Battery, and manufacturing method thereof

Abstract

To provide a battery capable of easily visually determining whether the folded parts on the outer periphery are heat-welded or not, and a manufacturing method.SOLUTION: Provided is a battery 10 is a battery that houses an electrode body inside, which includes an outer casing 12 that has overlapping peripheral edges 14 joined by heat welding and folded, and a manufacturing method thereof is provided. A coloring material 16 that changes color when heated is applied to the peripheral portion 14. Only the area where the color material 16 in the peripheral portion 14 has changed color is the bending point of the peripheral edge portion 14.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a battery and a method for manufacturing the same. [Background technology]

[0002] BACKGROUND ART A method for manufacturing a battery in which the heat-sealed peripheral edge of a laminate film that is the exterior body of a laminated battery is folded has been known for some time (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-228381 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the peripheral edge of the laminate film (exterior body) of a laminated battery needs to be folded, including the heat-sealed portion, but it is difficult to visually determine whether the folded portion of the peripheral edge of the laminate film (exterior body) is a heat-sealed portion or not.

[0005] Therefore, an object of the present invention is to provide a battery in which it is easy to visually determine whether or not the folded portion of the peripheral edge of the exterior body is a heat-welded portion, and a method for manufacturing the same. [Means for solving the problem]

[0006] In order to achieve the above object, a first aspect of the battery according to the present invention has an outer casing that houses an electrode body and has overlapping peripheral portions that are joined by thermal welding and then folded, and the peripheral portions are coated with a coloring material that changes color when heated, and only the portions of the peripheral portions where the coloring material has changed color are designated as the folded portions of the peripheral portions.

[0007] According to the first aspect of the invention, the outer casing housing the electrode assembly has overlapping peripheral portions joined by thermal welding and folded, and the peripheral portions are coated with a coloring material that changes color when heated, and only the portions of the peripheral portion where the coloring material has changed color are designated as folded portions of the peripheral portion. Therefore, it is easy to visually determine whether the folded portions of the peripheral portion of the outer casing are thermally welded portions.

[0008] A battery according to a second aspect of the present invention is the battery according to the first aspect, wherein the color material is applied to the entire peripheral edge portion.

[0009] According to the second aspect of the invention, the coloring material is applied to the entire peripheral edge, which makes it easier to visually determine the heat-sealed area compared to when the coloring material is applied to only a portion of the peripheral edge.

[0010] A battery according to a third aspect of the present invention is the battery according to the first or second aspect, wherein the coloring material is an irreversible coloring material that maintains a color change state.

[0011] According to the third aspect of the invention, the coloring material is an irreversible coloring material that maintains its discoloration state, which ensures that the folded portion of the periphery of the exterior body remains heat-sealed for a long period of time, compared to a coloring material that does not maintain its discoloration state.

[0012] In addition, a fourth aspect of the battery manufacturing method according to the present invention includes a coating step of coating the overlapping peripheral portions of an outer casing housing an electrode body therein with a coloring material that changes color when heated, a joining step of joining the peripheral portions by thermal welding, and a folding step of folding only the portions of the peripheral portions where the coloring material has changed color.

[0013] According to the fourth aspect of the invention, a coloring material that changes color when heated is applied to the overlapping peripheral portions of the exterior housing that houses the electrode assembly, and the peripheral portions are joined by thermal welding. Only the portions of the peripheral portions where the coloring material has changed color are designated as folding portions and folded. Therefore, it is easy to visually determine whether the folded portions of the peripheral portions of the exterior housing are thermally welded portions.

[0014] A fifth aspect of the battery manufacturing method according to the present invention is the fourth aspect of the battery manufacturing method, wherein in the applying step, the color material is applied to the entire peripheral edge portion.

[0015] According to the fifth aspect of the invention, the coloring material is applied to the entire peripheral edge in the application step, which makes it easier to visually determine the heat-sealed area compared to when the coloring material is applied only to a portion of the peripheral edge.

[0016] A sixth aspect of the battery manufacturing method according to the present invention is the third or fourth aspect of the battery manufacturing method, wherein the coloring material is an irreversible coloring material that maintains a color change state.

[0017] According to the sixth aspect of the invention, the coloring material is an irreversible coloring material that maintains its color change state, so that the folded portion of the periphery of the exterior body is guaranteed to be heat-sealed for a long period of time, compared to a coloring material that does not maintain its color change state. [Effects of the Invention]

[0018] As described above, according to the present invention, it is possible to easily determine by visual inspection whether or not the folded portion of the peripheral edge of the exterior body is a heat-welded portion. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic side view showing a state in which a coloring material is applied to the peripheral portion of a laminate film of a battery according to an embodiment of the present invention. FIG. [Figure 2]3 is a schematic side view showing a state in which the peripheral edge of the laminate film of the battery according to the present embodiment has been heat-welded. FIG. [Figure 3] 3 is a schematic side view showing a state in which the peripheral edge portion of the laminate film of the battery according to the embodiment is folded. FIG. [Figure 4] 1A is a schematic side view showing a state in which the peripheral edge of the laminate film of the battery according to the comparative example is heat-sealed, and FIG. 1B is a schematic side view showing a state in which the peripheral edge of the laminate film of the battery according to the comparative example is folded. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the sizes of components in each drawing are conceptual, and the relative size relationships between components are not limited to these. Furthermore, in this embodiment, 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.

[0021] Furthermore, the battery 10 according to this embodiment is, as an example, a battery cell housed inside a battery pack (not shown) that is mounted under the floor of a battery electric vehicle (BEV), not shown. Therefore, in the following description, the "battery 10" may be referred to as the "battery cell 10."

[0022] The battery pack is composed of multiple battery modules (not shown), which are electrically connected to each other. Each battery module contains multiple battery cells (batteries) 10 arranged in the thickness direction. Between adjacent battery cells 10, a cushioning material (not shown), which is, for example, an elastically deformable thin plate-like member, is arranged with its thickness direction aligned with the arrangement direction of the battery cells 10.

[0023] Figures 1 to 3 show a schematic view of a portion of a battery cell 10. As shown in Figures 1 to 3, the battery cell 10 is formed in a generally rectangular parallelepiped shape except for a peripheral edge portion 14, which will be described later, and houses an electrode assembly (not shown) inside. The electrode assembly is configured by laminating electrodes (negative and positive electrodes) and separators placed between the electrodes, and is sealed with a laminate film 12 as an exterior body.

[0024] The electrode may be, for example, a current collector having a layer containing an electrode active material formed on one or both sides thereof. The separator may be, for example, a microporous membrane made of a resin such as polyethylene. The laminate film 12 is a laminate having a metal layer containing a metal such as aluminum and a heat seal layer.

[0025] In this embodiment, as an example, the housing portion for the electrode body is formed by folding and bonding an embossed sheet-like laminate film 12. Note that the laminate film 12 can have either a single-cup embossed structure in which embossing is performed in one place, or a double-cup embossed structure in which embossing is performed in two places.

[0026] Next, a method for manufacturing the battery (battery cell) 10 configured as described above will be described.

[0027] The battery 10 manufactured by the manufacturing method according to this embodiment is a so-called laminate battery that uses a laminate film 12 as an exterior body. First, as shown in Fig. 1, the laminate film 12 is folded in two with an electrode body (not shown) housed inside, and the peripheral portions 14 of the laminate film 12 are overlapped. Then, a color material 16 that changes color when heated is applied to the entire outer surface, which is a metal layer, of the peripheral portion 14 (application step).

[0028] Next, as shown in Fig. 2, the inner surfaces of the overlapping peripheral portions 14, which are heat-sealed layers, are joined by heat welding (joining process). In other words, a welded portion 18 is formed on the overlapping inner surfaces of the peripheral portions 14. Thereafter, as shown in Fig. 3, the peripheral portions 14 are folded toward the storage section only at the locations where the coloring material 16 of the peripheral portions 14 has discolored (folding process). That is, the peripheral portions 14 are folded from the tip end of the peripheral portions 14 in one direction at 180°, 180°, and 90° angles in a predetermined length, forming a substantially spiral shape.

[0029] Here, the color material 16 in the heat-sealed portion (sealed portion 18) of the peripheral edge portion 14 has discolored, as shown in Fig. 2. Therefore, as shown in Fig. 3, when folding the peripheral edge portion 14, only the portion where the color material 16 in the peripheral edge portion 14 has discolored can be recognized as the folding portion of the peripheral edge portion 14. In other words, the peripheral edge portion 14 of the laminate film 12 needs to be folded including the heat-sealed portion (area), but the portion (area) of the peripheral edge portion 14 to be folded can be visually recognized as the heat-sealed portion (area).

[0030] The color material 16 applied to the outer surface of the peripheral edge 14 is preferably an irreversible color material that has insulating properties and maintains its discolored state, and since the welding temperature is about 160° C., it is preferable that the color material change color at about 150° C. Examples of such color materials 16 include the memory type Metamocolor (registered trademark) manufactured by Pilot Ink Co., Ltd. and Thermopaint (registered trademark) manufactured by Niyu Giken Kogyo Co., Ltd.

[0031] Next, the operation of the battery 10 according to this embodiment and the manufacturing method thereof configured as described above will be described.

[0032] First, a battery 100 according to a comparative example shown in Fig. 4 will be described. As shown in Fig. 4(A), a color material 16 is not applied to a peripheral edge 114 of a laminate film 112 of this battery 100. Therefore, even if the peripheral edge 114 is heat-sealed (a welded portion 118 is formed) in this state, it is not possible to recognize from the outside which portion of the peripheral edge 114 is heat-sealed. Therefore, as shown in Fig. 4(B), the battery may be folded without the heat-sealed portion (area) being considered as the folding portion (area).

[0033] In contrast, in the battery 10 according to this embodiment, as described above, the entire outer surface of the peripheral edge 14 of the laminate film 12 is coated with a coloring material 16 that changes color when heated, for example, to about 150°C. Therefore, the range of the welded portion 18 that is heat-welded at, for example, 160°C can be visually confirmed. In other words, the peripheral edge 14 of the laminate film 12 needs to be folded including the heat-welded portion (range), but the portion (range) where the coloring material 16 of the peripheral edge 14 has changed color can be easily visually determined as the portion (range) that should be folded, allowing for accurate folding.

[0034] Thus, with battery 10 according to this embodiment, it is possible to easily visually determine whether the folded portion (area) of peripheral edge 14 of laminate film 12 is a heat-sealed portion (area). Moreover, because color material 16 is applied to the entire peripheral edge 14, the range of heat-sealed welded portion 18 can be easily visually determined compared to when color material 16 is applied only to a portion of peripheral edge 14.

[0035] Furthermore, since this color material 16 has insulating properties, it is safe and is an irreversible color material that maintains its discolored state. Therefore, compared to a color material that does not maintain its discolored state (for example, a color material that returns to its original color after a certain period of time), it is possible to guarantee for a long period of time that the folded portion (range) of the peripheral portion 14 of the laminate film 12 is the heat-welded portion (range).

[0036] While the battery 10 and its manufacturing method according to the present embodiment have been described above with reference to the drawings, the battery 10 and its manufacturing method according to the present embodiment are not limited to those shown in the drawings and may be modified as appropriate within the scope of the present invention. For example, if it is known from the beginning that the base portion of the peripheral edge 14 (the portion opposite the tip portion) will not be heat-welded, the color material 16 does not need to be applied to the base portion.

[0037] Furthermore, the type and size of the electrode assembly and the number of electrodes and separators included in the electrode assembly are not particularly limited and are selected according to the scale and use of the battery 10. Furthermore, the vehicle is not limited to an electric vehicle, but may be a hybrid vehicle (HV) or a plug-in hybrid electric vehicle (PHEV) equipped with an engine. [Explanation of symbols]

[0038] 10 Battery Cells (Batteries) 12 Laminate film (exterior body) 14 Periphery 16 Colorants

Claims

1. The electrode assembly is housed therein, and an outer casing is provided, the overlapping peripheral portions of which are joined by thermal welding and which can be folded. a coloring material that changes color when heated is applied to the peripheral edge; The battery wherein only the portion of the peripheral edge where the coloring material has changed color is the folded portion of the peripheral edge.

2. The battery according to claim 1 , wherein the coloring material is applied to the entire peripheral portion.

3. 3. The battery according to claim 1, wherein the coloring material is an irreversible coloring material that maintains a color change state.

4. a coating step of coating a coloring material that changes color when heated on the overlapping peripheral portion of the exterior body that houses the electrode body therein; a joining step of joining the peripheral edge portion by thermal welding; a folding step of folding only the portion of the peripheral edge where the coloring material has changed color; A method for manufacturing a battery having the above structure.

5. The method for manufacturing a battery according to claim 4 , wherein in the coating step, the color material is coated over the entire peripheral edge portion.

6. 6. The method for manufacturing a battery according to claim 4, wherein the coloring material is an irreversible coloring material that maintains its color change state.

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