Battery

Abstract

To provide a battery which keeps moisture permeation resistance and also has high structural efficiency.SOLUTION: A battery 10 has: an electrode body 2; positive electrode foil and negative electrode foil provided on surfaces of the electrode body 2; a metal outer packaging pair which consists of a positive electrode metal outer packaging 41 making contact with the positive electrode foil and a negative electrode metal outer packaging 42 making contact with the negative electrode foil; and resin 6A, 6B which fixes the electrode body 2 to the metal outer packaging pair. The metal outer packaging pair has an exposed outer surface so that it can be electrically connected to the outside. At least one of the positive electrode metal outer packaging 41 and the negative electrode metal outer packaging 42 has a box-like shape which has a quadrangle bottom plate and four lateral plates each sharing one side with the bottom plate, and also has the electrode body 2 housed inside the box-like shape. A lateral surface of the electrode body 2, the positive electrode metal outer packaging 41, and the negative electrode metal outer packaging 42 are each insulated by the resin 6A, 6B.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] 2. Description of the Related Art Conventionally, batteries have been used in which the electrode assembly is sealed with a laminate film as an exterior body from the viewpoint of improving the strength of the battery and suppressing the permeation of water vapor into the interior. For example, Patent Document 1 discloses a solid-state battery comprising an exterior body, a seal provided on the exterior body, a bipolar electrode body housed inside the seal part of the exterior body, a tab protruding from the bipolar electrode body through the seal part to the outside of the exterior body, and a heat conductive part provided inside the exterior body, wherein the heat conductive part has insulating properties, contains a resin and a heat conductive material having higher thermal conductivity than the resin, and is in contact with the bipolar electrode body and the tab.

[0003] On the other hand, batteries have also been disclosed in which the electrode assembly is sealed with an exterior body other than a laminate film. For example, Patent Document 2 discloses an all-solid-state battery including: a stacked battery in which a plurality of current collector layers, a positive electrode mixture layer, a solid electrolyte layer, and a negative electrode mixture layer are laminated, and the current collector layers, the positive electrode mixture layer, and the negative electrode mixture layer constitute bipolar electrode layers; an outermost current collector that constitutes both end faces of the stacked battery in the stacking direction; and a resin that covers only the side surface of the stacked battery, wherein at least one layer of the current collector layers, the positive electrode mixture layer, the solid electrolyte layer, and the negative electrode mixture layer extends outward more than the other layers to form an extension layer, and a plurality of the extension layers extend on the side surface of the stacked battery, and the resin fills the gap between one of the extension layers and the other extension layers, and the outermost current collector and the resin form a battery case for sealing the stacked battery excluding the outermost current collector, and the outermost current collector serves as a battery terminal.

[0004] Patent Document 3 also discloses a secondary battery comprising an electrode assembly and an outer casing that houses the electrode assembly, wherein the outer casing is made up of two parts, a first metal outer casing and a second metal outer casing, and the first metal outer casing and the second metal outer casing, which are metal members, are combined without being crimped. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-150073 [Patent Document 2] Japanese Patent Application Publication No. 2017-220447 [Patent Document 3] International Publication No. 2021 / 149644 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional batteries use laminated films as their exteriors. However, to meet the moisture permeability requirements of the laminated film (i.e., its ability to act as a barrier against water vapor), it is necessary to increase the area of ​​the region where the edges of the laminated film are heat-sealed, which reduces the structural efficiency of the battery. In addition, the terminals for external connection must be exposed to the outside of the laminated film from the side of the electrode assembly, which also reduces the structural efficiency.

[0007] The present disclosure has been made in view of the above circumstances, and has an object to provide a battery that maintains moisture permeation resistance and has high structural efficiency. [Means for solving the problem]

[0008] <1> An electrode body; a positive electrode foil provided on one surface of the electrode body; a negative electrode foil provided on the other surface of the electrode body; a metal exterior body pair including a positive electrode metal exterior body made of metal and in contact with the positive electrode foil, and a negative electrode metal exterior body made of metal and in contact with the negative electrode foil; a resin that fixes the electrode body and the metal exterior body pair, The metal exterior body pair has an exposed outer surface so that it can be electrically connected to the outside, At least one of the positive electrode metal outer casing and the negative electrode metal outer casing has a box shape having a rectangular bottom plate and four side plates each sharing one side with the bottom plate, and houses the electrode body inside the box shape; a battery in which the side surface of the electrode body, the positive electrode metal outer casing, and the negative electrode metal outer casing are each insulated by the resin. <2> Both the positive electrode metal outer casing and the negative electrode metal outer casing are box-shaped, the positive electrode metal outer casing and the negative electrode metal outer casing are overlapped with each other so that the sides having the side plates face each other, one of the bottom plate of the positive electrode metal exterior body and the bottom plate of the negative electrode metal exterior body has a larger area than the other, and all of the side plates of the metal exterior body having the smaller bottom plate area are housed inside all of the side plates of the metal exterior body having the larger bottom plate area; <1> The battery described in <3> The resins include a first resin interposed between a side surface of the electrode body and the side plate of the metal exterior body having the smaller bottom plate area, and a second resin interposed between the side plate of the metal exterior body having the smaller bottom plate area and the side plate of the metal exterior body having the larger bottom plate area, the first resin is a resin having higher insulating properties than the second resin, The second resin is a resin having higher moisture permeability resistance than the first resin. <2> The battery described in <4> The metal outer casing having a larger area of ​​the bottom plate is a negative electrode metal outer casing. <2> or <3> The battery described in <5> the resin fills a gap between a side surface of the electrode body and the side plate of the metal exterior body having the smaller bottom plate area, and a gap between the side plate of the metal exterior body having the smaller bottom plate area and the side plate of the metal exterior body having the larger bottom plate area, a distance from the side plate of the metal exterior body having a smaller bottom plate area to the side plate of the metal exterior body having a larger bottom plate area is 0.1 mm or more and 1.0 mm or less; the distance in the thickness direction of the electrode body from the end of the side plate of the metal exterior body having the smaller bottom plate area opposite the bottom plate to the end of the side plate of the metal exterior body having the larger bottom plate area opposite the bottom plate is 1.0 mm or more and 50.0 mm or less; <2> ~ <4> 10. The battery according to claim 1 , <6> It is a solid-state battery <1> ~ <5> 10. The battery according to claim 1 , <7> The electrode body is formed by stacking a plurality of bipolar electrodes with solid electrolyte layers interposed therebetween. <1> ~ <6> 10. The battery according to claim 1 , [Effects of the Invention]

[0009] According to the present disclosure, a battery can be provided that maintains moisture permeation resistance and has high structural efficiency. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a battery according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic perspective view showing an electrode assembly, a positive electrode foil, and a negative electrode foil of a battery according to an embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic perspective view showing a positive electrode metal outer casing and a negative electrode metal outer casing of a battery according to an embodiment of the present disclosure. [Figure 4] FIG. 10 is a schematic cross-sectional view showing a battery according to another embodiment of the present disclosure. [Figure 5] FIG. 1 is a schematic cross-sectional view showing a conventional battery using a laminate sheet as an exterior body. [Figure 6]FIG. 1 is a schematic cross-sectional view showing an example of a solid-state battery. [Figure 7] 1 is a graph showing the relationship between the length and thickness of the sealed portion and the amount of moisture transmitted through the sealed portion. DETAILED DESCRIPTION OF THE INVENTION

[0011] The battery according to the present disclosure will be described in detail below with reference to the drawings. The drawings are schematic diagrams, and the size and shape of each part are appropriately exaggerated for ease of understanding.

[0012] <Battery configuration> FIG. 1 is a schematic cross-sectional view showing a battery according to an embodiment of the present disclosure. FIG. 2 is a schematic perspective view showing an electrode assembly, a positive electrode foil, and a negative electrode foil included in the battery according to an embodiment of the present disclosure. A battery 10 according to an embodiment of the present disclosure includes an electrode assembly 2, a metal exterior package pair consisting of a positive electrode metal exterior package 41 and a negative electrode metal exterior package 42, and resins 6A and 6B. As shown in FIG. 2, a positive electrode foil 2A is provided between the electrode assembly 2 and the positive electrode metal exterior package 41 so as to contact the positive electrode side surface of the electrode assembly 2, and a negative electrode foil 2B is provided between the electrode assembly 2 and the negative electrode metal exterior package 42 so as to contact the negative electrode side surface of the electrode assembly 2 (the positive electrode foil 2A and the negative electrode foil 2B are omitted from FIG. 1).

[0013] FIG. 3 is a schematic perspective view showing only a positive electrode metal outer package 41 and a negative electrode metal outer package 42 of a battery according to an embodiment of the present disclosure. The positive electrode metal exterior body 41 of the metal exterior body pair is made of metal and is arranged so as to contact the positive electrode foil 2A. The negative electrode metal exterior body 42 is made of metal and is arranged so as to contact the negative electrode foil 2B. Both the positive electrode metal exterior body 41 and the negative electrode metal exterior body 42 of the metal exterior body pair have at least a portion of their outer surfaces exposed so as to be electrically connectable to the outside. As shown in FIGS. 1 and 3 , the positive electrode metal exterior body 41 has a box-like shape including a rectangular bottom plate 41A and four side plates 41B, each of which shares one side with the bottom plate 41A. The positive electrode metal exterior body 41 houses the electrode assembly 2 inside the box-like shape formed by the bottom plate 41A and the side plates 41B. The negative electrode metal exterior body 42 has a box-like shape including a rectangular bottom plate 42A and four side plates 42B, each of which shares one side with the bottom plate 42A. The negative electrode metal exterior housing 42 houses the electrode assembly 2 inside its box-like shape consisting of a bottom plate 42A and side plates 42B. The positive electrode metal exterior housing 41 and the negative electrode metal exterior housing 42 are overlapped so that the side having the side plate 41B and the side having the side plate 42B face each other. The bottom plate 42A of the negative electrode metal exterior housing 42 has a larger area than the bottom plate 41A of the positive electrode metal exterior housing 41, and all of the side plates 41B of the positive electrode metal exterior housing 41 are housed inside all of the side plates 42B of the negative electrode metal exterior housing 42.

[0014] As shown in FIG. 1 , resins 6A and 6B fix the electrode assembly 2 and a metal exterior body pair consisting of a positive electrode metal exterior body 41 and a negative electrode metal exterior body 42. Resin 6A is interposed between the side surface of the electrode assembly 2 and the side plate 41B of the positive electrode metal exterior body 41, and the side surface of the electrode assembly 2 is covered by resin 6A. Resin 6B is interposed between the side plate 41B of the positive electrode metal exterior body 41 and the side plate 42B of the negative electrode metal exterior body 42. The side surface of the electrode assembly 2 is insulated from the metal exterior body pair consisting of the positive electrode metal exterior body 41 and the negative electrode metal exterior body 42 by resins 6A and 6B. Furthermore, the positive electrode metal exterior body 41 and the negative electrode metal exterior body 42 are insulated by resins 6A and 6B. The side surface of the electrode assembly 2, the positive electrode metal exterior body 41, and the negative electrode metal exterior body 42 are insulated from each other by resins 6A and 6B, thereby suppressing the occurrence of short circuits.

[0015] Conventional batteries use, for example, a laminate film as an exterior body. For example, a single laminate film is folded to cover the electrode assembly, and one end of the laminate film is overlapped with the other end and thermally welded to seal the battery. Another example is a battery 20 shown in FIG. 5, in which two laminate films 24A and 24B are overlapped to cover an electrode assembly 22 having a terminal 28, and the ends of the two laminate films 24A and 24B are thermally welded to each other to seal the battery. However, to satisfy the strength and moisture permeability resistance (i.e., water vapor barrier properties) of the laminate film, it is necessary to increase the area of ​​the heat-welded region (the so-called sealed portion), which reduces the structural efficiency of the battery. Furthermore, when a laminate film is used as the exterior body, the terminals for external connection (positive and negative terminals) must be exposed to the outside of the laminate film from the side of the electrode body, which also reduces structural efficiency.

[0016] In contrast, the battery according to the present disclosure uses a metal exterior body pair consisting of a positive electrode metal exterior body and a negative electrode metal exterior body instead of a laminate film as the exterior body, and the electrode body and the metal exterior body pair are fixed together with resin. One or both of the positive electrode metal exterior body and the negative electrode metal exterior body have a box-like shape with a rectangular bottom plate and four side plates, each of which shares a side with the bottom plate, and the electrode body is housed inside the box-like shape. By fixing and integrating the electrode body and the metal exterior body pair with resin and by giving at least one of the metal exterior body pair a box-like shape, the strength and moisture permeation resistance (water vapor barrier properties) required for the battery can be ensured. Furthermore, the heat-welded area (sealed portion) required when using a laminate film is not required, thereby improving structural efficiency.

[0017] The positive electrode metal outer casing and the negative electrode metal outer casing are made of metal, and the positive electrode metal outer casing is in contact with the positive electrode foil, and the negative electrode metal outer casing is in contact with the negative electrode foil. Furthermore, at least a portion of the outer surface of each of the positive electrode metal outer casing and the negative electrode metal outer casing is exposed so as to be electrically connectable to the outside. This allows the positive electrode metal outer casing and the negative electrode metal outer casing to function as terminals, i.e., the positive electrode and the negative electrode in the electrode assembly can be electrically connected to the outside through the positive electrode metal outer casing and the negative electrode metal outer casing, respectively. This eliminates the need for terminals exposed to the outside from the side of the electrode assembly, which is necessary when using a laminate film, thereby improving structural efficiency.

[0018] As described above, the battery according to the present disclosure can maintain moisture permeation resistance and improve the structural efficiency of the battery.

[0019] 1 and 3, the metal exterior body with the larger bottom plate area is the negative electrode metal exterior body 42. Thus, in the battery according to the present disclosure, from the standpoint of preventing short circuits, the metal exterior body with the larger bottom plate area can be the negative electrode metal exterior body.

[0020] In the battery 10 shown in FIGS. 1 and 3 , the bottom plate 42A of the negative electrode metal exterior housing 42 has a larger area than the bottom plate 41A of the positive electrode metal exterior housing 41, and all of the side plates 41B of the positive electrode metal exterior housing 41 are housed inside all of the side plates 42B of the negative electrode metal exterior housing 42. Thus, in the battery according to the present disclosure, it is preferable that one of the bottom plates of the positive electrode metal exterior housing and the negative electrode metal exterior housing has a larger area than the other, and all of the side plates of the metal exterior housing with the smaller bottom plate area are housed inside all of the side plates of the metal exterior housing with the larger bottom plate area. In this configuration, the outside of the side surface of the electrode body is doubly covered by the metal exterior housing, with the side plate of the metal exterior housing with the smaller bottom plate area and the side plate of the metal exterior housing with the larger bottom plate area. This allows the distance from the side surface of the electrode body to the portion of the resin covering the side surface of the electrode body exposed to the outside of the battery to be longer, thereby improving moisture permeability resistance (water vapor barrier property). Furthermore, the strength of the side surface of the electrode body can be increased.

[0021] 1 , resins 6A and 6B fill the gap between the side surface of the electrode body 2 and the side plate 41B of the positive electrode metal exterior body 41, and between the side plate 41B of the positive electrode metal exterior body 41 and the side plate 42B of the negative electrode metal exterior body 42. In this way, when resin fills the gap between the side surface of the electrode body and the side plate of the metal exterior body with the smaller bottom plate area, and between the side plate of the metal exterior body with the smaller bottom plate area and the side plate of the metal exterior body with the larger bottom plate area, the length of each portion of the resin is preferably as follows:

[0022] The distance from the side plate of the metal exterior housing with the smaller bottom plate area to the side plate of the metal exterior housing with the larger bottom plate area (for example, in the battery 10 shown in FIG. 1, the distance L1 from the side plate 41B of the positive electrode metal exterior housing 41 to the side plate 42B of the negative electrode metal exterior housing 42) is preferably 0.1 mm or more and 1.0 mm or less. Having a distance of 0.1 mm or more makes it easier to prevent short circuits between the metal exterior housings. On the other hand, having a distance of 1.0 mm or less can further improve the structural efficiency of the battery and can also further improve moisture permeation resistance (water vapor barrier properties). The above distance (distance L1 in FIG. 1) is more preferably 0.3 mm or more and 0.7 mm or less.

[0023] The distance mentioned above (distance L1 in Figure 1) is the average value of the distance between the side plate of the metal exterior body with the smaller bottom area and the side plate of the metal exterior body with the larger bottom area, measured at any five locations (20 locations in total) on each of the four side plates of the metal exterior body.

[0024] The distance in the thickness direction of the electrode body from the end of the side plate of the metal exterior body with the smaller bottom plate area opposite the bottom plate to the end of the side plate of the metal exterior body with the larger bottom plate area (for example, in the battery 10 shown in FIG. 1 , the distance L2 in the thickness direction of the electrode body 2 (i.e., the vertical direction in FIG. 1 ) from the end of the side plate 41B of the positive electrode metal exterior body 41 opposite the bottom plate 41A to the end of the side plate 42B of the negative electrode metal exterior body 42 opposite the bottom plate 42A) is preferably 1.0 mm or more and 50.0 mm or less. A distance of 1.0 mm or more can further improve moisture permeation resistance (water vapor barrier properties). On the other hand, a distance of 50.0 mm or less can prevent insufficient resin filling. The above distance (distance L2 in FIG. 1 ) is more preferably 2.0 mm or more and 10.0 mm or less.

[0025] The above distance (distance L2 in Figure 1) is the distance in the thickness direction of the electrode body from the end opposite the bottom plate of the side plate of the metal exterior body with the smaller bottom plate area to the end opposite the bottom plate of the side plate of the metal exterior body with the larger bottom plate area, measured at any five locations (20 locations in total) on each of the four side plates of the metal exterior body, and the average value is taken as the distance.

[0026] The moisture permeability coefficient of the resin was measured by allowing moisture to permeate through the resin evaluation sample for a fixed period of time, and the amount of moisture permeated was calculated using the following formula, with the results (graph) shown in Figure 7. Thermoplastic resin was used as the resin for the evaluation sample. Formula: Moisture permeation amount (g / day)=(σ / I×S)×RH (In the formula, σ is the permeation coefficient, I is the distance in the thickness direction of the electrode assembly from the edge of the side plate of the metal exterior body with the smaller bottom plate area opposite the bottom plate to the edge of the side plate of the metal exterior body with the larger bottom plate area opposite the bottom plate (distance L2 in Figure 1), S is the permeation cross-sectional area, and RH is the relative humidity.)

[0027] As shown in Figure 7, the shorter the distance from the side plate of the metal exterior body with the smaller bottom plate area to the side plate of the metal exterior body with the larger bottom plate area (distance L1 in Figure 1, referred to as the "sealing portion thickness" in Figure 7), the more moisture permeation is suppressed.It can also be seen that the longer the distance in the thickness direction of the electrode body from the end of the side plate of the metal exterior body with the smaller bottom plate area opposite the bottom plate to the end of the side plate of the metal exterior body with the larger bottom plate area opposite the bottom plate (distance L2 in Figure 1, referred to as the "sealing portion length" in Figure 7).

[0028] 1 and 3 shows a configuration in which both the positive electrode metal exterior housing 41 and the negative electrode metal exterior housing 42 are box-shaped, the bottom plate 42A of the negative electrode metal exterior housing 42 has a larger area than the bottom plate 41A of the positive electrode metal exterior housing 41, and all of the side plates 41B of the positive electrode metal exterior housing 41 are housed inside all of the side plates 42B of the negative electrode metal exterior housing 42. However, this is not limited thereto, and in the battery according to the present disclosure, it is sufficient that at least one of the positive electrode metal exterior housing and the negative electrode metal exterior housing has a box-shaped configuration.

[0029] Here, a battery according to another embodiment of the present disclosure will be described. Fig. 4 is a schematic cross-sectional view showing a battery according to another embodiment of the present disclosure. Note that the electrode body 2, positive electrode foil, and negative electrode foil are the same as those shown in Figs. 1 and 2, and therefore description thereof will be omitted.

[0030] In the battery 10B shown in FIG. 4, the positive electrode metal exterior body 43 of the metal exterior body pair is made of metal and is arranged so as to contact the positive electrode foil. The negative electrode metal exterior body 44 is made of metal and is arranged so as to contact the negative electrode foil. The positive electrode metal exterior body 43 and the negative electrode metal exterior body 44 of the metal exterior body pair both have at least a portion of their outer surfaces exposed so as to be electrically connectable to the outside. As shown in FIG. 4, the positive electrode metal exterior body 43 has a box-like shape including a rectangular bottom plate 43A and four side plates 43B, each of which shares one side with the bottom plate 43A. The positive electrode metal exterior body 43 houses the electrode assembly 2 inside the box-like shape formed by the bottom plate 43A and the side plates 43B. The negative electrode metal exterior body 44 is formed of a rectangular plate-like member.

[0031] In the battery 10B shown in FIG. 4, only one type of resin 6 is used to fix the electrode assembly 2 and a metal exterior body pair consisting of a positive electrode metal exterior body 43 and a negative electrode metal exterior body 44. The resin 6 is interposed between the side surface of the electrode assembly 2 and the side plate 43B of the positive electrode metal exterior body 43, and the side surface of the electrode assembly 2 is covered with the resin 6. The side surface of the electrode assembly 2 is insulated from the metal exterior body pair consisting of the positive electrode metal exterior body 43 and the negative electrode metal exterior body 44 by the resin 6. The positive electrode metal exterior body 43 and the negative electrode metal exterior body 44 are also insulated by the resin 6. The side surface of the electrode assembly 2, the positive electrode metal exterior body 43, and the negative electrode metal exterior body 44 are each insulated by the resin 6. This prevents short circuits from occurring.

[0032] Even when only one of the positive electrode metal outer casing and the negative electrode metal outer casing is box-shaped, as in battery 10B shown in FIG. 4, the strength and moisture permeability resistance (water vapor barrier properties) required of the battery can be ensured, and structural efficiency can be improved.

[0033] <Battery components> Next, each component constituting the battery according to the present disclosure will be described.

[0034] (1) Metallic exterior body The positive electrode metal outer casing and the negative electrode metal outer casing are made of metal, such as aluminum, aluminum alloy, stainless steel, copper, copper alloy, and nickel steel. The thickness of the positive electrode metal outer casing and the negative electrode metal outer casing is, for example, 0.05 mm or more and 2.0 mm or less.

[0035] (2) Resin 1 has resin 6A interposed between the side surface of electrode assembly 2 and side plate 41B of positive electrode metal exterior housing 41, and resin 6B interposed between side plate 41B of positive electrode metal exterior housing 41 and side plate 42B of negative electrode metal exterior housing 42. Thus, in the battery according to the present disclosure, it is preferable that the first resin interposed between the side surface of the electrode assembly and the side plate of the metal exterior housing with the smaller bottom plate area, and the second resin interposed between the side plate of the metal exterior housing with the smaller bottom plate area and the side plate of the metal exterior housing with the larger bottom plate area, are different types of resin. It is preferable that the first resin and the second resin have different functions. That is, it is preferable that the first resin has higher insulating properties than the second resin, and the second resin has higher moisture permeation resistance than the first resin. With this configuration, the highly insulating first resin can improve the insulation between the side surface of the electrode assembly and the metal exterior body pair, and the highly moisture permeation resistance second resin can further improve the moisture permeation resistance (water vapor barrier properties) of the battery.

[0036] A resin with high insulating properties means a resin that has a high electrical resistance when an electric current is passed through the resin. Resin with high moisture permeability resistance is the resin placed between two spaces with a relative humidity difference and the moisture permeability per unit area of ​​1m per 24 hours. 2 This means that the resin produces less water vapor per unit volume.

[0037] Examples of the first resin having high insulating properties include polyethylene (PE), polyamide (PA), polyester (PEs), polypropylene (PP), polyetherimide (PEI), polytetrafluoroethylene (PTFE), and polyurethane (TPU). Examples of the second resin having high moisture permeability resistance include polyethylene (PE), polypropylene (PP), polystyrene (PS), and cycloolefin copolymer (COC).

[0038] When only one type of resin is used in the battery, any of the resins listed above can be used.

[0039] (3) Electrode body The electrode assembly typically includes a current collector, a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer. In the present disclosure, the electrode assembly may be a stacked electrode assembly in which multiple electrode assemblies are stacked, or may include only one electrode assembly. The electrode body preferably has a configuration in which a plurality of bipolar electrodes are stacked with a solid electrolyte layer interposed therebetween. More specifically, the electrode body is preferably a stacked bipolar solid electrode body having a bipolar electrode having an electrode active material layer including a current collector, a positive electrode active material layer formed on one surface of the current collector, and a negative electrode active material layer formed on the other surface of the current collector, and a solid electrolyte layer containing a solid electrolyte, and having a configuration in which a plurality of bipolar electrodes are stacked with a solid electrolyte layer interposed therebetween.

[0040] The positive electrode active material layer contains at least a positive electrode active material. The positive electrode active material layer may further contain at least one of a conductive material, an electrolyte, and a binder. The positive electrode active material is, for example, in the form of particles. Examples of the positive electrode active material include oxide active materials. Sulfur (S) may also be used as the positive electrode active material.

[0041] The positive electrode active material preferably contains a lithium composite oxide. The lithium composite oxide may contain at least one element selected from the group consisting of F, Cl, N, S, Br, and I. The lithium composite oxide may have a crystal structure belonging to at least one space group selected from the space groups R-3m, Immm, and P63-mmc (also referred to as P63mc or P6 / mmc). The lithium composite oxide may have an O2-type structure in which the transition metal, oxygen, and lithium are primarily arranged.

[0042] Examples of lithium composite oxides having a crystal structure belonging to R-3m include Li x Me y O α X β(Me represents at least one selected from the group consisting of Mn, Co, Ni, Fe, Al, Cu, V, Nb, Mo, Ti, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, Ag, Ru, W, B, Si, and P, and X represents at least one selected from the group consisting of F, Cl, N, S, Br, and I, and satisfy the conditions 0.5≦x≦1.5, 0.5≦y≦1.0, 1≦α<2, and 0<β≦1.)

[0043] Examples of lithium composite oxides having a crystal structure belonging to Immm include Li x1 M 1 A 1 2(1.5≦x1≦2.3, M 1 contains at least one selected from the group consisting of Ni, Co, Mn, Cu and Fe, and A 1 contains at least oxygen, and A 1 The ratio of oxygen in the oxide is 85 atomic % or more. x1 M 1A 1-x2 M 1B x2 O 2-y A 2 y (0≦x2≦0.5, 0≦y≦0.3, and at least one of x2 and y is not 0, M 1A represents at least one selected from the group consisting of Ni, Co, Mn, Cu, and Fe, and M 1B represents at least one selected from the group consisting of Al, Mg, Sc, Ti, Cr, V, Zn, Ga, Zr, Mo, Nb, Ta and W, and A2 represents at least one selected from the group consisting of F, Cl, Br, S and P.

[0044] Examples of lithium composite oxides having a crystal structure belonging to P63-mmc include M1 x M2 yO2 (where M1 represents an alkali metal (preferably at least one of Na and K), M2 represents a transition metal (preferably at least one selected from the group consisting of Mn, Ni, Co, and Fe), and 0 < x + y ≦ 2). Examples of the composite oxide represented by this formula include those where M1 is an alkali metal (preferably at least one of Na and K), M2 is a transition metal (preferably at least one selected from the group consisting of Mn, Ni, Co, and Fe), and 0 < x + y ≦ 2).

[0045] Examples of the lithium composite oxide having an O2-type structure include, for example, Li x [Li α (Mn a Co b M c ) 1-α O2 (where 0.5 < x < 1.1, 0.1 < α < 0.33, 0.17 < a < 0.93, 0.03 < b < 0.50, 0.04 < c < 0.33, and M represents at least one selected from the group consisting of Ni, Mg, Ti, Fe, Sn, Zr, Nb, Mo, W, and Bi). Examples of the composite oxide represented by this formula include Li 0.744 [Li 0.145 Mn 0.625 Co 0.115 Ni 0.115 O2 and the like.

[0046] In addition, the positive electrode preferably contains a solid electrolyte selected from the group of solid electrolytes consisting of sulfide solid electrolytes, oxide solid electrolytes, and halide solid electrolytes in addition to the positive electrode active material. A mode where at least a part of the surface of the positive electrode active material is coated with a sulfide solid electrolyte, an oxide solid electrolyte, or a halide solid electrolyte is more preferable. Examples of the halide solid electrolyte for coating at least a part of the surface of the positive electrode active material include Li 6-(4-x)b (Ti 1-x Al x ) b F6 (where 0 < x < 1, 0 < b ≦ 1.5) [LTAF electrolyte] is preferable.

[0047] Examples of conductive materials include carbon materials. The electrolyte may be a solid electrolyte or a liquid electrolyte, but is preferably a solid electrolyte. The solid electrolyte may be an organic solid electrolyte such as a gel electrolyte, or an inorganic solid electrolyte such as an oxide solid electrolyte or a sulfide solid electrolyte. The liquid electrolyte (electrolytic solution) contains, for example, a supporting salt such as LiPF6 and a solvent such as a carbonate-based solvent. Examples of binders include rubber-based binders and fluoride-based binders.

[0048] The negative electrode active material layer contains at least a negative electrode active material. The negative electrode active material layer may further contain at least one of a conductive material, an electrolyte, and a binder. Examples of the negative electrode active material include metal active materials such as Li and Si, carbon active materials such as graphite, and Li4Ti5O 12 The negative electrode active material may be in the form of particles or foil, for example. The conductive material, electrolyte, and binder are the same as those described above.

[0049] The electrolyte layer is disposed between the positive electrode active material layer and the negative electrode active material layer and contains at least an electrolyte. The electrolyte may be a solid electrolyte or a liquid electrolyte. The electrolyte layer is preferably a solid electrolyte layer. The electrolyte layer may have a separator.

[0050] The solid electrolyte preferably contains at least one solid electrolyte species selected from the group consisting of sulfide solid electrolytes, oxide solid electrolytes, and halide solid electrolytes.

[0051] As a sulfide solid electrolyte, it is preferable to contain sulfur (S) as the main component of the anion element, and further preferably contain, for example, Li element, A element, and S element. The A element is at least one selected from the group consisting of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In. The sulfide solid electrolyte may further contain at least one of O and halogen elements. Examples of the halogen element (X) include F, Cl, Br, I, etc. The composition of the sulfide solid electrolyte is not particularly limited, and examples include xLi2S·(100 - x)P2S5 (70 ≤ x ≤ 80), yLiI·zLiBr·(100 - y - z)(xLi2S·(1 - x)P2S5) (0.7 ≤ x ≤ 0.8, 0 ≤ y ≤ 30, 0 ≤ z ≤ 30). The sulfide solid electrolyte may have a composition represented by the following general formula (1). Li 4-x Ge 1-x P x S4(0 < x < 1) ··· Formula (1) In Formula (1), at least a part of Ge may be substituted with at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb; at least a part of P may be substituted with at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb; a part of Li may be substituted with at least one selected from the group consisting of Na, K, Mg, Ca, and Zn; and a part of S may be substituted with a halogen. The halogen is at least one of F, Cl, Br, and I.

[0052] <{ As an oxide solid electrolyte, it is preferable to contain oxygen (O) as the main component of the anion element, and for example, it may contain Li, Q element (Q represents at least one of Nb, B, Al, Si, P, Ti, Zr, Mo, W, and S), and O. Examples of the oxide solid electrolyte include garnet-type solid electrolyte, perovskite-type solid electrolyte, NASICON-type solid electrolyte, Li-P-O-based solid electrolyte, Li-B-O-based solid electrolyte, etc. Examples of the garnet-type solid electrolyte include, for example, Li7La3Zr2O 12 、Li 7-x La3(Zr2-x Nb x )O 12 (0≦x≦2), Li5La3Nb2O 12 etc. Examples of perovskite-type solid electrolytes include, for example, (Li, La)TiO3, (Li, La)NbO3, (Li, Sr)(Ta, Zr)O3, etc. Examples of NASICON-type solid electrolytes include, for example, Li(Al, Ti)(PO4)3, Li(Al, Ga)(PO4)3, etc. Examples of Li-P-O-based solid electrolytes include Li3PO4, LIPON (a compound in which part of the O in Li3PO4 is replaced by N), and examples of Li-B-O-based solid electrolytes include Li3BO3, a compound in which part of the O in Li3BO3 is replaced by C, etc.

[0053] As the halide solid electrolyte, a solid electrolyte containing Li, M, and X (M represents at least one of Ti, Al, and Y, and X represents F, Cl, or Br) is preferred. Specifically, Li 6-3z Y z X6 (X represents Cl or Br, and z satisfies 0 < z < 2), Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≦ 1.5) is preferred. Among Li 6-3z Y z X6, Li3YX6 (X represents Cl or Br) is more preferred in terms of excellent lithium ion conductivity, and further Li3YCl6 is preferred. Also, Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≦ 1.5) is preferably included together with a solid electrolyte such as a sulfide solid electrolyte, from the viewpoint of suppressing, for example, the oxidative decomposition of the sulfide solid electrolyte.

[0054] In the case of a bipolar electrode, a current collector having conductivity and capable of forming a positive electrode active material layer and a negative electrode active material layer is used. For example, stainless steel, aluminum, nickel, iron, titanium, carbon, copper, etc. are mentioned. The shape of the current collector is, for example, foil-like or mesh-like.

[0055] On the other hand, the electrode body may have a configuration in which a positive electrode current collector, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode current collector are laminated in this order. The positive electrode current collector collects current from the positive electrode active material layer. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, iron, titanium, and carbon, and aluminum alloy foil or aluminum foil is preferred. The aluminum alloy foil and aluminum foil may be manufactured using powder. The positive electrode current collector may have a foil or mesh shape, for example. The positive electrode current collector may have a positive electrode tab for connection to a positive electrode current collector terminal. The negative electrode current collector collects current from the negative electrode active material layer. Examples of materials for the negative electrode current collector include metals such as copper, SUS, and nickel. Examples of the shape of the negative electrode current collector include foil and mesh. The negative electrode current collector may have a negative electrode tab for connection to a negative electrode current collector terminal.

[0056] (4) Positive and negative electrode foils A positive electrode foil is provided on the surface of the positive electrode side of the electrode body, and a negative electrode foil is provided on the surface of the negative electrode side. The positive electrode foil may be made of, for example, stainless steel, aluminum, nickel, iron, titanium, or carbon. The negative electrode foil may be made of, for example, copper, SUS, or nickel.

[0057] (5)Battery The battery in the present disclosure is preferably a solid-state battery, including so-called all-solid-state batteries that use an inorganic solid electrolyte as the electrolyte (batteries that use a solid electrolyte without an electrolytic solution).

[0058] The solid-state battery has a laminated structure of a positive electrode, a solid electrolyte layer, and a negative electrode. The positive electrode has a positive electrode active material layer and a current collector, and the negative electrode has a negative electrode active material layer and a current collector. The solid electrolyte layer may have a single layer structure or a multi-layer structure of two or more layers. The solid-state battery may have, for example, a cross-sectional structure shown in FIG. 6, and the solid electrolyte layer B may have a two-layer structure as shown in FIG. 6. FIG. 6 is a schematic cross-sectional view showing an example of a solid-state battery. The solid-state battery shown in FIG. 6 has a negative electrode including a negative electrode current collector 113 and a negative electrode active material layer A, a solid electrolyte layer B, and a positive electrode including a positive electrode current collector 115 and a positive electrode active material layer C. The negative electrode active material layer A includes a negative electrode active material 101, a conductive additive 105, and a binder 109. The positive electrode active material layer C includes a coated positive electrode active material 103, a conductive additive 107, and a binder 111, and the surface of the coated positive electrode active material 103 is coated with an LTAF electrolyte or a LiNbO electrolyte. The solid-state battery may be configured by sealing the end faces (side faces) of the laminated structure of the positive electrode / solid electrolyte layer / negative electrode with a resin. The current collector of the electrode may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on the surface.

[0059] Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. It is particularly preferable that the battery be used as a driving power source for HEVs, PHEVs, or BEVs. The battery of the present disclosure may also be used as a power source for mobile objects other than vehicles (e.g., trains, ships, and aircraft), or as a power source for electrical appliances such as information processing devices.

[0060] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Explanation of symbols]

[0061] 2 Electrode body 2A positive electrode foil 2B negative electrode foil 41, 43 Positive electrode metal outer casing 42, 44 Negative electrode metal casing 41A, 42A, 43A bottom plate 41B, 42B, 43B side plate 6, 6A, 6B resin 10, 10B, 20 batteries 22 Electrode body 24A, 24B Laminate Film 28 terminals 101 Negative electrode active material 103 Coated cathode active material 105, 107 Conductive additives 109, 111 Binder 113 Negative electrode current collector 115 Positive electrode current collector A negative electrode active material layer B Solid electrolyte layer C positive electrode active material layer

Claims

1. An electrode body; a positive electrode foil provided on one surface of the electrode body; a negative electrode foil provided on the other surface of the electrode body; a metal exterior body pair including a positive electrode metal exterior body made of metal and in contact with the positive electrode foil, and a negative electrode metal exterior body made of metal and in contact with the negative electrode foil; a resin that fixes the electrode body and the metal exterior body pair, The metal exterior body pair has an exposed outer surface so that it can be electrically connected to the outside, At least one of the positive electrode metal outer casing and the negative electrode metal outer casing has a box shape having a rectangular bottom plate and four side plates each sharing one side with the bottom plate, and the electrode body is housed inside the box shape; the resin insulates the side surface of the electrode body, the positive electrode metal outer casing, and the negative electrode metal outer casing, The resin fills the gap between the electrode body and the positive electrode metal outer casing or the negative electrode metal outer casing facing the electrode body, and covers the entire side surface of the electrode body in the thickness direction.

2. Both the positive electrode metal outer casing and the negative electrode metal outer casing are box-shaped, the positive electrode metal outer casing and the negative electrode metal outer casing are overlapped with each other so that the sides having the side plates face each other, The battery according to claim 1, wherein one of the bottom plate of the positive electrode metal exterior body and the bottom plate of the negative electrode metal exterior body has a larger area than the other, and all of the side plates of the metal exterior body having the smaller bottom plate area are housed inside all of the side plates of the metal exterior body having the larger bottom plate area.

3. The resins include a first resin that fills the gap between the side surface of the electrode body and the side plate of the metal exterior body having the smaller bottom plate area, and a second resin that is interposed between the side plate of the metal exterior body having the smaller bottom plate area and the side plate of the metal exterior body having the larger bottom plate area, the first resin is a resin having higher insulating properties than the second resin, 3. The battery according to claim 2, wherein the second resin is a resin having higher moisture permeability resistance than the first resin.

4. The battery according to claim 2 , wherein the metal outer casing having the larger area of ​​the bottom plate is a negative electrode metal outer casing.

5. the resin fills a gap between a side surface of the electrode body and the side plate of the metal exterior body having the smaller bottom plate area, and a gap between the side plate of the metal exterior body having the smaller bottom plate area and the side plate of the metal exterior body having the larger bottom plate area, a distance from the side plate of the metal exterior body having a smaller bottom plate area to the side plate of the metal exterior body having a larger bottom plate area is 0.1 mm or more and 1.0 mm or less; 3. The battery according to claim 2, wherein the distance in the thickness direction of the electrode body from the end of the side plate of the metal exterior body having the smaller bottom plate area opposite the bottom plate to the end of the side plate of the metal exterior body having the larger bottom plate area opposite the bottom plate is 1.0 mm or more and 50.0 mm or less.

6. The battery of claim 1 which is a solid-state battery.

7. The battery according to claim 1 , wherein the electrode assembly is formed by stacking a plurality of bipolar electrodes with solid electrolyte layers interposed therebetween.

8. An electrode body; a positive electrode foil provided on one surface of the electrode body; a negative electrode foil provided on the other surface of the electrode body; a metal exterior body pair including a positive electrode metal exterior body made of metal and in contact with the positive electrode foil, and a negative electrode metal exterior body made of metal and in contact with the negative electrode foil; a resin that fixes the electrode body and the metal exterior body pair, The metal exterior body pair has an exposed outer surface so that it can be electrically connected to the outside, Both the positive electrode metal outer casing and the negative electrode metal outer casing have a box shape having a rectangular bottom plate and four side plates each sharing one side with the bottom plate, and the electrode body is housed inside the box shape, the resin insulates the side surface of the electrode body, the positive electrode metal outer casing, and the negative electrode metal outer casing, the positive electrode metal outer casing and the negative electrode metal outer casing are overlapped with each other so that the sides having the side plates face each other, One of the bottom plate of the positive electrode metal exterior body and the bottom plate of the negative electrode metal exterior body has a larger area than the other, and all of the side plates of the metal exterior body with the smaller bottom plate area are housed inside all of the side plates of the metal exterior body with the larger bottom plate area. The resins include a first resin interposed between a side surface of the electrode body and the side plate of the metal exterior body having the smaller bottom plate area, and a second resin interposed between the side plate of the metal exterior body having the smaller bottom plate area and the side plate of the metal exterior body having the larger bottom plate area, The second resin is a resin having higher moisture permeability resistance than the first resin.

9. The battery according to claim 8 , wherein the first resin has higher insulating properties than the second resin.

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