JP3571262B2 - Sealed battery - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sealed battery, and more particularly, to a sealed battery having a feature in an electrode lead-out pin having a polarity different from that of a battery can.
[0002]
[Prior art]
Various batteries are used as power supplies for small electronic devices, and small, large-capacity sealed batteries are used as power supplies for mobile phones, notebook computers, camcorders, etc., and high-capacity lithium batteries and lithium ion batteries are used. Non-aqueous electrolyte batteries such as secondary batteries are used.
In response to miniaturization of devices, in addition to cylindrical batteries, rectangular sealed batteries that can effectively utilize a small space are widely used. In a prismatic battery, an electrode terminal separated by an insulating member and a battery can acting as one electrode of the battery is attached.
[0003]
An example of a conventional sealed battery will be described with reference to the drawings.
FIG. 3 is a diagram illustrating an example of a rectangular sealed battery.
A battery element formed by winding a stack of a positive electrode and a negative electrode via a separator is housed in a rectangular cylindrical metal container 1 (hereinafter, also referred to as a battery can) made of stainless steel, nickel-plated mild steel, or the like. At the upper end 2 of the battery can 1, a conductive connection terminal 4 (hereinafter also referred to as a positive electrode lead-out pin) is attached to a concave portion 3A provided in the metal plate 3 via an external insulating plate 14 and an electrode lead terminal 15. The upper surface of the electrode header 5 and the upper end 2 of the battery can are attached and sealed so as to be flush with each other, and a part of the electrode header 5 is provided with a pressure when the internal pressure of the battery is abnormally increased. In order to open, a thin portion 6 having a smaller thickness than other portions, an electrolyte solution is injected, and a small hole 12 for sealing after injection of the electrolyte solution is provided. , Embedded members made of metal such as stainless steel Welding to have sealing.
[0004]
4A and 4B are diagrams illustrating an example of the electrode header, FIG. 4A is an exploded perspective view, and FIG. 4B is a diagram illustrating a cross section of the assembled electrode header.
Explosion proof in which an inner insulating plate 13 made of polypropylene, fluororesin or the like is provided on the brim portion 4A of the positive electrode lead-out pin 4 made of a metal having good conductivity such as aluminum or an aluminum alloy, and the surface is made thinner than the surrounding thickness. A metal plate 3 made of a stainless steel, a nickel-plated mild steel plate or the like having a thin portion 6 having a function and a small hole 12 for injecting an electrolytic solution and having a through hole in a concave portion 3A provided on the upper surface is provided. Insert, then insert the external insulating plate 14 made of polypropylene, fluororesin, etc., and then sequentially insert the electrode lead terminal plate 15 made of nickel plate, nickel-plated iron plate, copper plate, nickel silver plate, etc. The tip 4B of the positive electrode lead-out pin and the flange portion 4A are crimped from above and below to form a conductive connection terminal together with the positive electrode lead-out terminal 15, thereby producing an integrated electrode header 5.
Further, a positive electrode tab 16 protected by an insulator 17 such as polyimide or fluororesin is electrically connected to a lower portion of the positive electrode lead-out pin 4.
[0005]
In such an electrode header, the battery is hermetically sealed by caulking the positive electrode lead-out pin and integrating the electrode header to seal between the constituent members. But not enough batteries.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a highly reliable sealed battery having excellent electrode insulating properties, airtightness, and high reliability in a battery having an electrode sealing structure in which an electrode lead-out pin is swaged and sealed. Is the subject.
[0007]
[Means for Solving the Problems]
An object of the present invention is to provide a sealed battery in which an insulating member having a through hole is interposed in an opening portion provided in a battery can, and an electrode lead pin conductively connected to a power generating element is caulked and fixed to the through hole. In the contact portion of the surface of the electrode lead-out pin composed of the collar portion and the cylinder portion coupled to the collar portion with the insulator, the cylinder has a center on the center axis of the cylinder portion and is formed integrally with the cylinder. The problem can be solved by a sealed battery having an electrode lead-out pin provided with at least one protruding ridge that goes around the surface.
In the above sealed battery, the protruding portion has a curved surface shape or a polygonal shape that intersects a surface parallel to a central axis of the electrode lead-out pin.
The above sealed battery is a lithium ion secondary battery.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The sealed battery of the present invention is a battery sealed by caulking electrode lead-out pins, and as a result of intensive studies on the cause of poor sealing such as leakage of electrolyte from between the electrode lead-out pins and the insulating member, these problems were found. Have been found to be caused by poor sealing between the electrode lead-out pin and the insulating member around the electrode lead-out pin.
[0009]
FIG. 5 is a diagram illustrating a sealing portion using an electrode lead-out pin of a sealed battery, and is a diagram illustrating a state of each member before caulking.
An internal insulating plate 13 is provided on the flange 4A of the positive electrode lead-out pin 4. The plate portion 13A of the internal insulating plate and the columnar portion 13B of the internal insulating plate that cover the columnar portion 4B of the positive electrode lead-out pin are integrally formed. On the upper surface of the plate portion 13A of the internal insulating plate 13, a metal plate 3 having a through hole passing through the columnar portion 13B of the internal insulating plate in the concave portion 3A is inserted, and then the external insulating plate 14 is inserted. Further, the electrode lead-out terminal plates 15 are sequentially inserted, and the positive electrode lead-out pins are crimped from above and below to form conductive connection terminals together with the positive electrode lead-out terminal plates 15, thereby forming the integrated electrode header 5. Further, the columnar portion 13B of the internal insulating plate extends above the metal plate whose polarity is opposite to that of the electrode lead-out pin, so that even if the amount of deformation of the positive lead-out pin becomes large, conductive connection between the positive lead-out pin and the metal plate occurs. Are not formed.
[0010]
When such a member is used, the upper portion of the electrode lead-out pin 4 is deformed by the swaging of the electrode lead-out pin 4 and the columnar portion 4B is also deformed. However, the amount of deformation of the electrode lead-out pin is small. The amount of deformation of each member of the inner insulating plate 13, the metal plate 3, and the outer insulating plate 14 is also small. The internal insulating plate 13 has a plate-shaped portion 13A and a columnar portion 13B of the internal insulating plate integrally formed, and an upper portion 13C of the columnar portion of the internal insulating plate is located above the metal plate 3 and has an electrode lead-out pin. The insulation between the metal plate 4 and the metal plate 3 is ensured.
[0011]
Furthermore, since the amount of deformation of the electrode lead-out pin is small, no crack or crack occurs in the electrode lead-out pin, and as a result, the airtightness between the electrode lead-out pin and the internal insulating plate is maintained, so that the sealing property is good. Battery can be obtained. Furthermore, the upper part 4C of the positive electrode lead-out pin maintains a substantially circular shape even after the caulking, and is located at the center of the positive electrode lead terminal plate 15, so that the positioning is easy even when a conductor is connected.
[0012]
In particular, by using annealed electrode lead-out pins, deformation during caulking becomes uniform, and the surface hardness is reduced, and cracks on the surface are less likely to occur. The sealing surface of the battery is good, but the contact surface between the electrode lead-out pin and the internal insulating plate is in a state of drawing a gentle arc and it is not a local pressurization, so when the internal pressure inside the battery rises However, it has not been possible to completely prevent the electrolyte from leaking from the contact surface between the electrode lead-out pin and the insulating plate, thereby causing a defective product in terms of battery characteristics.
[0013]
FIG. 1 is a diagram illustrating a sealed battery according to the present invention.
The electrode lead-out pin 4 is made of a metal having good conductivity such as aluminum or an aluminum alloy. The columnar portion 4B of the positive electrode lead-out pin 4 has a center at the center axis of the cylinder, and has a center at the center axis of the cylinder. The surface that intersects the vertical surface has a circular ridge 4E that is circular.
On the brim portion 4A of the positive electrode lead-out pin, a thermoplastic fluororesin such as polypropylene, tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), or tetrafluoroethylene-hexafluoropropylene copolymer (FEP) is formed. An internal insulating plate 13 is provided. The plate portion 13A of the internal insulating plate and the columnar portion 13B of the internal insulating plate that cover the columnar portion 4B of the positive electrode lead-out pin are integrally formed. On the upper surface of the plate portion 13A of the internal insulating plate 13, a metal plate 3 made of stainless steel, nickel-plated mild steel plate or the like having a through hole in the recess 3A penetrating the columnar portion 13B of the internal insulating plate is provided. Then, an external insulating plate 14 made of polypropylene, fluororesin or the like is inserted, and further, a nickel plate, a nickel-plated iron plate, a copper plate, an electrode lead terminal plate 15 made of a nickel silver plate or the like is sequentially inserted, The positive electrode lead-out pin 4 is crimped from above and below to form a conductive connection terminal together with the positive electrode lead-out terminal plate 15, whereby the integrated electrode header 5 is obtained. Further, the columnar portion 13B of the internal insulating plate extends above the metal plate whose polarity is opposite to that of the electrode lead-out pin, so that even if the amount of deformation of the positive lead-out pin becomes large, conductive connection between the positive lead-out pin and the metal plate occurs. Is not formed.
[0014]
By caulking the electrode lead-out pins 4, a conductive connection is formed between the electrode lead-out pins 4 and the electrode lead-out terminal plate 15, and the ridges 4 </ b> E of the electrode lead-out pins 4 bite into the columnar portions 13 </ b> B of the internal insulating plate 13. As described above, since the loads are concentrated and come into contact with each other, the sealing can be reliably performed at the contact portion.
In the above description, the example in which the inner insulating plate 13 and the outer insulating plate 14 are formed separately is described. However, the inner insulating plate and the outer insulating plate are integrally formed on a metal plate by a method such as injection molding. It may be.
[0015]
FIG. 2 is a diagram illustrating an electrode lead-out pin of the sealed battery according to the present invention.
The electrode lead-out pin has a diameter of a portion of the outer peripheral surface of the cylindrical portion of the electrode lead-out pin that contacts the columnar portion of the insulating plate is larger than a diameter of the portion that contacts the flange of the columnar portion. FIG. 2 (A) shows a cylindrical surface in which a ridge 4E having a center on the central axis of the cylindrical portion is formed. In addition, what is shown in FIG. 2 (B) is one in which two convex ridges 4E are provided in the columnar portion, and three or more convex ridges may be provided in the columnar portion.
[0016]
It is preferable that these ridges are formed by making a round around the circumference of the cylinder, and that a portion passing through the center of the ridge and intersecting with a plane perpendicular to the central axis of the columnar portion is a circle. Further, as shown in FIGS. 2C-1 to 2C-3, the shape of the surface where the ridge portion intersects with the surface parallel to the central axis of the electrode lead-out pin is a curved surface shape such as an arc shape or a base. The shape may be an arbitrary shape such as a polygonal shape such as a triangle.
[0017]
Also, the large diameter portion of the electrode lead-out pin varies depending on the size of the electrode lead-out pin. However, when the diameter of the upper end of the columnar portion of the electrode lead-out pin or the diameter of the junction between the cylindrical portion and the flange portion is 1.5 mm. Preferably has a size of 1.6 mm to 1.7 mm.
Also, the diameter of the inner insulating plate is set to about 1.6 mm when the diameter of the upper end of the cylindrical portion of the electrode lead-out pin or the joint portion between the cylindrical portion and the flange portion is 1.5 mm, so that the diameter is about 1.6 mm. Can be facilitated.
[0018]
The electrode lead pin that can be used in the present invention can be obtained by annealing a caulking pin manufactured by cold working from a wire of aluminum or an alloy thereof. Annealing can be manufactured by subjecting a caulking pin to a heat treatment at 300 ° C. to 350 ° C., preferably 330 ° C. to 350 ° C., and then gradually cooling. Heat treatment at a temperature lower than 300 ° C. is not sufficient, and heat treatment at a temperature higher than 350 ° C. is not preferable because the oxidation of aluminum increases or softening deformation occurs.
The heat treatment time is preferably set to 0.8 to 1.5 hours.
Since the surface of aluminum is covered with an oxide film in the atmosphere, the heat treatment at the time of annealing may be either heating in an inert gas or heating in the atmosphere.
[0019]
On the other hand, the electrode lead-out pin of the present invention temporarily decreases in hardness due to annealing, but since work hardening occurs due to the impact applied by caulking, the electrode lead-out pin after caulking is not subjected to annealing. Since the hardness is the same as that of, the sealing characteristics and the crimping strength of the electrode lead-out pin do not decrease.
[0020]
When a battery manufactured using the lead-out pin of the present invention and a battery manufactured using the lead-out pin having no protruding portion were subjected to an electrolyte leakage test, the protruding portion was formed on the lead-out pin. With no battery, 1 to 5 defective products were generated for 1000 batteries, but no defective product was generated for the battery using the lead pins of the present invention.
[0021]
【The invention's effect】
Since the sealed battery of the present invention uses a positive electrode lead-out pin whose diameter is increased by a method such as providing a protruding portion at a contact portion with the insulating plate, when crimped, the insulating plate and the protruding portion are used. Since the load is concentrated on the contact portion, a contact state with good hermeticity can be formed, so that a highly reliable sealed battery free from problems such as poor airtightness can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a sealing portion using an electrode lead-out pin of a sealed battery according to the present invention.
FIG. 2 is a diagram illustrating an example of an electrode lead-out pin of the sealed battery according to the present invention.
FIG. 3 is a diagram illustrating an example of a prismatic battery.
FIG. 4 is a diagram illustrating an example of an electrode header.
FIG. 5 is a diagram illustrating a conventional battery sealing structure in which an electrode lead-out pin is crimped and sealed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Metal container, battery can, 2 ... Upper end of battery can, 3 ... Metal plate, 3A ... Depression, 4 ... Conductive connection terminal or positive electrode lead-out pin, 4A ... Collar part, 4B ... Column part, 4C ... Tip part, 4E: convex ridge, 5: electrode header, 6: thin portion, 12: small hole, 13: internal insulating plate, 13A: plate portion of internal insulating plate, 13B: columnar portion of internal insulating plate, 13C: internal insulation Upper part of the columnar part of the plate, 14: external insulating plate, 15: electrode lead terminal, 16: positive electrode tab, 17: insulator

Claims (2)

In a sealed battery in which an insulating member having a through hole is interposed in an opening provided in a battery can, and an electrode lead pin conductively connected to a power generating element is caulked and fixed to the through hole, a collar portion and a collar are provided. The contact portion of the surface of the electrode lead-out pin, which is composed of a columnar portion coupled to the portion, with the insulator has a center on the central axis of the columnar portion, and at least circles around the surface of the cylinder formed integrally with the column. A sealed battery comprising: an electrode lead-out pin provided with one ridge. 2. The sealed battery according to claim 1, wherein a shape of a surface of the ridge portion that intersects with a surface parallel to a central axis of the electrode lead-out pin is any one of a curved surface shape and a polygonal shape.

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