JP2008305564A - Sealed battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed battery having electrode tab structure in which the electrode tab is bent in a prescribed position, and bending strength is held when the electrode tab drawn out of a battery element is connected to an electrode terminal and the electrode tab is bent and housed in a battery can. <P>SOLUTION: The positive electrode from which a positive tab is taken out and the negative electrode from which the negative tab 6 is taken out are laminated through the separator, and wound to form the battery element 8, the battery element 8 is housed in the battery can 1, and an opening is sealed with a rid connected with the negative tab to form the sealed battery. The negative tab 6 has a plurality of recessed embossed parts 6a, 6b in the length direction and has a zigzag pattern formed by being bent between the recessed embossed parts. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sealed battery, and more particularly to a sealed battery characterized by a tab drawn from a battery element.

  Various types of batteries are used as power sources for small electronic devices, and small and large-capacity sealed batteries are used as power sources for mobile phones and laptop computers. Recently, lithium-ion secondary batteries with particularly high energy density are used. A sealed battery using a non-aqueous electrolyte such as is used. In addition, along with the reduction in thickness of electronic devices, a rectangular battery suitable for a thin device is used because of its excellent space efficiency.

  In a sealed battery such as a prismatic battery, the positive electrode tab and the negative electrode tab drawn out from the battery element obtained by laminating and winding the positive electrode and the negative electrode accommodated in the battery can through the separator are connected to the cover plate and then folded. The structure was accommodated in a battery can (see, for example, Patent Document 1).

  FIG. 3 is a partial cross-sectional view of a conventional sealed battery. The assembly of a conventional sealed battery will be described with reference to FIG. A battery element 8 in which a positive electrode tab and a negative electrode tab 6 are drawn out is accommodated in a battery can 1 such as aluminum. The tip of the negative electrode tab 6 is connected to the negative electrode terminal 5 that is insulated from the central cover of the lid 2, and the negative electrode tab 6 and the lid 2 are assembled into the battery can 1 so that the negative electrode tab 6 is folded. At this time, the insulator 3 is disposed on the battery element 8 and the insulating plate 4 is disposed under the lid so that the negative electrode tab 6 does not contact the battery can 1 and the lid 2 serving as the positive electrode. Moreover, after connecting the negative electrode tab pulled out from the battery element and the negative electrode terminal at the center of the lid and folding the negative electrode tab, the battery element and the lid can be housed in a battery can.

  However, if a bending tool is used or a bending die is used when bending the negative electrode tab, the bending position of the negative electrode tab cannot be accurately determined. As shown in FIG. There was a possibility that it would contact the battery can 1 and cause an internal short circuit. In order to stabilize the folding position, there is a method of making a notch or a hole in the folding part, but in the lithium ion battery, the tab itself is also becoming thinner due to the small size and thinning, and the bending part is processed. As a result, the bending strength becomes weak, which causes a problem in quality.

JP 2003-242957 A

  An object of the present invention is to connect an electrode tab drawn out from a battery element to an electrode terminal of a lid, fold the electrode tab, and store the battery tab in a battery can so that the electrode tab is bent at a predetermined position and maintains bending strength. An object of the present invention is to provide a sealed battery having an electrode tab structure.

  The sealed battery of the present invention includes a battery element in which a positive electrode from which a positive electrode tab is derived and a negative electrode from which a negative electrode tab is derived are stacked and wound via a separator, and is stored in a battery can. And a sealed battery sealed with a cover plate connected to at least one of the negative electrode tabs, a plurality of concave embossed portions are formed in a length direction on at least one of the positive electrode tab and the negative electrode tab, and the concave embossed portion It has a zigzag folded portion that is folded between.

  According to the present invention, by providing a concave embossed portion on the electrode tab, the bending position of the electrode tab can be reliably ensured without impairing the strength of the electrode tab, and an internal short circuit can be prevented. Reliability is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a partial cross-sectional view of a sealed battery according to an embodiment of the present invention. For example, for a rectangular lithium ion battery, a battery element 8 in which a positive electrode tab and a negative electrode tab 6 are drawn out is accommodated in a battery can 1 such as aluminum. The tip of the negative electrode tab 6 is connected to the negative electrode terminal 5 which is insulated from the central cover of the lid 2, and the negative electrode tab 6 having a plurality of concave embossed portions 6 a and 6 b in the length direction is connected to the concave embossed portions 6 a and 6 b. After being folded, the negative electrode tab 6 and the lid 2 are assembled into the battery can 1 so as to be folded. At this time, the insulator 3 is disposed on the battery element 8 and the insulating plate 4 is disposed under the lid so that the negative electrode tab 6 does not contact the battery can 1 and the lid 2 serving as the positive electrode. Moreover, after connecting the negative electrode tab pulled out from the battery element and the negative electrode terminal at the center of the lid and folding the negative electrode tab, the battery element and the lid can be housed in a battery can.

  Next, the negative electrode tab will be described. 2A and 2B are diagrams showing a main part of the negative electrode tab of the sealed battery according to the embodiment of the present invention. FIG. 2A is a front view and FIG. 2B is a side view. The negative electrode tab 6 drawn out from the negative electrode is made of, for example, a nickel plate having a width of 2 to 4 mm and a thickness of 0.05 to 0.1 mm, and an end thereof is connected to the negative electrode terminal by welding or the like. As shown in FIG. 2, the negative electrode tab 6 has two concave embossed portions 6a and 6b. Between the concave embossed portions 6a and 6b, there is a bent portion 7 for folding the negative electrode tab 6 in a zigzag manner. The shape of the concave embossed portion varies depending on the thickness of the battery can and the width of the negative electrode tab. For example, the thickness of the battery can, that is, the outer dimension from the left battery can to the right battery can in FIG. When the width of 6 is 4 mm, the shape of the concave embossed portion 6 a on the bent portion 7 is a rectangular concave embossed portion having a width of 2.0 mm, a length of 2.5 mm, and a depth of 0.02 mm. The lower concave embossed portion 6b can have a width of 2.0 mm, a length of 1.0 mm, and a depth of 0.02 mm. The distance between the concave embossed portions 6a and 6b is 1.0 mm, and the negative embossed portions 6a and 6b are easily bent when the negative electrode tab 6 is bent. The concave embossed portions 6a and 6b may be formed by pressing or the like after the battery element is formed and before connection with the negative electrode terminal, or may be processed simultaneously with connection with the negative electrode terminal. The shape and quantity of the concave embossed portion are not limited to this example, and can be appropriately determined according to the structure of the negative electrode tab, battery can, lid, and negative electrode terminal.

  In addition, although the negative electrode tab which consists of a nickel plate used for a lithium ion battery etc. was demonstrated concretely here, the material is not limited to a nickel plate, the positive electrode tab which consists of an aluminum plate is processed similarly, and this invention is used. In addition, the present invention is not limited to a lithium ion battery, and can be applied to a sealed battery in which a positive electrode tab and a negative electrode tab are accommodated in a battery can.

1 is a partial cross-sectional view of a sealed battery according to an embodiment of the present invention. The figure which shows the principal part of the negative electrode tab of the sealed battery of embodiment of this invention, Fig.2 (a) is a front view, FIG.2 (b) is a side view. The fragmentary sectional view of the conventional sealed battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery can 2 Lid 3 Insulator 4 Insulation board 5 Negative electrode terminal 6 Negative electrode tab 6a, 6b Recessed embossed part 7 Bending part 8 Battery element

Claims (1)

  A battery element in which a positive electrode from which a positive electrode tab is derived and a negative electrode from which a negative electrode tab is derived is stacked and wound via a separator is housed in a battery can, and an opening is formed with at least one of the positive electrode tab and the negative electrode tab. In a sealed battery that is sealed with a connected lid plate, at least one of the positive electrode tab and the negative electrode tab is formed with a plurality of concave embossed portions in a length direction, and has a zigzag folded portion that is bent between the concave embossed portions. A sealed battery characterized by that.

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