KR20210096005A - Tab lead, battery and manufacturing method of tab lead - Google Patents

Abstract

Provided are a tab lead which can shorten sealing time of a sealing bag by welding, a battery, and a method for manufacturing the tab lead. The tab lead includes: a lead conductor having a first main surface and a second main surface on a side opposite to the first main surface; and a resin part covering the first main surface, the second main surface and both side faces between both ends in a first direction of the lead conductor while exposing both the ends. The resin part has a first crosslinking part covering the first main surface when viewed from the first main surface side; a first thermoplastic part extending to the outside from both ends of the first crosslinking part in a second direction vertical to the first direction; a second crosslinking part covering the second main surface when viewed from the second main surface side; and a second thermoplastic part extending to the outside from both ends of the second crosslinking part in the second direction.

Description

TAB LEAD, BATTERY AND MANUFACTURING METHOD OF TAB LEAD

The present disclosure relates to a tab lead, a battery, and a method of manufacturing the tab lead.

This application claims the priority based on Japanese Application No. 2020-011103 for which it applied on January 27, 2020, and uses all the content described in the said Japanese application.

Various fields WHEREIN: Resin which can suppress corrosion of the metal by the acidic liquid which has corrosiveness is calculated|required. For example, with the miniaturization of electronic devices and an increase in power consumption, development of secondary batteries (eg, lithium ion batteries, etc.) having high energy density while being lightweight and thin. In such a secondary battery, since there is a possibility of metal corrosion, the above resin is requested|required in some cases.

Patent Document 1 and Patent Document 2 disclose a configuration of a battery applicable to a secondary battery. This battery has a structure in which a positive electrode, a negative electrode, an electrolysis solution, etc. are sealed in a sealing bag, and a lead wire is connected to the positive electrode and the negative electrode, respectively. A part of the lead wire is taken out from the sealed bag. This lead wire is called a tab lead, and has a structure in which a resin molded body (resin film, etc.) is arranged in a part of the lead conductor. The resin molded body is disposed so as to seal a gap between the encapsulation bag and the lead conductor.

Japanese Patent Laid-Open No. Hei 11-354087 Japanese Patent Laid-Open No. 2017-69120

According to the tab lead described in Patent Documents 1 and 2, the intended purpose can be achieved, but the time required for sealing the sealed bag by welding is long.

Therefore, an object of the present disclosure is to provide a tab lead, a battery, and a method for manufacturing the tab lead capable of shortening the sealing time of the sealed envelope by welding.

The tab lead of the present disclosure includes a lead conductor having a first main surface and a second main surface opposite to the first main surface, and both ends of the lead conductor in a first direction are exposed, and the amount of the lead conductor is Between the ends, it has the first main surface, the second main surface, and a resin portion covering both side surfaces. The resin part includes a first bridge part covering the first principal surface when viewed from the first principal surface side, and a first bridge part extending outward from both ends of the first bridge part in a second direction perpendicular to the first direction. It has a 1st thermoplastic part, the 2nd bridge|crosslinking part which covers the said 2nd main surface when seen from the said 2nd main surface side, and the 2nd thermoplastic part extended outward from the both ends of the said 2nd bridge|crosslinking part in the said 2nd direction.

ADVANTAGE OF THE INVENTION According to this indication, the sealing time of the sealing bag by welding can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows the tab lead which concerns on 1st Embodiment.
Fig. 2 is a cross-sectional view showing a tab lead according to the first embodiment.
Fig. 3 is a cross-sectional view (part 1) showing a method for manufacturing a tab lead according to the first embodiment.
Fig. 4 is a cross-sectional view (part 2) showing a method for manufacturing the tab lead according to the first embodiment.
Fig. 5 is a cross-sectional view (part 3) showing a method for manufacturing the tab lead according to the first embodiment.
6 is a diagram showing an example of a battery according to the second embodiment.
Fig. 7 is a schematic diagram showing the internal structure of the sealed bag.
8 is a diagram showing a configuration example of a battery according to the second embodiment.
9 is a schematic cross-sectional view showing a battery in the second embodiment.
10 is a cross-sectional view showing a tab lead according to a reference example.

The form for implementing is demonstrated below.

[Description of embodiment of the present disclosure]

[1] A tab lead according to an aspect of the present disclosure includes a lead conductor having a first main surface and a second main surface opposite to the first main surface, and both ends of the lead conductor in a first direction are exposed and between the both ends of the lead conductor, the first main surface, the second main surface, and a resin portion covering both side surfaces, wherein the resin portion includes the first main surface when viewed from the first main surface side. A first crosslinked portion covering the main surface, a first thermoplastic portion extending outward from both ends of the first crosslinked portion in a second direction perpendicular to the first direction, and the second when viewed from the second main surface side It has a 2nd bridge|crosslinking part which covers a main surface, and the 2nd thermoplastic part extended outward from the both ends of the said 2nd bridge|crosslinking part in the said 2nd direction.

The resin portion includes a first cross-linked portion and a second cross-linked portion. Since the first cross-linked portion and the second cross-linked portion have excellent heat resistance, a fixed shape can be maintained on the tab lead when sealing the sealed bag by welding. In addition, since the first and second thermoplastic parts are softened even at a temperature lower than the softening temperature of the first and second crosslinked parts during sealing, the time required for sealing can be shortened.

[2] The first cross-linking portion protrudes from the first main surface in the second direction when viewed from the first main surface side, and the second cross-linking portion is provided in the second direction when viewed from the second main surface side It protrudes from the second main surface. Even when burrs occur in the lead conductor, the portion protruding from the first main surface of the first cross-linked portion and the portion protruding from the second main surface of the second cross-linked portion can prevent penetration of the resin portion of the burrs, and the like.

[3] The length of the portion protruding from the first main surface of the first bridge portion in the second direction is 0.1 mm or more, and the length of the portion protruding from the second main surface of the second bridge portion in the second direction The length is 0.1 mm or more. Penetration of the resin part of the burr, etc. can be prevented more reliably.

[4] A length in the second direction of a portion protruding from the first main surface of the first cross-linking portion is 50% or less of a length in the second direction of the first thermoplastic portion, and the second cross-linking portion is A length of the portion protruding from the second main surface in the second direction is 50% or less of a length of the second thermoplastic portion in the second direction. By sufficiently securing the first thermoplastic portion and the second thermoplastic portion, it is easy to shorten the sealing time.

[5] The resin part has a first flat part overlapping the lead conductor and having a surface parallel to the first main surface and the second main surface, and spaced apart from the lead conductor in the second direction; a second flat portion having a main surface and a surface parallel to the second main surface, and an inclined portion connecting the first flat portion and the second flat portion, the inclined portion having a surface inclined with respect to the first main surface and the second main surface and the first bridge portion and the second bridge portion are formed from the first flat portion to the inclined portion. Even when a burr|burr generate|occur|produces in a lead conductor, penetration etc. of the resin part of a burr can be prevented.

[6] The gel fraction on the surface of the first cross-linked part is higher than the gel fraction on the surface of the first thermoplastic part, and the gel fraction on the surface of the second cross-linked part is higher than the gel fraction on the surface of the second thermoplastic part. Even if the crosslinked portion is included in the first thermoplastic portion or the second thermoplastic portion, the time required for sealing can be shortened.

[7] The resin part has a first resin film including the first cross-linked part and the first thermoplastic part, and a second resin film including the second cross-linked part and the second thermoplastic part, and the lead conductor is sandwiched between the first resin film and the second resin film, the first thermoplastic portion and the second thermoplastic portion are non-crosslinked portions, and the first crosslinked portion is in the second direction when viewed from the first main surface side. to protrude from the first main surface, and the second bridge part protrudes from the second main surface in the second direction when viewed from the second main surface side.

[8] The battery according to another aspect of the present disclosure includes a wrapping material, a power generating element accommodated in the wrapping material, and the tab according to any one of [1] to [7], connected to an electrode of the power generating element It has a lead, and the one end of the said lead conductor and the said resin part in the said 1st direction is arrange|positioned on the outer side of the said wrapping material.

[9] A method for manufacturing a tab lead according to another aspect of the present disclosure includes the steps of: preparing a lead conductor having a first main surface and a second main surface opposite to the first main surface; forming a resin portion covering the first main surface, the second main surface, and both side surfaces between the both ends of the lead conductor while exposing both ends in one direction; A first bridge portion covering the first main surface when viewed from the first main surface side by selectively irradiating the surface on the first main surface side, and in a second direction perpendicular to the first direction, A step of forming a first thermoplastic portion extending outwardly from both ends of the first crosslinking portion, and selectively irradiating a surface on the side of the second main surface of the resin portion, when viewed from the second main surface side It comprises the process of forming a 2nd bridge|crosslinking part which covers two main surfaces, and the 2nd thermoplastic part extending outward from the both ends of the said 2nd bridge|crosslinking part in the said 2nd direction.

[Details of embodiment of the present disclosure]

Hereinafter, although embodiment of this indication is described in detail, this embodiment is not limited to these. In addition, in this specification and drawing, about the component which has substantially the same functional structure, by attaching|subjecting the same code|symbol, the overlapping description may be abbreviate|omitted.

(First embodiment)

First, the first embodiment will be described. A first embodiment relates to a tab lead.

[Tap Lead]

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows the tab lead which concerns on 1st Embodiment. Fig. 2 is a cross-sectional view showing a tab lead according to the first embodiment. FIG. 2 corresponds to a cross-sectional view taken along line I-I in FIG. 1 .

1 and 2 , the tab lead 1 according to the first embodiment includes a lead conductor 10 and a resin portion 20 . The lead conductor 10 has a first main surface 10A and a second main surface 10B opposite to the first main surface 10A. The lead conductor 10 has, for example, a rectangular planar shape. In this specification and drawings, in the planar shape of the lead conductor 10, the direction in which one pair of parallel sides extend is the X direction, the direction in which another pair of parallel sides extend is the Y direction, and the second Let the normal direction of 1 main surface 10A be the Z direction. The dimension in the X direction may be larger or smaller than the dimension in the Y direction, and may be the same as the dimension in the Y direction. The X direction is an example of the first direction, and the Y direction is an example of the second direction. The resin part 20 exposes both ends of the lead conductor 10 in the X direction, and between these ends, a first main surface 10A, a second main surface 10B, and both side surfaces 10C. cover the

[Lead conductor]

The lead conductor 10 is formed of, for example, aluminum (Al), nickel (Ni), an aluminum alloy, a nickel alloy, nickel-plated copper, or nickel-clad copper. For example, in a lithium ion battery or a lithium ion capacitor, aluminum or an aluminum alloy is used for the lead conductor 10 on the positive electrode side, and nickel, a nickel alloy or nickel-plated copper or the like is used for the lead conductor on the negative electrode side. .

As for the lead conductor 10, the surface treatment for improving adhesiveness may be performed, and the surface may be untreated. The resin molded body used for the resin part 20 has sufficiently high adhesiveness to the surface-untreated aluminum conductor. Therefore, the lead conductor 10 may be a surface-untreated aluminum conductor. In this case, the tab lead 1 in which the resin part 20 is arrange|positioned so that the resin part 20 may directly contact with the metal (surface untreated aluminum conductor) which comprises the lead conductor 10 can be obtained. A chromate treatment etc. are mentioned as surface treatment.

The lead conductor 10 has a band-like shape, and its dimensions are appropriately set as needed. For example, the thickness of the lead conductor 10 is 0.05 mm or more and 1.5 mm or less, the length of the X direction is 1 mm or more and 100 mm or less, and the length of the Y direction is 1 mm or more and 60 mm or less. Such a lead conductor 10 can be produced by, for example, cutting a metal foil with a thickness of 0.05 mm or more and 1.0 mm or less to a predetermined size.

[Resin part]

As shown in FIG. 2 , the resin part 20 includes, for example, a matrix 15 made of a resin component, and particles 16 of an acid soluble agent dispersed in the matrix 15 . The resin portion 20 is disposed so as to cover the outer peripheral side of a part of the region in the X direction except for the region including both ends of the lead conductor 10 in the X direction. Since both ends of the lead conductor 10 in the X direction are electrically connected to conductive parts such as electrodes and terminals, the resin portion 20 is not formed and is exposed. The resin portion 20 is disposed so as to cover the outer peripheral side in a part of the region other than the above-mentioned both ends. The resin portion 20 includes, for example, two resin films (corresponding to a resin molded body) 21 and 22 that are fitted with the lead conductor 10 interposed therebetween. The dimension in the Y-direction of the resin films 21 and 22 is larger than the dimension in the Y-direction of the lead conductor 10, thereby improving sealing properties. For example, the thickness of the resin films 21 and 22 is 30 micrometers or more and 200 micrometers or less, the length of the X direction is 2 mm or more and 20 mm or less, and the length of the Y direction is 3 mm or more and 110 mm or less.

The resin portion 20 overlaps the lead conductor 10 and includes a first flat portion 31 having a surface parallel to the first main surface 10A and the second main surface 10B of the lead conductor 10; It is spaced apart from the lead conductor 10 in the direction and has a second flat portion 32 having a surface parallel to the first major surface 10A and the second major surface 10B. The resin portion 20 also connects the first flat portion 31 and the second flat portion 32, and an inclined portion ( 33). Between the first flat portion 31 and the second flat portion 32 , the resin films 21 and 22 have the same thickness. In the first flat portion 31 , the lead conductor 10 is sandwiched between the resin film 21 and the resin film 22 , and in the second flat portion 32 , the resin films 21 and 22 are directly connected to each other. are in contact Accordingly, the thickness of the portion corresponding to the first flat portion 31 of the tab lead 1 is greater than the thickness of the portion corresponding to the second flat portion 32 by the lead conductor 10 . The surface of the inclined portion 33 is inclined due to such a difference in thickness.

In addition, "parallel" in this embodiment does not mean parallel in a strict sense, and the 1st main surface 10A and the 2nd main surface 20A are lined up to the extent that it can be regarded as parallel in social common sense. It would be good if In addition, the "same thickness" in the present embodiment does not mean that the thickness is the same in a strict sense, and it is sufficient that the thickness is close enough to be regarded as having the same thickness on a socially accepted basis. For example, a slight inclination may occur between the two surfaces, or a slight difference in thickness may arise due to manufacturing variations or the like.

The resin films 21 and 22 are, for example, a resin molded body made of a resin composition containing a resin component and an acid-acid agent. In addition, the form of a resin molded object may not necessarily be a film state. For example, the seamless resin part formed by apply|coating or extrusion molding a resin composition around the lead conductor 10 may be sufficient. In the case of using a film, it is also possible to form the resin portion 20 by winding a single film around the lead conductor 10 .

[Resin component]

The resin component contains an acid group-containing polyolefin resin in which an acid-containing group is introduced into the polyolefin resin. Polyolefin resin is a synthetic resin formed by superposing|polymerizing or copolymerizing the olefinic monomer which has a radically polymerizable unsaturated double bond. It does not specifically limit as an olefinic monomer, For example, alpha-olefins, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1- pentene, Conjugated dienes, such as butadiene and isoprene, etc. are mentioned. An olefinic monomer may be used independently, or 2 or more types may be used together.

It does not specifically limit as polyolefin resin, For example, polyethylene-type resin, such as a copolymer of ethylene and alpha-olefin other than ethylene containing 50 mass % or more of ethylene homopolymer (polyethylene), ethylene, propylene, of homopolymer (polypropylene), polypropylene resin such as a copolymer of propylene and α-olefin other than propylene containing 50 mass% or more of a propylene component, homopolymer of butene (polybutene), butadiene or isoprene, etc. homopolymers or copolymers of conjugated dienes of

Although it does not specifically limit as acidic radical containing polyolefin resin, The unsaturated carboxylic acid modified polyolefin resin in which polyolefin resin is modified|denatured with unsaturated carboxylic acid is preferable. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, maleic acid, cinnamic acid, itaconic acid, citraconic acid, fumaric acid, maleic anhydride, and itaconic acid anhydride. ) and unsaturated carboxylic acid anhydrides such as citraconic anhydride. Among them, maleic acid or maleic anhydride is preferable from the viewpoint of adhesiveness between the lead conductor 10 and the resin portion 20 and the like.

The acid group-containing polyolefin resin may have a component containing a polar group other than an acid group introduced by acid modification, and a non-polar component. A component containing a polar group and a nonpolar component may be copolymerized to form a main chain. A component having a polar group may be grafted onto the main chain composed of a non-polar component. In the acid group-containing polyolefin resin, the component containing a polar group and the non-polar component may be introduced regularly or irregularly. Although it does not specifically limit as said polar group, For example, an alkoxy group, an epoxy group, a carboxyl group, a hydroxyl group, maleic anhydride group, an isocyanate group, an aldehyde group, etc. are mentioned.

As the acid group-containing polyolefin resin, (anhydride) maleic acid-modified polyolefin resin is preferable. The (anhydrous) maleic acid-modified polyolefin resin has adhesiveness to the lead conductor 10 and is excellent in sealing properties. (Anhydrous) Maleic acid-modified polyolefin resin is graft-polymerized with (anhydrous) maleic acid to polyolefin resin. Examples of the (anhydrous) maleic acid-modified polyolefin resin include (anhydrous) maleic acid-modified polyethylene resin and (anhydrous) maleic acid-modified polypropylene resin. Among them, it is preferable that the acid group-containing polyolefin resin contains any one of a maleic anhydride-modified polypropylene and a combination of a polypropylene and an ethylene methacrylic acid copolymer.

Acidic radical containing polyolefin resin may be used independently, or 2 or more types may be used together. The said resin component may contain both the polyolefin resin containing an acidic radical, and the unmodified polyolefin resin which does not contain an acidic radical.

For example, preferably, the resin component has an acid group-containing site of 0.05 mass% or more and 5 mass% or less. As used herein, the term "acidic group-containing moiety" includes free acids such as free carboxylic acids and those in which a moiety containing an acidic group is chemically bonded to the polymer chain of the resin. From the viewpoint of improving the adhesiveness of the resin to the metal material, it is preferable that the moiety containing an acid group in the polymer chain of the resin is chemically bonded. In addition, not only acidic radicals, such as carboxylic acid and sulfonic acid, but also acid anhydride groups, such as an anhydride dicarboxylic acid, are contained in "acid group" of an acidic radical containing site|part.

The amount of the acid group-containing moiety can be calculated, for example, based on a known analysis method of a nuclear magnetic resonance (NMR) spectrum. The quantity of an acidic radical containing site|part can also be computed from the compounding quantity of the acid mix|blended for modification with respect to the quantity of the whole polyolefin resin. For example, in the case of maleic anhydride-modified polyolefin resin obtained by modifying polyolefin such as polyethylene or polypropylene with maleic anhydride, the ratio of maleic anhydride to polyolefin portion can be calculated from the NMR spectrum. The ratio of maleic anhydride may be quantitatively calculated based on the intensity of the peak derived from the carbonyl moiety detected in the vicinity of ^{1700 cm -1} by Fourier transform infrared spectrometer (FT-IR). .

In the case where the resin component is a mixture of an acid group-containing polyolefin resin and an acid group-free unmodified polyolefin resin, the amount of acid group-containing moieties is calculated as the ratio of acid group-containing moieties in the entire polyolefin resin including the unmodified polyolefin resin. can

For example, Preferably, the ratio of the acidic radical containing site|part in the whole resin component is 0.05 mass % or more and 5 mass % or less. When the ratio of the acidic radical containing site|part in the whole resin component is 0.05 mass % or more, the adhesiveness of the resin component with respect to a metal material can be maintained at a sufficient level. When the ratio of the acidic radical containing site|part in the whole resin component is 5 mass % or less, the fall of moldability can be suppressed. The lower limit is more preferably 0.1 mass%, still more preferably 0.5 mass%. The upper limit is more preferably 4 mass %, still more preferably 3 mass %.

[Oxalic Acid]

The resin composition includes an acid-acid agent. The oxalic acid is an inorganic compound containing at least one of magnesium and calcium.

Examples of the oxalic acid include magnesium compounds such as magnesium oxide, magnesium hydroxide, hydrotalcite (as a representative composition, Mg ₆ A ₁₂ (OH) ₁₆ CO ₃ .4H ₂ O, etc.) and calcium compounds such as calcium carbonate. can be heard Since handleability is easy, it is preferable that it is a weakly basic compound.

For example, the particle diameter of the particle|grains 16 of an acid-acid agent is 5 micrometers or less. In the present specification, the particle size of the acid oxidizer means the average particle size. Since the particle diameter is a fine particle of 5 micrometers or less, it can disperse|distribute in a favorable state in a resin composition. The particle size of the acid soluble agent is preferably 4 µm or less, and more preferably 3 µm or less.

The amount of the acid-acid agent is 1 mass part or more and 20 mass parts or less per 100 mass parts of resin components. By including 1 part by mass or more of the acid-acid agent per 100 parts by mass of the resin component, the dispersion trapping function is sufficiently exhibited, and the risk of peeling between the lead conductor 10 and the resin part 20 is reduced. Moreover, since the quantity of an acid-acid agent is 20 mass parts or less per 100 mass parts of resin components, the fall of the moldability of a resin composition can be suppressed. In addition, a particle diameter can be calculated|required by measuring a particle diameter with a laser diffraction method, and calculating the average value.

[Resin composition and resin film]

The resin composition for forming the resin films 21 and 22 is a dispersion in which particles 16 of an acid-acid agent are dispersed in a matrix 15 made of a resin component containing the acid group-containing polyolefin resin. A resin composition is prepared by adding and mixing the said acid-acid agent to a non-hardened resin component.

The method of adding an acid-acid agent to the resin component used as base resin is not specifically limited. Examples include a batch method (a method of adding and mixing an acidifying agent to the base resin for each batch of a certain amount) or a continuous method (a method of continuously adding and mixing a certain amount of an acidic acid to the base resin). .

Regarding the degree of dispersion of the acid-acid agent with respect to the resin component, for example, when the resin film 21, 22 having a thickness of 50 µm is molded by adding 1.0 parts by mass of the acid-acid agent per 100 parts by mass of the resin component, it is transparent to the naked eye. It can be judged that it is, and it is preferable to set it as the dispersion degree of the state in which the aggregated particle of an acid oxalic agent is not seen.

In the resin composition, in addition to the resin component used as the base resin and the acid-acid agent, various additives such as a flame retardant, an ultraviolet absorber, a light stabilizer, a heat stabilizer, a lubricant, and a colorant may be mixed as needed.

The resin films 21 and 22 can be produced as follows. First, with respect to the resin component used as base resin, a resin composition is prepared by adding and mixing an acid soluble agent and a necessary additive. Mixing can be performed using mixing apparatuses, such as an open roll, a pressure kneader, a single screw mixer, and a twin screw mixer. The resin films 21 and 22 are produced by shape|molding the obtained resin composition to desired thickness using molding apparatuses, such as an extrusion molding machine. As shown in FIG. 2, the obtained resin films 21 and 22 have the structure in which the particle|grains 16 of the acid acryloyl agent were disperse|distributed to every corner in the matrix 15 of a resin component.

[Cross-linked part, thermoplastic part]

The resin part 20 has the bridge|crosslinking part 41 which covers the 1st main surface 10A when seen from the 1st main surface 10A side. The bridge portion 41 protrudes from the first main surface 10A in the Y direction when viewed from the first main surface 10A side, and extends from the first flat portion 31 of the resin film 21 to the inclined portion 33 . formed across. The resin part 20 has the thermoplastic part 42 extending outward from the both ends of the bridge|crosslinking part 41 in the Y direction. The resin part 20 has the bridge|crosslinking part 43 which covers the 2nd main surface 10B when seen from the 2nd main surface 10B side. The bridge portion 43 protrudes from the second main surface 10B in the Y direction when viewed from the second main surface 10B side, and extends from the first flat portion 31 of the resin film 22 to the inclined portion 33 . formed across. As shown in FIG. 2 , the end portions of the bridge portions 41 and 43 are preferably at the inclined portions 33 . The resin portion 20 has a thermoplastic portion 44 extending outward from both ends of the bridge portion 43 in the Y direction. The crosslinking portions 41 and 43 are formed by crosslinking the resin component on the surfaces of the resin films 21 and 22 , and the thermoplastic portions 42 and 44 are formed on the surfaces of the resin films 21 and 22 . It is a non-crosslinked part in which crosslinking has not occurred in the said resin component. For example, the softening temperature of the thermoplastic part 42 is lower than the softening temperature of the cross-linked part 41 , and the softening temperature of the thermoplastic part 44 is lower than the softening temperature of the cross-linked part 43 . In addition, the gel fraction on the surface of the cross-linked part 41 is higher than the gel fraction on the surface of the thermoplastic part 42 , and the gel fraction on the surface of the cross-linked part 43 is higher than the gel fraction on the surface of the thermoplastic part 44 . For example, the gel fraction of the crosslinked parts 41 and 43 is 20% or more and 90% or less, and the gel fraction of the thermoplastic part 44 is 0%.

The crosslinking portions 41 and 43 can have higher heat resistance than the thermoplastic portions 42 and 44 by crosslinking. That is, the tab lead 1 is used for a non-aqueous electrolyte battery and the like, and as will be described later in detail, in heating when integrated with the battery pack, the thermoplastic parts 42 and 44 are softened while the cross-linked parts 41, 43) does not soften. For example, in the measurement by a thermomechanical analyzer (TMA) at 200° C. of the cross-linking portions 41 and 43, the residual heat deformation ratio is 30% or more.

In the tab lead 1 shown in Fig. 2, the resin films 21 and 22 are each shown in a single-layer structure, but instead of the single-layered resin film 21 and the resin film 22, a plurality of resin films are included. A laminate may be used. For example, as the resin films 21 and 22, a first layer made of a polyolefin resin such as maleic anhydride-modified low-density polyethylene (PE) and polypropylene (PP), and a second layer made of a polyolefin resin such as low-density polyethylene. It is possible to use a two-layer structure in which the And by selectively irradiating the 2nd layer, the bridge|crosslinking parts 41 and 43 can be formed.

According to the tab lead 1 configured as described above, since the cross-linked portions 41 and 43 have excellent heat resistance, a fixed shape can be retained by the tab lead 1 when sealing the sealed bag by welding. In addition, at the time of this sealing, since the thermoplastic parts 42 and 44 soften even at the temperature below the softening temperature of the bridge|crosslinking parts 41 and 43, the time required for sealing can be shortened.

Moreover, a burr|burr may generate|occur|produce in the corner part of the lead conductor 10. As shown in FIG. In this embodiment, the bridge|crosslinking part 41 protrudes from the 1st main surface 10A in the Y direction when seen from the 1st main surface 10A side, and is inclined from the 1st flat part 31 of the resin film 21. It is formed over the part 33. Further, the cross-linking portion 43 protrudes from the second main surface 10B in the Y direction when viewed from the second main surface 10B side, and the inclined portion 33 from the first flat portion 31 of the resin film 22 . ) is formed over the Therefore, even if burrs are generated in the corners of the lead conductor 10, the burrs are located inside the cross-linked portions 41 and 43 in plan view, and the burrs penetrate the resin portion 20 or the resin portion. The thickness of (20) can be prevented from being insufficient.

From the viewpoint of suppressing the influence of the burrs, the length in the Y direction of the portion protruding from the first main surface 10A and the second main surface 10B of the bridge parts 41 and 43 is preferably 0.1 mm or more, More preferably, it is 0.5 mm or more. On the other hand, the progress of the heat seal is more likely to be hindered as it protrudes from the first main surface 10A and the second main surface 10B of the bridge portions 41 and 43 . From the viewpoint of effectively advancing the heat sealing and more reliably shortening the sealing time, the length in the Y direction of the portion protruding from the first main surface 10A and the second main surface 10B of the bridge parts 41 and 43 is, Preferably, it is 50% or less of the length in the Y direction of the thermoplastic parts 42 and 44, More preferably, it is 30% or less.

The entire surface of the thermoplastic portions 42 and 44 does not need to be completely non-crosslinked, and even if a crosslinked portion is included, the softening temperature of the thermoplastic portions 42 and 44 is higher than the softening temperature of the crosslinked portions 41 and 43. If it is low, a certain effect can be obtained.

[Manufacturing method of tap lead]

Next, the manufacturing method of the tab lead 1 is demonstrated. 3 to 5 are cross-sectional views illustrating a method of manufacturing the tab lead 1 .

First, as shown in Fig. 3, the resin films 21 and 22 are prepared, and the resin films 21 and 22 are attached to each other with the lead conductor 10 interposed therebetween.

Next, as shown in FIG. 4 , the resin film 21 is irradiated with gamma rays using a mask 51 such as lead, and the resin film 22 is irradiated with gamma rays using a mask 52 such as lead. do. The mask 51 has an opening 51A that exposes the area where the crosslinking portion 41 is to be formed while covering the area where the thermoplastic portion 42 is to be formed. The mask 52 has an opening 52A that covers the area where the thermoplastic portion 42 is to be formed while exposing the area where the crosslinking portion 43 is to be formed.

A part of the resin films 21 and 22 are crosslinked by irradiation with gamma rays, and as shown in Fig. 5, crosslinked portions 41 and 43 are formed, and thermoplastic portions 42 and 44 that are non-crosslinked portions are lose

By such a method, the tab lead 1 can be manufactured.

(Second Embodiment)

Next, a second embodiment will be described. A second embodiment relates to a sealed envelope-type nonaqueous electrolyte battery using the tab lead 1 according to the first embodiment.

[battery]

6 is a diagram showing an example of a battery according to the second embodiment. Fig. 7 is a schematic diagram showing the internal structure of the sealed bag. 8 is a diagram showing a configuration example of a battery according to the second embodiment. 9 is a schematic cross-sectional view showing a battery according to a second embodiment.

6 to 8 , in the nonaqueous electrolyte battery 100 according to the second embodiment, the positive electrode 105a and the negative electrode 105b are overlapped with the separator 106 interposed therebetween. To the positive electrode 105a, the lead conductor 110a of the tab lead 101a for positive electrode is joined by welding or the like. To the negative electrode 105b, the lead conductor 110b of the tab lead 101b for negative electrode is joined by welding or the like. The positive electrode 105a and the positive electrode 105a so that a part of the positive electrode tab lead 101a and the negative electrode tab lead 101b (a part on the opposite side to the positive electrode 105a and the negative electrode 105b) protrudes to the outside of the sealing bag 111 , a negative electrode 105b , a separator 106 , a positive electrode tab lead 101a , and an assembly 130 including a negative electrode tab lead 101b is accommodated in the sealing bag 111 . The sealing bag 111 is an example of a wrapping material, and the positive electrode 105a, the negative electrode 105b, and the separator 106 are contained in a power generating element.

The above-described tab leads 1 are used for the tab leads 101a and 101b. That is, the tab lead 101a has a resin portion 120a having a crosslinked portion corresponding to the crosslinked portions 41 and 43 and a thermoplastic portion corresponding to the thermoplastic portions 42 and 44 . Moreover, the tab lead 101b has the resin part 120b provided with the bridge|crosslinking part 145 corresponded to the bridge|crosslinking parts 41 and 43, and the thermoplastic part corresponded to the thermoplastic parts 42,44. As shown in FIG. 9 , the resin parts 120a and 120b include a matrix 215 similar to the matrix 15 , and particles 216 of an acid oxalic agent similar to the particles 16 .

The electrolysis solution is injected into the sealing bag 111 . With the lead conductors 110a and 110b taken out to the outside interposed therebetween, the sealing envelope 111 is overlapped with the resin portions 120a and 120b of the tab leads 101a and 101b disposed in the opening of the sealing envelope 111. The opening of the hood is heat-sealed. One end of the lead conductors 110a and 110b and the resin portions 120a and 120b in the X direction is disposed outside the sealing bag 111 .

As shown in FIG. 9 , the encapsulation bag 111 includes a metal layer 109 such as aluminum foil, an outer layer 107 on the outside of the metal layer 109 , and an inner layer 108 on the inside of the metal layer 109 . has a layered structure of The outer layer 107 is a resin layer and functions as a protective layer. The inner layer 108 is a resin layer having heat-sealing properties. For example, a polyethylene terephthalate (PET) film is used for the outer layer 107 , and a thermoplastic film such as polyethylene is used for the inner layer 108 . The sealing bag 111 is sealed by the sealing part 104 .

The heat sealing of the opening part of the encapsulation bag 111 is performed at a temperature higher than the softening temperature of the thermoplastic portion and lower than the softening temperature of the crosslinked portion, for example, by welding using a hot press machine. In this welding, the thermoplastic part and the inner layer 108 are softened by heat. And, when cooled after softening, the thermoplastic portion and the inner layer 108 are firmly in close contact. If a thermoplastic portion corresponding to the thermoplastic portions 42 and 44 is not provided in the resin portions 120a and 120b and the entire surface of the resin portions 120a and 120b is crosslinked, the resin portions 120a and 120b are not softened. It is difficult, the time required for heat sealing becomes long, or temperature becomes high. On the other hand, in the tab leads 101a and 101b, even at a temperature lower than the softening temperature of the crosslinked portion, the surface of the thermoplastic portion is melted, so the time required for heat sealing can be shortened.

The positive electrode 105a and the negative electrode 105b each have a plate-like shape. By forming the positive electrode 105a and the negative electrode 105b into a plate shape, the thickness reduction of the nonaqueous electrolyte battery 100 is achieved. The positive electrode 105a and the negative electrode 105b have a structure in which an active material layer is formed on a metal substrate such as a metal foil called a current collector or an expand metal. The bonding method of the tab lead 101a for positive electrode and the positive electrode 105a and the bonding method of the tab lead 101b for negative electrode and the negative electrode 105b are not particularly limited, but the method of bonding by spot welding, ultrasonic welding, etc. is It can be used preferably.

Since a very high potential is applied to the positive electrode tab lead 101a, it is preferable that the material is not melted at a high potential. Therefore, as the material of the lead conductor 110a, aluminum, titanium, or an alloy of these metals can be preferably used. In particular, aluminum or an aluminum alloy is preferred.

In the negative electrode tab lead 101b, lithium may be deposited on the surface of the lead conductor 110b due to overcharging. In addition, the potential increases in overdischarge. Therefore, the lead conductor 110b is preferably made of a material that does not easily react with lithium and is difficult to dissolve at a high potential. In view of the above, as the material of the lead conductor 110b, nickel, copper, or an alloy of these metals can be preferably used. Nickel or nickel alloys are particularly preferred.

The resin portions 120a and 120b of the tab leads 101a and 101b are disposed in the openings of the sealing bag 111 . The resin parts 120a and 120b are made of the above-mentioned resin molded body. The resin parts 120a and 120b are fused to the inner film of the encapsulation envelope 111 to prevent a decrease in sealing properties, and at the same time, between the metal layer 109 of the encapsulation envelope 111 and the lead conductor 110a or the lead conductor 110b. It has the function of electrically insulating.

[Sealing time]

Next, the time required for sealing of the tab lead 1 is demonstrated, comparing it with a reference example. 10 is a cross-sectional view showing a tab lead according to a reference example.

As shown in FIG. 10 , the tab lead 201 according to the reference example includes a lead conductor 10 and a resin portion 220 . The material of the resin part 220 is the same as that of the resin part 20 , and the resin part 220 includes the first flat part 31 and the second flat part 32 , similarly to the tab lead 1 . , has an inclined portion (33). The resin portion 220 includes a cross-linked portion 241 formed over the entire surface of the resin film 21 and a cross-linked portion 243 formed over the entire surface of the resin film 22 . That is, in the resin part 220, the whole surface of the resin films 21 and 22 is bridge|crosslinked. The other configuration of the tab lead 201 is the same as that of the tab lead 1 .

Assume that a nonaqueous electrolyte battery including the tab leads 1 and 201 is manufactured, and the sealing bag is sealed using a hot press machine at this time. The hot press machine has a heater and a rubber which is in contact with the encapsulation bag and transmits the heat of the heater to the encapsulation bag. The temperature (surface temperature) of the surface in contact with the sealing bag of the rubber becomes lower than the set temperature of the heater. Table 1 shows the relationship between the set temperature of the heater in the tab lead 201, the surface temperature of the rubber, and the time required for sealing. Table 2 shows the relationship between the set temperature of the heater in the tab lead 1, the surface temperature of the rubber, and the time required for sealing. A "-" mark in the column of time in Tables 1 and 2 indicates that sealing cannot be performed even if time is spent.

[Table 1]

[Table 2]

As shown in Tables 1 and 2, according to the tab lead 1, even at a lower temperature than the tab lead 201, the sealing bag can be sealed. Moreover, if the set temperature of a heater and the surface temperature of a rubber are the same, according to the tab lead 1, sealing of an envelope can be performed in a shorter time than the tab lead 201.

As mentioned above, although embodiment was described above, it is not limited to a specific embodiment, In the range described in the claim, various deformation|transformation and change are possible.

1: tap lead 10: lead conductor
10A: 1st principal surface 10B: 2nd principal surface
10C: side 15: matrix
16: particle 20: resin part
21, 22: resin film 31: first flat part
32: second flat portion 33: inclined portion
41, 43: crosslinking part 42, 44: thermoplastic part
51, 52: masks 51A, 52A: openings
100: non-aqueous electrolyte battery 101a: tab lead for positive electrode
101b: tab lead for negative electrode 104: sealing part
105a: positive electrode 105b: negative electrode
106: separator 107: outer layer
108: inner layer 109: metal layer
110a, 110b: lead conductor 111: sealed envelope
120a, 120b: resin part 130: assembly
145: crosslinking part 201: tap lead
215: matrix 216: particles
220: resin part 241, 243: crosslinking part

Claims (9)

a lead conductor having a first main surface and a second main surface opposite to the first main surface;
a resin portion covering the first main surface, the second main surface, and both side surfaces between the both ends of the lead conductor while exposing both ends of the lead conductor in the first direction;
The resin part,
a first bridge portion covering the first main surface when viewed from the first main surface side;
In a second direction perpendicular to the first direction, a first thermoplastic portion extending outward from both ends of the first cross-linking portion;
a second bridge portion covering the second main surface when viewed from the second main surface side;
in the second direction, having a second thermoplastic portion extending outward from both ends of the second cross-linking portion
tap lead. The method of claim 1,
The first bridge portion protrudes from the first main surface in the second direction when viewed from the first main surface side,
The second bridge portion protrudes from the second main surface in the second direction when viewed from the second main surface side.
tap lead. 3. The method of claim 2,
The length in the second direction of the portion protruding from the first main surface of the first cross-linking portion is 0.1 mm or more,
The length of the portion protruding from the second main surface of the second bridge portion in the second direction is 0.1 mm or more
tap lead. 4. The method according to claim 2 or 3,
A length in the second direction of a portion protruding from the first main surface of the first cross-linking portion is 50% or less of a length in the second direction of the first thermoplastic portion,
A length in the second direction of a portion protruding from the second main surface of the second cross-linking portion is 50% or less of a length in the second direction of the second thermoplastic portion
tap lead. The method of claim 1,
The resin part,
a first flat portion overlapping the lead conductor and having a surface parallel to the first and second major surfaces;
a second flat portion spaced apart from the lead conductor in the second direction and having surfaces parallel to the first and second major surfaces;
connecting the first flat portion and the second flat portion, and having an inclined portion having a surface inclined with respect to the first and second main surfaces,
The first bridge portion and the second bridge portion are formed from the first flat portion to the inclined portion.
tap lead. The method of claim 1,
The gel fraction on the surface of the first cross-linked part is higher than the gel fraction on the surface of the first thermoplastic part,
The gel fraction on the surface of the second cross-linked part is higher than the gel fraction on the surface of the second thermoplastic part.
tap lead. The method of claim 1,
The resin part,
a first resin film including the first crosslinking part and the first thermoplastic part;
and a second resin film including the second crosslinking part and the second thermoplastic part,
The lead conductor is sandwiched between the first resin film and the second resin film,
The first thermoplastic part and the second thermoplastic part are non-crosslinked parts,
The first bridge portion protrudes from the first main surface in the second direction when viewed from the first main surface side,
The second cross-linking portion protrudes from the second main surface in the second direction when viewed from the second main surface side.
tap lead. pojae and
And the power generation element accommodated in the wrapping material,
It has the tab lead according to claim 1 connected to the electrode of the power generating element,
One end of the lead conductor and the resin part in the first direction is disposed outside the wrapping material
battery. preparing a lead conductor having a first main surface and a second main surface opposite to the first main surface;
forming a resin portion covering the first main surface, the second main surface, and both side surfaces between the both ends of the lead conductor while exposing both ends of the lead conductor in the first direction;
By selectively irradiating the surface on the side of the first main surface of the resin portion, a first bridged portion covering the first main surface when viewed from the first main surface side, and a second perpendicular to the first direction a step of forming a first thermoplastic portion extending outwardly from both ends of the first crosslinking portion in the direction;
a second bridged portion covering the second main surface when viewed from the second main surface side by selectively irradiating the surface on the second main surface side of the resin portion; 2 having a step of forming a second thermoplastic portion extending outward from both ends of the cross-linking portion;
A method for manufacturing a tap lead.

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