Laminated Battery

Abstract

To provide a laminate-type battery which can suppress burning even when the temperature of a battery element is increased.SOLUTION: A laminate-type battery 10A includes: a battery element; a laminate external body 2 for sealing the battery element by covering the battery element; and a deoxygenation material-containing layer 6A covering at least a part of the laminate external body 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a laminate-type battery. [Background technology]

[0002] In a laminated battery in which a battery element is enclosed in a laminate exterior body, there is a demand for improved safety when the temperature of the battery element rises, assuming that the temperature of the battery element may rise to an abnormally high level. For example, Patent Document 1 discloses "an ignition prevention device for an electricity storage device that is installed outside the internal gas release port of the electricity storage device, the ignition prevention device having a breathable casing filled with an agent for suppressing ignition and / or flame of flammable gas discharged from the internal gas release port of the electricity storage device." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-89885 Summary of the Invention [Problem to be solved by the invention]

[0004] In a laminated battery in which a battery element is enclosed in a laminate exterior body, there is a demand for improved safety when the temperature of the battery element rises, assuming that the temperature of the battery element may rise to an abnormally high level. The present disclosure has been made in consideration of the above-mentioned circumstances, and has an object to provide a laminate-type battery that can suppress combustion even when the temperature of the battery element increases. [Means for solving the problem]

[0005] <1> A battery element; a laminate exterior body that covers and encapsulates the battery element; an oxygen absorbing material-containing layer provided so as to cover at least a portion of the laminate exterior body; A laminated battery having the above structure. <2> The laminate exterior body has a laminate fusion portion in which inner surfaces are fused to each other, The oxygen absorbing material-containing layer is provided so as to cover at least the laminate fusion portion. <1> 2. The laminated battery according to claim 1 . <3> The oxygen absorbing material-containing layer is provided so as to cover the entire outer peripheral surface of the laminate exterior body. <2> 2. The laminated battery according to claim 1 . <4> The oxygen absorbing material contained in the oxygen absorbing material-containing layer is carbon. <1> ~ <3> 13. The laminated battery according to claim 12 . <5> The oxygen absorbing material-containing layer is a carbon sheet, and the entire outer circumferential surface of the laminate exterior body is covered with the carbon sheet. <1> ~ <4> 13. The laminated battery according to claim 12 . Effect of the Invention

[0006] According to the present disclosure, it is possible to provide a laminated battery that can suppress combustion even when the temperature of the battery element increases. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic perspective view illustrating a laminated battery according to a first embodiment. [Diagram 2] FIG. 2 is a schematic perspective view illustrating a method for providing an oxygen absorbing material-containing layer so as to cover the entire outer peripheral surface of a laminated exterior body in the laminated battery according to the first embodiment. [Diagram 3] FIG. 11 is a schematic perspective view illustrating a laminated battery according to a second embodiment. [Figure 4] FIG. 2 is a cross-sectional view showing a configuration of a test device in the examples. [Diagram 5] FIG. 11 is a cross-sectional view showing a configuration of a test device in a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The laminate type battery according to the present disclosure will be described in detail below.

[0009] The laminate type battery according to this embodiment has a battery element, a laminate exterior body that covers and encapsulates the battery element, and an oxygen absorbing material-containing layer provided so as to cover at least a portion of the laminate exterior body.

[0010] According to this embodiment, combustion can be suppressed even when the temperature of the battery element rises. The reason why this effect is achieved is presumed to be as follows.

[0011] When a temperature rise occurs in the battery element, it is important to reduce oxygen in the laminated battery in order to prevent ignition or combustion. In this embodiment, the oxygen absorbing material-containing layer is provided so as to cover at least a part of the laminated outer casing, and the oxygen in the laminated battery is reduced by the oxygen absorbing material-containing layer. For example, when the oxygen absorbing material contained in the oxygen absorbing material-containing layer is carbon, oxygen in the laminated battery is reduced by oxidation of the carbon as shown in the following chemical reaction formula. C(Carbon)+O 2 (Oxygen in laminated battery) + Heat (Heat from battery elements due to temperature rise) → CO 2 C(Carbon)+1 / 2O 2 (Oxygen in laminated battery) + Heat (Heat from battery elements due to temperature rise) → CO This makes it possible to suppress combustion even when the temperature of the battery element rises.

[0012] Next, an embodiment of a laminated battery according to the present disclosure will be described with reference to the drawings. Each of the drawings shown below is a schematic illustration, and the size and shape of each part are appropriately exaggerated for ease of understanding.

[0013] (First embodiment) FIG. 1 is a schematic perspective view illustrating a laminated battery according to a first embodiment. In the laminated battery 10A shown in FIG. 1, the entire outer periphery of an electrode body as a battery element is covered and enclosed by a laminated film 2 as a laminated exterior body. Two terminals (a positive electrode terminal and a negative electrode terminal) 4 are provided at both ends of the electrode body, and at least a part of the two terminals 4 is not covered by the laminated film 2 and is provided so as to be exposed to the outside. The laminated film 2 is composed of, for example, two films, and is provided so as to sandwich and cover the entire electrode body between these two films. The two films have a laminated fusion part 20 in which the ends (i.e., four sides) are fused together. The laminated fusion part 20 is formed over a total of four faces, including a pair of end faces on which the terminals 4 are provided and a pair of side faces extending perpendicularly to the pair of end faces.

[0014] The laminated battery 10A has a carbon sheet 6A as an oxygen absorbing material-containing layer provided so as to cover the entire outer peripheral surface of the laminated film 2. In other words, the electrode body covered with the laminated film 2 is further enclosed in a bag-shaped carbon sheet 6A. The carbon sheet 6A is provided so that at least a portion of the two terminals 4 is exposed to the outside.

[0015] A method for providing a carbon sheet 6A so as to cover the entire outer peripheral surface of the laminate film 2 in the laminated battery 10A according to the first embodiment will be described with reference to FIG. 2. The carbon sheet 6A as the oxygen absorbing material-containing layer is composed of, for example, a single sheet. The electrode body covered with the laminate film 2 is placed on this single carbon sheet 6A, and the carbon sheet 6A is folded back so as to encase the entire electrode body. Next, the ends of the carbon sheet 6A (the three sides excluding the folded back side) are fixed together by a method such as taping, thereby forming the carbon sheet 6A that covers the entire outer peripheral surface of the laminate film 2.

[0016] In the laminated battery 10A according to the first embodiment, a carbon sheet 6A serving as an oxygen absorbing material-containing layer is provided so as to cover the entire outer peripheral surface of the laminated film 2. Therefore, even if a rise in temperature occurs in the electrode body serving as a battery element, the oxygen in the laminated battery 10A can be reduced by the oxygen absorbing material (i.e., carbon), and ignition or combustion can be suppressed.

[0017] Second embodiment The oxygen absorbing material-containing layer may be provided so as to cover only a part of the laminated exterior body, rather than covering the entire outer periphery of the laminated exterior body. In this case, it is preferable to provide the oxygen absorbing material-containing layer so as to cover at least the laminated fusion part of the laminated exterior body. The energy released from the laminated battery to the outside is mainly released from the laminated fusion part, which is likely to be the starting point of events such as ignition and combustion. Therefore, by providing the oxygen absorbing material-containing layer so as to cover the laminated fusion part, it is possible to efficiently reduce oxygen in the area that is likely to be the starting point of events, and to efficiently suppress ignition and combustion.

[0018] Fig. 2 is a schematic perspective view illustrating a laminated battery according to the second embodiment. In the laminated battery 10B shown in Fig. 2, the electrode body as a battery element, the laminated film 2 as a laminated exterior body, the laminated fusion part 20 in the laminated film 2, and the two terminals 4 are all configured the same as in the first embodiment, and therefore description thereof will be omitted. The laminated battery 10B has a carbon sheet 6B as an oxygen absorbing material-containing layer that covers only a portion of the outer peripheral surface of the laminate film 2, and the carbon sheet 6B is provided so as to cover at least the laminate fusion portion 20. The carbon sheet 6B is provided so as to cover a total of four surfaces, namely, the four surfaces on which the laminate fusion portion 20 is provided, that is, the pair of end surfaces on which the terminals 4 are provided, and a pair of side surfaces extending perpendicularly to the pair of end surfaces. The carbon sheet 6B is provided so that at least a portion of the two terminals 4 is exposed to the outside.

[0019] (Battery components) Here, the electrode body (battery element), terminal, laminate film, and oxygen absorbing material-containing layer constituting the laminate type batteries according to the first and second embodiments will be described.

[0020] (1) Electrode body The electrode body functions as a power generating element of the battery. The shape of the electrode body is not particularly limited, but may be, for example, a rectangular parallelepiped shape as shown in Figures 1 and 3. The electrode body usually has 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, in this order in the thickness direction.

[0021] 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. Examples of the positive electrode active material include oxide active materials. Examples of the oxide active material include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 Rock salt layered active materials such as LiMn 2 O 4 Spinel-type active materials such as LiFePO 4 Examples of the positive electrode active material include olivine type active materials such as those mentioned above. Sulfur (S) may also be used as the positive electrode active material. The positive electrode active material may be in the form of particles, for example.

[0022] The conductive material may be, for example, a carbon material. The electrolyte may be a solid electrolyte or a liquid 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) may be, for example, LiPF 6 and a solvent such as a carbonate-based solvent. Examples of the binder include a rubber-based binder and a fluoride-based binder.

[0023] 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 Li 4 Ti 5 O 12 The oxide active material may be in the form of, for example, particles or foil. The conductive material, electrolyte and binder are the same as those described above.

[0024] 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 is the same as that described above. The electrolyte layer may have a separator.

[0025] The positive electrode current collector collects the current from the positive electrode active material layer. Examples of the material of the positive electrode current collector include metals such as aluminum, SUS, and nickel. Examples of the shape of the positive electrode current collector include a foil shape and a mesh shape. The positive electrode current collector may have a positive electrode tab for connecting to a positive electrode current collector terminal.

[0026] The negative electrode current collector collects the current from the negative electrode active material layer. Examples of the material 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 a foil shape and a mesh shape. The negative electrode current collector may have a negative electrode tab for connecting to a negative electrode current collector terminal.

[0027] (2) Terminal The terminal is disposed, for example, on an end surface of the electrode body. The laminated battery in the present disclosure may have one terminal for one electrode body, or may have two or more terminals. In the latter case, for example, as shown in Figs. 1 and 3, a pair of terminals 4 may be disposed so as to face the electrode body. The terminal is preferably a current collecting terminal. The current collecting terminal refers to a terminal having a current collecting portion at least in a part thereof. The current collecting portion is, for example, electrically connected to a tab in the electrode body. The current collecting terminal may be the current collecting portion in its entirety, or may be the current collecting portion in part.

[0028] (3) Laminate film Examples of the laminate film include a film having a metal layer, and a three-layer film having a resin layer on each side of the metal layer. In the three-layer film, the inner resin layer on the electrode body side (i.e., the resin layer forming the laminate fusion part) is the fusion resin layer, and the resin layer on the outer peripheral surface side opposite the electrode body side is the outer peripheral resin layer.

[0029] Examples of materials for the fusion resin layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the outer peripheral resin layer include polyethylene terephthalate (PET) and nylon. The thickness of the fusion resin layer is, for example, 40 μm or more and 100 μm or less. The thickness of the metal layer is, for example, 30 μm or more and 60 μm or less. The thickness of the outer peripheral resin layer is, for example, 20 μm or more and 60 μm or less. The thickness of the entire laminate film is, for example, 70 μm or more and 220 μm or less.

[0030] (4) Oxygen absorbing material-containing layer The oxygen absorbing material in the oxygen absorbing material-containing layer is a material that absorbs oxygen (O 2 ), such as materials that consume oxygen through an oxidation reaction.

[0031] Examples of the deoxidizing material contained in the deoxidizing material-containing layer include carbon and activated carbon. The deoxidizing material-containing layer preferably contains at least one of carbon and activated carbon, and more preferably contains carbon. Examples of the deoxidizing material-containing layer containing carbon include a carbon sheet.

[0032] (Laminated battery) The laminated battery in the present disclosure is typically a secondary battery. 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. The battery may also be used as a power source for moving objects other than vehicles (e.g., railways, ships, and aircraft), and may also be used as a power source for electrical appliances such as information processing devices. EXAMPLES

[0033] The present disclosure will be described more specifically below with reference to examples.

[0034] <Example> -Battery configuration- A laminated battery (laminate cell) was prepared, in which the entire outer peripheral surface of a laminate film was covered with a carbon sheet, as shown in FIG. Positive electrode: NCM (nickel cobalt manganese oxide) / solid electrolyte / binder SBR (styrene butadiene rubber) ·Positive electrode current collector foil: Al, t=15μm Negative electrode: LTO (lithium titanate) / solid electrolyte / binder SBR ·Negative electrode current collector foil: Al, t=15μm Separator: S-based solid electrolyte Evaluation cell: Laminated cell (laminate film thickness: 150 μm) Carbon sheet: 0.2mm thick

[0035] <Comparative Example> A laminated type battery was prepared in the same manner as in the Example, except that no carbon sheet was provided to cover the laminate film.

[0036] [Overcharge test] As shown in FIG. 4, a test apparatus was prepared in which a laminate cell 100 (a laminate cell covered with a carbon sheet 6A) prepared in the embodiment was sandwiched between insulating materials 12 from above and below, and further sandwiched and restrained by restraining plates 14 from above and below. Similarly, a test apparatus was prepared for the laminate cell 100 prepared in the comparative example, in which the laminate cell 100 was sandwiched between insulating materials 12 from above and below, and further sandwiched between restraining plates 14 from above and below, as shown in FIG. 5.

[0037] Each laminated cell (single cell) was overcharged at a rate of 5C in a room temperature and pressure environment until a fire occurred. In this way, tests were conducted under harsh conditions that would not occur in normal use. After the fire occurred, the time until the fire was extinguished was measured using the test equipment of the example and the comparative example. The results are shown in Table 1.

[0038] [Table 1]

[0039] The results of the overcharge test showed that in the laminate cell of the embodiment covered with a carbon sheet, combustion could be suppressed even when the temperature of the electrode assembly increased. [Explanation of symbols]

[0040] 2 Laminate film (laminated exterior body) 4 Terminals 6A, 6B Carbon sheet (layer containing oxygen absorbing material) 10A, 10B Laminated Battery 12. Insulation 14 Restraint plate 20 Laminate fusion section 100 Laminated Cell

Claims

1. A battery element; a laminate exterior body that covers and encapsulates the battery element and has a laminate fusion part in which inner surfaces are fused to each other; an oxygen absorbing material-containing layer that contains carbon as an oxygen absorbing material and is provided so as to cover only four surfaces of the laminate exterior body, the four surfaces being a pair of end surfaces on which terminals are provided and a pair of side surfaces extending in a direction perpendicular to the pair of end surfaces, the layer having the laminate fusion portion; A laminated battery having the above structure.

2. 2. The laminate type battery according to claim 1, wherein the oxygen absorbing material-containing layer is a carbon sheet.

Images