KR102485283B1 - Pouch exterior for battery and method for preparing the same - Google Patents

Abstract

The present invention sealant layer; base layer; a surface-modified aluminum thin film disposed between the sealant layer and the substrate layer; An adhesive layer disposed between at least one of the surface-modified aluminum thin film and the sealant layer or between the surface-modified aluminum thin film and the substrate layer, wherein the peel strength of the surface-modified aluminum thin film is 900 gf / inch to 1200 gf / inch, it relates to a pouch case for a battery and a manufacturing method thereof.

Description

Battery pouch exterior material and manufacturing method of the battery pouch exterior material {POUCH EXTERIOR FOR BATTERY AND METHOD FOR PREPARING THE SAME}

The present invention sealant layer; base layer; a surface-modified aluminum thin film disposed between the sealant layer and the substrate layer; and an adhesive layer disposed between at least one of the surface-modified aluminum thin film and the sealant layer and between the surface-modified aluminum thin film and the base layer, wherein the peel strength of the surface-modified aluminum thin film of 900 gf/inch to 1200 gf/inch, a pouch case for a battery, and a method for manufacturing the pouch case for a battery.

Recently, as technology development and demand for mobile devices increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, various studies on batteries that can meet various needs are being conducted.

In this regard, various types of batteries have been developed, but in all batteries, an exterior material for sealing battery elements such as an electrode assembly and an electrolyte is necessarily required.

Recently, an exterior material including a substrate layer, a metal layer, and a sealant layer has been used as an exterior material that is easy to process and lightweight. Furthermore, a technique for maintaining adhesion between the metal layer, the base layer, and the sealant layer by disposing an adhesive layer between the metal layer and the base layer or between the metal layer and the sealant layer has been introduced.

However, when using a metal layer that has not undergone a separate process, there is a problem in that peeling between the base layer and the metal layer or between the sealant layer and the metal layer frequently occurs. Conventionally, a technique of phosphate-chromonate treatment of the surface of the metal layer has been used to solve this problem, but the phosphate-chromate treatment is harmful to the environment and causes an excessive increase in production cost. Furthermore, even by the above treatment, the desired level of adhesive force cannot be derived.

Alternatively, there is a technique of immersing the metal layer in water and then applying an electric current to the metal layer or water to modify the surface of the metal layer. However, since the surface of the metal layer is not uniformly modified according to the above technique, a desired level of adhesive strength is still not obtained. Furthermore, a separate process of applying current is required, and the time required for surface modification is long, resulting in poor processability.

Therefore, in the present invention, it is intended to introduce a battery pouch exterior material that can have sufficient adhesive strength between a metal layer and a substrate layer and/or between a metal layer and a sealant layer and has excellent manufacturing processability and a manufacturing method thereof.

An object of the present invention is to provide a battery pouch case that can have sufficient adhesion between a metal layer and a substrate layer and/or between a metal layer and a sealant layer, and has excellent manufacturing processability and a manufacturing method thereof.

According to one embodiment of the present invention, the sealant layer; base layer; a surface-modified aluminum thin film disposed between the sealant layer and the substrate layer; and an adhesive layer disposed between at least one of the surface-modified aluminum thin film and the sealant layer and between the surface-modified aluminum thin film and the base layer, wherein the peel strength of the surface-modified aluminum thin film Is 900gf / inch to 1200gf / inch, a pouch case for a battery is provided.

In addition, according to another embodiment of the present invention, preparing an alkaline aqueous solution; Forming a surface-modified aluminum thin film by immersing the aluminum thin film in the alkaline aqueous solution for 65 seconds to 85 seconds; and drying the surface-modified aluminum thin film; wherein, in the preparing of the alkaline aqueous solution, the temperature of the alkaline aqueous solution is 55° C. or higher, the pH of the alkaline aqueous solution is 10 or higher, and the surface modification The forming of the aluminum thin film is provided with a method for manufacturing a battery pouch case that does not include supplying an external current to at least one of the aluminum thin film and the alkaline aqueous solution.

According to the present invention, there are a plurality of pores uniformly distributed on the surface of the aluminum thin film, and the pores are formed to an appropriate depth in the thickness direction of the aluminum thin film. Accordingly, it is possible to have sufficient adhesion between the surface-modified aluminum thin film and the substrate layer and/or between the surface-modified aluminum thin film and the sealant layer. In addition, manufacturing of the surface-modified aluminum thin film is simplified, process time can be saved, and processability can be improved.

1 is a graph showing the surface modification rate of an aluminum thin film according to the pH of an alkaline aqueous solution.
2 is a graph showing the surface modification time of an aluminum thin film according to the temperature of an alkaline aqueous solution.
3 is a graph showing the surface modification rate of an aluminum thin film according to the temperature of an alkaline aqueous solution.
Figure 4 is a photograph showing the result of modifying the surface of the aluminum thin film in the method of manufacturing a pouch case for a battery according to an embodiment of the present invention.
5 is a SEM photograph of each of Sample F-1, Sample G-1, and Sample G-2.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention. At this time, the terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor appropriately defines the concept of terms in order to explain his/her invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

<Battery Pouch Exterior Material>

A battery pouch exterior material according to an embodiment of the present invention includes a sealant layer; base layer; a surface-modified aluminum thin film disposed between the sealant layer and the substrate layer; and an adhesive layer disposed between at least one of the surface-modified aluminum thin film and the sealant layer and between the surface-modified aluminum thin film and the base layer, wherein the peel strength of the surface-modified aluminum thin film May be 900gf / inch to 1200gf / inch.

The battery pouch exterior may include a substrate layer, a sealant layer, an adhesive layer, and a surface-modified aluminum thin film.

The base layer is located on the outermost layer of the battery pouch case, protects the battery from friction and collision with the outside, and at the same time serves to electrically insulate the electrode assembly from the outside. Here, the outermost layer means a direction toward the outside in a direction opposite to the direction in which the electrode assembly is located based on the surface-modified aluminum thin film.

The base layer may include a polymer, and may be specifically made of a polymer. Although not necessarily limited thereto, the polymer is polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, It may include at least one material selected from the group consisting of polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. In particular, a polymer such as nylon resin or polyethylene terephthalate (PET) having wear resistance and heat resistance is mainly used for the base layer. Further, the base layer may have a single film structure made of any one material or a composite film structure formed by forming two or more materials, respectively.

The sealant layer may be positioned on the innermost layer of the battery pouch exterior material. The sealant layer may directly contact the electrode assembly. The battery pouch casing is manufactured by drawing and molding a laminated casing film using a punch or the like, and forming a cup portion including a bag-shaped accommodation space by stretching a portion thereof. Then, when the electrode assembly is accommodated in the accommodation space, the electrolyte is injected. Thereafter, the sealant layers are bonded to each other in the process of sealing the battery pouch exterior material. At this time, since the sealant layer directly contacts the electrode assembly, it should have insulating properties, and since it also contacts the electrolyte, it should have corrosion resistance. In addition, since the inside must be completely sealed to block the movement of materials between the inside and outside, it must have high sealing performance. That is, the portion where the sealant layers are adhered to each other must have excellent thermal bonding strength.

Although not necessarily limited thereto, the sealant layer is polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester , polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fibers may include one or more materials selected from the group consisting of. In particular, a polyolefin-based resin such as polypropylene (PP) or polyethylene (PE) may be used as the sealant layer. Polypropylene (PP) has excellent mechanical properties such as tensile strength, rigidity, surface hardness, abrasion resistance, and heat resistance, and chemical properties such as corrosion resistance, and is mainly used to prepare the sealant layer. Furthermore, the sealant layer may be composed of unstretched polypropylene (Cated Polypropylene) or a polypropylene-butylene-ethylene terpolymer. In addition, the sealant layer may have a single film structure made of any one material or a composite film structure formed by forming two or more materials, respectively.

The adhesive layer may be disposed at least one of between the surface-modified aluminum thin film and the sealant layer and between the surface-modified aluminum thin film and the base layer. The adhesive layer serves to enable adhesion between the substrate layer and the surface-modified aluminum thin film and/or adhesion between the sealant layer and the surface-modified aluminum thin film.

The adhesive layer includes an adhesive material. The adhesive material may include an acrylic polymer, a urethane polymer, an epoxy polymer, a polyolefin polymer, a rubber polymer, a silicone polymer, and the like.

The surface-modified aluminum thin film serves to secure the mechanical strength of the battery pouch exterior material, block the entry and exit of gas or moisture outside the battery, and prevent leakage of the electrolyte solution.

The surface-modified aluminum thin film may be formed by oxidizing the surface of the aluminum thin film. Accordingly, the surface of the surface-modified aluminum thin film includes a roughened surface (see FIG. 4).

The surface-modified aluminum thin film may include a plurality of pores. The pores may be distributed from the surface of the surface-modified aluminum thin film to 20 nm to 500 nm in the thickness direction of the surface-modified aluminum thin film, and may be specifically distributed to 30 nm to 300 nm. Here, the thickness direction is a direction perpendicular to the surface and toward the inside of the surface-modified aluminum thin film. When the above range is satisfied, the interface between the surface of the surface-modified aluminum thin film and the adhesive layer is present in a sufficient area, so that separation between the surface-modified aluminum thin film and the sealant layer and between the surface-modified aluminum thin film and the substrate layer occurs. can be effectively suppressed.

When the surface of the surface-modified aluminum thin film is checked through SEM, it can be seen that a plurality of pores formed in the thickness direction of the surface-modified aluminum thin film are uniformly distributed from the surface of the surface-modified aluminum thin film as shown in FIG. there is. Specifically, it can be seen that the pores are not formed only in the thickness direction on the surface of the surface-modified aluminum thin film, but are formed while being bent according to the thickness of the surface-modified aluminum thin film. That is, when viewed three-dimensionally, it can be thought of as a shape in which aluminum layers in a mesh shape are overlapped in a form that is not interlocked little by little. Accordingly, since the adhesive layer can be firmly bonded to the surface-modified aluminum thin film, peeling between the surface-modified aluminum thin film and the sealant layer and between the surface-modified aluminum thin film and the base layer can be effectively suppressed. .

The peel strength of the surface-modified aluminum thin film may be 900 gf/inch to 1200 gf/inch, specifically 950 gf/inch to 1200 gf/inch, and more specifically 1000 gf/inch to 1200 gf/inch. When the peel strength is less than 900 gf/inch, peeling between the surface-modified aluminum thin film and the sealant layer and between the surface-modified aluminum thin film and the base layer cannot be suppressed. When the peel strength is 1200 gf/inch or more, the process for achieving the peel strength takes too much time, resulting in a decrease in productivity.

The peel strength is significantly higher than that of an aluminum thin film that is not surface-modified or an aluminum thin film that is surface-modified by a conventional method (eg, anodizing). This is because, when the surface of the aluminum thin film is modified according to the present invention, uniform pores are formed as described above.

The peel strength evaluation may be performed through the tape in the following manner. TAXT plus texture analyzer (3M, Scotch ® Transparent Tape) was used. After attaching the tape (width 1 inch) to the fixed surface-modified aluminum thin film, pulling at 180° (horizontal direction) at a speed of 5 mm/sec to measure the peeling strength of the tape.

<Method of manufacturing battery pouch exterior material>

A method for manufacturing a battery pouch case according to another embodiment of the present invention includes preparing an alkaline aqueous solution; Forming a surface-modified aluminum thin film by immersing the aluminum thin film in the alkaline aqueous solution for 65 seconds to 85 seconds; and drying the surface-modified aluminum thin film; wherein, in the preparing of the alkaline aqueous solution, the temperature of the alkaline aqueous solution is 55° C. or higher, the pH of the alkaline aqueous solution is 10 or higher, and the surface modification The forming of the aluminum thin film does not include supplying an external current to at least one of the aluminum thin film and the alkaline aqueous solution.

Preparing the alkaline aqueous solution may include mixing a basic material with deionized water. Specifically, the step may include adding at least one of NaOH and KOH to deionized water. Accordingly, the pH of the alkaline aqueous solution can be adjusted to a desired level.

The pH of the alkaline aqueous solution may be 10 or more, specifically 10 to 13, and more specifically 11 to 13. When the pH of the alkaline aqueous solution is less than 10, since the surface modification of the aluminum thin film proceeds at an excessively slow rate, processability is rapidly inhibited. In other words, by adjusting the pH of the alkaline aqueous solution, the rate of surface modification to achieve the desired adhesive strength level is changed, and only when the pH range is satisfied, sufficient adhesive strength is derived while satisfying high fairness. can do.

The temperature of the alkaline aqueous solution may be 55 °C or higher, specifically 55 °C to 95 °C, and more specifically 60 °C to 90 °C. When the temperature of the alkaline aqueous solution is less than 55° C., the surface modification of the aluminum thin film proceeds at an excessively slow rate, thereby impairing fairness.

On the other hand, since the surface modification rate of the aluminum thin film hardly increases after the temperature exceeds 90 ° C, the temperature is preferably less than 90 ° C in terms of process speed and cost.

In the step of forming the surface-modified aluminum thin film, the aluminum thin film is immersed in the alkaline aqueous solution. The aluminum thin film may be an aluminum thin film in a state in which the surface is not modified, and may be, for example, an aluminum thin film that has not been treated such as anodizing. The immersion may be performed only on a portion requiring surface modification, or may be immersed so that the entire aluminum thin film is immersed in the alkaline aqueous solution. Accordingly, oxidation of aluminum occurs from the surface of the aluminum thin film, and materials such as Al(OH) ₃ , AlO(OH), and Al ₂ O ₃ are formed. At the same time, the surface of the aluminum thin film is etched to form the above-described plurality of pores, and the aluminum thin film includes a roughened surface. As a result, the aluminum thin film is changed into the surface-modified aluminum thin film by the immersion process.

The aluminum thin film may be immersed in the alkaline aqueous solution for 65 seconds to 85 seconds, specifically, 65 seconds to 80 seconds. The time corresponds to the appropriate time described above. That is, the time corresponds to a time for improving fairness while securing sufficient adhesive strength, and fairness is excessively inhibited when more time than the above time is required.

In the step of forming the surface-modified aluminum thin film of the present invention, no external current is supplied to at least one of the aluminum thin film and the alkaline aqueous solution. This is different from the prior art.

Specifically, a technique of immersing an aluminum thin film in a non-neutral aqueous solution and then applying a current to the aluminum thin film or the aqueous solution to modify the surface of the aluminum thin film has been conventionally used. However, since a separate current application process is used in this technique, the process is cumbersome. In addition, since current is not uniformly applied to the entire aluminum thin film, surface modification of the aluminum thin film does not occur uniformly. Accordingly, peeling between the surface-modified aluminum thin film and the sealant layer and between the surface-modified aluminum thin film and the base layer cannot be effectively suppressed. In addition, since the surface modification rate is also slow, processability is hindered. In addition, in the above process, a non-neutral acidic or basic aqueous solution serves as a channel for current to flow. That is, the pH adjusting additive added to the aqueous solution does not serve as an oxidizing agent per se, but simply serves to apply electric charge to the aluminum thin film.

On the other hand, since the forming of the surface-modified aluminum thin film of the present invention does not include a separate current application process, the process can be simplified. Furthermore, since there is no room for uneven current application, surface modification of the aluminum thin film can occur uniformly. In addition, since the surface modification rate can be improved through pH control, processability can be improved.

Drying the surface-modified aluminum thin film may be performed by a general method used in the art. Specifically, the drying may be performed through an oven.

The method for manufacturing a battery pouch case according to the present embodiment may further include disposing an adhesive layer on the surface-modified aluminum thin film. The adhesive layer may be disposed on one side or both sides of the surface-modified aluminum thin film. The adhesive layer is the same as the adhesive layer introduced in the above-described embodiment (a battery pouch exterior material).

The surface-modified aluminum thin film may be disposed between the sealant layer and the substrate layer. The adhesive layer is disposed at least one of between the sealant layer and the surface-modified aluminum thin film and between the base layer and the surface-modified aluminum thin film, and the sealant layer, the surface-modified aluminum thin film, and the base layer and the surface. Exfoliation of the modified aluminum thin film is prevented. The sealant layer and the substrate layer are the same as the sealant layer and the substrate layer introduced in the above-described embodiment (a battery pouch exterior material).

A method of manufacturing a battery pouch exterior material according to another embodiment of the present invention is similar to the above-described embodiment, but is different from the manufacturing method of the above-described embodiment in that the alkaline aqueous solution includes an additive. This explains the difference.

Preparing the alkaline aqueous solution may include mixing an additive with the alkaline aqueous solution. The additive may be at least one salt selected from the group consisting of NaCl and KCl. Due to the addition of the salt, the surface modification rate of the aluminum thin film may be improved.

The additive may be mixed in an amount of 1 part by weight to 30 parts by weight, specifically 1 part by weight to 10 parts by weight, based on 100 parts by weight of the alkaline aqueous solution. When the above range is satisfied, the surface modification rate of the aluminum thin film may be improved while manufacturing cost is reduced.

Hereinafter, some experiments are introduced for understanding of the present invention. However, the invention may be embodied in many different forms and is not limited to the experiments described herein.

(1) Surface modification rate of aluminum thin film according to pH of alkaline aqueous solution

Focusing on the fact that the light transmittance increases as the aluminum thin film is oxidized, the oxidation rate (corresponding to the surface modification rate) was evaluated as follows.

KOH was mixed with deionized water to form aqueous solutions (temperature: 80 ° C) with various pHs as follows (sample A-8 is neutral deionized water without NaOH addition, sample A-9 is an acidic aqueous solution prepared by adding acid) ). Thereafter, each aluminum thin film having a thickness of 160 nm and a size of 10 cm × 10 cm was immersed in each aqueous solution so as to be completely submerged. After measuring the time until the aluminum thin film was oxidized and showed a transmittance of 91% to 95%, the oxidation rate was calculated by a calculation method of “160 (nm) / surface modification time (sec)”. The results are shown in Table 1 and Figure 1.

pH time (sec) Transmittance (%) Oxidation rate (nm/sec) Sample A-1 11.79 45 93.37 3.5556 Sample A-2 11.47 65 93.54 2.4615 Sample A-3 11.37 70 94.02 2.2857 Sample A-4 11.03 135 94.64 1.1852 Sample A-5 10.49 205 94.50 0.7805 Sample A-6 10.15 230 94.19 0.6957 Sample A-7 9.35 420 93.64 0.3809 Sample A-8 7.50 1800 91.36 0.0889 Sample A-9 4.03 over 1800 below 10 Unable to measure (unreacted)

The transmittance was measured with COH-400 (spectrophotometer manufactured by NIPPON DENSHOKU INDUSTRIES).

Referring to Table 1 and FIG. 1, samples having a pH of 10 or more (Samples A-1 to A-6) have an oxidation rate of less than pH 10 (Samples A-7, A-6) with pH 10 as the boundary. 8), it can be seen that it is very fast. That is, when the specific basicity of pH 10 or more is exhibited, the surface modification rate of the aluminum thin film is fast, indicating that processability can be improved. In addition, Samples A-1 to A-4 having a pH of 11 or higher showed a much higher oxidation treatment rate than Samples A-5 and A-6 having a pH of 10.

On the other hand, in the case of Sample A-8, in which the surface modification of the aluminum thin film was attempted with only neutral deionized water, and Sample A-9, in which the surface modification of the aluminum thin film was attempted with an acidic aqueous solution, the oxidation rate was too slow.

Therefore, it can be seen that the "alkaline aqueous solution" having "appropriate pH" can effectively improve processability in manufacturing a battery pouch casing.

(2) Surface modification rate of aluminum thin film according to the temperature of alkaline aqueous solution

An alkaline aqueous solution of pH 11 was prepared by mixing NaOH with deionized water. Thereafter, each aluminum thin film having a thickness of 50 nm and a size of 10 cm × 10 cm was immersed in alkaline aqueous solutions (Samples B-1 to B-10) having various temperatures as follows. After measuring the time until the aluminum thin film was completely oxidized, the oxidation rate was calculated by a calculation method of “50 (nm) / surface modification time (sec)”. The results are shown in Table 2 and Figures 2 and 3.

(3) Surface modification rate of aluminum thin film according to NaCl addition

After mixing NaOH with deionized water to form an alkaline aqueous solution of pH 11, 10 parts by weight of NaCl was added to 100 parts by weight of the alkaline aqueous solution. Thereafter, each aluminum thin film having a thickness of 50 nm and a size of 10 cm × 10 cm was immersed in alkaline aqueous solutions (Samples C-1 to C-10) having various temperatures as follows. After measuring the time until the aluminum thin film was completely oxidized, the oxidation rate was calculated by a calculation method of “50 (nm) / surface modification time (sec)”. The results are shown in Table 2 and Figures 2 and 3.

No NaCl added Temperature (℃) time (sec) Oxidation rate (nm/sec) NaCl addition Temperature (℃) time (sec) Oxidation rate (nm/sec) Sample B-1 35 200 0.25 Sample C-1 35 130 0.38 Sample B-2 40 115 0.43 Sample C-2 40 90 0.56 Sample B-3 50 80 0.63 Sample C-3 50 55 0.91 Sample B-4 55 31 1.61 Sample C-4 55 21 2.38 Sample B-5 60 26 1.92 Sample C-5 60 19 2.63 Sample B-6 70 23 2.17 Sample C-6 70 17 2.94 Sample B-7 75 18 2.78 Sample C-7 75 13 3.85 Sample B-8 80 14 3.57 Sample C-8 80 12 4.17 Sample B-9 85 12 4.17 Sample C-9 85 11 4.55 Sample B-10 90 11 4.55 Sample C-10 90 11 4.55

Referring to Table 2 and FIGS. 2 and 3, oxidation of samples (Samples B-4 to B-10 and Samples C-4 to C-10) at 55 ° C or higher with the temperature of the alkaline aqueous solution as a boundary around 55 ° C. It can be seen that the rate is very fast compared to the samples below 55°C (Samples B-1 to B-3 and Samples C-1 to C-3). That is, since the surface modification rate of the aluminum thin film is fast when an alkaline aqueous solution of 55 ° C. or higher is used, it indicates that processability can be improved.

On the other hand, in the case of the alkaline aqueous solution to which NaCl was added (Sample C-1 to Sample C-10), it can be seen that the oxidation rate is faster than that of the alkaline aqueous solution to which NaCl is not added (Sample B-1 to Sample B-10). .

Therefore, it can be seen that an alkaline aqueous solution having an “appropriate temperature” can effectively improve the processability in manufacturing a battery pouch case, and the effect can be further improved when NaCl is added.

(4) Comparison of peel strength according to aluminum thin film immersion time

NaOH was mixed with deionized water to prepare an alkaline aqueous solution of pH 11 (temperature: 60°C). Thereafter, the entire aluminum thin film having a thickness of 50 nm and a size of 10 cm × 10 cm was immersed in the alkaline aqueous solution (sample D-1 to D-8) for various times as follows.

Then, after taking out the immersed aluminum thin film and drying it, the peel strength was evaluated in the following way, and the results are shown in Table 3.

Specifically, peel strength evaluation was performed using a TAXT plus texture analyzer (Scotch ® Transparent Tape, 3M Company). After the tape (width 1 inch) was attached to the fixed surface-modified aluminum thin film, the peeling strength of the tape was measured by pulling at a speed of 5 mm/sec at 180° (horizontal direction).

(5) Comparison of surface modification through alkaline aqueous solution without current application and surface modification through application of current to an aluminum thin film immersed in alkaline aqueous solution

NaOH was mixed with deionized water to prepare an alkaline aqueous solution of pH 11 (temperature: 60°C). Thereafter, an aluminum thin film having a thickness of 50 nm and a size of 10 cm × 10 cm was used as a working electrode and a graphite electrode as a counter electrode, and both electrodes were immersed in the alkaline aqueous solution. At this time, an alternating current having a frequency of 60 Hz and a current density of 7 A/dm2 was applied. After the immersion was conducted under the above conditions for the following time (Samples E-1 and E-2), the immersed aluminum thin film was taken out and dried, and the peel strength was evaluated in the same manner as described above, and the results are shown in Table 3. showed up

time (sec) Peel strength (gf/inch) Sample D-1 0 350 Sample D-2 10 550 Sample D-3 30 575 Sample D-4 55 650 Sample D-5 65 1100 Sample D-6 120 1100 Sample D-7 180 1100 Sample D-8 300 1100 Sample E-1 (applied current) 20 380 Sample E-2 (applied current) 40 500

Referring to Table 3, it can be seen that the aluminum thin films of Samples D-5 to D-8, which were immersed for 65 seconds or more, had significantly higher peel strength than those of Samples D-1 to D-4, which were immersed for less than 65 seconds. there is. As a result, it can be seen that when the aluminum thin film is immersed for an “appropriate time”, the peel strength is extremely high and the fairness is not impaired.

In addition, in the case of samples E-1 and E-2 to which current was applied, it can be seen that the peel strengths are significantly lower than those of samples D-5 to D-8. This is considered to be because ions that should directly participate in the aluminum oxidation reaction are used for the transfer of charge.

(6) SEM comparison of surface modification through alkaline aqueous solution without applying current and surface modification through applying current to aluminum thin film immersed in alkaline aqueous solution

1) Preparation of sample F-1

NaOH was mixed with deionized water to prepare an alkaline aqueous solution of pH 11 (temperature: 75°C). Thereafter, the entire aluminum thin film having a thickness of 50 nm and a size of 10 cm × 10 cm was immersed in the alkaline aqueous solution for 120 seconds. Thereafter, the immersed aluminum thin film was taken out and dried to prepare sample F-1.

2) Preparation of sample G-1

NaOH was mixed with deionized water to prepare an alkaline aqueous solution of pH 11 (temperature: 60°C). Thereafter, an aluminum thin film having a thickness of 50 nm and a size of 10 cm × 10 cm was used as a working electrode and a graphite electrode as a counter electrode, and both electrodes were immersed in the alkaline aqueous solution. At this time, an alternating current having a frequency of 60 Hz and a current density of 7 A/dm2 was applied for 20 seconds. Thereafter, the immersed aluminum thin film was taken out and dried to prepare sample G-1.

3) Preparation of Sample G-2

Sample G-2 was prepared in the same manner as in Sample G-1, except that the immersion time was set to 40 seconds.

The surfaces of Sample F-1, Sample G-1, and Sample G-2 were observed through SEM, and the results are shown in FIG. 5 . Referring to FIG. 5 , in the case of Sample F-1, it can be seen that pores having similar sizes are uniformly distributed. On the other hand, in the case of samples G-1 and G-2, it can be seen that the size of the pores is relatively irregular and the pores are non-uniformly distributed on the aluminum surface.

Claims (8)

delete delete Preparing an alkaline aqueous solution;
Forming a surface-modified aluminum thin film by immersing the aluminum thin film in the alkaline aqueous solution for 65 seconds to 85 seconds; and
Including; drying the surface-modified aluminum thin film,
In the step of preparing the alkaline aqueous solution,
The temperature of the alkaline aqueous solution is 55 ° C or higher,
The pH of the alkaline aqueous solution is 10 to 13,
Forming the surface-modified aluminum thin film does not include supplying an external current to at least one of the aluminum thin film and the alkaline aqueous solution.
The method of claim 3,
Preparing the alkaline aqueous solution;
A method for manufacturing a battery pouch case comprising adding at least one of NaOH and KOH to deionized water.
The method of claim 3,
Preparing the alkaline aqueous solution;
Method for producing a battery pouch case further comprising mixing at least one additive selected from the group consisting of NaCl and KCl to the alkaline aqueous solution.
The method of claim 5,
The additive is mixed in an amount of 1 part by weight to 30 parts by weight based on 100 parts by weight of the alkaline aqueous solution.
The method of claim 3,
Further comprising the step of disposing an adhesive layer on the surface-modified aluminum thin film, the manufacturing method of the battery pouch case.
The method of claim 3,
The surface-modified aluminum thin film is disposed between the sealant layer and the substrate layer, a method of manufacturing a battery pouch exterior material.

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