JP2015079654A - Tab lead and power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tab lead in which a solder joint is subjected to clad joint, and breaking at the boundary of the clad joint and non-clad joint is prevented.SOLUTION: A tab lead 3 has a clad joint 3c where a metal conductor for solder joint is clad joined to the side opposite from the lead connection side of the tab lead body 3b being connected with an electrode plate lead 5 in a nonaqueous electrolyte battery 1. The tab lead 3 has an insulating member 3a for hermetically sealing an inclusion body 2 while inserting the tab lead 3 into the inclusion body 2 of electrolyte of the nonaqueous electrolyte battery 1. The boundary portion of the clad joint 3c and non-clad joint of a metal conductor is covered with the insulating member 3a.

Description

  The present invention relates to a tab lead used for an electricity storage device such as a battery or a capacitor, and an electricity storage device having the tab lead.

  For example, non-aqueous electrolyte batteries such as lithium ion batteries are used as power sources for small electronic devices. In this non-aqueous electrolyte battery, a positive electrode plate, a negative electrode plate and an electrolytic solution are housed in an enclosure made of a multilayer film, and hermetically sealed so that tab leads connected to the positive electrode plate and the negative electrode plate are exposed to the outside from the enclosure. The thing of the structure which is made is known. In the nonaqueous electrolyte battery having this structure, the tab lead is used by being soldered to an external circuit.

  The terminal of the external circuit to which the tab lead is soldered is often formed from nickel or stainless steel. The tab lead on the positive electrode plate side is made of aluminum in order to prevent corrosion during the charge / discharge reaction. Since it is difficult to solder the tab lead on the positive electrode side and the terminal of the external circuit described above, in Patent Document 1, a nickel plate is clad-bonded to the solder connection portion of the tab lead so that the soldering is easy. Yes.

JP 2004-39651 A

  However, as disclosed in Patent Document 1, in the embodiment in which the metal plate is clad and joined to the solder connection portion, the tab lead may be broken at the boundary between the clad joint portion and the non-cladding joint portion.

  The present invention has been made in view of the above circumstances, and includes a tab lead in which a solder connection portion is clad-joined and prevented from being broken at the boundary between a clad junction portion and a non-cladding junction portion, and the tab lead. An object is to provide an electricity storage device.

  In order to solve the above-mentioned problems, a tab lead of the present invention has a clad joint portion in which a metal conductor different from the tab lead body is clad and joined for solder connection at one end of a tab lead body made of metal foil, An insulating member is provided in a portion excluding both ends of the tab lead main body, and an end portion on the inner side in the length direction of the tab lead of the clad joint portion of the metal conductor is covered with the insulating member.

  In the tab lead of the present invention, it is possible to prevent breakage at the boundary between the clad joint portion for solder joint and the non-cladd joint portion.

It is a figure explaining an example of the nonaqueous electrolyte battery using the tab lead of the present invention. It is sectional drawing of the nonaqueous electrolyte battery for demonstrating an example of the tab lead by this invention. It is a top view which shows an example of the tab lead by this invention. It is sectional drawing which shows the other example of the tab lead by this invention, and a nonaqueous electrolyte battery.

(Description of the embodiment of the present invention)
First, embodiments of the present invention will be listed and described.
(1) The tab lead of the present invention has a clad joint part in which a metal conductor different from the tab lead body is clad-joined for solder connection at one end of a tab lead body made of a metal foil, excluding both ends of the tab lead body. An insulating member is included in the portion, and an end portion on the inner side in the length direction of the tab lead of the clad joint portion of the metal conductor is covered with the insulating member. With such a configuration, it is possible to prevent the tab lead from being broken at the boundary between the clad junction portion and the non-clad junction portion.

(2) It is preferable that the tab lead body is subjected to a surface treatment for an electrolytic solution. Thereby, electrolyte solution resistance improves.
(3) The length of the portion covered with the insulating member of the metal conductor is, for example, 1 to 3 mm.

  (4) In the electricity storage device of the present invention, the tab lead of (1) above is connected to the electrode, the power generation element and the electrolytic solution are accommodated in the enclosure, the insulating member is hermetically sealed with the seal portion of the enclosure, and clad bonding At least a part of the portion is out of the enclosure. This electrolyte battery can prevent the tab lead from being broken at the boundary between the clad junction portion and the unclad junction portion.

(Details of the embodiment of the present invention)
Hereinafter, preferred embodiments of the tab lead and the electricity storage device of the present invention will be described with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes are included within the meaning and range equivalent to the claim. In the following inventions, the same reference numerals are used in different drawings, and the description thereof is omitted.

1 to 3 are diagrams for explaining an example of a nonaqueous electrolyte battery using the tab lead of the present invention, FIG. 1 is a perspective view of the nonaqueous electrolyte battery, and FIG. 2 is a positive electrode side in the nonaqueous electrolyte battery of FIG. FIG. 3 is a top view of the positive-side tab lead of FIG. 2.
The nonaqueous electrolyte battery 1 in FIG. 1 includes an enclosure 2, a tab lead 3 on the positive electrode side, and a tab lead 4 on the negative electrode side. The non-aqueous electrolyte battery 1 stores a positive electrode plate and a negative electrode plate laminated with a separator and an electrolytic solution in an enclosure 2, and tab leads 3 and 4 are sealed to the enclosure 2 via insulating resin films 3 a and 4 a. The unit 2a is hermetically sealed and taken out from the enclosure 2 and configured.

  The enclosure 2 serves as an outer case of the nonaqueous electrolyte battery 1 and is sealed by, for example, sealing the sealing portions 2a around the two multilayered films in a rectangular shape by heat welding. Insulating resin films 3a and 4a are joined in advance near the center of the tab leads 3 and 4 by heat welding. The insulating resin films 3a and 4a and the multilayer film of the enclosure 2 are thermally welded, and the tab leads 3 and 4 are hermetically sealed.

  The multilayer film forming the encapsulant 2 is formed of, for example, a three-layer laminate as shown in FIG. 2, and the innermost layer film 2b is not dissolved by the electrolyte solution and the electrolyte solution leaks from the seal portion 2a. Polyolefin resins (eg maleic anhydride modified low density polyethylene or polypropylene) are used as suitable for prevention. The metal foil layer 2c is made of a metal foil such as aluminum, copper, or stainless steel, and enhances hermeticity against the electrolytic solution. The outermost layer film 2d is for protecting the thin metal foil layer 2c, and is formed of polyethylene terephthalate (PET) or the like.

  The tab lead 3 on the positive electrode side of the tab leads 3 and 4 has a tab lead body 3b which is a flat conductor obtained by cutting a thin conductive foil into a rectangular shape. The tab lead body 3b has a positive electrode plate lead 5 in the nonaqueous electrolyte battery 1 connected to one end, and a clad joint 3c formed by clad joining a metal conductor for solder connection is formed at the other end.

  Since a high potential is applied to the tab lead body 3b, a metal material that does not dissolve in the electrolytic solution at a high potential, such as aluminum or an alloy thereof, such as a titanium aluminum alloy, is used. In addition, a metal different from the tab lead body 3b, for example, nickel, is used for the solder-connecting metal conductor used for the clad junction. The tab lead body 3b is preferably subjected to the following surface treatment for the purpose of improving the electrolytic solution resistance. For example, it is preferable to perform chemical conversion treatment or roughening treatment such as boehmite treatment, alumite treatment, chromate treatment, or ionomer treatment that crosslinks with a metal such as zirconia.

Furthermore, the tab lead 3 has two insulating resin films 3a bonded to both sides near the center of the tab lead main body 3b, which is a portion taken out from the enclosure 2.
The insulating resin film 3 a can be formed of, for example, two layers of an inner layer 3 d that is bonded or welded to the tab lead 3 and an outer layer 3 e that is fused to the enclosure 2. The inner layer 3d is brought into close contact with the tab lead 3 by heat melting in advance to form a good hermetic seal at the interface between the tab lead 3 and the insulating resin film 3a. The outer layer 3e has a melting point higher than that of the inner layer 3d, and retains its shape so as not to melt when sealed with the tab lead 3. Then, by sealing the outer layer 3e and the enclosure 2 at the time of sealing with the enclosure 2, the metal foil layer 2c and the tab lead 3 in the enclosure 2 can be prevented from being electrically short-circuited.

  The clad junction 3c is provided on the tab lead body 3b from one end of the tab lead 3 to the inside. On the surface of the tab lead 3 on which the clad joint 3c is provided, the inner end of the clad joint 3c is a line drawn in the width direction of the tab lead 3 as a boundary 3g between the clad joint 3b and the tab lead body 3c in FIG. Appears as

  In the tab lead 3, the insulating resin film 3 a is provided so as to cover at least the entire inner end portion (a boundary portion 3 g between the clad joint portion 3 b and the non-cladding joint portion 3 f) of the tab lead 3. As described above, in the tab lead 3, the encapsulant 2 of the nonaqueous electrolyte battery 1 is sealed with the insulating member, that is, the insulating resin film 3a in a state where the tab lead is inserted. Since the entire boundary portion 3g with the non-cladding joint portion 3f is covered, the tab lead 3 can be prevented from being broken at the boundary.

  The nonaqueous electrolyte battery 1 is mounted on a device such as a mobile phone, a notebook computer, a portable music play, or an electronic cigarette. The tab lead body 3b of the tab lead 3 differs depending on the shape and capacity of the battery, but for example, the thickness of the thickest part is 0.05 mm to 0.3 mm, the length (vertical direction) is 20 mm to 60 mm, and the width (horizontal). (Direction) is a metal foil of 1 mm to 5 mm. The thickness of the clad junction part 3c is, for example, 0.01 mm to half the thickness of the thickest part of the tab lead body 3b. The clad junction 3c is a metal foil that is smaller and thinner than the tab lead body 3b.

The insulating resin film 5a has a length (longitudinal direction) of 2 mm to 8 mm and a width of 3 to 10 mm, for example. The insulating resin film 5a is formed wider than the tab lead main body 3b and protrudes from both sides of the tab lead main body 3b, and the protruding insulating resin films 5a are pasted together. The insulating resin film 5a is affixed to the portion excluding both ends of the tab lead 3. Insulating resin film 5a is stuck so that the metal is exposed at portions of 5 mm or more at both ends of tab lead 3 respectively.
The length of the portion covered with the insulating resin film 5 a of the clad junction 3 c is 1 to 3 mm, or 3 to 30 times the thickness of the tab lead 3.

  In the figure, the clad junction 3c is formed from the end of the tab lead body 3b opposite to the electrode connection side, but may be formed near the center of the tab lead body 3b.

The tab lead 4 on the negative electrode side may have a configuration having a clad junction 3c similar to the tab lead 3 on the positive electrode side, or may have a configuration similar to a conventional tab lead on the negative electrode side. When the electricity storage device is a capacitor, since both the positive electrode and the negative electrode are aluminum terminals, the tab lead of the present invention can be used for the positive electrode and the negative electrode. In the case of the negative electrode, a copper or brass clad nickel joint can also be used.
Unlike the above, only the tab lead on the negative electrode side may be configured to cover the entire boundary portion between the clad junction and the non-clad junction with an insulating resin film.

FIG. 4 is a plan view showing another example of the tab lead and the nonaqueous electrolyte battery.
The nonaqueous electrolyte battery 1 ′ of FIG. 4 differs from the nonaqueous electrolyte battery 1 of FIG. 2 in the configuration of the tab lead on the positive electrode side. Therefore, only the tab lead on the positive electrode side will be described below, and the other configurations will be described. The description thereof will be omitted by attaching the same reference numerals.

  The tab lead 3 ′ in FIG. 4 has a non-aqueous positive electrode plate lead 5 connected to one end of the tab lead main body 3 b ′ and the other end connected to a metal for solder connection similarly to the tab lead 3 in FIG. A clad junction 3c ′ is formed by clad joining the conductors. The tab lead 3 ′ is an insulating resin film 3a composed of two layers of an inner layer 3d ′ and an outer layer 3e ′ so as to cover the entire boundary portion between the clad junction 3c ′ and the non-cladding junction of the tab lead 3. ing. However, in the tab lead 3 of FIG. 2, the boundary is located at the seal portion 2a of the enclosure 2, but in the tab lead 3 ′ of FIG. 4, the boundary is located outside the seal portion 2a.

DESCRIPTION OF SYMBOLS 1 ... Nonaqueous electrolyte battery, 2 ... Enclosure, 2a ... Seal part, 2b ... Innermost layer film, 2c ... Metal foil, 2d ... Outermost layer film, 3 ... Tab lead, 3a ... Insulating resin film, 3b, 3b '... Tab lead Main body, 3c, 3c '... clad junction, 3d ... inner layer, 3e ... outer layer, 3f ... non-clad junction, 3g ... boundary part, 4 ... tab lead, 5 ... electrode plate lead, 5a ... insulating resin film.

Claims (4)

At one end of the tab lead body made of a metal foil, the tab lead body has a clad joint portion in which a metal conductor different from the tab lead body is clad and joined for solder connection,
An insulating member is provided in a portion excluding both ends of the tab lead body,
A tab lead in which an end of the clad junction of the metal conductor on the inner side with respect to the length direction of the tab lead is covered with the insulating member.   The tab lead according to claim 1, wherein the tab lead main body is subjected to a surface treatment for an electrolytic solution.   The tab lead according to claim 1 or 2, wherein a length of a portion of the metal conductor covered with the insulating member is 1 to 3 mm.   The tab lead according to claim 1 is connected to an electrode, the power generating element and the electrolytic solution are accommodated in an enclosure, the insulating member is hermetically sealed with a seal portion of the enclosure, and at least a part of the clad junction is An electricity storage device that is outside the enclosure.

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