Laminated batteries

Abstract

To provide a laminated battery having excellent impact resistance against an external impact.SOLUTION: A laminated battery of the present disclosure includes an electrode body and laminate films that cover the electrode body and seal the electrode body inside. The laminate films include a fused portion in which end portions are superposed to fuse inner surfaces. The fused portion is folded along a folding line portion extending in a longitudinal direction of the fused portion. The fused portion has a surface facing the electrode body in a region closer to the tip side of the fused portion than the folding line portion, and has a wavy shape along the longitudinal direction of the fused portion.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a laminated battery.

Background Art

[0002] In a laminated battery in which an electrode body is covered with a laminated film, a part of the laminated film is fused to form a fused part in order to enclose the electrode body.

[0003] Patent Document 1 discloses a method for manufacturing a secondary battery having a bent portion at at least one end in an exterior body of a laminated secondary battery. The manufacturing method disclosed in Patent Document 1 includes a first step and a second step. The first step and the second step are carried out in this order. In the first step, a pressing plate is brought into contact with a bending base point of the end portion of the exterior body. In the second step, the pressing plate and a pressing plate arranged at a position facing the pressing plate are slid so as to sandwich the end portion, and the end portion is bent about the base point, and the bent portion is formed by sandwiching the end portion between the pressing plate and the pressing plate. A surface of the pressing plate that slides with the end portion has an inclined surface for bending the end portion and a sandwiching surface for sandwiching the end portion. In a cross section orthogonal to the width direction of the pressing plate, the cross-sectional area of the pressing plate is inclined so as to narrow in the sliding direction in the inclined surface. The inclined surface is inclined in the width direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In laminated batteries, where the electrode body is covered with a single laminate film, the electrode body is sealed by the laminate film by overlapping one end of the laminate film with the other end and fusing their inner surfaces to form a fused joint. In laminated batteries, where the electrode body is covered with multiple laminate films, the sealing is achieved by overlapping the ends of the multiple laminate films and fusing their inner surfaces to form a fused joint. To improve the structural efficiency of laminated batteries, these fused joints are sometimes folded, for example, to reduce the overall external size of the laminated battery.

[0006] If the electrodes inside a laminated battery are subjected to impact, the electrodes may be damaged, preventing the battery from performing as intended. Therefore, impact resistance is required for laminated batteries.

[0007] In the laminate-type battery disclosed in Patent Document 1, the portion of the fused joint on the tip side of the bending point (hereinafter also referred to as the "bent portion") is flat. Therefore, when the laminate-type battery is subjected to an external impact (for example, a side impact), the bent portion may not function well as an impact cushion. As a result, the impact resistance of the laminate-type battery disclosed in Patent Document 1 may not be sufficient.

[0008] This disclosure has been made in light of the circumstances described above. One embodiment of this disclosure aims to solve the problem of providing a laminated battery that is highly resistant to external impacts. [Means for solving the problem]

[0009] The following embodiments are included as means for solving the above problems.

[0010] <1> A laminated battery according to a first aspect of the present disclosure comprises an electrode body and a laminate film that covers the electrode body and seals it inside, wherein the laminate film has a fused portion where its ends are overlapped and its inner surface is fused together, the fused portion is folded along a fold line extending in the longitudinal direction of the fused portion, the fused portion has a surface facing the electrode body in the region closer to the tip than the fold line, and has a wavy shape along the longitudinal direction of the fused portion.

[0011] In the first embodiment, the fused portion has a surface facing the electrode body in the region toward the tip of the bent line portion (hereinafter also referred to as the "bent region"), and has a wavy shape (hereinafter also referred to as the "wave shape") along the longitudinal direction of the fused portion. The bent region usually has moderate shape retention. Therefore, when an external impact (e.g., a side impact) is applied to the bent region, the bent region is more likely to function as an impact buffer than if the bent region were flat. As a result, the laminated battery of the first embodiment has excellent impact resistance against external impacts.

[0012] <2> A laminated battery according to a second aspect of the present disclosure has two or more wave peaks of the shape, and the height difference between the wave peaks and wave troughs of the shape at the tip of the fused portion is 0.5 mm or more. <1> This is a laminated battery as described above.

[0013] In this disclosure, "the difference in elevation between the crest and trough of a wave" refers to the distance between the peak of the crest and the bottom of the adjacent trough.

[0014] In the second embodiment, when an external impact (e.g., a side impact) is applied to the bent region, the bent region functions more effectively as an impact absorber than when the bent region does not meet the conditions of the second embodiment. As a result, the laminated battery of the second embodiment has superior impact resistance against external impacts.

[0015] <3>The laminated battery according to the third aspect of the present disclosure is the laminated battery according to <1> or <2>, wherein the fusion part is bent in an angular or arc shape along the bending line part.

[0016] In the third aspect, the bending region has better shape retention than when the fusion part is not bent in an angular or arc shape along the bending line part. As a result, the laminated battery according to the third aspect is more excellent in shock resistance against external impacts.

[0017] <4>The laminated battery according to the fourth aspect of the present disclosure is the laminated battery according to any one of <1> to <3>, wherein the length at the tip of the shape is longer than the length at the bending line part of the fusion part in the longitudinal direction of the fusion part.

[0018] In the fourth aspect, when an external impact (for example, side collision, etc.) is applied to the bending region, the bending region functions more easily as a shock buffer than when the bending region does not satisfy the conditions of the fourth aspect. As a result, the laminated battery according to the fourth aspect is more excellent in shock resistance against external impacts.

Advantages of the Invention

[0019] According to the present disclosure, a laminated battery excellent in shock resistance against external impacts is provided.

Brief Description of the Drawings

[0020] [Figure 1] It is an external perspective view of a laminated battery according to an embodiment of the present disclosure. [Figure 2] It is a cross-sectional view taken along line C2 - C2 of FIG. 1. [Figure 3] It is a top view of a laminated battery according to an embodiment of the present disclosure. [Figure 4] It is an external perspective view of a semi-finished product of a laminated battery according to an embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0021] In the present disclosure, a numerical range indicated by using "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described step by step in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, the term "step" includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step is achieved.

[0022] Hereinafter, embodiments of the laminate battery, battery stack, and manufacturing method of the laminate battery of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description will not be repeated.

[0023] (1) Laminate battery As shown in FIG. 1, the laminate battery 1 according to the embodiment of the present disclosure includes an electrode body 10, a laminate film 20, and a pair of terminals 30. One of the pair of terminals 30 is a positive electrode terminal. The other of the pair of terminals 30 is a negative electrode terminal. The laminate battery 1 is a rectangular parallelepiped.

[0024] In the present embodiment, one side in the short side direction of the main surface of the laminate battery 1 is defined as the positive X-axis direction, and the opposite side is defined as the negative X-axis direction. One side in the longitudinal direction of the main surface of the laminate battery 1 is defined as the positive Y-axis direction, and the opposite side is defined as the negative Y-axis direction. One side in the thickness direction of the laminate battery 1 is defined as the positive Z-axis direction, and the opposite side is defined as the negative Z-axis direction. Each of the X-axis, Y-axis, and Z-axis is perpendicular to each other. Note that these directions do not limit the direction of use of the laminate battery 1 of the present disclosure.

[0025] A pair of terminals 30 are arranged facing each other via an electrode body 10. The electrode body 10 is electrically connected to each of the pair of terminals 30. The laminate film 20 covers and encloses the electrode body 10. The laminate film 20 covers a portion of the pair of terminals 30.

[0026] (1.1) Laminating film The laminate film 20 is a single sheet. The laminate film 20 has a fused portion 21 where the edges are overlapped and the inner surfaces are fused together. The fused portion 21 is folded along a fold line R. The fold line R extends along the longitudinal direction (i.e., the Y-axis direction) of the fused portion 21. In this embodiment, as shown in Figure 2, the fused portion 21 is folded into an arc shape AS along the fold line R.

[0027] The fused portion 21 has a folded region 211 and an unfolded region 212. The folded region 211 is folded relative to the main surface (XY plane) of the laminated battery 1. The folded region 211 is the area on the tip side of the fused portion 21 relative to the folded line R of the fused portion 21. The unfolded region 212 is not folded relative to the main surface (XY plane) of the laminated battery 1. The unfolded region 212 is the area on the opposite side of the fused portion 21 from the tip side of the fused portion 21 relative to the folded line R of the fused portion 21.

[0028] (1.1.1) Wave shape The bent region 211 has a surface S211 facing the electrode body 10. The bent region 211 has a wavy shape WS (hereinafter also referred to as "wave shape WS") along the longitudinal direction (Y-axis direction) of the fused portion 21. In this embodiment, as shown in Figure 3, the number of wave crests M in the wave-shaped WS is two or more. At the tip of the fused portion 21, the height difference L1 (see Figure 3) between the wave crest M and the wave trough V of the wave-shaped WS is 0.5 mm or more.

[0029] In this embodiment, in the longitudinal direction (Y-axis direction) of the fused portion 21, the length L2 at the tip T21 (see Figure 2) of the wave-shaped WS is longer than the length L3 at the bent line portion R of the fused portion 21.

[0030] Figure 4 shows an external perspective view of a semi-finished product 100 of the laminate-type battery 1. The configuration of the semi-finished product 100 is the same as that of the laminate-type battery 1, except that the fused portion 21 has not been subjected to bending processing. The wave shape WS is formed by bending the semi-finished product 100 using a known roll forming method. Specifically, when the fused portion 21 of the semi-finished product 100 is passed between each of a plurality of pairs of rollers to bend the fused portion 21 in stages, the tip T21 of the fused portion 21 is pulled in the opposite direction from the bending line R in the short direction of the fused portion 21 and undergoes plastic deformation. As a result, a wave shape WS is formed in the bending region 211. The length L2 of the wave shape WS is mainly adjusted by the bending angle due to the passage of the pair of rollers and the roll pitch of adjacent pairs of rollers. "Bending angle" refers to the angle of the bending region 211 with respect to the main surface (XY plane) of the laminate-type battery 1.

[0031] (1.1.2) Film composition The laminate film 20 may be any known laminate film used in laminate-type batteries, and may be a three-layer film. The three-layer film has a metal layer, a first resin layer disposed on one main surface of the metal layer, and a second resin layer disposed on the other main surface of the metal layer. The first resin layer may function as a fusion layer, and the second resin layer may function as a protective layer.

[0032] Examples of materials for the fusion 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 fusion layer may be 40 μm to 100 μm. The thickness of the metal layer may be 30 μm to 60 μm or less. The thickness of the protective layer may be 20 μm to 60 μm. The thickness of the laminate film 20 may be 70 μm to 220 μm.

[0033] (1.2) Electrode body The electrode body 10 functions as a power generation element of the laminate-type battery 1. The shape of the electrode body 10 is not particularly limited, but examples include a rectangular parallelepiped shape, a shape with inclined end faces, etc. The electrode body is made up of multiple unit electrode layers stacked along the Z-axis direction. The unit electrode layers are made up of a positive electrode current collector, a positive electrode composite layer, a solid electrolyte layer, a negative electrode composite layer, and a negative electrode current collector stacked in this order along the Z-axis direction.

[0034] The material of the positive electrode current collector may be, for example, aluminum, copper, stainless steel, nickel, iron, titanium, or carbon. The shape of each positive electrode current collector may be, for example, foil-like or mesh-like.

[0035] The positive electrode composite layer contains a positive electrode active material (e.g., LiCoO2, LiMn2O4, or LiFePO4). The positive electrode composite layer may further contain, if necessary, a solid electrolyte (e.g., a sulfide solid electrolyte, an oxide solid electrolyte, or a halogenated solid electrolyte), a conductive material (e.g., acetylene black, metal particles, or a conductive polymer), and a binder (e.g., styrene-butadiene rubber or polyvinylidene fluoride).

[0036] The solid electrolyte layer contains a solid electrolyte (e.g., a sulfide solid electrolyte, an oxide solid electrolyte, or a halogenated solid electrolyte), and may further contain a binder (e.g., styrene-butadiene rubber or polyvinylidene fluoride) as needed. The composition of the sulfide solid electrolyte is, for example, xLi2S·(100-x)P2S5 (70≦x≦80), yLiI·zLiBr·(100-yz)(xLi2S·(1-x)P2S5) (0.7≦x≦0.8, 0≦y≦30, 0≦z≦30). Examples of oxide solid electrolytes include garnet-type solid electrolytes, perovskite-type solid electrolytes, nasicone-type solid electrolytes, Li-PO-based solid electrolytes, Li-BO-based solid electrolytes, etc. Examples of halogenated solid electrolytes include Li 6-3z Z z X6(X is at least one of Cl and Br, and z is 0 <z<2である)である。

[0037] The material of the negative electrode current collector may be, for example, aluminum, copper, stainless steel, nickel, iron, titanium, or carbon. The shape of the negative electrode current collector may be, for example, foil-like or mesh-like.

[0038] The negative electrode composite layer contains a negative electrode active material (e.g., metallic lithium, graphite, lithium titanate, or elemental Si). The negative electrode composite layer may further contain, if necessary, a solid electrolyte (e.g., sulfide solid electrolyte, oxide solid electrolyte, or halogenated solid electrolyte), a conductive material (e.g., acetylene black, metal particles, or conductive polymer, etc.), and a binder (e.g., styrene-butadiene rubber or polyvinylidene fluoride).

[0039] (1.3) Terminals Terminal 30 is a rectangular parallelepiped with the X-axis direction as its longitudinal direction and the Z-axis direction as its short direction. The material of the terminal 30 may be metal (for example, stainless steel (SUS), etc.).

[0040] (1.4) Purpose Applications of the laminated battery 1 include, for example, power sources for vehicles, power sources for other mobile devices (e.g., trains, ships, aircraft), and power sources for electrical products (information processing devices, etc.). Examples of vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline cars, and diesel cars.

[0041] (1.5) Effects As explained with reference to Figures 1 to 4, the laminated battery 1 comprises an electrode body 10 and a laminate film 20. The laminate film 20 has a fusion portion 21. The fusion portion 21 is folded along a folding line R. In the folded region 211, the fusion portion 21 has a surface S211 facing the electrode body 10 and has a wave shape WS. The bent region 211 typically has moderate shape retention. Therefore, when an external impact (e.g., a side impact) is applied to the bent region 211, the bent region 211 functions more effectively as a shock absorber than if it were flat. As a result, the laminated battery 1 has excellent shock resistance against external impacts.

[0042] As explained with reference to Figures 1 to 4, the laminated battery 1 has two or more wave peaks M in the wave shape WS, and the height difference L1 (see Figure 3) at the tip T21 of the fusion portion 21 is 0.5 mm or more. As a result, when an external impact (e.g., a side impact) is applied to the bent region 211, the bent region 211 functions more effectively as an impact absorber than when the bent region 211 does not meet the above conditions. Consequently, the laminated battery 1 has superior impact resistance against external impacts.

[0043] As explained with reference to Figures 1 to 4, in the laminated battery 1, the fused portion 21 is bent in an arc shape along the bend line R. As a result, the bent region 211 has better shape retention than when the fused portion 21 is not bent in an angular or arc shape along the bending line R. Consequently, the laminated battery 1 has superior impact resistance against external impacts.

[0044] As explained with reference to Figures 1 to 4, in the laminated battery 1, the length L2 (see Figure 3) at the tip T21 of the wave-shaped WS in the longitudinal direction (Y-axis direction) of the fused portion 21 is longer than the length L3 at the bent line portion R of the fused portion 21. As a result, when an external impact (e.g., a side impact) is applied to the bent region 211, the bent region 211 functions more effectively as an impact absorber than when the bent region 211 does not meet the above conditions. Consequently, the laminated battery 1 has superior impact resistance against external impacts.

[0045] (2) Variant In laminated battery 1, the number of wave crests M of the wave-shaped WS is two or more, and the height difference L1 (see Figure 3) is 0.5 mm or more, but the disclosure is not limited thereto. Laminated battery of the disclosure does not have to satisfy at least one of the following conditions: the number of wave crests M of the wave-shaped WS is two or more, and the height difference L1 (see Figure 3) at the tip T21 of the fused portion 21 is 0.5 mm or more.

[0046] In the laminated battery 1, the fused portion 21 is bent in an arc shape along the bending line R, but the disclosure is not limited thereto. The fused portion 21 may be bent in an angular shape along the bending line R, or it may be bent into a shape different from both an arc and an angular shape. "Angular" refers to a shape having corners.

[0047] The electrode body 10 is an all-solid-state battery comprising a solid electrolyte layer, but it may also be a lithium secondary battery comprising a non-aqueous electrolyte, or a metal ion secondary battery (for example, a sodium ion secondary battery, a magnesium ion secondary battery, etc.). [Explanation of symbols]

[0048] 1. Laminated battery 10 Electrode body 20 Laminating film 21 Fusion part T21 Tip 211 Folding area S211 side 212 Non-folding area 30 terminals 100 semi-finished products AS arcuate R-shaped bend line M mountain V valley WS wave shape

Claims

1. Electrode body and The electrode body is electrically connected to a positive terminal and a negative terminal, A laminate film that covers a portion of the positive electrode terminal and the negative electrode terminal, and covers the electrode body together with the positive electrode terminal and the negative electrode terminal, and seals it inside; It is a laminated battery, The laminated battery is a rectangular parallelepiped, The positive electrode terminal, the electrode body, and the negative electrode terminal are arranged in this order along the longitudinal direction of the main surface of the laminated battery. The laminate film has a fused portion where the edges are overlapped and the inner surfaces are fused together. The fused portion is bent along a fold line that extends in the longitudinal direction of the fused portion, which is parallel to the longitudinal direction of the main surface of the laminate-type battery. The aforementioned fusion portion, In the region closer to the tip than the aforementioned bent line portion, there is a bent region that is bent toward the side of the laminate-type battery, has a surface facing the electrode body, and has a wavy shape along the longitudinal direction of the fused portion, In the region opposite to the tip side of the aforementioned fold line, there is an unfolded region that is not folded toward the side of the laminated battery, A laminated battery consisting of [the following components].

2. The laminated battery according to claim 1, wherein the number of wave crests of the aforementioned shape is two or more, and the height difference between the wave crest and wave trough of the aforementioned shape at the tip of the fused portion is 0.5 mm or more.

3. The laminated battery according to claim 1 or claim 2, wherein the fused portion is bent in a square or arc shape along the bending line portion.

4. The laminated battery according to claim 1 or claim 2, wherein in the longitudinal direction of the fused portion, the length at the tip of the shape is longer than the length at the bent line portion of the fused portion.

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