JP2015022828A - Lead metal with composite coating layer and method of manufacturing lead member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a lead member having an excellent durability against hydrofluoric acid with the surface treated without chromium by uniformly and efficiently applying treatment liquid on a metal member used for the lead member.SOLUTION: To the surface of a lead wire metal, treatment liquid containing a resin component containing polyacrylic acid and polyacrylic amide, and metal salt is adhered, and a composite coating layer 5 is formed by spraying gas thereon in a layered state along the surface of a metal member.

Description

  The present invention relates to a lead metal with a composite coating layer in which a composite coating layer is formed on the surface of a metal member, and a method for manufacturing a lead member in which an insulating layer is bonded to a lead metal with a composite coating layer.

  For example, non-aqueous electrolyte batteries such as lithium ion batteries are used as power sources for small electronic devices. In this non-aqueous electrolyte battery, a positive electrode plate, a negative electrode plate, and an electrolytic solution are housed in an enclosure made of a multilayer film, and lead members (lead wires) connected to the positive electrode plate and the negative electrode plate are hermetically sealed to the outside. The structure of taking out is known.

  As the multilayer film forming the encapsulant, a highly hermetic multilayer film in which a metal foil layer made of a metal such as aluminum is sandwiched between the innermost layer film and the outermost layer film is used. Then, for example, by sealing the periphery of the two laminated films cut into a rectangular shape, the inner layer films are fused and sealed together to form a bag-shaped enclosure. The lead member connected to the positive and negative electrodes is covered with an insulator so that an electrical short circuit does not occur with respect to the metal foil of the laminated film, and the lead member is sealed and sealed at a predetermined edge of the enclosure. Retrieved in state.

  However, if the sealing portion of the laminated film and the lead portion of the lead member are not completely covered and the sealing adhesion is insufficient, moisture will enter the battery from the outside, and the internal electrolyte solution Hydrofluoric acid is generated by the reaction. As the lead metal constituting the lead member, aluminum, nickel (including nickel plating), copper, or the like is used, but the lead metal is corroded by the hydrofluoric acid. Even if the surface of the lead metal is hermetically sealed with an insulator, the surface is gradually corroded over a long period of time, and the sealed form with the insulator is destroyed, causing liquid leakage and lowering the characteristics.

  As a method for improving this, there is a method of covering a surface portion of a lead metal (tab) sealed with an insulator with a chemical conversion treatment layer. As the chemical conversion treatment for hydrofluoric acid resistance, chromium-based chemical conversion treatment is useful and has been used in many fields. However, chemical conversion treatment technology using non-chromium is required in each field due to the problem of environmental pollution.

  For example, Patent Document 1 discloses a non-aqueous electrolyte battery surface-treated with non-chromium and excellent in acid resistance to hydrogen fluoride and its lead wire. This non-aqueous electrolyte battery has a resin component containing polyacrylic acid or polyacrylic acid and polyacrylic acid amide and a metal salt on the surface of the lead metal sealed and taken out by an encapsulant made of a laminated film containing a metal foil. A treatment liquid containing is applied to form a composite film layer. And the insulator for sealing to an enclosure is provided in the outer side of the composite film layer. This lead wire forms a composite film layer in which a treatment liquid is applied to the surface of a lead metal with a gravure coater and then the metal surface is heated and dried.

  Patent Document 2 discloses a method for producing a lead member that is surface-treated with non-chromium and has excellent resistance to hydrogen fluoride acidity. In this manufacturing method, a composite coating layer is formed by spraying a treatment liquid containing a resin component containing polyacrylic acid and polyacrylic amide and a metal salt on the surface of the lead metal by a spray method, and both sides of the lead metal The insulator is stuck together.

JP 2006-128096 A JP 2011-81992 A

  Patent Document 1 describes that a treatment liquid is applied to the surface of a lead metal with a gravure coater as described above. With a gravure coater, it is applied according to conditions such as cell pattern such as cell depth and size of gravure rolls, wettability of the object to be applied with treatment liquid, viscosity of the applied object, or coating speed at the time of application. The film thickness of the object can be controlled. However, the treatment liquid to be applied to the surface of the lead metal has a low viscosity, and there is a limit to the amount of application that can be applied even if the cell pattern is changed, and the applied material depends on the wettability and surface roughness of the object to be applied. Therefore, it is difficult to accurately apply the treatment liquid with a desired film thickness. In the case of a gravure coater, it is difficult to apply the treatment liquid to the end surface of the thin lead metal (surface formed in the thickness direction of the metal side end).

  Also, as in Patent Document 2, when the treatment liquid is sprayed and applied by a spray method, the treatment liquid can be applied to the end surface of the lead metal, but the uncoated portion is eliminated so that there is no uneven coating. For this purpose, it is necessary to repeatedly perform the spraying process with the application areas overlapping. Further, in order to minimize the overlap, it is necessary to reduce the diameter of the nozzle for spraying the processing liquid and to minimize the discharge amount of the processing liquid from the nozzle. However, reducing the discharge amount to the minimum level causes a decrease in productivity and also causes problems such as nozzle clogging, which affects the mass productivity for industrial use.

  The present invention has been made in view of the above-described circumstances. By applying a treatment liquid uniformly and efficiently to a metal member used for a lead member, the lead member is surface-treated with non-chromium and has excellent resistance to hydrofluoric acid. Is to provide a lead metal with a composite coating layer and a method for producing a lead member.

In the method for producing a lead metal with a composite coating layer according to the present invention, a treatment liquid containing a resin component containing polyacrylic acid and polyacrylic acid amide and a metal salt is attached to the surface of the metal member, and along the surface of the metal member Then, a composite film layer is formed by blowing gas in layers. In the method for producing a lead metal with a composite coating layer according to the present invention, the standard deviation of the thickness distribution of the composite coating layer is preferably 30% or less of the target value.
Moreover, it is preferable that the manufacturing method of the lead member by this invention shall stick an insulator from both surfaces of a lead metal with a composite film layer.

  According to the present invention, by uniformly and efficiently applying a treatment solution to a metal member used for a lead member, a lead metal with a composite coating layer and a lead member that is surface-treated with non-chromium and has excellent acid resistance to hydrogen fluoride can be easily obtained. Can be manufactured.

It is an external view which shows an example of the nonaqueous electrolyte battery manufactured by the manufacturing method of the lead member of this invention. It is principal part sectional drawing which shows the structure of the lead wire part of the nonaqueous electrolyte battery of FIG. It is a figure for demonstrating an example of the formation process of the composite film layer applied to the manufacturing method of the lead member of this invention. It is a figure which shows the whole structure of a lead member. It is a figure which shows the film thickness distribution of the process liquid of the surface of the lead metal obtained by the process of Example 1, and a back surface. It is a figure which shows the film thickness distribution of the process liquid of the surface of the lead metal obtained by the process by the comparative example 1, and a back surface.

  With reference to the drawings, an embodiment of a lead metal with a composite coating layer and a method for producing a lead member according to the present invention will be described. FIG. 1 is an external view showing an example of a non-aqueous electrolyte battery, and FIG. 2 is a cross-sectional view of a main part showing a configuration of a lead wire portion of the non-aqueous electrolyte battery of FIG. The lead member 1 manufactured by the manufacturing method of the present embodiment is used for taking out an electric current from the inside of the non-aqueous electrolyte battery 10 having a thin structure. In this lead member 1, the lead metal (metal member) 2 made of a flat conductor or metal foil made of nickel, nickel-plated copper, aluminum, or the like is covered with an insulator 6. The lead member 1 is in close contact with the seal portion 3a of the enclosure 3 at the insulator 6 portion. The lead metal 2 is connected to the electrode terminal inside the encapsulating bag 3, and the lead metal 2 is drawn out of the enclosing bag 3.

  The encapsulant 3 is formed by forming a peripheral seal portion 3a into a bag shape by heat sealing by heat sealing. In the enclosure 3, a single electrochemical cell including a positive electrode, a negative electrode, a diaphragm, and the like and a nonaqueous electrolytic solution in which an electrolyte (for example, a lithium compound) is dissolved in a nonaqueous solvent (for example, an organic solvent). Is sealed and stored.

  The lead member 1 is taken out from the seal portion 3 a for electrical connection to the outside, and the lead metal 2 in the lead-out portion is covered and insulated with an insulator 6. The insulator 6 prevents electrical contact between the metal foil 4 a of the laminated film 4 forming the encapsulant 3 and the lead metal 2. The lead metal 2 of the lead member 1 has a composite film layer 5 formed on the surface thereof, and an insulator 6 is hermetically bonded to the outer surface thereof, and the laminated film 4 is sealed to the outer surface of the insulator 6. The lead metal 2 on which the composite film layer 5 is formed constitutes a lead metal with a composite film layer.

  The composite coating layer 5 is formed by applying a treatment liquid containing a resin component containing polyacrylic acid and polyacrylic amide and a metal salt to the surface of the lead metal 2. The composite coating layer 5 prevents the lead metal 2 from being corroded by hydrofluoric acid.

The insulator 6 covers the portion where the lead metal 2 is taken out and performs electrical insulation from the metal foil 4 a of the laminated film 4, and is preferably formed of two layers, an adhesive layer 7 and an insulating layer 8.
For the adhesive layer 7, for example, thermoplastic polyolefin resin or the like, preferably low-density polyethylene, acid-modified low-density polyethylene, or acid-modified polypropylene is used, and is heat-sealed to the composite coating layer 5 on the lead metal 2.

The insulating layer 8 is fused to the encapsulant 3 to draw out the lead metal 2 in a sealed state. The insulating layer 8 is formed of a resin material that does not melt at the heat sealing temperature when the sealing portion 3a of the encapsulant 3 is heat-sealed. For example, the insulating layer 8 is a cross-linked polyolefin resin, preferably a cross-linked low-density polyethylene, acid-modified polypropylene, or ethylene. -Vinyl alcohol polymer (example: ethylene ratio 44%, thickness 100 μm, melting point 165 ° C.) is used.
When the innermost layer film of the encapsulant 3 is formed of acid-modified low density polyethylene, the seal portion 3a is heat sealed at about 110 ° C., but the insulating layer 8 is not melted at this heat seal temperature, and the lead metal 2 In the take-out portion, electrical insulation between the metal foil 4a of the laminated film 4 and the lead metal 2 can be ensured.

The composite coating layer 5 adheres a treatment liquid containing a resin component containing polyacrylic acid and polyacrylic amide and a metal salt to the surface of the lead metal (metal member) 2, along the surface of the lead metal 2. To form a film by spraying in layers. As the metal salt, it is preferable to use, for example, zirconium salt, titanium salt, other molybdenum salt and the like that do not contain chromium. Zirconium ammonium hydroxide [(NH ₄ ) ₃ ZrOH (CO ₃ ) ₃ ], fluorinated zirconate, zirconium carbonate, zirconium phosphate and the like can be used as the zirconium salt. Further, chelate organic titanium or the like can be used as the titanium salt, and molybdate can be used as the molybdenum salt. As a result, the composite coating layer 5 that does not contain hexavalent chromium, which is an environmental pollutant, and trivalent chromium that may be regulated in the future, is uniformly formed on the surface of the lead metal 2 and has excellent hydrofluoric acid resistance. The lead member 1 can be obtained.

Composite coating layer 5, the resin component is ^{1mg / m 2 ~200mg / m 2} , it is preferred that the metal salt (adhesion amount) is formed with ^{0.5mg / m 2 ~50mg / m 2} . When the resin component is less than 1 mg / m ² , the flexibility of the composite coating layer 5 is reduced and cracks are likely to occur, and when it exceeds 200 mg / m ² , the adhesion of the insulator 6 to the adhesive layer 7 is reduced. To do. If the metal salt is less than 0.5 mg / m ² , the acid resistance to hydrogen fluoride is insufficient, and if it exceeds 50 mg / m ² , a brittle film layer is formed.

  The composite coating layer 5 is preferably formed such that the ratio of the resin component to the metal salt is, for example, 1: 3 to 6: 1. If the ratio of the organic resin component to the inorganic metal salt is less than 1: 3, the adhesive strength for the resin component to embed the metal salt and bond becomes poor, and the hydrogen fluoride acid resistance cannot be satisfied. On the other hand, if the ratio exceeds 6: 1, the relative amount of the inorganic content in the composite coating layer 5 is reduced, so that the hydrogen fluoride acid resistance cannot be satisfied.

  The thickness of the composite coating layer 5 is preferably 30% or less of the target value. For example, when the target value of the thickness of the composite coating layer 5 is 7 nm, it is preferable to set the standard deviation of the thickness distribution to 2.1 or less. Thereby, the composite coating layer 5 having a uniform thickness distribution can be formed with an appropriate coating amount, and reliable acid resistance to hydrogen fluoride can be imparted throughout the lead member 1.

Next, the manufacturing method of the lead metal 2 with composite film layer and the lead member 1 will be described in more detail.
When the lead member 1 is manufactured, as a pretreatment for forming the composite coating layer 5 on the surface of the lead metal 2, a tempering treatment of a surface state for ensuring wettability is performed. Specifically, the cathode electric field degreasing treatment using a sodium hydroxide aqueous solution can be performed on a metal foil such as nickel, nickel-plated copper, or aluminum that becomes the lead metal 2. Electrolytic degreasing performs electrolysis in an alkaline solution and promotes degreasing and mechanical peeling by the stirring action of hydrogen gas generated along with the saponification reaction to improve wettability.

Next, the composite coating layer 5 is formed.
FIG. 3 is a view for explaining an example of the formation process of the composite coating layer, and is a diagram schematically showing the state of the formation process of the composite coating layer 5 as viewed from above. The lead metal 2 is long and is extended along the pass line 11 in FIG. 2 with its width direction aligned with the vertical direction, and conveyed in the direction of arrow T. The lead metal 2 that has been wound up is stretched and applied to the apparatus, and after the composite coating layer 5 is formed, it is wound up.
Here, first, a treatment liquid containing a resin component containing polyacrylic acid and polyacrylic acid amide and a metal salt is attached to the surface of the lead metal 2. In this process, for example, the processing liquid is flowed out from the processing liquid coating apparatus 12, the lead metal 2 is passed through the flowing processing liquid, and the processing liquid is attached to the surface of the lead metal 2. Here, the surface of the lead metal 2 is filled with the treatment liquid, which is the same as the state in which the lead metal 2 is immersed in the treatment liquid.

  Then, the film thickness of the treatment liquid of the lead metal 2 to which the treatment liquid is adhered by the above treatment is adjusted. The film thickness can be adjusted using an air blow 14 provided on the downstream side of the treatment liquid coating apparatus 12 via the partition plate 13. The air blow 14 includes two box-shaped air blowing portions 15 each having a nozzle 15a, and is arranged so that the longitudinal direction of each air outlet coincides with the vertical direction. And gas (here air) is sent in the inside of the air spraying part 15, and air is sprayed on the both surfaces side of the lead metal 2 from the nozzle 15a. As a result, air is blown in layers along the surface of the lead metal 2.

By the air blown to the lead metal 2 by the air blow 14, the processing liquid adhering to the surface of the lead metal 2 is removed to a desired film thickness, and a coating film having a uniform thickness can be obtained. In this processing example, the processing liquid is sufficiently adhered to the lead metal 2 and then the excess processing liquid is removed by the air blow 14 to form a processing liquid layer with a desired thickness and a uniform film thickness. can do. The film thickness of the treatment liquid can be adjusted by the distance between the nozzles 15a of the air blow 14, the flow rate of air ejected from each nozzle 15a, and the like.
FIG. 4 is a diagram illustrating the overall configuration of the lead member. The lead metal 2 is cut into a predetermined dimension after the composite coating layer 5 is formed. A film-like insulator 6 is bonded to a part of the cut lead metal 2 with the lead metal 2 interposed therebetween. That is, the insulator 6 is provided on both sides of the lead metal 2.

Example 1
As the lead metal 2, a 100 mm × 100 mm square aluminum metal foil was used, and as a pretreatment for ensuring wettability, a tempering treatment of the surface state by cathode electric field degreasing using sodium hydroxide was performed. Then, a polyacrylic acid and polyacrylic acid amide resin comprising the components, carbide zirconium hydroxide ammonium _{[(NH 4) 3 ZrOH (} CO 3) 3] treatment solution containing a metal salt by applied to the metal member.
Here, an apparatus as shown in FIG. 2 was used, and the treatment liquid was adhered to the surface of the lead metal 2 by allowing the aluminum foil to be the lead metal 2 to pass through the treatment liquid flowing out. And the air was blown with the air blow with respect to the metal member which the process liquid adhered, and the excess process liquid on the metal member surface was removed. The film thickness of the target processing solution at this time was 7 nm.

FIG. 5 is a graph showing the film thickness distribution of the treatment liquid on the front and back surfaces of the lead metal 2 obtained by the treatment of Example 1. FIG. In FIG. 5, the horizontal axis indicates the position of the lead metal 2, and the positions obtained by dividing the lead metal 2 into 32 equal parts in the width direction (vertical direction of the air blowing process in FIG. 3) are indicated by numbers 1 to 32. The vertical axis indicates the film thickness (nm) of the treatment liquid at each position.
As shown in FIG. 5, the treatment liquid is adhered to the surface of the lead metal 2 according to the first embodiment, and a gas is blown in layers along the surface of the lead metal 2 by the air blow 14 to form a composite coating layer by the treatment liquid. Thus, it was possible to form a composite film layer having a uniform film thickness with little coating unevenness. The standard deviation σ of the film thickness distribution at this time was 1.78, and the standard deviation σ could be within 30% of the target value. Thus, it was found that the treatment liquid can be applied to the individual lead-shaped lead metal 2 with a uniform appearance, and excellent hydrofluoric acid resistance can be secured.

(Comparative Example 1)
As in Example 1, a 100 mm × 100 mm square aluminum metal foil was used as the lead metal 2, and as a pretreatment for ensuring wettability, the surface condition was tempered by cathodic electric field degreasing using sodium hydroxide. Went.
And in this comparative example, with respect to the lead metal 2 which performed the pre-processing, the process liquid was apply | coated using the gravure coater. In this case, a treatment liquid containing a resin component containing polyacrylic acid and polyacrylic acid amide and a metal salt of zirconium ammonium hydroxide [(NH ₄ ) ₃ ZrOH (CO ₃ )] is used as a lead metal 2 using a gravure coater. It was applied to. The film thickness of the target treatment liquid was 7 nm.

FIG. 6 is a diagram showing the film thickness distribution of the treatment liquid on the front and back surfaces of the lead metal 2 obtained by the treatment according to Comparative Example 1. In FIG. 6, the horizontal axis indicates the position of the lead metal 2, and the positions obtained by dividing the lead metal 2 into 32 parts in the width direction of the gravure roll are indicated by numbers 1 to 32. The vertical axis indicates the film thickness (nm) of the treatment liquid at each position.
As shown in FIG. 6, when the treatment liquid was applied using a gravure coater, there was a large variation in film thickness, and there was a portion where no treatment liquid was applied. At this time, the film thickness distribution was greatly disturbed with a standard deviation σ = 3.44 of the film thickness distribution. This indicates that, for example, when used as a lead metal of a nonaqueous electrolyte battery, liquid leakage may occur due to corrosion by hydrofluoric acid after long-term use.

(Comparative Example 2)
As in Example 1, a 100 mm × 100 mm square aluminum metal foil was used as the lead metal 2, and as a pretreatment for ensuring wettability, the surface condition was tempered by cathodic electric field degreasing using sodium hydroxide. Went.
And in this comparative example, with respect to the lead metal 2 which performed the pre-processing, it is based on the resin component containing polyacrylic acid and polyacrylic acid amide, and ammonium zirconium hydroxide [(NH ₄ ) ₃ ZrOH (CO ₃ )]. A treatment liquid containing a metal salt was applied to the lead metal 2 by spraying using a spray method. The film thickness of the target treatment liquid was 7 nm.

Here, the treatment liquid was sprayed on the surface of the lead metal 2 with a particle diameter of 5 μm or less using a spray nozzle. The particle diameter is represented by the diameter of the spots formed by the treatment liquid adhering to the surface of the lead metal 2. In this case, in order to apply the treatment liquid evenly to the lead metal 2, the treatment by the overlap three times was necessary. The process by overlap means that the spray process of the processing liquid by the spray nozzle is repeated on the lead metal 2.
As a result, the work processing time for applying the processing liquid to the 100 mm × 100 mm lead metal 2 by the spray method was required for 3 seconds. On the other hand, in the process using the air blow 14 of Example 1, the work processing time for applying the processing liquid to the lead metal 2 of the same size is 1 second, and the decrease in productivity due to the spray method was remarkable. .

  As described above, according to the present invention, a lead with a composite coating film layer that is surface-treated with non-chromium and has excellent acid resistance to hydrogen fluoride by applying a treatment liquid uniformly and efficiently to a metal member used for a lead member. It becomes possible to easily manufacture the metal and the lead member.

DESCRIPTION OF SYMBOLS 1 ... Lead wire, 2 ... Lead metal, 3 ... Enclosure, 3a ... Seal part, 4 ... Laminated film, 4a ... Metal foil, 5 ... Composite film layer, 6 ... Insulator, 7 ... Adhesive layer, 8 ... Insulating layer DESCRIPTION OF SYMBOLS 10 ... Non-aqueous electrolyte battery, 11 ... Pass line, 12 ... Treatment liquid coating device, 13 ... Partition plate, 14 ... Air blow, 15 ... Air spraying part, 15a ... Nozzle.

Claims (3)

  A composite in which a treatment liquid containing a resin component including polyacrylic acid and polyacrylic acid amide and a metal salt is attached to the surface of a metal member, and a gas is blown in layers along the surface of the metal member to form a composite coating layer Manufacturing method of lead metal with coating layer.   The method for producing a lead metal with a composite coating layer according to claim 1, wherein a standard deviation of the thickness distribution of the composite coating layer is set to 30% or less of a target value.   The manufacturing method of the lead member which bonds an insulator from both surfaces of the lead metal with a composite film layer of Claim 1 or 2.

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