripheral wall portion 32 is arranged inside the first peripheral wall portion 9. Also, the bent peripheral wall portion 33 is arranged inside the first peripheral wall portion 9, and the fusion layer of the bent peripheral wall portion 33 and the fusion layer of the first peripheral wall portion 9 are thermally fused.

[0042] By fusing the fusion layer of the bent peripheral wall portion 33 and the fusion layer of the first peripheral wall portion 9, a sealing portion 5 is formed. Thus, the outer periphery of the accommodating portion 4 is sealed by the sealing portion 5. With the above structure, the first container 7 and the second container 8 are overlapped and joined to form the exterior body 2. The sealing portion 5 is formed in a cylindrical shape outside the accommodating portion 4. In the housing portion 4, a sealed space is formed by overlapping the first container 7 and the second container 8. Specifically, the housing portion 4 is defined by a first bottom wall portion 6, a second bottom wall portion 31, and a second peripheral wall portion 32, and is formed in a circular shape in plan view.

[0043] (Electrode body) Figs. 3 to 5 are views showing the electrode body 3 of the present embodiment. The electrode body 3 has a laminated structure in which a plurality of structures in which a negative electrode layer 14 and a positive electrode layer 16 are laminated via a solid electrolyte layer 15 are laminated. As shown in Fig. 6, the negative electrode body 10 is a strip-shaped structure having a plurality of disk-shaped negative electrode current collectors 11 and a negative electrode connection portion 12 connecting these negative electrode current collectors 11. The negative electrode body 10 is made of, for example, a copper foil. In the negative electrode body 10, negative electrode layers 14 such as metallic lithium are formed on both the front and back surfaces of the negative electrode current collector 11 by means such as vapor deposition. In the negative electrode body 10 shown in Fig. 6, ten negative electrode current collectors 11 are provided, and they are linearly connected by a strip-shaped negative electrode connection portion 12. A strip-shaped negative electrode tab 13 is extended from the negative electrode current collector 11 on one end side in the length direction of the negative electrode body 10 so as to extend the arrangement direction of the negative electrode connection portion 12.

[0044] The negative electrode current collector 11 is formed of a metal material such as copper, nickel, or stainless steel. The negative electrode layer 14 contains a negative electrode active material, a conductive assistant, a binder, a thickener, and the like. For example, the negative electrode layer 14 is formed of a carbon material such as graphite. For example, examples of the conductive assistant include carbon blacks, carbon materials, and metal fine powders. For example, examples of the binder include resin materials such as polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). For example, examples of the thickener include resin materials such as carboxymethyl cellulose (CMC). Alternatively, the negative electrode layer 14 may be a vapor deposition film of metallic lithium vapor-deposited by a resistance heating vapor deposition method or the like. The negative electrode layer 14 may be a layer of metallic lithium attached by a thermal pressure bonding method such as hot pressing or an adhesion method using an alloying reaction.

[0045] In the negative electrode body 10, the negative electrode current collector 11 provided with the negative electrode tab 13 can be referred to as the first negative electrode current collector 11, and a total of 10 negative electrode current collectors 11 are provided in the negative electrode body 10, namely the second negative electrode current collector 11 to the tenth negative electrode current collector 11 in sequence. In the structure shown in FIG. 6, the negative electrode layer 14 is vapor-deposited only on one side of only the first negative electrode current collector 11, and the negative electrode layer 14 on the other side is omitted. The negative electrode layer 14 is vapor-deposited on both the front and back surfaces of the second negative electrode current collector 11 to the tenth negative electrode current collector 11. It should be noted that the reason for providing the negative electrode layer 14 only on one side of only the first negative electrode current collector 11 is to avoid an inadvertent reaction because when the negative electrode layer 14 is provided on both surfaces of the first negative electrode current collector 11, in the case of the folding structure described later, the negative electrode layer 14 on one surface of the first negative electrode current collector 11 will be exposed. If there is no concern about the aforementioned inadvertent reaction, the negative electrode layer 14 may be provided on both surfaces of the first negative electrode current collector 11.

[0046] FIG. 7 shows a negative electrode composite body 17 in which a solid electrolyte layer 15 is applied and dried on the surface side of the negative electrode layer 14 disposed on both surfaces of the negative electrode body 10 shown in FIG. 6. In the negative electrode composite body 17, the solid electrolyte layer 15 is formed only on the side where the negative electrode layer 14 is provided on the first negative electrode current collector 11. In addition, on the second negative electrode current collector 11 to the tenth negative electrode current collector 11, a substantially circular negative electrode layer 14 and a solid electrolyte layer 15 are formed on both the front and back surfaces in plan view, respectively. The surface of the solid electrolyte layer 15 is shown enlarged in FIG. 9, and the state where the negative electrode layer 14 is provided on the back surface side of the solid electrolyte layer 15 is shown in FIG. 10. In order to facilitate the folding structure described later, it is preferable to provide a flat portion 15a in which a part of the outer peripheral edge of the solid electrolyte layer 15 is cut out. In the example shown in FIGS. 9 and 10, four flat portions 15a are formed at intervals of 90° around the outer periphery of the solid electrolyte layer 15.

[0047] FIG. 8 shows a positive electrode body 18, and this positive electrode body 18 has a strip-like structure in which ten disc-shaped positive electrode current collectors 19 made of a metal foil are linearly connected by a positive electrode connection portion 20 made of a metal foil, and disc-shaped positive electrode layers are formed on the front and back surfaces of the positive electrode current collectors 19. Also in the positive electrode body 18, similar to the negative electrode body 10 shown in FIG. 6, the positive electrode layers 16 are formed on both the front and back surfaces of the second to tenth positive electrode current collectors 19. And the positive electrode layer 16 is formed only on one side of the first positive electrode current collector 19, and the positive electrode layer 16 on the other side is omitted (see FIG. 8(b)). A strip-shaped positive electrode tab 21 is formed on the positive electrode current collector 19 at one end side in the length direction of the positive electrode body 18 so as to extend in the arrangement direction of the positive electrode connection portion 20.

[0048] The positive electrode current collector 19 is formed of a metal material such as aluminum, an aluminum alloy, or stainless steel. The positive electrode layer 16 is composed of a metallic lithium layer or a layer containing a positive electrode active material, a conductive assistant, a binder, a thickener, and the like. For example, the positive electrode active material layer is formed of a composite metal oxide such as lithium cobaltate or lithium nickelate. For example, examples of the conductive assistant include carbon blacks, carbon materials, and metal fine powders. For example, examples of the binder include resin materials such as polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). For example, examples of the thickener include resin materials such as carboxymethyl cellulose (CMC).

[0049] The electrode body 3 is configured by alternately laminating the negative electrode composite body 17 shown in FIG. 7 and the positive electrode body 18 shown in FIG. 8. As an example, as shown in FIG. 11, the negative electrode composite body 17 is arranged obliquely sideways in the front so that the negative electrode tab 13 and the first negative electrode current collector 11 are positioned on the left side. On the other hand, the positive electrode body 18 and the negative electrode composite body 17 are arranged in an L shape so that the tenth positive electrode current collector 19 of the positive electrode body 18 approaches the first negative electrode current collector 11 of the negative electrode composite body 17.

[0050] From this state, as shown in FIG. 12, the tenth positive electrode layer 16 of the positive electrode body 18 is stacked on the first solid electrolyte layer 15 of the negative electrode composite body 17, and after stacking, the negative electrode composite body 17 and the positive electrode body 18 are alternately bent and stacked with the negative electrode connection portion 12 or the positive electrode connection portion 20 of each other as a base point. By this folding process, the tenth positive electrode layer 16 of the positive electrode body 18 can be folded onto the first negative electrode layer 14 of the negative electrode composite 17 via the solid electrolyte layer 15. Thereafter, the second solid electrolyte layer 15 of the negative electrode composite 17 is stacked on the tenth positive electrode layer 16 of the positive electrode body 18, and then a folding process is performed in which the ninth positive electrode layer 16 of the positive electrode body 18 is folded onto the second solid electrolyte layer 15 of the negative electrode composite 17. By folding the negative electrode composite 17 and the positive electrode body 18 in order and stacking the layers on top of each other in this way, and by folding back the last positive electrode tab 21, an electrode body 3 having a folded structure in which the positive electrode tab 21 is folded back on the positive electrode side as shown in FIG. 13 can be obtained. Further, by folding back the negative electrode tab 13, the negative electrode tab 13 on the negative electrode side of the electrode body 3 is folded back to the negative electrode side of the electrode body 3 as shown in FIG. 14.

[0051] As described above, an electrode body 3 in which a negative electrode composite 17 having a negative electrode layer 14 containing a negative electrode active material on a plurality of negative electrode current collectors 11 connected by a negative electrode connection portion 12 and a positive electrode layer 16 containing a positive electrode active material pasted thereon via a solid electrolyte layer 15, and a positive electrode body 18 having a plurality of positive electrode current collectors 19 connected by a positive electrode connection portion 20 are alternately folded can be obtained.

[0052] (Detailed structure of the solid electrolyte layer) As an example, the solid electrolyte layer 15 is composed of a pseudo solid electrolyte layer containing 65 to 85% by mass of a non-aqueous electrolyte containing a lithium salt, 10 to 30% by mass of oxide particles, and 1 to 5% by mass of a binder.

[0053] To manufacture the solid electrolyte layer 15, a non-aqueous electrolyte containing a lithium salt, oxide particles, and a binder are put into a solvent at a predetermined ratio and stirred to prepare a slurry. A plasticizer or a dispersant may be added to the solvent. This slurry is applied to the surface of the carrier film to a required thickness by the doctor blade method, sheet forming method, etc., and this coated product is heat-treated in the atmosphere, an electric furnace, etc. and dried to obtain a pseudo solid electrolyte sheet. This pseudo solid electrolyte sheet is peeled off from the carrier film so as to have a required shape to obtain a solid electrolyte layer 15 which is a pseudo solid electrolyte layer. It may be printed in a planar shape shown in Fig. 9 in advance by a coating method such as the doctor blade method described above, or after punching into the planar shape shown in Fig. 9 by a method such as punching, the solid electrolyte layer 15 may be peeled off from the carrier film. The drying of the pseudo solid electrolyte layer may be actively heated in an electric furnace or the like to volatilize the solvent and dry it, or it may be dried in the atmosphere.

[0054] As the solvent used when mixing the non-aqueous electrolyte, oxide particles, and binder, one or a mixture of two or more of NMP (N-methyl-2-pyrrolidone), 1-propanol, 2-propanol, ethanol, acetone, ethylene carbonate, and propylene carbonate can be used.

[0055] In the non-aqueous electrolyte containing the lithium salt, as the lithium salt, LiTFSI (lithium bis(fluorosulfonyl)imide), LiFSI (bisfluorosulfonylimide), LiPF6 (lithium hexafluorophosphate), LiBF4 (lithium borofluoride), LiClO4 (lithium perchlorate), etc. can be used. As the solvent used for the non-aqueous electrolyte, cyclic carbonates, chain carbonates, chain ethers, cyclic sulfones, etc. can be used. As the cyclic carbonate, propylene carbonate (PC), ethylene carbonate (EC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), etc. can be used. As the chain carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), etc. can be used. As the chain ether, glyme solvents such as dimethoxyethane (DME) and tetraglyme can be used. As the cyclic sulfone, sulfolane and the like can be used.

[0056] The non-aqueous electrolyte contained in the solid electrolyte layer 15 is desirably in the range of 65% by mass or more and 85% by mass or less. If the content of the non-aqueous electrolyte is within the above range, when more non-aqueous electrolyte is applied than the amount of the non-aqueous electrolyte supported on the oxide particles, the excess non-aqueous electrolyte will penetrate into the positive electrode layer 16 (or the negative electrode layer 14), and the battery contact with the solid electrolyte layer 15 formed by coating will be good, the ion conduction will be high, and the battery performance will be improved.

[0057] The oxide particles contained in the solid electrolyte layer 15 are desirably 10% by mass or more and 30% by mass or less. Regarding the content of the oxide particles, the range of 14 to 30% by mass is more preferable, and the range of 15 to 30% by mass is most preferable. By setting the content of the oxide particles within the above preferable range, the discharge rate characteristics (current characteristics of the discharge capacity) when the battery 1 is configured can be improved. As described above, the solid electrolyte layer 15 containing the non-aqueous electrolyte containing the lithium salt, the oxide particles, and the binder in an appropriate ratio will have an appropriate amount of non-aqueous electrolyte serving as a supporting salt around the oxide particles. Therefore, good ion conductivity can be obtained, which contributes to the improvement of the discharge rate characteristics. Since the solid electrolyte layer 15 contains an appropriate amount of oxide particles in the above range, it has an appropriate density as a partition between the positive electrode body 18 (positive electrode layer 16) and the negative electrode body 10 (negative electrode layer 14), and exhibits good ion conductivity while preventing short circuit between the positive and negative electrodes. The average particle diameter (median diameter: D 50 ) of the oxide particles is desirably 5 nm or more and 50 nm or less. The oxide particles contained in the solid electrolyte layer 15 can be selected. As the material constituting the particles, for example, as a non-ionic conductive material, one or more of SiO2, Al2O3, TiO2, ZrO2, and MgO can be used. Alternatively, as the material constituting the particles, as an ion conductive material, Li1.3 Al 0.3 Ti 1.7 (PO)4, Li 1.5 Al 0.5 Ge 1.5 (PO)4, Li7La3Zr2O 12 , Li5La3Ta2O 12 Among these, one or more than two kinds can be used. When the content of the oxide particles contained in the solid electrolyte layer 15 is small, the density of the solid electrolyte layer 15 decreases, so there is a risk of short circuit between the positive and negative electrodes. If the content of the oxide particles is within the above-mentioned range, there is no risk of short circuit between the positive and negative electrodes, and the ionic conductivity becomes high.

[0058] The amount of the non-aqueous electrolyte supported by the oxide particles is considered to affect the specific surface area of the oxide particles. The smaller the particle size of the oxide particles, the larger the specific surface area, and the amount of the non-aqueous electrolyte supported increases, so the ionic conductivity becomes high. However, when the particle size of the oxide particles becomes small, the aggregability of the particles becomes high, causing a problem that the oxide particles cannot be uniformly dispersed. When the particle size of the oxide particles is larger than 50 nm, the ionic conductivity becomes low, but the problem of particle dispersibility hardly occurs. If the average particle diameter (D 50 ) of the oxide particles is within the above-mentioned range (5 nm or more and 50 nm or less), high ionic conductivity can be obtained, and a solid electrolyte layer 15 in which the particles are uniformly dispersed can be obtained. The average particle diameter of the oxide particles can be the particle diameter at the cumulative 50% on a volume basis determined by a general laser diffraction / scattering method.

[0059] The binder contained in the solid electrolyte layer 15 is desirably 1% by mass or more and 5% by mass or less. As the material forming the binder, one or more of PVdF (polyvinylidene fluoride), PVdF-HFP (hexafluoropropylene), PVA (polyvinyl alcohol), PVB (polybutyral), PVP (polyvinylpyrrolidone), PEO (polyethylene oxide), and PEG (polyethylene glycol) can be used. Multiple binders may be used in combination. For example, PVdF can be used to improve the mechanical strength of the solid electrolyte layer 15, and PEO can be used to impart flexibility to the solid electrolyte layer 15.

[0060] As described above, the solid electrolyte layer 15 with the aforementioned configuration is used by being adhered to the surface of the negative electrode layer 14 as explained previously with reference to FIG. 7. To adhere the solid electrolyte layer 15 to the negative electrode layer 14, a thermal pressure bonding method using hot pressing may be employed, or the aforementioned slurry may be directly applied to the surface of the negative electrode layer 14 and dried.

[0061] If the electrode body 3 shown in FIGS. 13 and 14 is obtained as described above, it is housed inside the exterior body 2. Next, the negative electrode tab 13 is joined to the negative electrode side electrode plate 26 of the first container 7 and the positive electrode tab 21 is joined to the positive electrode side electrode plate 38 of the second container 8 by bonding methods such as pasting with conductive paste or welding. Next, the electrochemical cell 1 can be obtained by thermally fusing the peripheral wall portions of the first container 7 and the second container 8. Any method such as laser welding, resistance welding, or ultrasonic welding may be used for tab welding. Also, a metal plate of Ni, Al or a metal plate with good corrosion resistance such as a stainless steel plate may be pasted on the outer surface sides of the negative electrode side electrode plate 26 and the positive electrode side electrode plate 38.

[0062] Also, in the above manufacturing method, the production pattern and order are not particularly limited, and various methods can be adopted. For example, in the negative electrode body 10, the solid electrolyte layer 15 is not formed on the surface of the negative electrode layer 14, and the solid electrolyte layer 15 is formed on the surface side of the positive electrode layer 16 of the positive electrode body 18. The electrode body can also be configured by alternately folding the negative electrode body 10 without the solid electrolyte layer 15 and the positive electrode body 18 with the solid electrolyte layer 15. Each time they are folded, the solid electrolyte layer 15 is sandwiched between the negative electrode layer 14 and the positive electrode layer 16. In this way, a positive electrode body having a positive electrode layer 16 containing a positive electrode active material on a plurality of positive electrode current collectors 19 connected by a positive electrode connection portion 20 and a negative electrode body 10 having a negative electrode layer 14 containing a negative electrode active material on a plurality of negative electrode current collectors 11 connected by a negative electrode connection portion 12 can be obtained by interposing a solid electrolyte layer 15 between the positive electrode layer 16 and the negative electrode layer 14 and laminating them on top of each other.

[0063] There are no particular restrictions on the materials used when manufacturing the above-described battery 1, but in addition to the components described so far, the following can be exemplified. · Positive electrode active material or negative electrode active material: Carbon-based materials such as soft carbon and hard carbon, lithium, sulfur. Oxides containing or not containing Li can be used. · Conductive assistant: Carbon black, acetylene black, etc. can be added. · Material of current collector: Copper, aluminum, SUS, nickel, etc. can be selected. · Solvent: Water, alcohol-based, ketone-based, etc. can be selected. · A dispersant and a plasticizer may be added. General dispersants and plasticizers used when producing a green sheet can be added.

[0064] · Dimensions of the battery: The thickness of each of the positive electrode layer, negative electrode layer, and electrolyte layer can be 100 μm or less. The diameter can be 20 mm or less. · The thickness of the current collector foil can be 20 μm or less. · Exterior: Any one of a metal laminate, a metal can, a resin coating, and an oxide coating can be selected. · Shape of the electrode body: Examples include circular, elliptical, polygonal, etc.

[0065] Composition of the positive electrode layer: Li 1.3 Al 0.3 Ti 1.7 P3O 12 In the case of, a mixture with graphite can be selected, and for the firing conditions: 800 °C, in order to suppress the combustion of graphite, a nitrogen, argon, or vacuum atmosphere can be selected. Composition of the negative electrode layer: Lithium (unfired) can be selected as the negative electrode active material.

[0066] ·Those that cannot be sintered in one batch Li, which is a common oxide-based solid electrolyte 1.5 Al 0.5 Ge 1.5 P3O 12 (LAGP) and other glass-ceramic systems have a firing temperature of about 800 °C. Li7La3Zr2O 12 (LLZ) and other crystal systems are above 1000 °C. Therefore, as active materials, lithium (melting point about 180 °C), which is attracting attention for its high energy density, sulfur (melting point 115 °C), etc. cannot be used as battery constituent materials in the case of one-batch sintering. Aluminum (melting point about 660 °C), which is common as a current collector, also cannot be used. In contrast, in the above example, since the solid electrolyte layer 15 containing a non-aqueous electrolyte is used, there is no problem of heat when using lithium, sulfur, or aluminum. For this reason, the electrochemical cell 1 with excellent battery characteristics can be obtained.

[0067] "Method for manufacturing a laminate container" When manufacturing the battery 1 provided with the exterior body 2 having a structure made of the laminate film shown in FIGS. 1 to 4, it can be manufactured by the method described below based on FIGS. 15 to 17. For example, prepare a disk-shaped first container material 115 made of a laminate film shown in FIG. 15 and a hat-shaped second container material 116 made of a laminate film. The electrode body 3 is accommodated inside the protrusion 117 of the second container material 116, the electrodes are connected, and the outer peripheral portion 116a of the second container material 116 and the outer peripheral portion 115a of the first container material 115 are overlapped and joined by a joining method such as thermal welding to form a joined body 118 shown in FIG. 15. Next, prepare a mold 120 composed of a lower mold 121 and an upper mold 122 and a punch 123 as shown in FIG. 16. Forming holes 121a and 122a into which the protrusion 117 of the joined body 118 can be loosely inserted are formed at the central portions of the lower mold 121 and the upper mold 122, and the outer peripheral portion of the joined body 118 is clamped between the lower mold 121 and the upper mold 122.

[0068] In addition, a forming protrusion 124 made of an annular wall is provided at the upper end of the punch 123, and the punch 123 can be raised from the position shown in Fig. 16 while sandwiching the outer peripheral portion of the joined body 118 between the lower die 121 and the upper die 122. As shown in Fig. 17, when the forming protrusion 124 is raised from the forming hole 121a to 122a, the outer peripheral portion of the joined body 118 can be cut from the outer peripheral edge portion of the joined body 118 while processing the outer peripheral portion of the joined body 118 into a reverse U-shaped cross section by the forming protrusion 124 over the entire circumference. By this pressing process, the battery 1 provided with the exterior body 2 shown in Figs. 1 to 4 can be obtained.

[0069] In this specification, as described above, various shapes can be adopted for the negative electrode composite and the positive electrode body, and various shapes can also be adopted for the folded structure, and it goes without saying that it is not limited to the examples described so far. Note that, as an example of the electrochemical cell according to the present invention, a button-type exterior body 2 having a circular shape in plan view and composed of the above-described laminate film-made first container 7 and second container 8 has been given. However, the present invention is not limited to this, and either one or both of the first container and the second container may be a metal container. Further, an exterior body using a bottomed cylindrical metal positive electrode can, a lid-shaped metal negative electrode can for closing the opening of the positive electrode can, and a gasket for insulating the positive electrode can and the negative electrode can may be used, and the shape and structure of the exterior body can be widely applied to general ones for batteries.

Example

[0070] <First Embodiment> As a non-aqueous electrolyte, a non-aqueous electrolyte solution in which LiPF6 was mixed to be 1 M in a solvent in which VC was added at 2% by weight to a mixed solution of EC:PC:EMC in a volume ratio of 1:1:1 was prepared. As the oxide particles, SiO2 particles (average particle diameter 35 nm (D 50 )) were prepared. The binder was prepared by mixing PEO and PVdF-HFP at a weight ratio of 1:2. The above non-aqueous electrolyte was prepared at a ratio of 85% by mass, oxide particles (SiO2 particles) at 14% by mass, and binder (PEO + PVdF-HFP) at 1% by mass. First, the non-aqueous electrolyte and oxide particles were put into an acetone solvent and mixed, and then the binder was added to the acetone solvent and mixed to obtain a slurry-like mixture.

[0071] For a negative electrode body in which ten disc-shaped negative electrode current collectors made of copper foil shown in Fig. 6 were connected by a strip-shaped negative electrode connection part, lithium was thermocompression-bonded to both sides of the negative electrode current collector to form a lithium layer, and a negative electrode composite was obtained. For a positive electrode body in which ten disc-shaped positive electrode current collectors made of aluminum foil shown in Fig. 8 were connected by a strip-shaped positive electrode connection part, a slurry-like mixture composed of 67.6% by mass of lithium cobaltate (LiCoO2) as a positive electrode active material, 21.0% by mass of PVDF as a binder, 1.8% by mass of acetylene black as a conductive assistant, and 9.6% by mass of NMP as a solvent was applied to both sides of the positive electrode current collector by the doctor blade method and dried in the air, thereby forming a positive electrode layer containing a positive electrode active material on both sides of the positive electrode current collector, and a positive electrode body was obtained. Furthermore, the above slurry-like mixture was applied to both sides of the positive electrode body by the doctor blade method to form a disc-shaped coating layer (thickness 40 μm), and the coating layer was dried in the air. By drying, the coating layer can be used as a quasi-solid electrolyte layer, and a positive electrode composite having a positive electrode layer and a quasi-solid electrolyte layer on both the front and back surfaces of the positive electrode current collector was obtained. The negative electrode composite and the positive electrode composite were alternately folded according to the fixation shown in Figs. 11 and 12, and the folded structure was pressed to form an electrode body. When the energization test of this electrode body was carried out, the generation of voltage was confirmed. Then, the electrode body was sealed in an exterior body made of a laminate film to fabricate a battery. This battery was pre-charged (formed) to 3.9 V at 0.02C (charging current 0.2 mA). Then, it was charged to 4.2 V under the conditions of CC (0.1C, 1.4 mA) / CV (0.05C, 0.7 mA cut-off), discharged to 3.0 V at 0.1C, and then the charge-discharge capacity was measured under the same charge-discharge conditions. As a result, a sufficient capacity as a battery could be obtained as shown in the graph of Fig. 18.

[0072] <Second Embodiment> Figures 19 to 21 are drawings showing a second embodiment in which the electrochemical cell according to the present invention is applied to a all-solid-state battery. The electrochemical cell (battery) 50 of this embodiment is a button-type battery having a circular shape in plan view shown in FIG. 21. This battery 50 includes an exterior body 52 made of a container-shaped metal can and an electrode body 53 housed inside the exterior body 52. The exterior body 52 consists of a negative electrode side metal can 55 and a positive electrode side metal can 56. Inside the negative electrode side metal can 55, a negative electrode body 57 and a solid electrolyte layer 58 are housed as shown in FIG. 19. Inside the positive electrode side metal can 56, a positive electrode body 59 is housed as shown in FIG. 20. The negative electrode side metal can 55 is formed in a covered cylindrical shape (hat shape) having a circular substrate 55a and a peripheral wall 55b erected from the periphery of this substrate 55a.

[0073] The positive electrode side metal can 56 is formed in a bottomed cylindrical shape having a circular substrate 56a and a peripheral wall 56b erected from the periphery of this substrate 56a. Although not shown in FIG. 19, the negative electrode body 57 is electrically connected to the substrate 55a via a conductive adhesive layer such as a conductive paste layer. Similarly, although not shown in FIG. 20, the positive electrode body 59 is electrically connected to the substrate 56a via a conductive adhesive layer such as a conductive paste layer. The tip of the peripheral wall 55b of the negative electrode side metal can 55 is configured to enter the peripheral wall 56b of the positive electrode side metal can 56. The negative electrode side metal can 55 and the positive electrode side metal can 56 are configured to be able to integrate the metal cans by inserting the peripheral wall 56b outside the peripheral wall 55b with a gasket (not shown) interposed therebetween and fitting and combining the two.

[0074] The outer diameter of the negative electrode body 57 is slightly smaller than the inner diameter of the negative electrode side metal can 55, and a space portion 55c is formed around the negative electrode body 57. The outer diameter of the positive electrode body 59 is slightly smaller than the inner diameter of the positive electrode side metal can 56, and a space portion 56c is formed around the positive electrode body 59. In the example of the figure, the height (thickness) of the positive electrode body 59 is formed to be about half of the height of the peripheral wall 56b of the positive electrode side metal can 56.

[0075] The inside of the positive electrode side metal can 56 shown in FIG. 20 is filled with an electrolytic solution 63 almost to the brim using an injector 62 or the like, and the negative electrode side metal can 55 shown in FIG. 19 and the positive electrode side metal can 56 shown in FIG. 20 are fitted and integrated as shown in FIG. 21, whereby the battery (electrochemical cell) 50 shown in FIG. 21 is constructed. Although not shown in FIG. 21, a gasket made of an insulating material is interposed between the fitting portions of the peripheral wall 55b of the negative electrode side metal can 55 and the peripheral wall 56b of the positive electrode side metal can 56, and the negative electrode side metal can 55 and the positive electrode side metal can 56 are insulated and separated via the gasket. The filling amount of the electrolytic solution 63 injected into the positive electrode side metal can 56 is preferably an amount that can almost fill the internal space of the exterior body 52 with the electrolytic solution 63 when the negative electrode side metal can 55 and the positive electrode side metal can 56 are integrated to form the exterior body 52 as shown in FIG. 21. Also, the fitting portion of the peripheral wall 55b of the negative electrode side metal can 55 and the peripheral wall 56b of the positive electrode side metal can 56 may be integrally formed by separately providing an adhesive layer or the like, or may be mechanically integrated by caulking or the like.

[0076] As shown in FIG. 19, the height of the laminate of the negative electrode body 57 and the solid electrolyte layer 58 corresponds to the height of the peripheral wall 55b, and as shown in FIG. 20, the height of the positive electrode body 59 is about half the height of the peripheral wall 56b. Therefore, when the negative electrode side metal can 55 and the positive electrode side metal can 56 are combined and integrated as shown in FIG. 21, the negative electrode body 57 and the positive electrode body 59 stacked via the solid electrolyte layer 58 are accommodated between the integrated negative electrode side metal can 55 and positive electrode side metal can 56. The electrode body 53 is constituted by the negative electrode body 57 and the positive electrode body 59 stacked via the solid electrolyte layer 58. Also, in this example, it is preferable that the space portion existing inside the exterior body 52 and outside the electrode body 53 is filled with the electrolytic solution 63.

[0077] The negative electrode body 57 is made of a material equivalent to the material constituting the negative electrode layer 14 used in the first embodiment. For example, it is formed of a compacted body of the powder material constituting the negative electrode layer 14 described above. Similarly, the positive electrode body 59 is made of a material equivalent to the material constituting the positive electrode layer 16 used in the first embodiment. For example, it is formed of a compacted body of the material constituting the positive electrode layer 16 described above. The negative electrode body 57 is adhered to the negative electrode side metal can 55 via the conductive adhesive layer as described above, and the positive electrode body 59 is adhered to the positive electrode side metal can 56 via the conductive adhesive layer as described above. The negative electrode body 57 may be configured such that the material constituting the negative electrode layer 14 is formed on the negative electrode current collector 11 described above, and the positive electrode body 59 may be configured such that the material constituting the positive electrode layer 16 is formed on the positive electrode current collector 19 described above. The solid electrolyte layer 58 is made of a material equivalent to the solid electrolyte layer 15 used in the first embodiment.

[0078] The battery 50 having the configuration shown in FIG. 21 has a negative electrode body 57 and a positive electrode body 59 stacked via the solid electrolyte layer 58, and the negative electrode body 57 is connected to the negative electrode side metal can 55 and the positive electrode body 59 is connected to the positive electrode side metal can 56. Therefore, it functions as a battery having the same operational effects as the battery 1 of the first embodiment. In particular, regarding the oxide particles contained in the material constituting the solid electrolyte layer 58, by setting the range to 14 to 30% by mass, a battery 50 can be provided in which the current characteristics (rate characteristics) of the discharge capacity are improved as in the above-described embodiment.

[0079] <Third Embodiment> FIGS. 22 to 24 are drawings showing a third embodiment in which the electrochemical cell according to the present invention is applied to a all-solid-state battery. The electrochemical cell (battery) 60 of the present embodiment is a button-type battery having a circular shape in plan view shown in FIG. 24. This battery 60 includes an exterior body 52 made of a container-shaped metal can and an electrode body 64 housed inside the exterior body 52. The configuration of the exterior body 52 is equivalent to that of the second embodiment. In the third embodiment, the electrolytic solution is not contained inside the exterior body 52 composed of the negative electrode side metal can 55 and the positive electrode side metal can 56. Instead, the inside of the exterior body 52 is filled with the solid electrolyte layer 61. Also, a part of the solid electrolyte layer 61 is interposed between the negative electrode body 57 and the positive electrode body 59. In this embodiment, the negative electrode body 57 and the positive electrode body 59 have a structure in which they are stacked with a part of the solid electrolyte layer 61 interposed therebetween.

[0080] To manufacture the battery 60 of the third embodiment, as shown in FIG. 22, after attaching the negative electrode body 57 inside the negative electrode side metal can 55 in the same manner as in the previous embodiment, the solid electrolyte layer 61a is accommodated so as to fill the inside of the negative electrode side metal can 55. Similarly, as shown in FIG. 23, after attaching the positive electrode body 59 inside the positive electrode side metal can 56 in the same manner as in the previous embodiment, the solid electrolyte layer 61b is accommodated so as to fill more than half of the inside of the positive electrode side metal can 56. As an example, as shown in FIG. 23, the solid electrolyte layer 61b is accommodated so that the upper surface of the positive electrode body 59 is covered with the solid electrolyte layer 61b having a predetermined thickness. The battery 60 can be configured by integrating the negative electrode side metal can 55 shown in FIG. 22 and the positive electrode side metal can 56 shown in FIG. 23 as shown in FIG. 24 to form the exterior body 52. In the battery 60, the solid electrolyte layer 61a accommodated in the negative electrode side metal can 55 and the solid electrolyte layer 61b accommodated in the positive electrode side metal can 56 are combined and integrated inside the exterior body 52. Thereby, the solid electrolyte layer 61 that substantially fills the inside of the exterior body 52 is formed.

[0081] The battery 60 having the configuration shown in FIG. 24 has the negative electrode body 57 and the positive electrode body 59 stacked via the solid electrolyte layer 61, and the negative electrode body 57 is connected to the negative electrode side metal can 55, and the positive electrode body 59 is connected to the positive electrode side metal can 56. Therefore, it functions as a battery having the same operational effects as the battery 1 of the first embodiment. In particular, regarding the oxide particles contained in the material constituting the solid electrolyte layer 6, by setting it in the range of 14 to 30% by mass, a battery 60 having good current characteristics of the discharge capacity can be provided in the same manner as in the previous embodiments.

[0082] <Second Example> Similar to the first embodiment described above, as the non-aqueous electrolyte, a non-aqueous electrolyte solution was prepared by mixing LiPF6 to 1.5 M in a mixed solution of EC:PC:EMC with a volume ratio of 1:1:3. As the oxide particles, SiO2 particles (average particle diameter 35 nm (D 50 )) were prepared. The binder was prepared by mixing PEO and PVdF-HFP at a weight ratio of 1:2. Four kinds of quasi-solid electrolytes were prepared by using 80-85% by mass of the non-aqueous electrolyte described above, 14%, 15%, 17%, or 19% by mass of the oxide particles (SiO2 particles), and 1% by mass of the binder (PEO+PVdF-HFP). First, the binder was added to the acetone solvent and mixed, and then the oxide particles and the non-aqueous electrolyte solution were added to the acetone solvent in this order and mixed to obtain a slurry-like mixture. The mixing was carried out at 40 °C.

[0083] Lithium cobalt oxide (LiCoO2) was prepared as the positive electrode active material at a ratio of 90% by mass, PTFE as the binder at 2% by mass, and carbon black as the conductive assistant at 8% by mass. Next, a positive electrode body was obtained by forming the powder mixture thus obtained into a compacted body with a diameter of 6.3 mm, a thickness of 737 μm, and a weight of 75.1 mg. As the negative electrode active material, lithium titanate (Li4Ti5O 12 ) was prepared at a ratio of 88% by mass, carboxyvinyl polymer as the binder at 2% by mass, and carbon black as the conductive assistant at 10% by mass. Next, a positive electrode body was obtained by forming the powder mixture thus obtained into a compacted body with a diameter of 6.7 mm, a thickness of 718 μm, and a weight of 55.5 mg. The slurry-like mixture was dropped onto the surface of the negative electrode body to form a disc-shaped coating layer, and then the coating layer was dried in the air. By this drying, the coating layer can be used as a quasi-solid electrolyte layer, and a negative electrode body having a quasi-solid electrolyte layer on the surface of the negative electrode body was obtained.

[0084] The negative electrode body was fixed to the inner bottom surface of the negative electrode side metal can with a conductive paste, the positive electrode body was fixed to the inner bottom surface of the positive electrode side metal can, and after filling the inside of the positive electrode side metal can with the above-mentioned electrolytic solution, the positive electrode side metal can and the negative electrode side metal can were fitted and integrated through a resin gasket to obtain a battery sample with an outer diameter of φ9.5 mm and a height of 2.0 mm having the cross-sectional structure shown in Fig. 21. As the positive electrode side metal can, a metal can made of SUS329J4L (with a single-sided electroless nickel plating layer), having a height of 1.97 mm, a plate thickness of 0.2 mm, and an inner diameter of 9.02 mm was used. As the negative electrode side metal can, a metal can made of SUS304 (with a single-sided electroless nickel plating layer), having a height of 1.50 mm and a plate thickness of 0.2 mm was used.

[0085] When manufacturing the above-mentioned battery sample, a pseudo solid electrolyte with a ratio of 14% by mass of oxide particles (SiO2), 85% by mass of electrolytic solution, and 1% by mass of binder was applied. Similarly, hereinafter, a pseudo solid electrolyte with a mass ratio of oxide particles: electrolytic solution: binder of 15:84:1, a pseudo solid electrolyte with a mass ratio of 17:82:1, and a pseudo solid electrolyte with a mass ratio of 19:80:1 were each prepared. As shown in Table 1 below, the battery was configured according to the amount of oxide particles (SiO2) blended, the type of electrode constructed, the thickness of the pseudo solid electrolyte, and the configuration shown for the diameter of the outer package. Since Samples No. 1 to 5 shown in Table 1 are batteries having a configuration based on the second embodiment shown in Fig. 21, they are batteries filled with an electrolytic solution. However, since Sample No. 7 is a battery having a configuration based on the third embodiment shown in Fig. 24, the inside of the outer package is filled with a pseudo solid electrolyte layer. Note that the battery of Sample No. 6 is a battery in which a non-woven fabric made of PP (polypropylene) is installed as a separator between the negative electrode body and the positive electrode body instead of the pseudo solid electrolyte layer.

[0086]

Table 1

[0087] As shown in Table 1 below, for the batteries with oxide particles added in the range of 14% to 19% by mass, as the measurement results after battery assembly, batteries with fewer internal short - circuit numbers could be obtained. Also, when measuring the current characteristics (rate characteristics) of the discharge capacity of each battery with respect to the battery of Sample No. 6, for the batteries with oxide particles added in the range of 15% to 19% by mass, high rate characteristics could be obtained as shown in Figures 25 to 28 below.

[0088] Figure 25 is a graph showing the relationship between the discharge current (mA) and the discharge capacity (mAh) in the batteries of Sample Nos. 1 to 6. From the results shown in Figure 25, it can be seen that when the amount of oxide particles is increased in the range of 14% to 19% by mass, the current characteristics of the discharge capacity are improved. Figure 26 shows the result of measuring the ratio of capacity increase of the battery of Sample No. 3 with respect to the battery of Sample No. 6. From Figure 26, it was found that the battery of Sample No. 3 has an 80% (1.8 times) increase in capacity at 3 mA discharge compared to the battery of Sample No. 6.

[0089] Figure 27 shows the relationship between the discharge current and the discharge capacity in the batteries of Sample Nos. 3, 6, and 7. Figure 28 shows the result of measuring the ratio of capacity increase of the battery of Sample No. 4 with respect to the battery of Sample No. 6 and the result of measuring the ratio of capacity increase of the battery of Sample No. 7 with respect to the battery of Sample No. 6. From Figure 27, it can be seen that the current characteristics of the discharge capacity of the battery of Sample No. 7 are further improved. From Figure 28, it was found that the battery of Sample No. 7 has a 120% (2.2 times) increase in capacity at 3 mA discharge compared to the battery of Sample No. 6. Also, it was found that the battery of Sample No. 4 has an approximately 80% (1.8 times) increase in capacity at 3 mA discharge compared to the battery of Sample No. 6. From the above test results, it was found that in the structure containing the solid electrolyte layer and the electrolytic solution shown in Fig. 21 and the structure containing the solid electrolyte layer shown in Fig. 24, excellent current characteristics of discharge capacity were exhibited in both cases. Also, as the oxide particles contained in the solid electrolyte layer, the range of 14 to 19% by mass is more preferable, and the range of 15 to 19% by mass is considered to be the most preferable range.

Explanation of Reference Numerals

[0090] 1…Battery (electrochemical cell), 2…Outer package, 3…Electrode body, 7…Negative electrode side container (first container), 8…Positive electrode side container (second container), 9…First peripheral wall portion, 10…Negative electrode body, 11…Negative electrode current collector, 12…Negative electrode connection portion, 13…Negative electrode tab, 14…Negative electrode layer, 15…Solid electrolyte layer, 16…Positive electrode layer, 17…Negative electrode composite, 18…Positive electrode body, 19…Positive electrode current collector, 20…Positive electrode connection portion, 21…Positive electrode tab, 26…Negative electrode side electrode plate, 38…Positive electrode side electrode plate, 50…Battery (electrochemical cell), 52…Outer package, 53…Electrode body, 55…Negative electrode side metal can, 56…Positive electrode side metal can, 57…Negative electrode body, 58…Solid electrolyte layer, 59…Positive electrode body, 60…Battery (electrochemical cell), 61…Solid electrolyte layer, 63…Electrolytic solution, 64…Electrode body.

Claims

1. An electrode body in which a positive electrode body having a positive electrode layer containing a positive electrode active material and a negative electrode body having a negative electrode layer containing a negative electrode active material are stacked with a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, The solid electrolyte layer is a pseudo solid electrolyte layer containing 65 to 85% by mass of a non-aqueous electrolyte containing a lithium salt, 10 to 30% by mass of oxide particles, and 1 to 5% by mass of a binder. An electrochemical cell characterized by that.

2. The electrochemical cell according to claim 1, wherein the average particle size of the oxide particles is 5 nm or more and 50 nm or less.

3. The electrochemical cell according to claim 1 or 2, wherein the pseudo solid electrolyte layer contains 14 to 19% by mass of oxide particles.

4. The electrochemical cell according to claim 1 or 2, wherein the pseudo solid electrolyte layer contains 15 to 19% by mass of oxide particles.

5. A negative electrode body having a negative electrode layer containing a negative electrode active material on a plurality of negative electrode current collectors connected by a negative electrode connection portion, and a positive electrode body having a positive electrode layer containing a positive electrode active material on a plurality of positive electrode current collectors connected by a positive electrode connection portion And a solid electrolyte layer provided between the negative electrode layer and the positive electrode layer, and the negative electrode body and the positive electrode body are folded so as to overlap the negative electrode layer and the positive electrode layer via the solid electrolyte layer. The electrochemical cell according to claim 1 or 2, characterized by having an electrode body.

6. The electrochemical cell according to claim 1 or 2, wherein the electrode body is housed in a container-shaped exterior body.

7. A non-aqueous electrolyte containing a lithium salt, oxide particles, and a binder are put into a solvent at a predetermined ratio and mixed, and then the solvent is volatilized by heat treatment to obtain a non-aqueous electrolyte containing a lithium salt: 65 to 85% by mass, oxide particles: 10 to 30% by mass, and a binder: 1 to 5% by mass to prepare a slurry of a pseudo solid electrolyte, Using the slurry to prepare a pseudo solid electrolyte sheet, A method for manufacturing an electrochemical cell, characterized in that an electrode body is formed by overlapping a positive electrode body and a negative electrode body via a solid electrolyte layer obtained from the pseudo solid electrolyte sheet.

8. The method for manufacturing an electrochemical cell according to claim 7, wherein the slurry contains 14 to 19% by mass of oxide particles.

9. The method for manufacturing an electrochemical cell according to claim 7, wherein the slurry contains 15 to 19% by mass of oxide particles.

10. A positive electrode body having a positive electrode layer on a plurality of positive electrode current collectors connected at a positive electrode connection portion, a negative electrode body having a negative electrode layer on a plurality of negative electrode current collectors connected at a negative electrode connection portion, and using the solid electrolyte layer, A method for manufacturing an electrochemical cell according to claim 7 or claim 8, characterized in that the positive electrode body and the negative electrode body are overlapped with each other with the solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer to form an electrode body, and the electrode body is housed in an exterior body.

11. The method for manufacturing an electrochemical cell according to claim 10, characterized in that the exterior body is composed of a positive electrode side container made of a positive electrode side laminate film and a negative electrode side container made of a negative electrode side laminate film.

12. The method for manufacturing an electrochemical cell according to claim 11, characterized in that the peripheral wall of the positive electrode side container and the peripheral wall portion of the negative electrode side container are overlapped and heat-sealed.

13. A method for manufacturing an electrochemical cell according to claim 7 or claim 8, characterized in that the electrode body obtained by overlapping the positive electrode body and the negative electrode body with the solid electrolyte layer interposed therebetween is housed inside a metal exterior body.

14. A method for manufacturing an electrochemical cell according to claim 7 or claim 8, characterized in that the electrode body obtained by overlapping the positive electrode body and the negative electrode body with the solid electrolyte layer interposed therebetween is housed inside a metal exterior body together with an electrolytic solution.

Images