KR102002801B1 - Chromeless surface treatment of lead tab for improving corrosion resistance - Google Patents

Abstract

The present invention relates to a chromeless surface treatment method of a lead tab for improving corrosion resistance and, more specifically, to a method for improving corrosion resistance (chemical resistance and electrolyte resistance) while environmentally-friendly surface treating a metal tab part of a lead tab as one of components of a lithium secondary battery. A surface treatment method of a lead tab with improved corrosion resistance according to the present invention has an effect of remarkably improving adhesion strength between a metal tab and a polymer film, and remarkably improving life time of a battery. In particular, the chromeless surface treatment method has human body-friendly and eco-friendly characteristics, thereby having an effect of being useful as the most effective alternative to a regulation policy for use of chrome. In addition, the chromeless surface treatment method of a lead tab with improved corrosion resistance of the present invention is capable of achieving excellent corrosion resistance without an anodizing process, thereby relatively simplifying a process and being useful in terms of costs.

Description

[0001] The present invention relates to a chromium-free surface treatment of lead tabs for improving corrosion resistance,

More particularly, the present invention relates to a method for treating a chromium-free surface of a lead tab for improving corrosion resistance, and more particularly, to a method for treating a chromium-free surface of a lead tab for improving corrosion resistance, Electrolyte resistance) of the battery.

BACKGROUND ART Lithium-ion batteries and lithium polymer secondary batteries are widely used in electronic devices such as cellular phones and notebook computers. In recent years, electric bicycles, hybrid vehicles (HEV), electric vehicles (EV), plug- ), And energy storage devices (ESS).

2. Description of the Related Art Generally, a pouch type secondary battery includes an electrode group in which an anode, a separator, and a cathode are stacked, a lead tab connected to an external terminal, And a casing for packaging the electrode assembly.

Among these, a lead tab is a part that performs an insulating function between an anode, a cathode, and a terminal electrode in a battery and a packaging material. The lead tab is composed of a negative electrode lead interposing the negative electrode material inside the lithium polymer secondary battery and a positive electrode lead connected to the positive electrode, and is an important component affecting the output and stability of the battery. The lead tab has a plate or rod shape and is formed of a composite of a metal tab and a polymer film. Further, the metal is made of a conductive metal selected from aluminum (Al), nickel (Ni), copper (Cu), and alloys thereof, which are advantageous in terms of conductivity.

The lead tab facilitates the adhesion between the metal tap and the polymer film, and the surface treatment of the metal tab is required in order to prevent the occurrence of defects such as corrosion or peeling due to stimulation inside and outside the battery in the actual use environment after bonding. The surface treatment technique is a very important technique because it affects the performance such as adhesion strength with the film and electrolyte resistance depending on the physical and chemical resistance of the surface treatment layer of the metal tab.

On the other hand, hexavalent chromium has been used as a material for the conventional surface treatment technique for increasing the bonding strength between the metal tab and the film. However, surfaces coated with hexavalent chromium exhibit excellent bonding strength and electrolyte resistance, while methods of surface treatment using chromium are restricted in their use worldwide due to human health hazards and environmental problems And is used in a limited manner.

In addition, there is an example in which trivalent chromium is used instead of hexavalent chromium. However, there is a risk that trivalent chromium can be oxidized to become hexavalent chromium, and therefore, in the manufacturers of lithium polymer secondary batteries including Europe, . Therefore, development of eco-friendly surface treatment technology without using chromium is an indispensable task according to the demand of the market.

In this regard, Japanese Patent Application No. 2002-216741 discloses a method of coating a surface portion of a lead wire metal (tab) sealed with an insulator with a chemical conversion treatment layer and a method of coating a chromium acid aqueous solution containing a phosphate A common phosphate chromate treatment that chemically produces a film is disclosed. It is also described that a chemical conversion coating is formed by dipping a chemical treatment liquid containing a phenol resin-containing resin and containing a metal salt such as titanium or zirconium. As described above, as a chemical treatment for hydrofluoric acid, a chromium-based chemical conversion treatment is useful and has been used in many fields. However, in the field of environmental pollution, a chrome-free chemical treatment technique is developed in each field, and it is expected that a chromium-free process in the whole chromium will be required in the future.

However, in case of using chrome-free system, the performance is insufficient compared with the case of using chromium. However, there is a continuing need for surface treatment methods that exclude chromium-based materials. In the future, it is necessary to develop excellent surface treatment methods while completely excluding chromium in preparation for the global regulation of chromium materials.

Accordingly, in the present invention, when studying a method of surface treatment of the lead taps using an environmentally friendly method that does not use chromium, in the case where metal oxide is formed on the surface of the lead taps, A surface treatment method was developed, and the chromium-free surface treatment method of the present invention was completed.

Japanese Patent No. 2002-216741

An object of the present invention is to provide a chrome-free surface treatment method of a corrosion-resistant lead tab.

Another object of the present invention is to provide a lead tab surface-treated from the surface treatment method.

In order to achieve the above object,

According to the present invention,

A pretreatment step comprising at least one pretreatment step selected from the group consisting of degreasing, etching, and electrolytic polishing of the metal taps; And

And a step of sealing the metal taps after the pretreatment step.

In addition,

The lead tabs surface-treated from the surface treatment method of the lead tabs are provided.

Further,

And a surface-treated lead tab.

The surface treatment method of the lead tab having improved corrosion resistance according to the present invention has an effect of remarkably improving the bonding strength between the metal tab and the polymer film and has an effect of remarkably improving the service life of the battery. Particularly, the chrome-free surface treatment method has a human-friendly and environmentally friendly characteristic, and thus has an advantageous effect as the most effective alternative to the regulatory policy on the use of chromium.

The chrome-free surface treatment method of the lead taps according to the present invention having improved corrosion resistance can remarkably achieve excellent corrosion resistance without anodizing, so that the process can be relatively simplified and also has a beneficial effect in terms of cost .

1 is a view showing a lithium ion pouch type secondary battery, a lead tab used therein, and a cross-sectional view thereof.
Fig. 2 is a graph showing the electrolyte-adhesive strength (N / 12 mm) of the lead taps prepared in Examples 1-8 in which the process steps are different from each other shown in Table 2. Fig.
FIG. 3 is a graph showing the internal electrolyte adhesive strength (N / 12 mm) of the lead tabs according to the sealing treatment time of the degreasing O-etching O treatment group and the degreasing O-etching X treatment group.
4 shows the electrolyte adhesion strength (N / m 2) of the lead tab of Example 4, which is a degreasing O-etched O-seam (10 min) 12 mm).
FIG. 5 is a graph showing the results of the pretreatment of the degreasing and etching process and the final post-treatment process in the same manner as the sealing treatment, except that only one of the electrolytic polishing and the anodic oxidation process is selectively performed (Examples 5 and 7) (N / 12 mm) of the lead tab in the case where both of the lead tabs (Example 6) or both of the lead tabs were not formed (Example 1).
FIG. 6 is a graph showing the relationship between the resistance to electrolytic solution adhesion of the lead taps and the amount of electrolytic polishing of the lead taps in the case of selectively performing the degreasing and etching treatment and the electrolytic polishing pretreatment step (Example 1 and Example 8) And the strength (N / 12 mm).
FIG. 7 is a graph comparing the adhesion strength (N / 12 mm) of the electrolyte tack in the lead taps according to the presence or absence of the anodizing process and the condition of the sealing process time after degreasing and etching.
FIG. 8 is a photograph of water droplets and a contact angle measured when a metal tap and water are brought into contact with each other according to a control group (all process untreated), Examples 1, 2, 3, 4, 9, 10, It is a table showing the measured contact angle from the instrument.
FIG. 9 is a photograph showing a surface of a metal tab treated with different conditions of time (0 minute, 1 minute, 10 minutes, and 60 minutes) with a degreasing and etching pretreatment process and observation with an optical microscope.

Hereinafter, the present invention will be described in detail.

The following description is provided to assist the understanding of the invention, and the present invention is not limited to the following description.

According to the present invention,

A pretreatment step comprising at least one pretreatment step selected from the group consisting of degreasing, etching, and electrolytic polishing of the metal taps; And

And a step of sealing the metal taps after the pretreatment step.

The lead tab consists of a negative lead (MINUS LEAD) that connects the anode material inside the lithium polymer secondary battery and the outside, and a positive lead (PLUS LEAD) that is connected to the cathode. It is an important part to influence.

At this time, such a lead tab may be formed of a composite of a metal tab and a film (high molecular weight type such as polyolefin). Since the adhesion strength between the film and the metal tab affects the safety of the secondary battery, Is a very important part when considering the stability of the secondary battery.

However, in the prior art, in the surface treatment of metal taps, negative materials such as hexavalent chromium have been used, and means for improving the bonding strength between the metal taps and the film without using chromium are required.

Therefore, in the surface treatment method of the present invention, the surface treatment process of the metal tab is developed so as to improve the bonding strength between the metal tab and the film without using chromium, and in particular, a conventional metal oxide layer is formed, The present invention provides a surface treatment method capable of achieving a superior effect of corrosion resistance (chemical resistance and electrolyte resistance), rather than anodization, rather than forming a metal oxide layer on the surface of the metal tab.

In addition, since the lead taps having better corrosion resistance are provided without the anodic oxidation process, advantages and disadvantages of the conventional anodic oxidation are unexpected in terms of cost and effectiveness of the process itself.

On the other hand, the metal tab includes a metal or an alloy containing one or more metals such as aluminum (Al), nickel (Ni), and copper (Cu).

In one aspect of the present invention, the pretreatment step may include a pretreatment step that may be performed on a metal tap, and may include any pretreatment of a metal tap used in a battery for a secondary battery. Further, Ion batteries, preferably conventional pretreatment processes applied to metal taps used in pouch-type lithium ion batteries.

In one embodiment of the present invention, the pretreatment step may be one or more of pretreatment processes including, but not limited to, degreasing, etching, electrolytic polishing, and the like,

In another embodiment, the pretreatment step may be a pretreatment for degreasing only, a pretreatment for degreasing and etching, or a pretreatment for electrolytic polishing only.

In another embodiment, the pretreatment step may be a pretreatment for degreasing and etching, or a pretreatment for conducting only electrolytic polishing.

In another embodiment, the pretreatment step may be a pretreatment that performs degreasing and etching.

On the other hand, in the following Experimental Examples of the present invention, it has been surprisingly found that the pre-treatment for degreasing and etching, or the electrolytic polishing for selective pretreatment can be superior to the pretreatment for other combinations, It has been experimentally proved that the corrosion resistance of the lead taps finally produced in the pretreatment for degreasing and etching is most favorable.

It should be understood, however, that the above description is to be understood as a description, and the present invention is not limited thereto. Surprisingly, the present invention proves that the sealing process is a crucial factor in the lead tapped surface treatment method other than the pre- , Before the setting of the pretreatment process, the sealing process must be essentially included in the surface treatment method of the lead tab of the present invention.

In one aspect of the present invention, the sealing process may include a sealing process of a metal tab known in the art and may include a sealing process of a metal tab for a secondary cell, and further, It can be understood to include a conventional sealing process to be carried out.

In one aspect of the present invention, the surface treatment method of the present invention essentially includes the step of treating the seals.

In one embodiment of the present invention, the sealing process may be a sealing process that is not particularly timed, but may be a sealing process preferably performed for 1 to 60 minutes, alternatively 1-50 minutes, 1-40 Minute, 1-35 minutes, 2-60 minutes, 5-60 minutes, 5-50 minutes, 5-40 minutes, 5-35 minutes, 5-30 minutes, 3-25 minutes, 5-25 minutes, 5-20 Min, 5-15 minutes, 7-60 minutes, 7-40 minutes, 7-35 minutes, 7-25 minutes, 7-15 minutes, 8-40 minutes, 8-30 minutes, 8-25 minutes, 8-15 Min, 9-35 min, 9-25 min, 9-15 min, 9-11 min, or about 10 min.

In one aspect of the present invention, it has been found that, in the following experimental example, it is surprisingly found that the sealing time can be set differently according to the setting of the pre-treatment process. Particularly during the setting of the pre- The lead tabs having the most remarkable corrosion resistance can be produced in the same manner as in the above-described setting process of the sealing process time or in the sealing process for about 10 minutes. As a result, among the surface treatment methods of chromium- The surface treatment method capable of achieving the corrosion resistance of the lead taps is described above.

Meanwhile, in one aspect of the present invention, the surface treatment method is not limited thereto, but may preferably be a surface treatment method of the lead taps, which does not include an anodizing step.

In one aspect of the invention, the present invention surprisingly provides an alternative to the conventional chromium-using surface treatment method, which, unlike the method of forming a film through anodic oxidation of metal taps, It has been experimentally confirmed that a lead tab having excellent corrosion resistance can be provided.

In one embodiment of the present invention, the surface treatment method of the present invention essentially includes a sealing treatment, and depending on the presence or absence of an anodizing step as shown in the following Experimental Example, in order to achieve an excellent electrolyte- It is preferable to exclude the oxidation process.

However, it is to be understood that the method of surface treatment of the present invention is to selectively exclude the anodic oxidation process and to include the anodic oxidation process, if the sealing process is essentially included.

Meanwhile, in one aspect of the present invention, the sealing process is a conventional sealing process in the art, for example, it can be understood that the sealing process can be used for a lead tab for a secondary battery. Preferably, Any surface treatment that can be applied to a metal tap can be understood to be included in the present invention without limitation.

In one embodiment of the present invention, the sealing treatment may be a sealing treatment using at least one member selected from the group consisting of water, distilled water, boiling water, steam, an inorganic aqueous solution, and an organic aqueous solution.

On the other hand, in one aspect of the present invention, the etching may include all conventional etching processes applied to the field of metal taps, including, for example, alkali etching, acid etching and the like, Etch. ≪ / RTI >

In one embodiment of the invention, it may be preferred that the etching be acid etching using an acidic solution.

On the other hand, in one aspect of the present invention, the electrolytic polishing is a metal polishing using the fact that the minute convex portion on the metal surface of the anode is selectively dissolved in comparison with the other surface portion in the electrolysis, Can be easily applied by the above electrolytic polishing since it is to grind a tab made of a metal material.

At this time, the electrolytic polishing may be performed for 10-200 seconds, 20-150 seconds, 30-150 seconds, or about 120 seconds under a voltage of 3-30 V, 5-15 V, 5-20 V, or about 10 V . If the electrolytic polishing is performed outside the voltage and time conditions, the adhesion strength between the metal tab and the film may be deteriorated.

Meanwhile, in one aspect of the present invention, it may be desirable to exclude the anodization process. For example, if the anodization process is included in the surface treatment method of the present invention, A current is applied to the object as an anode, and an oxide film is formed on the anode surface by oxygen generated from the anode. A metal oxide is formed on the surface of the metal tab in consideration that the metal tab constituting the lead tab can be applied as the anode of the anodizing process.

In one embodiment of the invention, the anodizing process is performed under conditions of 10-80 V, 20-80 V, 30-70 V, or about 40 V, for 30-200 seconds, 50-200 seconds, 100-180 seconds, 150 seconds. ≪ / RTI >

If the anodic oxidation process is performed outside the voltage and time conditions, the adhesion strength between the metal tab and the film may be deteriorated.

It is to be understood that, in one aspect of the present invention, the foregoing description should be construed as illustrative of the possible scope of the invention, and that ordinary skill in the art will recognize, It is to be understood that the invention is not limited to the specifically disclosed embodiments.

In another aspect of the present invention, based on the effects shown in Experimental Examples 1-3 below, the surface treatment method of the present invention can be set most suitably or can be changed on the basis thereof, and in particular, surprisingly, It is considered that the conventional anodic oxidation is considered to be an all-chromium-free chromium-free surface treatment method, and the corrosion resistance of the lead taps is improved rather than expected, and furthermore, the surface treatment Among the methods, it has been confirmed that the corrosion resistance of the lead taps is improved by setting the pretreatment for degreasing and etching, or the pretreatment for electrolytic polishing, particularly in processes such as degreasing, etching, electropolishing and the like belonging to the pretreatment step, And it was confirmed that lead tabs having the best corrosion resistance were produced by pretreatment with only etching. On the other hand, the surface treatment method of the lead taps according to the present invention includes the sealing treatment as essential, and it has been confirmed that the corrosion resistance of the lead taps is improved according to the setting of the sealing treatment time. A processing method is provided.

Therefore, it can be understood that the surface treatment method of the lead taps identified in the present invention was unpredictable from the prior art and known effects, and that it was difficult to derive.

According to another aspect of the present invention, there is provided a method of surface treating a metal tab, And

And adhering the surface treated metal to the polymer film. The present invention also provides a method of manufacturing a lead tab having improved corrosion resistance.

In one aspect of the present invention, the surface treatment method and the metal tab are as described above, while the polymer film is generally included in a polymer that can be adhered to a tap without limitation, Or an adhesive polymer used for a lead tab for a secondary cell, preferably an adhesive polymer in a pouch type lithium ion battery.

Considering that the present invention relates to a surface treatment method of a metal tab among the lead taps to be provided in the present invention, it is preferable that the surface-treated metal tab and the adhesion of the surface treated with the surface treatment method of the present invention described above, Polymer electrolyte membrane can be used as the above polymer film without limitation as long as it can be used in a direction in which the electrolytic solution resistance is achieved, and a polypropylene (PP) film can be used as in the following experimental example.

Further, the present invention provides a lead tab manufactured from the method of manufacturing the lead tab.

The present invention also provides a lithium secondary battery including the lead tab.

In one aspect of the present invention, the lead taps and the rechargeable batteries or the lithium secondary batteries or the pouch type lithium secondary batteries comprising the lead taps include lead taps having improved corrosion resistance by the surface treatment method of the present invention described above, The field technology can achieve the desired excellent function and effect.

In one embodiment of the present invention, the lead taps have a resistance value of 5 N / 12 mm or more, 10 N / 12 mm or more, 11 N / 12 mm or more, or 15 N / It was confirmed that the surface treatment method of the present invention can provide a more excellent lead tab compared with the conventional surface treatment method using chromium. Further, in recent years, It has been experimentally proved that remarkably excellent corrosion resistance is achieved compared to the conventional surface treatment method using anodic oxidation, which has been proposed as a general alternative to the chromium surface treatment method but has not yet achieved the desired level of corrosion resistance. The surface treatment method of the present invention, The lead tab provided is one of the best techniques for chromium-free surface treatment to date.

Hereinafter, the present invention is described in detail by way of Production Examples, Examples and Experimental Examples.

However, the following Production Examples, Examples and Experimental Examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following Production Examples, Examples and Experimental Examples.

≪ Preparation Example > Preparation of lead tab

The information of the metal tab and the polymeric film material used in the lead tab of the present invention is shown in Table 1 below and the steps 1 to 5 shown in Table 2 were selectively performed to obtain the lead tabs of Examples 1-15 of the present invention Respectively.

Kinds Rating standard Metal tap Al (aluminum) A1050 60 (width) X 37 (length) X 0.3 (thickness) mm Polymer film PP (polypropylene) - 12 (width) X 0.1 (thickness) mm

fair process
Degreasing solution 5% Na ₂ SiO ₃ Temperature 45 ° C time 30 seconds Rinse with Kim Tech with a degreasing liquid -> Wash 2 times
etching solution 1M H ₂ SO ₄ Temperature 24 ℃ time 30 seconds Rinse with Kim Tech with Etchant -> Wash 2 times
Electrolytic polishing solution HClO ₄ : EtOH = 1: 4 Voltage 10 V time 120 seconds SuSe 2 times
Anodic oxidation solution 0.3 M oxalic acid Voltage 40 V time 150 seconds SuSe 2 times
Sealing solution Distilled water Temperature 80 ℃ time 10 minutes SuSe 2 times adhesion
Tap jig temperature / film jig temperature 148 ° C / 145 ° C Tap Adhesion Time / Film Adhesion Time 40 seconds / 9 seconds

The steps of each step of Table 2 were carried out as follows:

1. Degreasing

(1) The aluminum metal tab was immersed in a solution of 5% Na ₂ SiO ₃ (sodium silicate, sodium silicate) at 45 ° C for 30 seconds.

(2) Then, the aluminum metal tab was taken out and rubbed with a Kim Tech Science wiper impregnated with the degreasing solution.

(3) Thereafter, washing with water was carried out twice.

2. Etching

(1) An aluminum metal tap was immersed in a 1M H ₂ SO ₄ (sulfuric acid) solution at 24 ° C for 30 seconds.

(2) Then, the aluminum metal tab was taken out and rubbed with a Kim Tech Science wiper impregnated with the etching solution.

(3) Thereafter, washing with water was carried out twice.

3. electrolytic polishing

(1) An aluminum metal tab was fixed to a Teflon cell and prepared as a working electrode.

(2) A graphite rod was prepared as a reference and counter electrode.

(3) A solution of perchloric acid: ethanol (HClO ₄ : EtOH) = 1: 4 was prepared as an electrolytic polishing solution.

(4) The prepared graphite rod and the aluminum metal tab were immersed in the electrolytic polishing solution.

(5) After connecting the graphite rod and the aluminum metal tap to the DC power supply, the reaction was carried out at a voltage of 10 V for 120 seconds.

(DC power supply: EX 2500 Series Programmable SMPS, EX 100V-24A, manufacturer: ODA Technological Co., Ltd.)

(6) Thereafter, washing with water was carried out twice.

4. Anodic oxidation

(1) An aluminum metal tab was fixed to a Teflon cell and prepared as a working electrode.

(2) A graphite rod was prepared as a reference and counter electrode.

(3) A 0.3M oxalic acid solution was prepared as an anodic oxidation solution.

(4) The prepared graphite rod and aluminum metal taps were immersed in the anodizing solution.

(5) After the graphite rod and the aluminum metal tap were connected to the DC power supply, the reaction was carried out at a voltage of 40 V for 150 seconds.

(DC power supply: EX 2500 Series Programmable SMPS, EX 100V-24A, manufacturer: ODA Technological Co., Ltd.)

(6) Thereafter, washing with water was carried out twice.

5. Sealing

(1) An aluminum metal tap was immersed in distilled water (hot water) at 80 DEG C for a predetermined time. Here, the predetermined time was set to 0 to 60 minutes in accordance with the different process conditions of Examples 1-15 below.

(2) Thereafter, washing with water was carried out twice.

6. Adhesion

(1) A polypropylene film (12 mm X 0.1 T) was placed on an aluminum metal tap, followed by heat sealing.

(2) At this time, the temperature of the tab jig at the time of adhesion was set at 148 占 폚, the temperature of the film jig was set at 145 占 폚, the tapping time was 40 seconds, and the film was adhering for 9 seconds.

≪ Example 1 > Tap surface treatment of lead tab 1

The lead tapped surface treatment of Example 1 was carried out in the order of degreasing, etching, sealing, and bonding without performing the electrolytic polishing and anodizing steps, The lead tabs were prepared,

Here, the sealing step was performed by immersing an aluminum metal tap in distilled water (hot water) at 80 DEG C for 10 minutes.

Example 2: Tab surface treatment of lead tab 2

The lead tapped surface treatment of Example 2 was carried out in the order of degreasing, etching, and adhesion without performing the electrolytic polishing, anodizing, and pouring steps as described in Preparation Example 2 and described above, And a lead tab was prepared.

Example 3: Tab surface treatment of lead tab 3

The lead tapped surface treatment of Example 3 was carried out in the order of the preparation example 2 and the description, but without performing the etching, electrolytic polishing, anodizing and sealing processes, degreasing, and adhesion in this order, And a lead tab was prepared.

Example 4 Tab surface treatment of lead tabs 4

The lead tapped surface treatment of Example 4 was carried out in the order of degreasing, sealing and bonding without performing the etching, electrolytic polishing, and anodizing steps as described in Production Example Table 2 and described above, The lead tabs were prepared,

Here, the sealing step was performed by immersing an aluminum metal tap in distilled water (hot water) at 80 DEG C for 10 minutes.

Example 5: Tab surface treatment of lead tabs 5

The lead tapped surface treatment of Example 5 was carried out in the same manner as described in Preparation Example 2, and without performing the anodizing process, in the order of degreasing, etching, electrolytic polishing, The lead tabs were prepared,

Here, the sealing step was performed by immersing an aluminum metal tap in distilled water (hot water) at 80 DEG C for 10 minutes.

<Example 6> Tab surface treatment of lead tabs 6

The lead tapped surface treatment of Example 6 was carried out in the order of degreasing, etching, electrolytic polishing, anodizing, sealing, and bonding in the same manner as described in Production Example 2 and described above, Tap,

Here, the sealing step was performed by immersing an aluminum metal tap in distilled water (hot water) at 80 DEG C for 10 minutes.

<Example 7> Tab surface treatment of lead tab 7

The lead tapped surface treatment of Example 7 was carried out in the same manner as described in Preparation Example 2, but without performing the electrolytic polishing step, in the order of degreasing, etching, anodizing, The lead tabs were prepared,

Here, the sealing step was performed by immersing an aluminum metal tap in distilled water (hot water) at 80 DEG C for 10 minutes.

<Example 8> Tab surface treatment of lead tabs 8

The lead tapped surface treatment of Example 8 was carried out in the order of electrolytic polishing, sealing, and bonding, without performing degreasing, etching, and anodizing, The lead tab was prepared,

Here, the sealing step was performed by immersing an aluminum metal tap in distilled water (hot water) at 80 DEG C for 10 minutes.

<Example 9> Tab surface treatment of lead tab 9

The aluminum metal taps were surface-treated in the same manner as in Example 1 except that the time of the piercing step was set to 1 minute to prepare lead taps.

<Example 10> Tab surface treatment of lead tab 10

The aluminum metal taps were surface-treated in the same manner as in Example 1 except that the time of the piercing step was set to 60 minutes to prepare lead taps.

Example 11: Tab surface treatment of lead tabs 11

The aluminum metal taps were surface-treated in the same manner as in Example 4 except that the time of the piercing step was set to 1 minute to prepare lead taps.

<Example 12> Tab surface treatment of lead tabs 12

The aluminum metal taps were surface-treated in the same manner as in Example 4 except that the time of the piercing step was set to 60 minutes to prepare lead taps.

&Lt; Example 13 > Tap surface treatment of lead tab 13

The aluminum metal taps were surface-treated in the same manner as in Example 7 except that the time of the piercing step was set to 20 minutes to prepare lead taps.

Example 14 Tab Surface Surface Treatment of Lead Tab 14

The aluminum metal taps were surface-treated in the same manner as in Example 7 except that the time of the piercing step was set to 40 minutes to prepare lead taps.

&Lt; Example 15 > Surface treatment of the tab surface of the lead tab 15

The aluminum metal taps were surface-treated in the same manner as in Example 7 except that the time of the piercing step was set to 60 minutes to prepare lead taps.

The surface treatment processes of the lead tabs prepared in Examples 1-15 are shown in Table 3 below.

Example Degreasing etching Electrolytic polishing Anodic oxidation Seonggong adhesion One O O X X O
(10 minutes) O 2 O O X X X O 3 O X X X X O 4 O X X X O
(10 minutes) O 5 O O O X O
(10 minutes) O 6 O O O O O
(10 minutes) O 7 O O X O O
(10 minutes) O 8 X X O X O
(10 minutes) O 9 O O X X O
(1 minute) O 10 O O X X O
(60 minutes) O 11 O X X X O
(1 minute) O 12 O X X X O
(60 minutes) O 13 O O X O O
(20 minutes) O 14 O O X O O
(40 minutes) O 15 O O X O O
(60 minutes) O

Experimental Example 1 Evaluation of corrosion resistance of lead tab

In order to evaluate the corrosion resistance (chemical resistance, electrolyte resistance) of the lead tab of the present invention, the following experiment was conducted.

Specifically, the electrolyte tack strength of the lead taps of Examples 1-15 manufactured by the above different surface treatment methods was measured, and the corrosion resistance of the lead taps of the present invention was evaluated.

The experiments were carried out in the following order:

(1) First, the lead tabs of Examples 1-15 were immersed in a PP bottle containing an electrolyte, and then stored at 85 DEG C for 24 hours.

(2) After 24 hours, the lead tab was taken out of the electrolytic solution, washed with distilled water, and then wiped with a Kim Tech Science wiper.

(3) Thereafter, the lead tab was dried at room temperature for 15 minutes.

(4) The film of the lead tab was peeled 1 cm.

(5) The film and tab portions were fixed to UTM at 180 °, and then the adhesive strength was measured. Here, the UTM speed was set at 20 mm / min.

(6) The average adhesive strength (N / 12 mm) of the section where the adhesive strength was constant was recorded.

The data of each experimental result obtained from the above-mentioned experiment are shown in Table 4 below.

Example Adhesion strength of electrolyte
(N / 12 mm) One 16.9 2 0 3 0 4 11.0 5 11.3 6 6.4 7 7.9 8 14.2 9 13.0 10 13.3 11 4.7 12 14.1 13 9.0 14 10.2 15 12.4

As shown in Table 4, it was confirmed that the bonding strength of the lead tab of the present invention was remarkably increased especially when the sealing process was performed for at least 1 minute, and most preferably, After the pretreatment, when the sealing treatment was performed for 10 minutes without electrolytic polishing and anodic oxidation, the maximum bonding strength of 16.4 N / 12 mm was confirmed.

<1-1> Evaluation of adhesion strength of electrolytic solution with and without sealing process

Particularly, in order to evaluate the effect on the corrosion resistance of the lead taps depending on whether or not the sealing process was carried out, Examples 1 and 2 were compared, and Examples 3 and 4 were compared and evaluated.

fair Example 1 Example 2 Example 3 Example 4 Degreasing O O etching O X Electrolytic polishing X X Anodic oxidation X X Seonggong O
(10 minutes) X X O
(10 minutes) Electrolytic solution resistance
Adhesive strength
(N / 12 mm)
16.9
0
0
11.0

As shown in Table 5, in Examples 1 and 2, surface treatment of the same process was performed except that the sealing treatment was performed for 10 minutes. However, in Example 2 in which no sealing treatment was performed, The result was 0 N / 12 mm.

The comparison of Examples 3 and 4 also showed that the surface treatment of the same process was performed except that the sealing treatment was performed for 10 minutes. However, in the case of Example 3 in which no sealing treatment was performed, N / 12mm.

Therefore, in the surface treatment process of the lead tab of the present invention, it has been found that the sealing process must be performed in order to manufacture the lead tab having corrosion resistance. Particularly, It is possible to replace the surface treatment method using chromium, and it has been confirmed that very remarkable corrosion resistance is achieved.

<1-2> Evaluation of Adhesion Strength of Electrolyte Liquid by Pre-Sealing Process

On the other hand, in order to evaluate the electrolyte resistance of the lead taps according to the present invention depending on the selection and execution of the degreasing, etching, electrolytic polishing, and anodizing process in the process before the sealing process, Tap adhesion strength of the electrolyte.

fair Example 1 Example 4 Example 5 Example 6 Example 7 Example 8 Degreasing O O O O O X etching O X O O O X Electrolytic polishing X X O O X O Anodic oxidation X X X O O X Seonggong O
(10 minutes) Electrolytic solution resistance
Adhesive strength
(N / 12 mm)
16.9
11.0
11.3
6.4
7.9
14.2

As shown in Table 6, all of the surface treatment methods of Examples 1 and 4-8 performed the same sealing treatment for 10 minutes in the same manner, except that the performances of degreasing, etching, electrolytic polishing, and anodizing were set differently As a result, when the anodic oxidation was carried out (Examples 6 and 7), the electrolyte adhesion strength tended to be lowered. On the contrary, in the case where the anodic oxidation was not carried out, all of the improved electrolyte- Strength appeared.

On the other hand, in the comparison of the examples in which the anodic oxidation was not carried out, the degreasing and etching (Example 1) and the etching (etching) were performed rather than the degreasing, etching and electrolytic polishing steps (Example 5) Or the electrolytic polishing (Example 8) was carried out, the more improved the liquid electrolyte adhesion strength was.

Therefore, it can be seen that the method of surface treatment of the lead taps according to the present invention can provide a lead tab with improved corrosion resistance, which is required to perform the sealing process, and is selected by performing degreasing and etching or electropolishing in the pretreatment process .

&Lt; 1-3 > Evaluation of Adhesion Strength of Electrolytic Solution according to Sealing Time

From the results of the above-mentioned < 1-1 > and < 1-2 >, it can be understood that the lead tapped surface treatment method of the present invention requires sealing treatment, It is most preferable to carry out the above-

On the other hand, in performing the sealing process, in order to evaluate the change in the adhesive strength of the electrolytic solution according to the treatment time, the sealing treatment was carried out at 0 minute, 1 minute, 10 minutes and 60 minutes in Examples 2, 9, The results of the treatments were compared, and the results of sealing treatment in Examples 3, 11, 4 and 12 at 0 minute, 1 minute, 10 minutes and 60 minutes were compared.

fair Example 2 Example 9 Example 1 Example 10 Example 3 Example 11 Example 4 Example 12 Degreasing O O etching O X Electrolytic polishing X X Anodic oxidation X X Seonggong 0 One 10 60 0 One 10 60 Electrolytic solution resistance
Adhesive strength
(N / 12 mm)
0
13.0
16.9
13.3
0
4.7
11.0
14.1

As shown in Table 7, the same surface treatment processes were carried out in Examples 2, 9, 1, and 10, respectively, except that the sealing time was different. As a result, It was surprisingly found that the sealing treatment time tended to be excellent in a specific range. Most preferably, when the sealing treatment was set to 10 minutes as in Example 1 And the most excellent electrolyte adhesive strength appeared.

Therefore, when degreasing and etching are performed in the pretreatment process, when the setting of the sealing process time is carried out in the range described in the present specification based on about 10 minutes or 10 minutes, the remarkable corrosion resistance It was found that there was an amazing effect achieved.

On the other hand, when degreasing was performed only in the pretreatment process, the adhesive strength of the electrolytic solution was also increased as the sealing time increased, and the strength increased rapidly until 10 minutes of sealing, A strength increase was confirmed.

Therefore, from the results of the above-mentioned <1-1>, <1-2>, and <1-3>, it can be understood from the results of the analysis of the surface treatment of the lead taps according to the present invention that, in order to improve the corrosion resistance, And most preferably degreasing and etching, whilst the time setting of the sealing process is set to the time range set forth herein on a 10 or 10 minute basis It has been found that the present invention can provide a chrome-free surface treatment method of lead taps having improved corrosion resistance, since lead tabs are provided in which unexpectedly high corrosion resistance is achieved.

&Lt; 1-4 > Evaluation of adhesion strength of electrolytic solution with time of sealing process 2

On the other hand, it was found that it is preferable not to perform anodization in the pretreatment process from the above <1-2>. In order to examine the change of the electrolyte adhesion strength even in the case of anodization, , 14, and 15 were compared.

fair Example 7 Example 13 Example 14 Example 15 Degreasing O etching O Electrolytic polishing X Anodic oxidation O Seonggong 10 20 40 60 Electrolytic solution resistance
Adhesive strength
(N / 12 mm)
7.9
9.0
10.2
12.4

As shown in Table 8, even when an anodizing treatment not preferred is performed, the electrolyte-based adhesive strength tends to increase with an increase in the sealing time.

The achievement of the remarkable corrosion resistance improvement achieved from the setting of the seaweed treatment time in the range described herein on the basis of 10 minutes or 10 minutes, even when looking from there, especially when degreasing and etching are carried out in the pretreatment process, I could see that it was not in the time range.

Accordingly, the chrome-free surface treatment method of the lead taps according to the present invention is characterized in that a sealing treatment is essentially performed, but not anodic oxidation but a degreasing and etching or electrolytic polishing in the pretreatment step, and most preferably degreasing and etching While surprisingly the time setting of the sealing process is set to the time range set forth herein on a 10 minute or 10 minute basis, a lead tab can be provided in which an unexpectedly significant corrosion resistance is achieved.

&Lt; Experimental Example 2 > Evaluation of tap metal surface characteristics of lead taps

In order to evaluate the surface characteristics of the lead tab of the present invention, the contact angle of water on the surface of the tap metal was measured.

Specifically, the experiments were carried out using the contact angle measuring instrument (Model: PHOENIX-300 TOUCH, manufactured by SEIKO CORPORATION, contact angle measurement range: 0 to 180 degrees, accuracy: 0.1 degree or more) 5 μL of distilled water was dropped on the aluminum metal tap surface of the untreated test group, and the contact angle was measured. The results are shown in FIG.

Referring to FIG. 8, in the case of the metal untreated test group, the contact angle is about 65 degrees, and lipophilic surface characteristics can be confirmed.

On the other hand, when the sealing process is performed for one minute or more, it can be confirmed that the surface of the aluminum metal tab is modified to have a hydrophilic property at a level at which the contact angle can not be measured.

On the other hand, in the case of Example 3 in which only degreasing is performed, a shape in which the organic substance is removed from the metal surface to lower the contact angle can be observed.

On the other hand, in the case of Example 2 in which only degreasing and etching were performed, organic matter was enhanced on the metal surface through degreasing, but the contact angle again increased through etching.

<Experimental Example 3> Optical microscope observation of the tap metal surface of the lead tab

In order to observe the surface of the metal tab portion of the lead tab of the present invention according to the processing process, it was observed with an optical microscope.

Specifically, when degreasing and etching were performed only in the pretreatment of Examples 2, 9, 1, and 10, and the sealing process was performed at 0 minute, 1 minute, 10 minutes, and 60 minutes, respectively, Were observed under an optical microscope, and the results are shown in Fig.

9, it is observed that the convex points increase on the surface of the metal tab when the sealing process is performed even for 1 minute, and when the sealing time is prolonged from 1 minute to 10 minutes, However, it was difficult to see a specific trend when the length of the sealing process from 10 minutes to 60 minutes was long, because the number of points was similar to the number of the points.

On the other hand, referring to the results of Experimental Example 1 described above, the results of Experimental Example 3 show that, in particular, only degreasing and etching are most preferably performed by the pretreatment, and the sealing treatment is performed for 10 minutes or 10 minutes The adhesive force is improved from the interaction between the convex points suitably formed by the sealing process in the time range and the plastic insulating film, and the adhesive strength of the electrolyte in the lead tab is increased Was increased.

Therefore, the chromeless surface treatment method of the lead taps having improved corrosion resistance, which is clarified by the present invention, is advantageous in that when the degreasing, etching, electropolishing, or degreasing and etching are preferably performed in the pretreatment step, Since the specification is made within one time range, an unexpected optimization of the lead tab corrosion resistance improvement is confirmed, so that the lead tab with the most excellent corrosion resistance can be provided.

Meanwhile, the present invention is an eco-friendly surface treatment technology that can replace the trivalent chromium having the environmental risk, which is the most important issue in the related art, and it can be understood that it is a useful invention that can cope with the regulation policy on the use of chromium.

Claims (10)

A pretreatment step comprising at least one pretreatment step selected from the group consisting of degreasing, etching, and electrolytic polishing of the metal taps; And
And a step of sealing the metal taps without the anodizing step after the pretreatment step.
The method according to claim 1,
Wherein the sealing treatment is performed for 1 minute to 60 minutes.
The method according to claim 1,
Wherein the pretreatment is a pre-treatment for degreasing and etching, or a pretreatment for electrolytic polishing.
delete The method according to claim 1,
Wherein the sealing treatment is carried out using at least one selected from the group consisting of water, distilled water, boiling water, water vapor, an inorganic aqueous solution, and an organic aqueous solution.
The method according to claim 1,
Wherein the etching is an acid etching using an acidic solution.
The method according to claim 1,
Wherein the metal tab comprises a metal or an alloy including at least one selected from the group consisting of aluminum, nickel, and copper.
According to the surface treatment method of claim 1, the surface treatment of the metal tab is carried out. And
And bonding the surface treated metal and the polymer film to each other.
A lead tab produced from the manufacturing method of claim 7.
A lithium secondary battery comprising the lead tab of claim 9.

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