JP2011249153A - Lead member, lead member with lead wire and power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead member capable of soldering a lead wire to a lead conductor, a lead member with the lead conductor employing the same and a power storage device.SOLUTION: In a lead member 25, a pair of insulator films 23 wider than a lead conductor 27 comprised of a plate-like metal material are deposited on both surface sides in a part of a length direction of the lead conductor 27. In the lead conductor 27, a notched part 30 is formed by partially cutting the lead conductor so as to surround a partial area at a position exposed from the insulator films 23. In the area surrounded with the notched part 30, a voltage monitoring lead wire 28 is conductively connected by a solder 29.

Description

  The present invention relates to a lead member, a lead member with a lead wire, and an electricity storage device used for a nonaqueous electrolyte electricity storage device sealed with an encapsulant.

  Non-aqueous electrolyte electricity storage devices are used in applications such as small electronic devices such as mobile phones, hybrid vehicles, electric vehicles, and power storage power sources. The nonaqueous electrolyte electricity storage device has, for example, a structure in which a positive electrode and a negative electrode to which a lead member is connected are sealed with an encapsulant together with an electrolyte medium, and the lead member is in close contact with the encapsulant with an insulating film.

  As an example of an electricity storage device, an assembled battery in which a first battery and a second battery are connected in series with each other is known. In such an assembled battery, the aluminum electrode tab provided in the first battery and the aluminum electrode tab provided in the second battery are connected via a conductive filler, and a lead wire is connected to the conductive filler. It is known that a circuit that is electrically connected and that detects a voltage of a first battery and a second battery is connected to a lead wire (see, for example, Patent Document 1). In Patent Document 1, since it is difficult to solder a lead wire to an aluminum electrode tab, a conductive filler and an organic binder are interposed between the electrode tab joints so that the lead wire is sandwiched. .

  As another example of the electricity storage device, a plurality of bipolar electrodes in which a positive electrode layer is formed on one surface of a current collector and a negative electrode layer is formed on the other surface are arranged in series with an electrolyte layer interposed therebetween. There is known a bipolar secondary battery in which a single battery layer having a laminated structure of a positive electrode layer, an electrolyte layer and a negative electrode layer is laminated. In such a bipolar secondary battery, a battery in which a voltage measurement lead wire is bonded to a current collector via a conductive adhesive is known (for example, see Patent Document 2).

JP 2008-2335030 A JP 2008-117626 A

As described above, there is a demand to attach a lead wire for voltage monitoring to the lead conductor. However, even if the solder is heated on the lead conductor, the heat escapes to the entire lead conductor, and the temperature at the soldering portion does not rise, causing a phenomenon that the lead conductor and the solder are not compatible. For this reason, it has been difficult to solder the conductive wire on the lead conductor.
The technique of Patent Document 1 can be applied only when electrode tabs are joined together, and the technique of Patent Document 2 uses a conductive adhesive without using solder.

  An object of the present invention is to provide a lead member capable of soldering a lead wire to a lead conductor, a lead member with a lead wire using the lead member, and a power storage device.

The lead member of the present invention capable of solving the above-mentioned problems is a pair of insulating films having a width larger than the width of the lead conductor on a part of both sides in the length direction of the lead conductor made of a flat metal material. Is a lead member pasted,
The lead conductor is characterized in that a notch portion partially cut out so as to surround a part of the region is formed at a portion exposed from the insulating film.

  In the lead member of the present invention, it is preferable that the notch is provided at an end of the lead conductor in the length direction.

  The lead member with a conductive wire of the present invention is characterized in that a voltage monitoring conductive wire is soldered to the region of the lead member of the present invention.

  In the electricity storage device of the present invention, the positive electrode and the negative electrode to which the lead member of the present invention is connected are sealed together with an electrolyte medium with an encapsulant, the insulating film of the lead member is in close contact with the encapsulant, and the notch The portion is exposed to the outside of the encapsulant, and a voltage monitoring conductor is soldered to the region.

According to the lead member of the present invention, since the notch is formed so as to surround a part of the region in the lead conductor, when the region is heated, heat is not easily transmitted to the outside, and the temperature is easily raised. Therefore, if the lead wire is soldered in the area surrounded by the notch, the soldering heat will not easily escape from the area, and the temperature of the soldering point will be raised and the lead conductor and the solder will be blended. Conductor can be soldered.
The lead member with a conducting wire and the electricity storage device using this lead member can be provided with a conducting wire for voltage monitoring inexpensively and reliably attached.

It is a perspective view which shows an example of the electrical storage device provided with the lead member of this invention. It is a permeation | transmission top view which shows the electrical storage device of FIG. It is a top view which shows the example of the notch part in the lead member of this invention. It is a side view which shows the example which joined lead members. It is a top view which shows arrangement | positioning of the notch part in a large sized lead member.

  Hereinafter, examples of embodiments of a lead member, a lead member with a conductive wire, and an electricity storage device according to the present invention will be described with reference to the drawings.

Nonaqueous electrolyte electricity storage devices include nonaqueous electrolyte batteries such as lithium ion batteries, capacitors such as electric double layer capacitors (EDLC) and lithium ion capacitors, and the like. In the electric double layer capacitor, aluminum is used for the conductor of the lead member on both the positive electrode side and the negative electrode side. In lithium ion batteries and lithium ion capacitors, aluminum is used for the conductor of the lead member on the positive electrode side, and copper is used on the negative electrode side. Copper is often used after nickel plating. In any non-aqueous electrolyte electricity storage device, an electrolyte is enclosed in a bag-like or box-like encapsulant, and a lead member is taken out from a part of the sealed portion of the encapsulant.
Hereinafter, a non-aqueous electrolyte battery will be described as an example, but the lead member according to the present invention can also be applied to other non-aqueous electrolyte electricity storage devices such as an electric double layer capacitor.

As shown in FIGS. 1 and 2, the nonaqueous electrolyte battery (electric storage device) 10 includes an encapsulant 11 and lead members 24 and 25 connected to the positive electrode 12 and the negative electrode 13.
The encapsulating material 11 is a peripheral seal portion 16 formed into a bag shape by heat-sealing by heat sealing. In the encapsulating material 11, the positive electrode 12 and the negative electrode 13 are interposed between the positive electrode 12 and the negative electrode 13. A single electrochemical cell including a non-aqueous electrolyte medium 15 in which an electrolyte (for example, a lithium compound) is dissolved in a provided diaphragm 14 and a non-aqueous solvent (for example, an organic solvent) is hermetically stored.

  The lead members 24 and 25 are used as lead wires of the nonaqueous electrolyte battery 10 and have lead conductors 26 and 27 made of a flat conductor or metal foil. The lead conductor 26 is connected to the positive electrode 12 in the encapsulant 11, and the lead conductor 27 is connected to the negative electrode 13 in the encapsulant 11.

  The encapsulant 11 is a laminated body in which laminated films are provided on both surfaces of a metal foil, and the non-aqueous electrolyte medium 15 is prevented from leaking from the seal portion 16 in the innermost laminated film without being dissolved by the electrolytic solution. Suitable for this is a polyolefin resin (eg maleic anhydride modified low density polyethylene or polypropylene). The outermost laminated film is for protecting the inner metal foil from damage, and is formed of polyethylene terephthalate (abbreviated as PET) or the like.

Examples of the electrolyte accommodated in the encapsulating material 11 include organic solvents such as propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, 1,2-dimethoxyethane, and tetrahydrodofuran, LiClO ₄ , LiBF ₄ , LiPF ₆ , and LiAsF. A nonaqueous electrolytic solution in which an electrolyte such as ₆ is dissolved, a lithium ion conductive solid electrolyte, or the like is used.

  The lead members 24 and 25 are taken out from the seal portion 16 for electrical connection to the outside, and the lead conductors 26 and 27 are covered and insulated by a pair of insulating films 23 at the take-out portion to form the encapsulating material 11. It prevents electrical contact with the metal foil.

  The lead conductors 26 and 27 are made of a flat metal material such as nickel, nickel-plated copper or aluminum having a thickness of 0.1 mm or more and 1.5 mm or less, and the width dimension in the case of in-vehicle use is, for example, 30 mm, 50 mm, 70 mm and 90 mm.

  The insulating film 23 has a two-layer structure having a cross-linked layer and an adhesive layer, and has a width larger than the width of the lead conductors 26 and 27. The adhesive layer is made of a resin such as polypropylene (PP). The cross-linked layer is formed from a resin such as polypropylene. The insulating film 23 is heat-sealed with the adhesive layers facing inward, and the adhesive layers are bonded to each other on both sides in the width direction of the lead conductors 26 and 27. Further, the cross-linked layer of the insulating film 23 is in close contact with the seal portion 16 of the encapsulant 11 without a gap.

  One of the lead members 24 and 25 is electrically connected to a portion 28 exposed from the insulating film 23 by a solder 29 for voltage monitoring. In the present embodiment, the lead wire 28 is soldered to the lead conductor 27 of the lead member (lead member with lead wire) 25 connected to the negative electrode 13. A circuit (not shown) for detecting voltage is connected to the other end side of the lead wire 28 connected to the lead conductor 27, and the voltage of the nonaqueous electrolyte battery 10 can be monitored to prevent overcharge and overdischarge.

  A portion of the lead conductor 27 where the conductive wire 28 is soldered has a notch 30 formed around it. The notch 30 is formed in a process prior to the process of soldering the conductor 28 in the manufacturing process of the lead member 25, and surrounds the area in the lead conductor 27 where the conductor 28 is to be soldered. The lead conductor 27 is partially cut off.

The shape of the notch 30 can illustrate what is shown, for example in FIG. 3 (a), (b), (c). The cutout portion 30 a shown in FIG. 3A is formed by cutting inward from both sides of the corner portion of the lead conductor 27. A region 31a of the part is surrounded. This notch 30a can be formed by press molding or cutting. The cutout portion 30b in FIG. 3B is formed by forming four linear cutouts so as to surround a partial region 31b of the lead conductor 27 in a square shape. The notch 30b can be easily formed by press molding in a straight line. The notch 30c in FIG. 3C is formed by forming four arc-shaped notches so as to surround a partial region 31c of the lead conductor 27 in a circular shape. This notch 30c can be formed by press molding. In order to connect the conducting wire 28, the area of the notch 30 may be about 50 to ²⁰⁰ mm ² .

  When the lead wire 28 is soldered to a region (30a, 30b, 30c, etc.) surrounded by the notch 30, the region is heated together with the solder 29. If the notch 30 is not provided, heat is transmitted radially from the heated region to the surface of the lead conductor 27, and the temperature of the soldering region is unlikely to rise. By providing the notch 30, the cross-sectional area of the portion connecting the inner area and the outer area of the notch 30 is greatly reduced, so that heating is performed in the inner area of the notch 30. It is difficult for the generated heat to diffuse outside, and the temperature of the soldering point is easily raised. Therefore, the metal of the lead conductor 27 at the location to be soldered and the molten solder 29 are well adapted, and the conductor 28 can be soldered well. Thus, the conductive wire 28 can be conductively connected to the lead conductor 27 without using a conductive adhesive or the like, and the lead member 25 is provided with the conductive wire 28 for voltage monitoring inexpensively and reliably attached. Can do.

  The nonaqueous electrolyte battery 10 shown in FIG. 1 is in the form of a so-called unit cell, but the electricity storage device of the present invention may be an assembled battery. FIG. 4 shows a part of the assembled battery 10a. The assembled battery 10a is formed by laminating a plurality of single cells 10b, joining the positive lead conductor 41 and the negative lead conductor 41 of the adjacent single cells 10b, and connecting the single cells 10b in series. ing. Joining of the lead conductors 41 is performed by bending the lead conductor 41 on the side extending from the encapsulant 11 and bringing the lead conductor 41 close to the mating joint and welding. In each unit cell 10 b, the voltage monitoring conductor 28 is conductively connected to the lead conductor 41 by solder 29. A notch 30 (see FIG. 5) is formed around the portion where the conductive wire 28 is soldered, as in the case of the nonaqueous electrolyte battery 10, and the conductive wire 28 is stably soldered to the lead conductor 41. ing. Thereby, the voltage of each unit cell 10b constituting the assembled battery 10a can be monitored, and the variation of the voltage of each unit cell 10b is detected, and the deterioration of the specific unit cell 10b proceeds. It is possible to prevent the battery cell 10b from being overcharged or overdischarged.

  In the form of a battery pack, a wide lead member 40 may be used as shown in FIG. When the lead conductors 41 are joined to each other as shown in FIG. 4, the lead conductors 41 are bent in the middle. Further, when soldering the conductive wire 28 after joining the lead conductors 41 to each other, the soldering work is easier to connect to the end of the lead conductor 41. Therefore, it is preferable to form a notch portion at any position of the end portion in the length direction of the lead conductor 41 as shown in A, B, and C of FIG.

10: non-aqueous electrolyte battery (electric storage device), 10a: assembled battery (electric storage device), 11: encapsulant, 12: positive electrode, 13: negative electrode, 15: electrolyte medium, 23: insulating film, 24, 25: lead member, 26, 27: lead conductors, 30, 30a, 30b, 30c: notches, 31a, 31b, 31c: partial areas

Claims (4)

A lead member in which a pair of insulating films having a width larger than the width of the lead conductor is attached to a part of both sides of the length direction of the lead conductor made of a flat metal material,
The lead member is characterized in that a notch portion that is partially cut out so as to surround a part of the region is formed at a portion exposed from the insulating film. The lead member according to claim 1,
The lead member according to claim 1, wherein the notch is provided at an end of the lead conductor in a length direction.   A lead member with a lead wire, wherein a lead wire for voltage monitoring is soldered to the region of the lead member according to claim 1 or 2.   The positive electrode and the negative electrode to which the lead member according to claim 1 or 2 is connected are sealed with an encapsulant together with an electrolyte medium, the insulating film of the lead member is in close contact with the encapsulant, and the notch is the A power storage device, characterized in that a voltage monitoring conductor is soldered to the region exposed to the outside of the encapsulant.

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