Laminated battery

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 laminate-type battery. [Background technology]

[0002] In a laminate type battery in which an electrode body is covered with a laminate film, a fused portion is formed by fusing a part of the laminate film in order to encapsulate the electrode body.

[0003] Patent Document 1 discloses a method for manufacturing a secondary battery having a folded portion at at least one end of a laminated exterior body of the 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 performed in this order. In the first step, a pressing plate is brought into contact with the base point of the folding of the end of the exterior body. In the second step, the pressing plate and a pressing plate arranged at a position opposite the pressing plate are slid to sandwich the end, bending the end around the base point, and the pressing plate and the pressing plate hold the end between them to form the folded portion. The surface of the pressing plate that slides against the end has an inclined surface that folds the end and a holding surface that holds the end. The inclined surface is inclined so that the cross-sectional area of ​​the pressing plate narrows in the sliding direction in a cross section perpendicular to the width direction of the pressing plate. The inclined surface is inclined in the width direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-200973 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a laminated battery in which the electrode body is covered with a single laminate film, one end side and the other end side of the laminate film are overlapped and the inner surface is fused to form a fused portion, thereby encapsulating the electrode body with the laminate film. In a laminated battery in which the electrode body is covered with multiple laminate films, the ends of multiple laminate films are overlapped and the inner surface is fused to form a fused portion, thereby encapsulating the electrode body. In order to improve the structural efficiency of the laminated battery, these fused portions are, for example, folded to reduce the external size of the entire laminated battery.

[0006] When an electrode assembly included in a laminated battery is subjected to an impact, the electrode assembly may be damaged and the battery may not be able to exhibit the required performance, so impact resistance is required for laminated batteries.

[0007] The portion of the laminated battery disclosed in Patent Document 1 that is on the tip side of the folding base point of the fused portion (hereinafter also referred to as the "bent portion") is flat. Therefore, when the laminated battery receives an external impact (e.g., a side impact, etc.), the bent portion may not function well as an impact buffer. As a result, the impact resistance of the laminated battery disclosed in Patent Document 1 may not be sufficient.

[0008] The present disclosure has been made in consideration of the above circumstances. An object of one embodiment of the present disclosure is to provide a laminate-type battery that has excellent impact resistance against external impact. [Means for solving the problem]

[0009] Means for solving the above problems include the following embodiments.

[0010] <1> A laminated battery of a first embodiment of the present disclosure is a laminated battery comprising an electrode body and a laminate film that covers the electrode body and encloses it inside, the laminate film having a fused portion where ends are overlapped and the inner surface is fused, 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 a region tip side of the fold line, and has a wavy, undulating shape along the longitudinal direction of the fused portion.

[0011] In the first embodiment, the fusion part has a surface facing the electrode body in a region (hereinafter also referred to as the "folded region") on the tip side of the folding line part, and has a wave-like undulating shape (hereinafter also referred to as the "wave shape") along the longitudinal direction of the fusion part. The folded region usually has a moderate shape retention. Therefore, when an impact (e.g., a side impact, etc.) is applied to the folded region from the outside, the folded region is more likely to function as an impact buffer than when the folded region is 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 embodiment of the present disclosure is characterized in that the number of wave crests of the shape is two or more, and the height difference between the wave crest and the wave trough of the shape at the tip of the fused portion is 0.5 mm or more. <1> 2. The laminated battery according to claim 1 .

[0013] In the present disclosure, the "height difference between a wave crest and a wave trough" refers to the distance between the top of a crest and the bottom of the trough adjacent to this crest.

[0014] In the second embodiment, when an external impact (e.g., a side impact) is applied to the folding region, the folding region is more likely to function as an impact buffer than when the folding region does not satisfy the conditions of the second embodiment, and as a result, the laminated battery of the second embodiment has better impact resistance against external impact.

[0015] <3> In a third aspect of the present disclosure, there is provided a laminated battery, wherein the fused portion is folded along the folding line portion into an angular or arcuate shape. <1> or the above <2> 2. The laminated battery according to claim 1 .

[0016] In the third embodiment, the folded region has better shape retention than when the fused portion is not folded into an angular or arc shape along the fold line, and as a result, the laminated battery of the third embodiment has better impact resistance against external impact.

[0017] <4> In a fourth aspect of the present disclosure, there is provided a laminated battery, wherein a length of the tip of the shape in a longitudinal direction of the fused portion is longer than a length of the fused portion at the folding line portion. <1> ~The above <3> 10. The laminate type battery according to claim 9, wherein the first and second electrodes are electrically connected to the first and second electrodes.

[0018] In the fourth embodiment, when an external impact (e.g., a side impact) is applied to the folding region, the folding region is more likely to function as an impact buffer than when the folding region does not satisfy the conditions of the fourth embodiment, and as a result, the laminated battery of the fourth embodiment has better impact resistance against external impact. Effect of the Invention

[0019] According to the present disclosure, a laminate-type battery having excellent impact resistance against external impact is provided. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is an external perspective view of a laminated battery according to an embodiment of the present disclosure. [Diagram 2] 2 is a cross-sectional view taken along line C2-C2 of FIG. 1. [Diagram 3] FIG. 2 is a top view of a laminated battery according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is an external perspective view of a semi-finished laminated battery according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

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

[0023] (1) Laminated battery As shown in Fig. 1, a laminated battery 1 according to an embodiment of the present disclosure includes an electrode assembly 10, a laminated 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 laminated battery 1 is a rectangular parallelepiped object.

[0024] In this embodiment, one side of the short side of the main surface of the laminated battery 1 is defined as the X-axis positive direction, and the opposite side is defined as the X-axis negative direction. One side of the long side of the main surface of the laminated battery 1 is defined as the Y-axis positive direction, and the opposite side is defined as the Y-axis negative direction. One side of the thickness direction of the laminated battery 1 is defined as the Z-axis positive direction, and the opposite side is defined as the Z-axis negative direction. The X-axis, Y-axis, and Z-axis are mutually orthogonal. Note that these directions do not limit the orientation of the laminated battery 1 of the present disclosure during use.

[0025] The pair of terminals 30 are disposed opposite each other via the electrode body 10. The electrode body 10 is electrically connected to each of the pair of terminals 30. The laminate film 20 covers the electrode body 10 and encapsulates it therein. The laminate film 20 covers a portion of the pair of terminals 30.

[0026] (1.1) Laminate film The laminate film 20 is a single sheet. The laminate film 20 has a fused portion 21 in which the ends are overlapped and fused at the inner surface. The fused portion 21 is folded along a folding line R. The folding line R extends along the longitudinal direction of the fused portion 21 (i.e., the Y-axis direction). In this embodiment, as shown in FIG. 2, the fused portion 21 is folded along the folding line R into an arc shape AS.

[0027] The fused portion 21 has a bent region 211 and a non-bent region 212. The bent region 211 is bent relative to the main surface (XY plane) of the laminated battery 1. The bent region 211 refers to the region on the tip side of the fused portion 21 relative to the bend line R of the fused portion 21. The non-bent region 212 is not bent relative to the main surface (XY plane) of the laminated battery 1. The non-bent region 212 refers to the region on the opposite side of the bend line R of the fused portion 21 to the tip side of the fused portion 21.

[0028] (1.1.1) Wave shape The folded region 211 has a surface S211 facing the electrode body 10. The folded region 211 has a wave-like undulating shape WS along the longitudinal direction of the fused portion 21 (Y-axis direction) (hereinafter also referred to as a "wave shape WS"). In this embodiment, as shown in Fig. 3, the number of wave crests M of the corrugated shape WS is two or more. At the tip of the fused portion 21, the height difference L1 (see Fig. 3) between the wave crests M and the wave troughs V of the corrugated shape 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 of the tip T21 (see FIG. 2) of the corrugated shape WS is longer than the length L3 of the fused portion 21 at the bending line portion R.

[0030] FIG. 4 shows an external perspective view of a semi-finished product 100 of the laminated battery 1. The configuration of the semi-finished product 100 is the same as that of the laminated battery 1, except that the fused portion 21 is not subjected to a folding process. The corrugated shape WS is formed by folding the semi-finished product 100 by a known roll forming method. In detail, 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 stepwise, the tip T21 of the fused portion 21 in the short direction of the fused portion 21 is pulled in the opposite direction to the bending line R and plastically deformed. As a result, the corrugated shape WS is formed in the bending region 211. The length L2 of the corrugated shape WS is adjusted mainly by the bending angle by passing through the pair of rollers and the roll pitch of the pair of adjacent rollers. The "bending angle" indicates the angle of the bending region 211 with respect to the main surface (XY plane) of the laminated battery 1.

[0031] (1.1.2) Film composition The laminate film 20 may be a known laminate film used in laminate type batteries, and may be a film having a three-layer structure. The film having a three-layer structure 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 the material of the adhesive layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of the material of the metal layer include aluminum, aluminum alloy, stainless steel, etc. Examples of the material of the protective layer include polyethylene terephthalate (PET) and nylon, etc. The thickness of the adhesive 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 generating element of the laminated battery 1. The shape of the electrode body 10 is not particularly limited, but examples include a rectangular parallelepiped shape and a shape with inclined end faces. The electrode body is formed by stacking a plurality of unit electrode layers along the Z-axis direction. The unit electrode layer is formed by stacking 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 in this order along the Z-axis direction.

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

[0035] The positive electrode mixture layer contains a positive electrode active material (e.g., LiCoO2, LiMn2O4, or LiFePO4). The positive electrode mixture layer may further contain 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, etc.), and a binder (e.g., styrene butadiene rubber or polyvinylidene fluoride) as necessary.

[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 necessary. 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 the oxide solid electrolyte include a garnet-type solid electrolyte, a perovskite-type solid electrolyte, a Nasicon-type solid electrolyte, a Li-PO-based solid electrolyte, and a Li-BO-based solid electrolyte. Examples of the halogenated solid electrolyte 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 is, for example, aluminum, copper, stainless steel, nickel, iron, titanium, or carbon. The shape of the negative electrode current collector is, for example, a foil or mesh shape.

[0038] The negative electrode mixture layer contains a negative electrode active material (e.g., metallic lithium, graphite, lithium titanate, or simple Si). The negative electrode mixture layer may further contain 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, etc.), and a binder (e.g., styrene butadiene rubber or polyvinylidene fluoride) as necessary.

[0039] (1.3) Terminal The terminal 30 is a rectangular parallelepiped object whose longitudinal direction is the X-axis direction and whose lateral direction is the Z-axis direction. The terminal 30 may be made of a metal (for example, stainless steel (SUS)).

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

[0041] (1.5) Effects As described with reference to Figures 1 to 4, the laminate type battery 1 includes an electrode body 10 and a laminate film 20. The laminate film 20 has a fused portion 21. The fused portion 21 is folded along a folding line R. In the folding region 211, the fused portion 21 has a surface S211 facing the electrode body 10, and has a wave shape WS. The folding region 211 usually has a suitable degree of shape retention. Therefore, when the folding region 211 receives an external impact (e.g., a side impact), the folding region 211 is more likely to function as an impact buffer than if the folding region 211 were flat. As a result, the laminated battery 1 has excellent impact resistance against external impacts.

[0042] As described with reference to FIGS. 1 to 4, in laminated battery 1, the number of wave crests M of corrugated shape WS is two or more, and the height difference L1 (see FIG. 3) at tip end T21 of fused portion 21 is 0.5 mm or more. This allows the folding region 211 to function more effectively as a shock absorber when an external impact (such as a side impact) is applied to the folding region 211 than when the folding region 211 does not satisfy the above conditions, resulting in the laminated battery 1 having superior shock resistance against external impacts.

[0043] As described with reference to FIGS. 1 to 4, in the laminated battery 1, the fused portion 21 is folded along the folding line R into an arc shape. This allows the folding region 211 to have better shape retention than when the fused portion 21 is not folded into an angular or arc shape along the folding line R. As a result, the laminated battery 1 has better impact resistance against external impacts.

[0044] As described with reference to Figures 1 to 4, in the laminated battery 1, in the longitudinal direction (Y-axis direction) of the fused portion 21, the length L2 (see Figure 3) at the tip T21 of the corrugated shape WS is longer than the length L3 at the folding line portion R of the fused portion 21. This allows the folding region 211 to function more effectively as a shock absorber when an external impact (such as a side impact) is applied to the folding region 211 than when the folding region 211 does not satisfy the above conditions, resulting in the laminated battery 1 having superior shock resistance against external impacts.

[0045] (2) Variations In the laminated battery 1, the number of wave crests M of the corrugated shape WS is two or more and the height difference L1 (see FIG. 3) is 0.5 mm or more, but the present disclosure is not limited thereto. The laminated battery of the present disclosure does not have to satisfy at least one of the number of wave crests M of the corrugated shape WS being two or more and the height difference L1 (see FIG. 3) being 0.5 mm or more at the tip T21 of the fused portion 21.

[0046] In the laminated battery 1, the fused portion 21 is folded into an arc along the folding line R, but the present disclosure is not limited thereto. The fused portion 21 may be folded into an angular shape along the folding line R, or may be folded into a shape other than an arc or an angular shape. "Angular" refers to a shape having corners.

[0047] The electrode body 10 is an all-solid-state battery having a solid electrolyte layer, but may be a lithium secondary battery having 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-folded area 30 Terminals 100 semi-finished products AS arcuate R Bending line M mountain V valley WS wave shape

Claims

1. An electrode body; A laminate film that covers the electrode body and encapsulates it therein; Equipped with The laminate film has a fused portion where the ends are overlapped and the inner surfaces are fused, The fused portion is folded along a folding line portion extending in a longitudinal direction of the fused portion, A laminated battery, wherein the fused portion has a surface facing the electrode body in a region on the tip side of the folding line portion, and has a wavy shape along the longitudinal direction of the fused portion.

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

3. 3. The laminated battery according to claim 1, wherein the fused portion is folded along the folding line into an angular or arcuate shape.

4. 3 . The laminated battery according to claim 1 , wherein a length of the fused portion at a tip end of the shape in a longitudinal direction is longer than a length of the fused portion at the folding line portion.

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