Battery

Abstract

To provide a battery that suppresses short circuits caused by contact between the metal layer and the terminals. [Solution] A battery comprising an electrode body, a terminal 20 electrically connected to the electrode body, a laminate film 30 covering the entire surface of the electrode body and a part of the surface of the terminal 20 and having at least a metal layer 34, and a weldable resin layer 36 interposed between the terminal 20 and the metal layer 34, wherein the weldable resin layer 36 contains insulating particles 50A.

Description

[Technical Field]

[0001] This disclosure relates to batteries. [Background technology]

[0002] Batteries such as lithium-ion secondary batteries typically comprise an electrode body having a current collector, a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer. The electrode body is sealed in an internal space surrounded by an outer casing, for example. For example, Patent Document 1 discloses a laminate-type energy storage element in which an electrode body, in which a sheet-like positive electrode and a negative electrode are laminated with a separator inside an outer casing made of a flat bag-shaped laminate film, is sealed together with an electrolyte, wherein the flat plate-shaped positive and negative electrode terminal plates connected to the positive and negative electrodes respectively are provided with electrode terminal portions that are led out from a predetermined edge of the outer casing, the outer casing is made by welding together the laminate films that face each other with the same outer shape at a peripheral region that encircles a planar area, the laminate film has an insulating resin layer formed on both the front and back surfaces of a metal foil base material, the end surface of the base material is exposed at the predetermined edge of the outer casing, the peripheral region is welded via a tab film in a region along the predetermined edge, the tab film deviates outward from the outer casing in a region of the predetermined edge and has a deformed portion formed in a shape that covers both the front and back surfaces of the base end of the electrode terminal portion. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 6796417 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventionally, when sealing an electrode body and a terminal in a battery with a laminate film, the resin layer interposed between the terminal and the metal layer in the laminate film melts and becomes liquid. At this time, if an excessive load is applied to a part of the laminate film, the resin that has become liquid flows from the portion where the load is applied, and the metal layer and the terminal may come into contact with each other to cause a short circuit.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a battery in which a short circuit due to contact between a metal layer and a terminal is suppressed.

Means for Solving the Problems

[0006] <1> An electrode body, A terminal electrically connected to the electrode body, A laminate film having at least a metal layer, covering the entire surface of the electrode body and a part of the surface of the terminal, A resin layer interposed between the terminal and the metal layer, comprising: A battery in which the resin layer contains insulating particles. <2> As the resin layer, the laminate film has a welded resin layer on the surface of the metal layer on the terminal side, and the welded resin layer contains the insulating particles. The battery according to <1>. <3> As the resin layer, there is a welded resin film interposed between the terminal and the laminate film, and the welded resin film contains the insulating particles. The battery according to <1> or <2>.

Advantages of the Invention

[0007] According to the present disclosure, a battery in which a short circuit due to contact between a metal layer and a terminal is suppressed can be provided.

Brief Description of the Drawings

[0008] [Figure 1] It is a schematic perspective view showing a battery according to an embodiment of the present disclosure. [Figure 2]Figure 1 is a schematic cross-sectional view showing the XX section. [Figure 3] This is an enlarged cross-sectional view showing the terminals, tab film, and laminate film in Figure 2. [Figure 4] Figure 2 is an enlarged cross-sectional view showing the condition when excessive load is applied to a portion of the terminal, tab film, and laminate film. [Figure 5] This is an enlarged cross-sectional view showing the terminals, tab film, and laminate film of a battery according to another embodiment of the present disclosure. [Figure 6] This is an enlarged cross-sectional view showing the terminals, tab film, and laminate film of a conventional battery. [Modes for carrying out the invention]

[0009] The battery described in this disclosure will be explained in detail below with reference to the drawings. The following figures are schematic representations, and the size and shape of each part have been exaggerated as appropriate for ease of understanding.

[0010] <Battery> • First embodiment First, a battery according to an embodiment of this disclosure (first embodiment) will be described. Figure 1 is a schematic perspective view illustrating a battery in this disclosure. Figure 2 is a schematic cross-sectional view showing the XX cross-section in Figure 1. The battery 100 shown in Figure 1 has its outer circumference covered with a laminate film 30. An electrode body is sealed inside the laminate film 30, and the entire surface of the electrode body is covered with the laminate film 30. In addition, terminals 20 that are electrically connected to the electrode body are provided at one end and the other end of the electrode body. As shown in Figures 1 and 2, a portion of the terminal 20 is covered with the laminate film 30, and a portion of each end is exposed. The laminate film 30 is, for example, a single film, and this single laminate film 30 is folded to cover the electrode body and the terminal 20. As shown in Figure 2, the ends of the laminate film 30 are overlapped and welded together to form a welded portion Y. In addition, a tab film 40, which is a welding resin film, is interposed between the terminal 20 and the laminate film 30.

[0011] Figure 3 is an enlarged cross-sectional view showing the terminal 20, tab film 40, and laminate film 30 in Figure 2. The laminate film 30 has, in order from the terminal 20 side, a weldable resin layer 36, a metal layer 34, and a protective layer 32. In other words, the battery shown in Figure 3 has a tab film 40 and a weldable resin layer 36 as resin layers interposed between the terminal 20 and the metal layer 34. The weldable resin layer 36 contains insulating particles 50A.

[0012] Now, let's discuss conventional batteries. Figure 6 is an enlarged cross-sectional view showing the terminals, tab film, and laminate film of a conventional battery. The conventional battery has an electrode body (not shown), terminals 200, a laminate film 300 covering the electrode body and terminals 200, and a tab film 400 interposed between the terminals 200 and the laminate film 300. The laminate film 300 has, in order from the terminal 200 side, a welded resin layer 360, a metal layer 340, and a protective layer 320. The tab film 400, which is the resin layer interposed between the terminals 200 and the metal layer 340, and the welded resin layer 360 do not contain insulating particles.

[0013] In conventional batteries, when the surface of the terminal 200 is sealed with a laminate film 300, the tab film 400 and the welded resin layer 360, which act as resin layers, melt and become liquid. At this time, if an excessive load is applied to a part of the laminate film 300, the liquid resin will flow from the area where the load is applied, and as shown in Figure 6, the metal layer 340 of the laminate film 300 and the terminal 200 may come into contact, causing a short circuit. Furthermore, if there is a slight protrusion (so-called burr) on the terminal 200, even a slight flow of the liquid resin can easily cause a short circuit. Also, if the heating temperature during sealing with the laminate film 300 is too high and the viscosity of the molten resin decreases too much, the resin will flow easily, making a short circuit more likely. For these reasons, even if an attempt is made to apply the load evenly to prevent excessive load on a part of the laminate film 300 during sealing, it was not easy to suppress short circuits caused by contact between the metal layer 340 and the terminal 200.

[0014] In contrast, the battery shown in Figure 3 contains insulating particles 50A in the welded resin layer 36. Therefore, even if an excessive load is applied to a part of the laminate film 30 and the liquid resin flows from the loaded area, insulating particles 50A are interposed between the metal layer 34 and the terminal 20 in the laminate film 30, as shown in Figure 4. This prevents contact between the metal layer 34 and the terminal 20, and suppresses short circuits between the metal layer 34 and the terminal 20.

[0015] Furthermore, the inclusion of insulating particles 50A prevents the thickness of the welded resin layer 36 after sealing from becoming smaller than the particle size of the insulating particles 50A. This allows for uniform thickness of the welded resin layer 36, and further, uniform thickness of the entire laminate film 30. Here, the welded portion Y shown in Figure 1 may be bent to improve the structural efficiency of the battery 100. In this case, because the overall thickness of the laminate film 30 is uniform, the occurrence of areas with bending defects is suppressed, and good bendability is obtained.

[0016] · Modification The batteries shown in Figures 2 and 3 have a tab film 40 between the laminate film 30 and the terminals 20, but are not limited to this configuration. In other words, there may be a configuration in which the tab film 40 is not present, and the laminate film 30 and the terminals 20 are in direct contact.

[0017] The battery shown in Figure 1 is configured such that the electrode body and terminals 20 are covered with a single laminate film 30, but it is not limited to this configuration, and the electrode body and terminals may be sealed with multiple laminate films. For example, when sealing the electrode body and terminals with two laminate films, the entire surface of the electrode body and a portion of the terminals can be covered with the two laminate films from one side and the other side in the thickness direction of the electrode body, and the edges of the two laminate films can be welded together to seal them.

[0018] Furthermore, in a battery in which the electrode body and terminals are covered from one side and the other side in the thickness direction of the electrode body by two laminate films and the ends of the two laminate films are welded together, the occurrence of a short circuit in the entire battery can be suppressed by including insulating particles in the welding resin layer of the laminate films. This is because if one of the two laminate films is short-circuited with the positive electrode of the electrode body, and the other laminate film is short-circuited with the negative electrode, and if the two laminate films are also short-circuited with each other, an undesirable situation will occur in which a short circuit occurs in the entire battery. However, by including insulating particles in the welding resin layer of the two laminate films, a short circuit between the two laminate films is suppressed, and as a result, the occurrence of a short circuit in the entire battery can be suppressed.

[0019] • Second embodiment Next, a battery relating to another embodiment of the present disclosure (a second embodiment) will be described.

[0020] Figure 5 is an enlarged cross-sectional view showing the terminals, tab film, and laminate film of a battery according to another embodiment of the present disclosure. The battery shown in Figure 5 comprises an electrode body (not shown), a terminal 20, a laminate film 30 covering the electrode body and terminal 20, and a tab film 40 interposed between the terminal 20 and the laminate film 30. The laminate film 30 has, in order from the terminal 20 side, a welded resin layer 36, a metal layer 34, and a protective layer 32. In other words, the battery shown in Figure 5 has a tab film 40 and a welded resin layer 36 as resin layers interposed between the terminal 20 and the metal layer 34. The tab film 40 contains insulating particles 50B.

[0021] In the battery shown in Figure 5, since the tab film 40 contains insulating particles 50B, even if an excessive load is applied to a part of the laminate film 30 and the liquid resin flows from the loaded area, the insulating particles 50B are interposed between the metal layer 34 and the terminal 20 in the laminate film 30. This prevents contact between the metal layer 34 and the terminal 20 and suppresses short circuits between the metal layer 34 and the terminal 20.

[0022] Furthermore, in the battery shown in Figure 5, since the tab film 40 provided around the terminal 20 contains insulating particles 50B, the amount of insulating particles can be reduced compared to the case where insulating particles are contained in the welding resin layer 36 of the laminate film 30 that covers a portion of the surface of the terminal 20 and the entire surface of the electrode body.

[0023] <Battery components> Next, we will describe each component that makes up the battery of this disclosure.

[0024] Laminating film The laminate film in this disclosure preferably has at least a metal layer, and further has a welding resin layer on the terminal side of the metal layer. The welding resin layer corresponds to a resin layer interposed between the terminal and the metal layer. The laminate film may also have a protective layer on the side of the metal layer opposite to the terminal. Examples of materials for the welding 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 protective layer include polyethylene terephthalate (PET) and nylon. The thickness of the welded resin layer is preferably, for example, 20 μm to 100 μm, more preferably 20 μm to 60 μm, and even more preferably 40 μm to 60 μm. The thickness of the metal layer is, for example, 30 μm to 60 μm. The thickness of the protective layer is, for example, 20 μm to 60 μm. The overall thickness of the laminate film is, for example, 70 μm to 220 μm.

[0025] • Tab film The battery according to this disclosure preferably has a weldable resin film (so-called tab film) interposed between the terminal and the laminate film. The weldable resin film corresponds to the resin layer interposed between the terminal and the metal layer. The weldable resin film is provided so as to cover a portion of the surface of the terminal and be interposed between the terminal and the laminate film. Examples of materials for the weldable resin film include olefin resins such as polypropylene (PP) and polyethylene (PE). The thickness of the weldable resin film is preferably 20 μm to 100 μm, more preferably 20 μm to 60 μm, and even more preferably 40 μm to 60 μm.

[0026] Furthermore, the thickness of the resin layer interposed between the terminal and the metal layer, which contains insulating particles (for example, a welded resin film, a welded resin layer in a laminate film, etc.), is preferably 20 μm or more and 100 μm or less, more preferably 20 μm or more and 60 μm or less, and even more preferably 40 μm or more and 60 μm or less.

[0027] Here, the thickness of each layer is defined as the average value of measurements taken at 10 arbitrarily selected locations.

[0028] • Insulating particles Insulating particles are contained in the resin layer (e.g., welding resin film, welding resin layer in laminate film, etc.) interposed between the terminal and the metal layer. Insulation in insulating particles refers to the property of not conducting electricity, and specifically, the volume resistivity of the material of the insulating particles is 10 14 This refers to a value of Ω·cm or greater. The volume resistivity of a material can be measured by the method specified in JIS C2141:1992.

[0029] Examples of insulating particles include inorganic particles and metal oxide particles, and it is preferable to include one or more particles selected from this group. The shape of the insulating particles is not particularly limited, but from the viewpoint of efficiently suppressing short circuits between the metal layer and the terminals, a spherical shape is preferred.

[0030] The average particle size of the insulating particles is preferably 30 μm to 50 μm, and more preferably 35 μm to 45 μm, from the viewpoint of efficiently suppressing short circuits between the metal layer and the terminals. Here, the average particle diameter of the insulating particles is determined by taking SEM images of the cross-section of the resin layer containing the insulating particles, measuring the maximum diameter of 50 arbitrarily selected insulating particles, and calculating the average value.

[0031] From the viewpoint of efficiently suppressing short circuits between the insulating particles contained in the resin layer, the average spacing between them is preferably 100 μm to 1000 μm, and more preferably 200 μm to 500 μm. Here, the average spacing of the insulating particles is determined by taking SEM images of the cross-section of the resin layer containing the insulating particles, measuring the spacing (i.e., the shortest distance) between 50 arbitrarily selected pairs of adjacent insulating particles, and calculating the average value.

[0032] For example, it is preferable that the resin layer interposed between the terminal and the metal layer has an average thickness of 20 μm or more and 60 μm or less, an average particle diameter of 30 μm or more and 50 μm or less, and an average spacing between insulating particles of 100 μm or more and 1000 μm or less.

[0033] ·Electrode body The electrode body in this disclosure typically comprises 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.

[0034] The positive electrode active material layer contains at least one 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 shape of the positive electrode active material is, for example, particulate. Examples of positive electrode active materials include oxide active materials. Sulfur (S) may also be used as the positive electrode active material.

[0035] 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 also have a crystal structure belonging to at least one space group selected from the space groups R-3m, Immmm, and P63-mmc (also called P63mc or P6 / mmc). Furthermore, the lithium composite oxide may have an O2-type structure in which the main arrangement of the transition metal, oxygen, and lithium is located.

[0036] 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, satisfying 0.5 ≦ x ≦ 1.5, 0.5 ≦ y ≦ 1.0, 1 ≦ α < 2, and 0 < β ≦ 1.) Compounds represented thereby are exemplified.

[0037] Examples of the lithium composite oxide having a crystal structure belonging to Immm include, for example, Li x1 M 1 A 1 2 (satisfying 1.5 ≦ x1 ≦ 2.3, M 1 includes at least one selected from the group consisting of Ni, Co, Mn, Cu, and Fe, A 1 includes at least oxygen, and the ratio of oxygen in A 1 is 85 atomic% or more.) Composite oxides represented thereby (specific example: Li2NiO2), Li x1 M 1A 1-x2 M 1B x2 O 2-y A 2 y (0 ≦ x2 ≦ 0.5, 0 ≦ y ≦ 0.3, 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, 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.) Composite oxides represented thereby are exemplified.

[0038] Examples of the lithium composite oxide having a crystal structure belonging to P63 - mmc include, for example, 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 include composite oxides represented by this formula.

[0039] As the lithium composite oxide having an O2-type structure, for example, Li x [Li α (Mn a Co b M c ) 1-α O2 (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 such composite oxides include Li 0.744 [Li 0.145 Mn 0.625 Co 0.115 Ni 0.115 O2, etc.

[0040] 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 in which 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. As the halide solid electrolyte for coating at least a part of the surface of the positive electrode active material, Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≤ 1.5) [LTAF electrolyte] is preferable.

[0041] Examples of conductive materials include carbon materials. 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 (electrolyte solution) may contain, 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.

[0042] 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 negative electrode active materials include metallic active materials such as Li and Si, carbon active materials such as graphite, and Li4Ti5O 12 Examples of oxide active materials include the following. The shape of the negative electrode active material is, for example, particulate or foil-like. The conductive material, electrolyte, and binder are the same as described above.

[0043] The electrolyte layer is positioned 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. A solid electrolyte layer is preferred for the electrolyte layer. The electrolyte layer may have a separator.

[0044] Preferably, the solid electrolyte includes at least one solid electrolyte species selected from the group of solid electrolytes consisting of sulfide solid electrolytes, oxide solid electrolytes, and halogenated solid electrolytes.

[0045] 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 by at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. Also, at least a part of P may be substituted by 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 by at least one selected from the group consisting of Na, K, Mg, Ca, and Zn. A part of S may be substituted by a halogen. The halogen is at least one of F, Cl, Br, and I.

[0046] 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 a part of O in Li3PO4 is replaced by N), and examples of Li-B-O-based solid electrolytes include Li3BO3, a compound in which a part of O in Li3BO3 is replaced by C, etc.

[0047] 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 suitable. 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 oxidative decomposition of the sulfide solid electrolyte, etc.

[0048] The positive electrode current collector collects current from the positive electrode active material layer. Examples of materials for the positive electrode current collector include stainless steel, aluminum, nickel, iron, titanium, and carbon, with aluminum alloy foil or aluminum foil being preferred. Aluminum alloy foil and aluminum foil may be manufactured using powder. The shape of the positive electrode current collector may be, for example, foil-like or mesh-like. The positive electrode current collector may have a positive electrode tab for connection to the positive electrode current collection terminal.

[0049] 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, stainless steel (SUS), and nickel. Examples of shapes for the negative electrode current collector include foil-like and mesh-like forms. The negative electrode current collector may also have a negative electrode tab for connecting to the negative electrode current collection terminal.

[0050] Terminals The terminals in this disclosure are located on the side surface of the electrode body. Examples of terminals include current collector terminals. A current collector terminal is a terminal having a current collector portion in at least part of it. The current collector portion is electrically connected, for example, to a tab in the electrode body. The current collector terminal may be entirely a current collector portion, or only partially a current collector portion. Examples of terminal materials include metals such as SUS.

[0051] ·battery The battery in this disclosure is typically a lithium-ion secondary battery. Applications of the battery include, for example, powering vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. It is particularly preferable for the battery to be used as a power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). Furthermore, the battery in this disclosure may be used as a power source for mobile devices other than vehicles (e.g., railways, ships, aircraft), or as a power source for electrical products such as information processing devices.

[0052] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure.

[0053] Here, the effectiveness of the battery described in this disclosure was confirmed through experiments.

[0054] In Experimental Example 1, a battery having the configuration shown in Figure 3 was prepared. Specifically, the battery had an electrode body, terminals 20, a laminate film 30 covering the electrode body and terminals 20, and a tab film 40 interposed between the terminals 20 and the laminate film 30. The laminate film 30 had, in order from the terminal 20 side, a welded resin layer 36, a metal layer 34, and a protective layer 32. The welded resin layer 36 contained insulating particles 50A.

[0055] In Experimental Example 2, a battery with the configuration shown in Figure 5 was prepared. That is, a battery with the same layer configuration as the battery shown in Figure 3 was prepared, but with insulating particles contained in the tab film 40 instead of the welded resin layer 36.

[0056] On the other hand, as a comparative example, a battery having the configuration shown in Figure 6 was prepared. That is, a battery with the same layer configuration as the battery shown in Figure 3 was prepared, but without insulating particles in either the welded resin layer 36 or the tab film 40.

[0057] For the batteries in Experimental Examples 1 and 2 and the Comparative Example, we confirmed whether or not short circuits occurred due to contact between the terminals and the metal layer during the welding (sealing) of the laminate film around the terminals. We also measured the thickness of the area where the tab film and laminate film were welded around the terminals (especially the thickness at the location where a short circuit occurred, or the seal thickness). The results are shown in Table 1.

[0058] [Table 1]

[0059] As shown in Table 1, in Experimental Examples 1 and 2, where insulating particles are included in the welded resin layer 36 or tab film, which is a resin layer interposed between the terminal and the metal layer, it can be seen that the occurrence of short circuits is suppressed. [Explanation of Symbols]

[0060] 20, 200 terminals 30,300 Laminating Film 32, 320 protective layer 34, 340 metal layer 36, 360 welding resin layer 40,400 Tab Film 50A, 50B insulating particles 100 batteries

Claims

1. Electrode body and A terminal electrically connected to the electrode body, A laminate film having at least a metal layer and covering the entire surface of the electrode body and a portion of the surface of the terminal, The terminal and the metal layer are interposed in a resin layer, The aforementioned resin layer contains insulating particles, The laminate film has a welded portion where the laminate films are overlapped and welded together, The welded portion of the laminate film is folded at the folding portion. A battery in which, when viewed from the direction in which the terminals protrude from the laminate film, the bent portion is positioned on the terminals.

2. The laminate film has an edge weld portion where the edges of the laminate film are overlapped and welded together. The battery according to claim 1, wherein the end welded portion is bent.

3. When the battery is cut along a plane perpendicular to the direction in which the terminal protrudes from the laminate film, the cross-sectional shape of the terminal is rectangular. The battery according to claim 2, wherein the bent portion is positioned above at least one of the four corners of the terminal.

4. When the battery is cut along a plane perpendicular to the direction in which the terminal protrudes from the laminate film, the cross-sectional shape of the terminal is rectangular. The battery according to claim 2, wherein the bent portion is located only on the four corners of the terminal.

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