JP4932092B2 - Sealed battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealed battery, and more particularly to a sealed battery such as a small lithium ion battery having good sealing properties.
[0002]
[Prior art]
Portable electronic devices are becoming smaller and lighter and have advanced functions. As a result, batteries for power supplies used in these electronic devices are required to be small, light and large in capacity per volume.
Lithium ion batteries using positive and negative active materials doped and dedoped with lithium ions have a higher energy density per volume or mass than conventional nickel cadmium and lead batteries. As a secondary battery, it is used as a power source for small electronic devices.
A lithium ion battery is a battery element manufactured by winding a positive electrode and a negative electrode through a separator, or a battery element in which a positive electrode and a negative electrode are stacked in a metal can, and then an electrode having a polarity different from that of the battery can A lid provided with an electrode insulated by an insulating member is attached and sealed by welding.
[0003]
FIG. 4 is a diagram illustrating an example of a battery header, FIG. 4 (A) is an exploded perspective view, and FIG. 4 (B) is a diagram illustrating a cross-section of the assembled battery header, which is made of aluminum. It is a figure explaining the battery header attached to the battery can.
The battery header 2 is made of a cover metal plate 3 provided with a through hole for taking out an electrode terminal, a flange 4A of an electrode pin 4 made of nickel, nickel alloy or the like, a washer 6, polypropylene, fluororesin, or the like. By passing the internal insulating plate 7 through the hole provided in the lid metal plate 3, attaching the external insulating plate 8 from the upper part of the lid metal plate 3, and caulking the tip portion 4 </ b> B of the electrode pin 4, The inner insulating plate and the outer insulating plate are sealed and fixed between the electrode pin 4 and the lid metal plate 3. Further, the lid insulating plate 3 is provided with a small hole 9 for injecting an electrolytic solution and a pressure release valve 10 composed of a thin portion that releases the internal pressure when the pressure inside the battery increases.
[0004]
Next, as shown in a sectional view in the thickness direction of the upper part of the conventional battery in FIG. 5, after the battery header is fitted into the opening at the upper part of the battery can, the laser is applied to the wall of the battery can and the meeting part of the battery header. 11 is irradiated and sealed by laser welding.
However, the portion of the external insulating plate 8 protruding above the lid metal plate 3 contracts due to the heat 12 of the laser 11 applied during welding of the meeting portion between the battery can 1 and the lid metal plate 3. A gap is formed between the external insulating plate 8 and the electrode pin 4 or between the external insulating plate 8 and the metal plate for the lid, resulting in a defective sealing. It sometimes deteriorated.
[0005]
In particular, aluminum used as a battery can material for small and light batteries has a higher thermal conductivity than materials such as nickel-plated mild steel, and therefore, a large amount of heat energy is lost from the welded area to the surroundings. For this reason, when a battery header is joined to a battery can made of aluminum or an alloy thereof by laser welding, more heating energy is required compared to welding of a nickel-plated battery can. Thermal effects are also increased.
[0006]
[Problems to be solved by the invention]
The present invention provides a sealed battery that does not cause a sealing failure between an electrode terminal and an insulating member attached to the battery lid of the sealed battery via an insulating member, or between the battery lid and the insulating member. It is an object to do.
[0007]
[Means for Solving the Problems]
An object of the present invention is to provide an insulating battery provided between an electrode terminal and a battery lid body in a sealed battery in which a battery lid body to which an electrode terminal is attached via an insulating member is joined to an opening of a battery can by welding. Among the members, the external insulating plate facing the outer surface of the battery can is mounted at a position that does not protrude above the upper surface of the battery lid, and the external insulating plate is caulked by the electrode terminal forming member that penetrates the external insulating plate. a sealed battery in which is fixed, the portion located on the outer surface of the outer insulating plates of conductive terminal, said having an engagement portion of the protection member for protecting the upper surface of the electrode terminal or the battery lid It is a sealed battery.
The protective member is the above sealed battery that is attached after the battery lid and the battery can are joined by welding.
In the sealed battery, the protection member is an electrode terminal protection member that prevents a short circuit of the electrode terminal, or a battery header insulating plate that covers the battery header.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the sealed battery in which the battery lid is joined and sealed to the battery can by laser welding, when the sealing failure in the electrode terminal portion of the battery lid is joined to the battery can by laser welding, The present invention has been conceived by discovering that the cause is that the insulator located between the electrode terminal and the battery lid is thermally damaged to cause a sealing failure.
[0009]
The present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a sealed battery according to the present invention, and is a diagram illustrating a cross section of an electrode terminal portion on the upper side of the sealed battery.
The battery of the present invention is obtained by joining a battery header 2 to a battery can 1 made of aluminum or an aluminum alloy by laser welding or the like. The battery plate 3 is provided with a through hole for taking out an electrode terminal. On the flange 4A of the electrode pin 4 which is an electrode terminal forming member made of nickel, nickel alloy or the like, a washer 6 and an internal insulating plate 7 made of synthetic resin such as polypropylene or fluororesin are provided on the metal plate 3 for lid. By penetrating the hole, attaching the external insulating plate 8 from the upper part of the lid metal plate 3 and caulking the tip 4B of the electrode pin 4, the inner insulating plate and the external insulating plate are used as electrode pins and lid metal. The plate 3 is fixed in a sealed state.
[0010]
Further, the upper end portion of the external insulating plate 8 does not protrude from the upper surface of the lid metal plate 3, and the upper end portion 8A of the external insulating plate 8 is the same as the upper surface of the lid metal plate 3. It is located below the upper surface.
For this reason, when joining the battery header 2 to the battery can 1 by laser welding, it is possible to prevent the heat from the laser from being directly applied to the external insulating plate and causing deformation or the like due to the heat to cause a sealing failure. Is possible.
Further, a tab (not shown) connected to the battery element is connected to the flange portion of the electrode pin 4 to form a conductive connection.
Further, in the battery of the present invention, the side surface direction of the electrode terminal formed by caulking of the tip end portion of the electrode pin is exposed, but depending on the usage mode of the battery, it is necessary to insulate the side surface direction of the electrode terminal. If it occurs, an insulating plate may be attached to the electrode terminal.
[0011]
FIG. 2 is a view for explaining the insulating plate attached to the electrode terminal, and is a cross-sectional view in the thickness direction of the battery for explaining the electrode terminal portion of the battery.
FIG. 2A shows the battery header 2 joined by laser welding or the like. The electrode terminal has an engaging portion 20 formed thereon, and the electrode terminal protection member 21 is fixed by the engaging portion 20. Yes. For this reason, an electrode terminal will be protected from danger, such as a short circuit.
FIG. 2B shows an example in which a battery header insulating plate 22 that covers the battery header 2 on the upper side of the battery is attached to the engaging portion 20 formed on the electrode terminal.
This completely covers the top surface of the battery and protects it from dangers such as short circuits.
The electrode terminal protecting material and the battery header insulating plate shown in FIGS. 2 (A) and 2 (B) are both engaged with the electrode terminals after the battery header is joined and the battery is cleaned. Can be attached to the part.
[0012]
FIG. 3 is a diagram for explaining another example and explaining the thickness direction of the battery.
FIG. 3A illustrates an example in which the present invention is applied to a thin battery.
In the battery of this example, the upper end portion 8A of the external insulating plate 8 does not protrude from the surface of the lid metal plate 3 of the battery header 2, and the external insulating plate 8 is less likely to be damaged by heat. In addition, it becomes possible to reduce the distance d between the joining portion of the meeting portion of the battery can 1 and the battery header 2 by laser welding and the electrode terminal 4, and manufacture a battery having good sealing characteristics even in a thin battery. It becomes possible to do.
FIG. 3B is a diagram for explaining a battery with enhanced engagement characteristics between the external insulating plate and the electrode terminal.
In the example shown in FIG. 3B, the external insulating plate 8 is provided with a recess 8B for engaging the electrode terminal. As a result, the electrode terminal 4 is caulked, and the engagement of the recess 8B of the external insulating plate 8 is also produced. As a result, more sufficient engagement can be obtained.
[0013]
【Effect of the invention】
In the sealed battery of the present invention, since the insulating plate constituting the electrode terminal portion of the battery is structured not to protrude from the surface of the metal plate for the lid, laser welding is used when joining the battery header to the battery can. Since the insulating plate is not adversely affected by heat, a battery having good sealing properties can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a sealed battery according to the present invention, and is a diagram illustrating a cross-section of an electrode terminal portion on the top of the sealed battery.
FIG. 2 is a diagram illustrating an insulating plate attached to an electrode terminal, and is a cross-sectional view in the thickness direction of the battery illustrating an electrode terminal portion of the battery.
FIG. 3 is a diagram for explaining another example and explaining the thickness direction of the battery.
FIG. 4 is a diagram illustrating an example of a battery header.
FIG. 5 is a diagram illustrating a cross-sectional view in the thickness direction of the upper part of a conventional battery.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Battery can, 2 ... Battery header, 3 ... Metal plate for lid bodies, 4 ... Electrode pin, 4A ... Flange, 4B ... Tip part, 6 ... Washer, 7 ... Internal insulating plate, 8 ... External insulating plate, 8A ... Upper end portion, 8B ... concave portion, 9 ... small hole, 10 ... pressure release valve, 11 ... laser, 12 ... heat, 20 ... engagement portion, 21 ... electrode terminal protection material, 22 ... battery header insulating plate

Claims (2)

In a sealed battery in which a battery lid having an electrode terminal attached thereto via an insulating member is joined to an opening of the battery can by welding, among the insulating members provided between the electrode terminal and the battery lid, the battery can faces the outer surface outside the insulating plate, the upper surface of the battery lid on the top is mounted at a position not projecting, in which the outer insulating plates are fixed by caulking of the electrode terminal forming member passing through the outer insulating plate A sealed battery characterized in that an engaging portion of a protective member for protecting the electrode terminal or the upper surface of the battery lid is formed on a portion of the electrode terminal forming member located on the outer surface of the external insulating plate . The sealed battery according to claim 1, wherein the protective member is an electrode terminal protective member that prevents a short circuit of the electrode terminal, or a battery header insulating plate that covers the battery header.

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