JP2012043732A - Film-armored battery and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film-armored battery which is capable of increasing an effect of preventing damage caused by scratches and dents.SOLUTION: The film-armored battery comprises a battery element 3 and a film 2 wrapping up the battery element 3. Protrusions with rounded tips are continuously formed on a outer surface of the film 2.

Description

  The present invention relates to a film-clad battery in which battery elements are wrapped with a film, and a method for manufacturing the same.

  In recent years, with the widespread use of electric vehicles and hybrid vehicles, non-aqueous electrolyte secondary batteries represented by lithium ion secondary batteries have been actively developed as power sources for driving them. Such a battery generally has a structure in which a battery element in which a plurality of positive electrode sheets and a plurality of negative electrode sheets are laminated via a separator is accommodated in an exterior material. Patent Document 1 discloses a battery in which a battery element is wrapped with a two-layer exterior material.

  FIG. 5 is a cross-sectional view showing the configuration of the sheet material type battery disclosed in Patent Document 1. As shown in FIG. The sheet material type battery 100 shown in FIG. 5 has the concavo-convex plate materials 18 and 20 that sandwich the battery power generation element 40. The concavo-convex plate members 18 and 20 are formed with a concavo-convex shape on the surface opposite to the surface sandwiching the battery power generation element 40. The sheet material 22 is laminated on the uneven plate material 18 along the uneven shape of the uneven plate material 18, and the sheet material 23 is laminated on the uneven plate material 20 along the uneven shape of the uneven plate material 20. As a result, a concave / convex shape including the convex portions 30 and the concave portions 32 is formed on the outer surfaces of the sheet materials 22 and 23. This uneven shape increases the heat dissipating area of the surface portion of the battery power generation element 40, so that the heat dissipating property can be improved.

JP 2006-49054 A

  In the development of a battery used as a driving power source for an electric vehicle or a hybrid vehicle, weight reduction and thinning are strongly demanded. For this reason, a film has begun to be used in place of a metal can case in order to achieve a reduction in weight and thickness of a battery element exterior material. When the exterior material is a film, since the film is soft, if the entire outer surface of the film is flat, scratches and dents are easily formed in the transport process and the inspection process. In the sheet materials 22 and 23 described in Patent Document 1, since the tip of the convex portion 30 is rounded, scratches and dents are less likely to occur than a film having a flat outer surface. However, in the concavo-convex shape formed on the sheet members 22 and 23, the convex portions 30 are arranged in a dispersed manner, and the flat concave portion 32 occupies most of the sheet members 22 and 23. Therefore, the film-clad battery described in Patent Document 1 has a low effect of preventing damage due to scratches and dents.

  Then, an object of this invention is to provide the film exterior type | mold battery which can raise the prevention effect of the damage by a damage | wound or a dent, and its manufacturing method.

  In order to achieve the above object, a film-clad battery according to the present invention has a battery element and a film enclosing the battery element, and a convex shape with a rounded tip is continuously formed on the outer surface of the film. Is formed.

  In addition, in order to achieve the above object, the film-clad battery manufacturing method according to the present invention includes a step of continuously forming a convex shape with a rounded tip on the outer surface of the film, and the convex shape is formed. Wrapping the battery element with a film.

  According to the present invention, the convex shape formed on the outer surface of the film has a rounded tip and is continuous. Therefore, compared with the structure where the convex portions are dispersed and arranged, the outer surface of the film is less likely to be scratched or dented. Therefore, it is possible to enhance the effect of preventing damage due to scratches and dents.

It is a disassembled perspective view which shows one Embodiment of the film-clad battery of this invention. It is sectional drawing which shows the structure of the film of the film-clad battery of FIG. It is a schematic diagram which shows the method of the embossing in this embodiment. FIG. 4 is an external view of the film-clad battery shown in FIG. It is sectional drawing which shows the structure of the sheet material type battery disclosed by patent document 1. FIG.

  FIG. 1 is an exploded perspective view showing an embodiment of a film-clad battery of the present invention. First, the structure of the film-clad battery of this embodiment will be described.

  A film-clad battery 1 shown in FIG. 1 has a pair of films 2. Each film 2 is formed with a depression. The outer peripheral part (periphery part of a hollow) of each film 2 is adhere | attached airtight by heat sealing | fusion. When the film 2 is bonded, an internal space is formed by the depression of the film 2. The battery element 3 is accommodated in the internal space. A positive electrode current collector 4 and a negative electrode current collector 5 are drawn out from both ends of the battery element 3. A positive electrode tab 6 is connected to the positive electrode current collector 4. A negative electrode tab 7 is connected to the negative electrode current collector 5.

  In the battery element 3, a plurality of positive electrode sheets and a plurality of negative electrode sheets are stacked with (separated) via separators. Each positive electrode sheet and each negative electrode sheet are formed by uniformly applying an active material layer to a predetermined region on a current collector made of a metal foil or the like.

  The positive electrode current collector 4 is configured to connect a plurality of positive electrode sheets on one end side of the battery element 3. The negative electrode current collector 5 is configured to connect a plurality of negative electrode sheets on the other end side of the battery element 3. The positive electrode sheets are connected together by welding, such as ultrasonic welding, together with the positive electrode tab 6 on the active material uncoated portion of the metal foil in each positive electrode sheet. On the other hand, the connection between the negative electrode sheets is also collectively performed by welding, such as ultrasonic welding, together with the negative electrode tab 7 on the non-coated portion of the metal foil in each negative electrode sheet. A protective sheet 8 is attached to a region covering the positive electrode tab 6, the connection portion by ultrasonic welding, and the end of the positive electrode tab 6 in the positive electrode current collector 4. The positive electrode tab 6 and the negative electrode tab 7 extend outward from the outer peripheral portion which is a joint portion between the films 2.

  FIG. 2 is a cross-sectional view showing the structure of the film 2. As shown in FIG. 2, the film 2 has a three-layer structure in which a resin layer 11 (first resin layer) and a resin layer 12 (second resin layer) are individually laminated on both surfaces of a metal layer 10. Laminated film.

  The metal layer 10 is made of a thin aluminum film. The material of the metal layer 10 is not limited to aluminum, and may be any metal that can prevent permeation of the electrolyte, moisture, and gas injected into the battery element 3. In the metal layer 10, a plurality of convex portions 13 are formed on the surface (one surface) on which the resin layer 11 is laminated. As shown in FIG. 2, each convex portion 13 has a rounded tip. Moreover, each convex part 13 is continuing (it adjoins mutually).

  The resin layer 11 is laminated on the metal layer 10 along the shape of the convex portion 13. The resin layer 11 constitutes the outer surface of the film 2 and functions as a protective layer for the metal layer 10. The resin layer 12 is laminated on the surface (the other surface) opposite to the surface on which the resin layer 11 of the metal layer 10 is laminated. The outer peripheral portion of the resin layer 12 is heat-sealed and functions as a heat seal layer. As the material of the resin layers 11 and 12, plastics represented by nylon, polyethylene, and polypropylene can be applied.

  Next, the manufacturing method of the film-clad battery 1 is demonstrated.

  First, the convex part 13 mentioned above is formed in the metal layer 10 by embossing. FIG. 3 is a schematic diagram showing the embossing method in the present embodiment. In the present embodiment, as shown in FIG. 3, the air blast (sand blast) 14 projects the spray material 15 onto the surface of the metal layer 10, whereby the convex portion 13 is formed. The height H (see FIG. 3) of the convex portion 13 is preferably 0.020 mm or less in consideration of the thickness of the metal layer 10. After forming the convex portion 13 on the metal layer 10, each of the resin layers 11 and 12 is laminated on the metal layer 10. Thereby, the film 2 is completed.

  Subsequently, the battery element 3 is housed (wrapped) with a pair of films 2. And after inject | pouring electrolyte solution into the battery element 3, the outer peripheral part of the resin film 12 is heat-sealed, and the battery element 3 is sealed airtightly. Thereby, the film-clad battery 1 is completed as shown in FIG.

  In the film-clad battery 1 manufactured through the above-described steps, a convex shape with a rounded tip is continuously formed on the outer surface of the film 2. Therefore, compared to the uneven shape shown in FIG. 5, the metal layer 10 is less likely to be damaged by scratches and dents. Therefore, it is possible to prevent the problem of air intrusion due to a decrease in insulating properties of the film 2 and cracks. As a result, an effect of improving the long-term reliability of the battery can be obtained.

  Moreover, since the convex shape formed on the outer surface of the film 2 becomes a frictional resistance and the outer surface of the film 2 becomes less slippery, it becomes difficult to fall during carrying.

DESCRIPTION OF SYMBOLS 1 Film exterior type battery 2 Film 3 Battery element 4 Positive electrode current collection part 5 Negative electrode current collection part 6 Positive electrode tab 7 Negative electrode tab 8 Protective sheet 10 Metal layer 11, 12 Resin layer 13 Convex part 14 Air blast 15 Propellant 18, 20 Unevenness Plate material 22, 23 Sheet material 30 Convex part 32 Concave part 40 Power generation element 100 for battery Sheet material type battery

Claims (4)

A battery element;
A film enclosing the battery element,
A film-clad battery in which a convex shape having a rounded tip is continuously formed on the outer surface of the film.   The film has a metal layer in which a plurality of convex portions with rounded ends are continuously formed on one surface, and is laminated along the shape of the plurality of convex portions on the one surface of the metal layer. The film-clad battery according to claim 1, further comprising: a first resin layer; and a second resin layer laminated on the other surface of the metal layer. A step of continuously forming a rounded convex shape on the outer surface of the film;
A step of wrapping the battery element with the film having the convex shape formed;
A method for producing a film-clad battery, comprising:   The manufacturing method of the film-clad battery of Claim 3 which forms the some convex part corresponding to the said convex shape by embossing.

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