WO2008044763A1

WO2008044763A1 - Tab lead material and process for producing the same

Info

Publication number: WO2008044763A1
Application number: PCT/JP2007/069939
Authority: WO
Inventors: Satoshi Yamazaki; Ikuo Tabata
Original assignee: Kyoritsu Chemical & Co., Ltd.; Nets Co., Ltd.
Priority date: 2006-10-13
Filing date: 2007-10-12
Publication date: 2008-04-17
Also published as: JP2010003711A

Abstract

A tab lead material which comprises a thin metal sheet material and which, when used in a laminate package type cell or capacitor, has improved adhesion to a film material to be bonded to this tab lead material. It is intended to thus heighten the reliability of the cell or capacitor. This tab lead material (10) comprises a thin metal sheet (11) and a nickel sulfamate deposit film (12) formed by plating on the surface thereof. It may further have, formed on the surface of the deposit film, a primer film (13) comprising chitosan or a derivative thereof. In this tab lead material, the thin metal sheet preferably is one which has undergone a heat treatment and the deposit film has a thickness of preferably 1.0-3.0 µm. The metal may be copper or aluminum.

Description

Specification

Tab lead material and manufacturing method thereof

Technical field

TECHNICAL FIELD [0001] The present invention relates to a tab lead material and a manufacturing method thereof, and more particularly to a tab lead material suitable for use in a nonaqueous electrolyte battery or a capacitor and a manufacturing method thereof.

Background art

In recent years, in order to reduce the exhaust gas of automobiles, automobiles using batteries as driving power sources have been studied. This battery is required to have a large energy capacity, and as such a battery, a lithium secondary battery, a fuel cell, or the like is prominent.

[0003] In a lithium secondary battery, a film-like positive electrode and a negative electrode are opposed to each other via a separator, and a non-aqueous electrolyte is interposed therebetween to transmit lithium ions to enable charging / discharging. These power generation elements are covered with a highly airtight exterior material, and electricity can be taken out from the negative electrode and the positive electrode by a tab lead material (see Patent Document 1). .

[0004] In the electrolyte accommodated in the battery, when the carbonate-based solvent is mainly used as a solvent for the electrolytic solution, and such a solvent leaks outside from the exterior material, the battery does not function. Depending on the power and the materials used, there is a risk of ignition, which is not preferable. For this purpose, even in the severe usage mode of the battery for automobiles, improvement in the sealing property between the tab lead material of the battery and the member in contact with the battery is strongly demanded.

[0005] Furthermore, lithium-based nonaqueous electrolyte batteries contain a fluorine atom such as LiPF.

6

Lithium salt dissolved in the organic solvent is used as an electrolyte. By the way, this fluorine-containing electrolyte such as LiPF chemically decomposes and generates HF when it comes into contact with water.

6

To do. This HF is a highly corrosive substance, which erodes the metal such as aluminum that constitutes the tab lead material and reduces the adhesive strength with the insulating film adhered to the surface, causing peeling. It was.

[0006] The above-mentioned problem is a problem in a film exterior type non-aqueous electrolyte battery. It is used in an extremely severe situation because it is used in an automobile, and moreover in a vibration or temperature environment. Therefore, there is a strong demand for the solution of the above problems.

Patent Document 1: JP-A-11 224652

Disclosure of the invention

Problems to be solved by the invention

[0007] The present invention was made to eliminate the drawbacks of the prior art in the tab lead material. When the tab lead material made of a thin metal plate material is used in a laminate package type battery or capacitor, this tab lead material is used. The purpose is to improve the reliability of the battery or capacitor by improving the adhesion between the film and the film material adhered to it.

Means for solving the problem

[0008] A first aspect of the present invention is a tab lead material comprising a thin metal plate and a nickel sulfamate coating formed on the surface thereof.

[0009] In the first aspect of the present invention, there is provided a thin metal plate, a nickel sulfamate sulfamate coating formed on the surface thereof, and a polymer film including chitosan or a derivative thereof formed on the surface thereof. I prefer to do it.

[0010] In the tab lead material, the metal thin plate is preferably subjected to heat treatment. The thickness of the plating film is preferably 1. O ^ m or more and 3.0 m or less, and a nickel plating film is preferably formed on the entire surface of the metal thin plate. As the metal, it is possible to use the same or an anorium.

[0011] The second aspect of the present invention includes a step of applying nickel sulfamate plating to the surface of a metal thin plate, and a step of forming a primer film containing chitosan or a derivative thereof on the surface of the plating film. This is a method for producing a tab lead material.

[0012] In the second aspect of the present invention, it is preferable that the metal thin plate is annealed. The annealing treatment may be performed after the nickel plating treatment. The invention's effect

[0013] According to the present invention, the chemical resistance of the tab lead material using the metal thin plate is improved by applying nickel sulfamate to the surface of the metal thin plate. In addition, the surface By forming the limer layer, the adhesiveness with the plastic film heat-sealed to the surface is improved and the reliability is improved.

Brief Description of Drawings

FIG. 1 is a cross-sectional view of a tab lead material of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] [First embodiment: Tab lead material]

A cross-sectional view of the tab lead material of the present embodiment is shown in FIG.

As shown in FIG. 1, this tab lead material 10 has a nickel sulfamate plating layer 12 formed on the surface of a thin metal plate 11, and a primer layer 13 containing chitosan or a derivative thereof is formed on the surface. It is. The tab lead material will be described below.

[0016] (Metal sheet)

As the metal thin plate forming the tab lead material of the present embodiment, copper or aluminum is suitable because of its electrical conductivity. As the copper material, rolled oxygen-free copper is preferable. The metal thin plate may be a metal foil made of these alone, or a laminated thin plate with these materials or other metal materials! /.

The metal sheet material is preferably subjected to annealing treatment. This will be described later.

Since the metal sheet material is used as a tab lead material, the thickness is preferably in the range of 0.;! To 0.5 mm. The width is preferably 10 to 100 mm and the length is 40 to 100 mm.

[0017] (matte nickel plating film)

In this embodiment, matte nickel plating is applied to the surface of the thin metal plate. This can improve the chemical resistance of the tab lead material, particularly the resistance to hydrogen fluoride, which is expected to occur in the electrolyte solution in a non-aqueous electrolyte battery.

[0018] As a method for forming a dull nickel plating film, a plating method using a known dull nickel plating bath such as a nickel sulfamate plating bath or a Watt bath can be adopted, but the stress of the nickel plating film is 1 to A method of forming a film of about 7 kg · mm ² is preferable. Matte nickel plating means that the fineness of the crystal of the coating film is normal in nickel plating. Without adding brighteners such as aromatic sulfonates, aromatic sulfonamides, aromatic sulfonimides, aldehydes, aryl compounds, acetylene compound nitriles, etc. It is a method of applying a texture.

As such a plating method, electrolytic plating using a nickel sulfamate plating bath is preferred. According to this method, the nickel plating film to be formed has low stress and excellent flexibility, and the nickel plating film can be prevented from being damaged when the electrode is formed by press molding at the time of assembling a battery or the like. In addition, handling during use of the battery becomes easy.

In other words, a general nickel plating (glossy plating) cannot be used because it cracks when a metal sheet with a hard coating is bent at an angle of 180 degrees. In addition, 0.2 mmt x 8 mm wide x 60 mm long lead material with electroless Ni plating will crack once and will not withstand actual use. On the other hand, the nickel plating film formed by the nickel sulfamate plating method did not generate cracks even if it was bent four times by the same method (partial cracks occurred at the fifth time).

In the tab lead material of the present invention, it is indispensable to bend the terminal lead when assembling a battery or the like, and a material that is predicted to generate cracks cannot withstand actual use and cannot be used.

[0019] The thickness of the nickel plating film of the present embodiment is preferably in the range of 1.0 μm to 3.0 μm. If the thickness of the nickel plating film falls below this range, the surface of the thin metal sheet will be exposed due to scratching of the plating film when handling the tab coating material with the coating film, and the chemical resistance of the tab lead material will be greatly increased. The reliability of the battery or capacitor decreases. On the other hand, in order to make the thickness of the nickel plating film beyond this range, only a long time is required for the plating, and no improvement in characteristics corresponding to this is seen, which is economically disadvantageous. A more preferable range of the thickness of the plating film is 2.0 · 2.5 to 01.

[0020] The nickel plating film may be a single film! /, But it can also be formed into a multilayer plating film by a plurality of plating processes. This makes it possible to obtain a reliable film free from defects such as pinholes in the plating film. In addition, the surface of the nickel sulfamate coating should be coated with other metal materials such as gold, silver, and cobalt to form a multilayer film. You can also.

Even when forming a multilayer plating film, the thickness of each plating layer is not particularly limited, as long as the entire multilayer plating film can sufficiently cover the entire surface of the thin metal sheet. In the case of multilayer plating, the total film thickness is preferably the same as that of a single film.

The nickel plating film is preferably formed on the entire surface of the thin metal plate. That is, it is preferable to form a textured film not only on the main surface but also on the side surfaces of the thin plate.

[0021] (Primer film)

A primer (primer) film is formed on the surface of the tab lead material of the present invention in order to improve the adhesion with the insulating film adhered to the surface. This primer is made of a material composed of chitosan or a derivative thereof described in detail below.

The thickness of the primer is preferably about 2001 111 to 5 111. When the thickness force is less than 200 nm, the force S for improving the adhesiveness between the tab lead material and the insulating film on the surface cannot be achieved, and it is easily peeled off. On the other hand, when the film thickness exceeds δπι, if a force for peeling the tab lead material and the insulating film is applied, the primer itself causes cohesive failure and breaks, so that the adhesive strength decreases.

[0022] (Primer material)

Chitosan, the main component of this primer, is chicken, which is a naturally occurring polymer obtained from shells or mushrooms such as shrimp, shrimp and insects, ie, / 3-polypolyacetyl-D-darcosamine It is a substance obtained by deacetylation and is a polysaccharide containing an amino group with 2-amino-2-deoxy-D-glucose as a structural unit. It is a material that forms a salt with various acids and becomes cationic when dissolved in water. is there. Since it is a compound having such a high reactivity, it is possible to adhere to both surfaces of the hydrophilic material surface and the hydrophobic material surface!

[0023] Chitosan or a derivative thereof used in the present invention may be a polymer substance composed of only 2-amino-2-deoxy D-glucose, or a co-polymer in which this is polymerized with other glucose. They can be combined. Further, it may be a derivative in which another substituent is introduced into a part of the functional group of glucosamine constituting this polymer. Specifically, those represented by the following chemical formula can be used. [0024] [Chemical 1]

R = -CH ₂ — CH— CH ₂ — OH or Π

OH

[0025] Such chitosan is produced industrially, is supplied in various grades, and is commercially available.

In the present invention, chitosan and derivatives thereof having a degree of deacetylation of 80% or more are suitable. When the degree of deacetylation is lower than the above range, it is difficult to dissolve in water because it dissolves in water to form an aqueous solution, which is inappropriate for the present invention.

The weight average molecular weight is more preferably in the range of 10,000 to 1,000,000, preferably 1,000 to 2,000,000. If the molecular weight is below this range, it is inappropriate for use in the present invention in terms of forming a film of the adhesive layer. On the other hand, if the molecular weight exceeds this range, the viscosity of the solution becomes too high. In view of handling such as workability, it is inappropriate for use in the present invention.

Preferred chitosan derivatives include chitosan, chitosan pyrrolidone carboxylate, hydroxypropyl chitosan, glycerylated chitosan, cationized chitosan, chitosan lactate, chitosan adipate, etc. It is preferable that the chitosan derivative further contains an organic compound having at least one carboxyl group in the molecule.

[0026] As long as the primer is used in a thickness within the above range, it does not impair the solderability even if it is formed on the surface of the tab lead material. Therefore, it is possible to employ a simple soldering method for electrical connection. S can be advantageous.

[Second Embodiment: Method for Manufacturing Tab Lead Material]

Hereinafter, the manufacturing method of the tab lead material of the present embodiment will be described in accordance with the manufacturing process. The The tab lead material of the present embodiment is provided with a nickel plating process on the surface of the metal thin plate, and can be performed by adding a subsequent primer film forming process.

[0028] (Nickel plating process)

[0029] Nickel plating is applied to the surface of the thin metal plate constituting the tab lead material. This metal thin plate is preferably annealed. This annealing process will be described later.

[0030] The nickel plating treatment of the present embodiment is preferably performed by the electrolytic plating using a nickel sulfamate plating bath, in addition to the ability of the resulting coating film to have low stress and flexibility. An example of the composition of the nickel sulfamate plating bath used in the present embodiment is shown.

Ni (NH SO) 4Η O: 250 ~ 780g / 1

2 3 2 2

NiCl6Η O: 10-50g / 1

twenty two

H BO: 30-60g / l

3 3

Higher alcohol surfactant: 1 to 10ml / l

These components are dissolved in water, more preferably pure water, to constitute a plating bath.

[0031] The conditions for performing nickel sulfamate plating can be appropriately determined according to the composition of the plating solution used, but in the case of the nickel sulfamate plating bath described above, the liquid temperature is 30 to 60 °. C, Cathode current density 0.;! ~ 50A / dm ² , preferably liquid temperature 50 ~ 60 ° C, Cathode current density 0.4 ~; lOA / dm ²

[0032] Prior to the formation of the coating film on the surface of the thin metal plate, it is preferable to perform pretreatment such as degreasing and pickling on the surface of the thin metal plate by a known method.

[0033] (Primer film forming step)

Next, a primer film is formed on the surface of the thin metal plate subjected to the nickel plating. This primer film improves the adhesion between the metal thin plate and the film disposed on the surface thereof. In this embodiment, a primer containing chitosan or a derivative thereof is used as the primer layer material. Use.

This primer is preferably used as an aqueous solution of the aforementioned chitosan or a derivative thereof, or an organic solvent solution. The concentration is preferably in the range of 0.;! To 20% by mass. When the concentration of chitosans is less than 0.1% by mass, the effect of improving adhesiveness is improved. It is not practical. On the other hand, when the concentration of chitosan exceeds the above range, the viscosity of the chitosan solution increases and handling becomes difficult.

In addition to the above chitosans, this primer includes an organic compound having at least one carboxyl group in the molecule, a trivalent chelate-forming metal compound, a rheo-mouth property improving agent, and a xotropy improving agent. It is possible to use additives such as oxidants and antioxidants in combination. In particular, when a chelate-forming compound is used in combination, a chelate compound is formed together with the amino group of chitosan, and the film formability is improved.

Formation of this primer film is preferably carried out by immersing a metal thin plate in a primer solution and drying it. The primer film is preferably formed on the surface and side surfaces of the metal thin plate.

[0034] (Annealing process)

As described above, the metal thin plate used in the present invention may have high rigidity due to the effects of residual stress and the like due to various machining during the manufacturing process. When such a thin metal plate is used, cracks may occur or break at the stage of handling. In order to eliminate such problems, it is preferable to perform annealing. This annealing treatment may be performed before the nickel plating or after the nickel plating.

[0035] The annealing treatment is a technique commonly known as annealing treatment, and is preferably performed in the range of 100 ° C to 500 ° C in an inert or reducing atmosphere. Although the treatment time is related to the treatment temperature, it can usually be carried out in about 1 minute to 1 hour.

[0036] [Use of tab lead material]

The tab lead material has improved chemical resistance to chemicals such as hydrofluoric acid, and the adhesiveness to a film or the like that is bonded to the surface by a method such as heat fusion is remarkably improved. Therefore, this tab lead material may come into contact with chemicals such as hydrofluoric acid, and is preferably applied to the field where it is used as an assembly with a film. Such fields include, but are not limited to, non-aqueous electrolyte secondary batteries and non-aqueous electrolyte capacitors.

In particular, as a non-aqueous electrolyte secondary battery, the tab lead material of the present invention is extremely excellent in adhesiveness, and can be used in HEVs (Hybrid Electric Vehicles) that can be used in harsh conditions. Suitable for use!

Example

Hereinafter, examples of the present invention will be described.

(Example)

Prepare an annealed copper sheet with a thickness of 0.2 mm, a width of 8. Omm, and a length of 60 mm. Ni (NH SO) 4Η O: 500g / 1, NiCl6Η O: 30g / 1, H BO: 50g

2 3 2 2 2 2 3 3

/ 1, and higher alcohol surfactant: Using a plating bath having a composition of 5 ml / l, a plating treatment is performed at a bath temperature of 50 ° C. under a current density of 1 OA / dm ² and a thickness of 1. Three types of test samples were prepared with a coating film of O ^ m, 2. ,, m, and 3.0 · m.

Next, a primer in which glyceryl chitosan was dissolved in water was applied to the surface of these test samples to a thickness of 1 μm or less, and dried to prepare a tab lead material sample.

A test sample was prepared by heat-sealing maleic anhydride-modified polypropylene phenolic (thickness 0.1 mm, width 10 mm, length 12 mm) on the surface of the obtained tab lead material sample.

[0038] (Comparative Example 1)

A test sample as Comparative Example 1 was prepared in the same manner as in the above example, except that the nickel sulfamate plating treatment was not performed.

[0039] (Comparative Example 2)

A test sample as Comparative Example 2 was prepared in the same manner as in the above example, except that the primer layer forming treatment containing chitosan or its derivative was not performed.

[0040] (Comparative Example 3)

In the above examples, the test sample to be used in Comparative Example 3 was prepared in the same manner except that the nickel sulfamate treatment and the primer layer formation treatment containing chitosan or its derivative were not affected. Created.

[0041] (Evaluation)

The test samples prepared in the above Examples and Comparative Examples 1, 2, and 3 were immersed in 1% HF aqueous solution for 90 minutes, corrosiveness by HF, and reliability of film and tab material welding (hydrofluoric acid resistance test) Evaluated.

As a result, the test piece of this example that had been subjected to the plating treatment and the primer treatment was The welded film with no discoloration due to oxidation did not peel off.

On the other hand, the copper material of Comparative Example 1 that was not subjected to the plating treatment was discolored to brown, and the film welding interface also peeled 4 to 6 mm from the welding part where the film edge was 10 mm.

In Comparative Example 2 and Comparative Example 3, which are film-welded tabs that were not subjected to primer treatment, the PP film on which both were deposited all peeled off in 30 minutes.

From the above results, it is clear that the chemical resistance of the metal thin plate is improved by forming a nickel sulfamate plating film on the surface of the metal thin plate, and the adhesion is improved by forming a primer film on the surface. It became.

From these results, it was found that the tab lead material used for HEV applications, particularly the tab lead material used for the negative electrode, is important for improving Ni resistance and chemical resistance and adhesion by performing Ni plating and primer treatment. .

Claims

The scope of the claims

[I] A tab lead material characterized by comprising a thin metal plate and a matte nickel plating film formed on the surface thereof.

[2] The tab lead material according to [1], wherein the matte nickel plating film is a nickel sulfamate plating film.

[3] A tab lead material comprising a thin metal plate, a matte nickel plating film formed on the surface thereof, and a primer film containing chitosan or a derivative thereof formed on the surface thereof.

[4] The tab lead material according to [3], wherein the matte nickel plating film is a nickel sulfamate coating.

[5] The tab lead material according to claim 1 or claim 3, wherein the metal thin plate is heat-treated.

6. The tab lead material according to claim 1, wherein the thickness force of the plating film is 1.0 m or more and 3.0 m or less.

7. The tab lead material according to claim 1, wherein the nickel plating film is formed on the entire surface of the metal thin plate.

8. The tab lead material according to claim 1, wherein the metal is copper or aluminum.

[9] A method for producing a tab lead material, comprising a step of applying a matte nickel plating to the surface of a thin metal plate.

10. The method for producing a tab lead material according to claim 9, wherein the matte nickel plating strength is nickel sulfamate plating.

[I I] A step of applying a matte nickel plating to the surface of a thin metal plate;

Forming a primer film containing chitosan or a derivative thereof on the surface of the plating film,

A method for producing a tab lead material, comprising:

12. The method for producing a tab lead material according to claim 11, wherein the matte nickel plating power is nickel sulfamate plating.

13. The method for producing a tab lead material according to claim 9 or claim 11, wherein the metal thin plate is annealed.

[14] applying a matte nickel plating to the surface of the thin metal plate;

A step of heat-treating the metal thin plate subjected to the nickel sulfamate plating, and a step of forming a primer film containing chitosan or a derivative thereof on the surface of the plating layer.

A method for producing a tab lead material, comprising:

15. The method for producing a tab lead material according to claim 14, wherein the matte nickel plating strength is nickel sulfamate plating.