KR102559632B1 - Window type cell pouch film for thin battery on which electrode active materials can be applied and method for preparing the same, thin battery using the same and manufacturing method thereof - Google Patents

Abstract

A cell pouch film for a window-type thin film battery to which an electrode active material can be applied, wherein the cell pouch film is composed of a metal layer and a sealant film in the form of a window frame bonded to the metal layer and does not have an outer layer, and the window frame-shaped sealant film exposes the metal layer at a window portion, and a cell pouch film in which the metal layer of the exposed window portion is an electrode active material application area, a method for effectively manufacturing the same, a thin film battery using the same, and a manufacturing method thereof are disclosed. According to the cell pouch film, since there is no outer layer, it is possible to effectively manufacture a thin film battery having excellent durability such as electrolyte resistance and puncture strength while minimizing the thickness. Such a thin film battery is useful for ultra-small thin film batteries for wearable electronic devices or IC cards.

Description

Window type cell pouch film for thin film battery to which electrode active material can be applied and method for manufacturing the same, thin film battery using the same and manufacturing method thereof

The present specification relates to a cell pouch film for a window-type thin film battery capable of applying an electrode active material and a method for manufacturing the same, a thin film battery using the same, and a manufacturing method thereof, and more particularly, relates to a cell pouch film for a window-type thin film battery capable of applying an electrode active material that can be used as an electrode for a micro-thin film battery such as a wearable device, a manufacturing method thereof, a thin film battery using the same, and a manufacturing method thereof.

Lithium secondary batteries (LiB) are being applied to many applications based on various advantages such as high energy density and excellent output.

A secondary battery pouch film is a multi-layered packaging film that surrounds the electrode group and electrolyte of such a secondary battery, and is a key component material that determines the stability, lifespan characteristics, and durability of a battery. Mechanical flexibility and strength, high oxygen / water vapor barrier properties, high thermal sealing strength, chemical resistance to electrolytes, electrical insulation, high temperature stability, etc. are required.

A secondary battery pouch film is usually largely composed of an outer layer/barrier layer/inner sealant layer.

The outer or outermost layer is made of nylon, a mixed material of nylon and PET (polyethylene terephthalate), OPP (stretched polypropylene), polyethylene, or the like. Heat resistance, pinhole resistance, chemical resistance, moldability and insulation are required as required properties of the outer layer or the outermost layer.

The barrier layer requires moldability as well as barrier properties against water vapor or other gases. In this respect, formable metals such as aluminum (Al), iron (Fe), copper (Cu), and nickel (Ni) are used for the barrier layer, and aluminum is currently used most often.

Since the sealant layer of the inner layer is a layer in contact with the electrolyte along with thermal adhesion and moldability, electrolyte resistance and insulation resistance are required.

On the other hand, due to the rapid development of microprocessing technology, the advancement of technology for microscopic devices and subminiature mechanical parts such as semiconductors and MEMS is accelerating, and the on-chip demand for on-chip parts with functions and peripheral circuits controlling these parts has begun to increase.

However, in order to meet these demands, it is necessary to develop an energy source for driving the device. That is, a micro-miniature battery that meets the size of a smaller device is required, and it is essential to develop a high-performance ultra-thin film battery for the realization of a more complete micro system.

In exemplary embodiments of the present invention, in one aspect, it is intended to provide a window-type cell pouch film for a thin film battery capable of applying an electrode active material having excellent durability such as electrolyte resistance and puncture strength while minimizing the thickness because there is no outer layer.

In exemplary embodiments of the present invention, in another aspect, a method for manufacturing a cell pouch film for a window-type thin film battery capable of applying an electrode active material, in which the manufacturing process of the cell pouch film is efficient, and thus a thin film battery can be effectively manufactured, and a corresponding thin film battery manufacturing method are provided.

In exemplary embodiments of the present invention, in another aspect, it is intended to provide an adhesive protective film and a sealant layer film usefully used in the above-described thin film battery manufacturing method.

In exemplary embodiments of the present invention, there is provided a cell pouch film for a window-type thin film battery to which an electrode active material can be applied, wherein the cell pouch film is composed of a metal layer and a sealant film in the form of a window frame laminated to the metal layer, and does not have an outer layer, and the metal layer is exposed at a window portion of the window frame-shaped sealant film, and the metal layer at the exposed window portion is an electrode active material application area.

In exemplary embodiments of the present invention, a thin film battery including an electrode formed on the above-described cell pouch film and an exposed metal layer of the cell pouch film is provided.

In exemplary embodiments of the present invention, a method for manufacturing a cell pouch film for a window-type thin film battery to which an electrode active material can be applied, a first base film, a first pressure-sensitive adhesive layer, a second base film, a second pressure-sensitive adhesive layer, and a third base film are sequentially stacked. Preparing an adhesive protective film; Partially punching out from the first base film of the adhesive protective film to a part of the third base film; partially removing the first base film from the partially cut-out adhesive protective film so that the first base film has one or more window portions; laminating the adhesive protective film from which the window portion of the first base film is partially removed with the metal layer so that the side of the first base film faces the metal layer; After the lamination, the electrode active material on the metal layer is to be applied by removing the adhesive protective film while leaving a partially punched area including the window portion of the adhesive protective film - corresponding to the area to be applied with the electrode active material - on the metal layer Forming a cover layer; coating a resist on a portion of the metal layer except for the cover layer; removing the cover layer from the metal layer; and laminating a sealant layer film having a window frame shape corresponding to the resist-coated region to the resist-coated region.

In exemplary embodiments of the present invention, a thin film battery manufacturing method including the above-described manufacturing steps of the cell pouch film and further comprising applying an electrode active material to the metal portion from which the cover layer is removed is provided.

In exemplary embodiments of the present invention, as an adhesive protective film used in the thin film battery manufacturing method, a first base film, a first pressure-sensitive adhesive layer, a second base film, a second pressure-sensitive adhesive layer, and a third base film are sequentially laminated. An adhesive protective film is provided.

In exemplary embodiments of the present invention, as a sealant film for a cell pouch film for a window-type thin film battery capable of applying an electrode active material, a cell pouch sealant film having a window frame shape in which an area corresponding to an area to which an electrode active material is applied on a metal layer of a cell pouch is removed is provided.

According to exemplary embodiments of the present invention, it is possible to effectively manufacture a thin film battery having excellent durability such as electrolyte resistance and puncture strength while minimizing the thickness because there is no outer layer. Such a thin film battery is useful for ultra-small thin film batteries for wearable electronic devices or IC cards.

1A is a schematic side view of an adhesive protective film used in manufacturing a cell pouch film for a window-type thin film battery capable of applying an electrode active material according to exemplary embodiments of the present invention.
Figure 1b is a schematic side view showing that the adhesive protective film of Figure 1a was partially punched out with an auto cutter.
FIG. 1C is a schematic side view showing a state in which a window region is removed from the partially punched-out adhesive protective film of FIG. 1B and laminated with a metal layer.
Figure 1d is a schematic side view showing the appearance of removing the adhesive protective film leaving a cover layer after the lamination of Figure 1c.
FIG. 2A is a schematic diagram showing a planar view of a metal layer on which a cover layer is partially formed after the process of FIG. 1D.
FIG. 2B is a schematic diagram illustrating a state in which the cover layer is removed after resist coating is applied to a portion except for the cover layer of FIG. 2A.
3 is a schematic view showing a sealant film in the form of a window frame without a window portion corresponding to an area to be coated with an electrode active material of a metal layer.
FIG. 4A is a schematic plan view illustrating the sealant film of FIG. 3 attached to a metal layer from which a cover layer has been removed.
Figure 4b is a schematic side view of the cell pouch film of Figure 4a.
5 is a schematic diagram showing a state in which a cell pouch film having an electrode formed according to an exemplary embodiment of the present invention is applied to a thin film battery.
6 is a photograph showing a completed cell pouch film according to an embodiment of the present invention.
FIG. 7A is an exemplary photograph showing that graphite is coated as an electrode active material on a completed cell pouch film, and FIG. 7B is a photograph showing manufacturing a thin film battery by folding the graphite-coated cell pouch film of FIG. 7A in half.
8 is a photograph showing a completed thin film battery.

term definition, etc.

In the present specification, a window or a window or a window portion or window area refers to an open portion (ie, a pierced portion), and is not limited to a commonly known rectangular shape.

In this specification, a window frame (frame) means a blocked part except for the open part.

In this specification, when a manufacturing method includes 'steps', even if each step is sequentially described, it does not necessarily mean that each step is performed in order unless otherwise specified. For example, below, 'removing the cover layer from the metal layer' and 'laminating a sealant layer film having a window frame shape corresponding to the resist-coated area to the resist-coated area' may be performed in reverse order.

Description of Exemplary Embodiments

Exemplary embodiments of the present invention are detailed below.

Due to its characteristics, a pouch film used in a thin film battery needs to function as an electrode while having a thickness as small as possible. In addition, the pouch film used in the thin film battery does not require much formability in terms of characteristics, but sufficient puncture strength or electrolyte resistance is required because it is for a thin film battery with a thin thickness. On the other hand, since the conventional cell pouch film manufacturing process cannot be used when manufacturing a cell pouch film for a thin film battery, an effective manufacturing method capable of increasing manufacturing process efficiency is also required.

In exemplary embodiments of the present invention, an effective method for manufacturing a window-type cell pouch film for a thin film battery to which an electrode active material can be applied and a cell pouch film for a thin film battery obtained thereby having excellent puncture strength and electrolyte resistance properties are provided.

1A is a schematic side view of an adhesive protective film used in manufacturing a cell pouch film for a window-type thin film battery capable of applying an electrode active material according to exemplary embodiments of the present invention.

As shown in FIG. 1A, the first base film 110, the first pressure-sensitive adhesive layer 111, the second base film 120, the second pressure-sensitive adhesive layer 121, and the third base film 130 are sequentially laminated. An adhesive protective film 100 is first prepared.

In an exemplary embodiment, the adhesive protective film 100 has, for example, a total thickness of 100 μm or more. The thickness of the first base film 110 is, for example, 10 to 20 μm, the thickness of the second base film 120 is also, for example, 10 to 20 μm, and the thickness of the third base film 130 is, for example, 90 to 100 μm.

The thickness of each pressure-sensitive adhesive layer 111, 121 is, for example, less than 5 μm.

FIG. 1B is a schematic side view showing partially punching the adhesive protective film of FIG. 1A to a certain depth with, for example, an auto cutter.

As shown in FIG. 1B , a portion of the adhesive protective film 100 is cut from the first base film 110 to a portion of the third base film 130 (that is, cut only to a portion) with a cutter. At this time, the minimum cutting depth of the cutting equipment should be 100 μm or more so that the cutting may pass through the second base film 120 and reach a part of the third base film 130 .

In an exemplary embodiment, the first to third substrate films may be, for example, PET films.

In an exemplary embodiment, known adhesives may be used as the first and second adhesives, but as shown in experimental examples to be described later, the adhesive strength of the first adhesive is greater than the second adhesive strength, and the adhesive strength of the first adhesive is, for example, 100 gf / inch or more, and the adhesive strength difference between the first adhesive and the second adhesive strength is preferably about 40 to 50 gf / inch, for example.

FIG. 1C is a schematic side view showing a state in which the partially punched adhesive protective film 100 from which the window W of FIG. 1B is removed is laminated with the metal layer 200. Referring to FIG.

As shown in FIG. 1C , the first base film 110 is partially removed from the partially cut-out adhesive protective film 100 so that the first base film 110 has at least one window W. Subsequently, the adhesive protective film 100 from which the window portion W of the first base film 110 is partially removed is laminated with the metal layer 200 such that the side of the first base film 110 faces the metal layer 200.

In an exemplary embodiment, the first base film 110 partially removed to have the one or more windows W may be laminated with the metal layer 200 under a load of, for example, 2 kfg.

FIG. 1D is a schematic side view showing a state in which the adhesive protective film is removed leaving the cover layer (C) after the lamination of FIG. 1C. FIG. 2A is a schematic diagram showing a planar view of a metal layer on which a cover layer is partially formed after the process of FIG. 1D.

As shown in FIG. 1D, the portion of the metal layer 200 to which the cover layer (C) is attached is a portion to be coated with an electrode active material later. As described above, since the adhesive protective film 100 is partially punched out, when the third base film 130 is slowly pulled, only the cover layer (C) remains and the remaining adhesive protective film 100 is removed. Accordingly, the cover layer (C) is formed on the portion of the metal layer 200 where the electrode active material is to be applied by the partial punching.

FIG. 2B is a schematic diagram showing a state in which the cover layer is removed after resist coating (or surface treatment) is applied to a portion except for the cover layer of FIG. 2A.

As shown in FIG. 2B , a resist is coated on a portion 250 of the metal layer 200 excluding the cover layer (C). Here, the resist coating may be performed by, for example, chromium coating. If the chrome surface treatment is applied to the entire area, the surface treated area has high surface resistance and low electrical conductivity, which may cause problems during electrode coating, so only the area except for the cover layer (C) is treated with chrome. By performing the surface treatment in this way, adhesion between the metal layer 200 and the sealant layer film 300 made of a resin to be attached later can be increased and chemical resistance can be increased.

After surface treatment through resist coating, the metal layer 200 is exposed by removing the cover layer (C).

FIG. 3 is a schematic view showing a sealant film 300 in the form of a window frame F without a window portion corresponding to an area of the metal layer 200 to be coated with an electrode active material. As shown in FIG. 3 , the corresponding sealant film 300 has a window frame F shape corresponding to the resist-coated region 250 of the metal layer 200, and the window portion corresponding to the region to be coated with the electrode active material is removed.

In an exemplary embodiment, an adhesive such as an epoxy adhesive, preferably an epoxy adhesive capable of drying at a low temperature, is applied to the sealant film 300 so that the sealant film 300 can be laminated with the metal layer (the surface of the metal layer coated with the resist). This adhesive is applied to the sealant film 300 and dried to remove or reduce the sticky (or tacky) characteristic, that is, the so-called tacky characteristic. It is advantageous for lamination when this tacky property is removed or reduced. Even if the lamination is performed after removing or reducing the tacky property, there is no difference in adhesive strength after curing the adhesive.

In a non-limiting example, a two-component epoxy adhesive may be used to remove or reduce tacky properties when dried at a temperature of, for example, 50° C. or higher for 40 seconds or longer.

Meanwhile, in exemplary embodiments, the cover layer (C) is removed from the metal layer 200, and the sealant film 300 in the form of a window frame (F) prepared in FIG. Thereafter, aging is performed at a temperature of 60° C. or higher for 3 days or longer.

In one exemplary embodiment, as a modified example, a sealant film in the form of a window frame may be first attached and the cover layer of the metal layer may be removed. Manufacturing in this way is easier to manufacture.

FIG. 4A is a schematic plan view showing the sealant film 300 of FIG. 3 attached to the metal layer 200 from which the cover layer C is removed, and FIG. 4B is a schematic side view of the cell pouch film of FIG. 4A.

As shown in FIGS. 4A and 4B , a cell pouch film 500 for a thin film battery of a window type capable of applying an electrode active material is obtained. The cell pouch film 500 is a cell pouch film 500 made of a metal layer 200 and a sealant film 300 in the form of a window frame laminated to the metal layer 200 and having no outer layer. The sealant film 300 in the form of a window frame exposes the metal layer 200 at a window portion, and an electrode active material may be applied to the metal layer 200 at the exposed window portion.

As described above, the cell pouch film 300 of exemplary embodiments of the present invention does not include an outer layer (usually composed of a film such as nylon, PET, PBT, or NY+PET). Instead, the area to which the outer layer is attached is directly used as a current collector.

In this regard, the pouch for a thin film battery may use two tabs or one tab. Depending on the design of the battery, the side to which the outer layer of the metal layer is attached is used as a cleaning agent while using one tab. It can be designed to directly come into contact with the internal conductor of the battery module. In this configuration, one tap can be reduced, which can reduce cost and has an advantage in energy density per battery weight.

In an exemplary embodiment, the metal layer 200 may be composed of a metal such as SUS alloy, Al, Cu, Ni, etc., but the cell pouch film 500 of the present invention exposes the metal layer itself without an outer layer to form an electrode therein.

In this regard, the steel of the SUS alloy can be divided into three types: austenitic, ferritic, and martensitic. In the case of ferritic and martensitic steels, corrosion resistance is lower than that of austenite and has magnetism. Magnetism can affect the environment, including the use of magnets or wireless charging, for example, finished devices using SUS cell pouches. Therefore, in exemplary embodiments of the present invention, it is preferable to use an austenitic steel grade as the SUS.

In non-limiting examples, 304, 304L, 304J1, 316, 316L, etc., which are particularly excellent in corrosion resistance and workability, may be used. Here, the L-type steel is a low-carbon steel, which has higher corrosion resistance, but has a disadvantage in that the price rises. Considering this point, 304, 304J1, 316, etc. can be used. In particular, the 316 steel grade contains 2-3% of molybdenum, making it the most corrosion-resistant steel grade. Since the cell pouch film of exemplary embodiments of the present invention requires high corrosion resistance without using an outer film, it is preferable to use 316L steel. In relation to the high degree of corrosion resistance, among the five SUS alloys, SUS 316L, SUS 316, SUS 304L, SUS 304, and SUS 316J1 are in order of high corrosion resistance.

In an exemplary embodiment, the metal layer 200 is preferably subjected to cleaning and degreasing processes. Accordingly, the surface tension of the metal layer 200 preferably has a surface tension of 60 dyne or more, and may be 70 dyne or more.

In an exemplary embodiment, the sealant layer film 300 is made of polypropylene (PP), preferably a non-stretched polypropylene (CPP) film, and may contain various additives (rubber component, elastomer, slip agent, etc.) according to required physical properties. The sealant film 300 is a component that determines important physical properties such as thermal adhesion, insulation, formability, and bendability.

In an exemplary embodiment, the thickness of the metal layer 200 may be, for example, 15 to 30 μm, 10 to 25 μm, or 15 to 20 μm. The thickness of the sealant film 300 may be, for example, 20 to 50 μm, 20 to 40 μm, or 20 to 30 μm. The thickness of the entire cell pouch film 500 is, for example, 35 to 85 μm, or 38 to 83 μm, or 38 to 80 μm, or 38 to 75 μm, or 38 to 70 μm, or 38 to 65 μm, or 38 to 60 μm, or 38 to 55 μm, or 38 to 50 μm, or 38 to 45 μm, or 38 to 40 μm.

As a non-limiting example, in the experiments described later, a 15 μm-thick SUS alloy was used as the metal layer 200 and a 20 μm-thick unstretched polypropylene (CPP) was used as the sealant film 300 . The thickness of the entire cell pouch film 500 is 38 μm.

On the other hand, the thin film battery manufacturing method according to exemplary embodiments of the present invention includes the manufacturing steps of the cell pouch film 500 described above, and additionally the metal layer 200 from which the cover layer (C) is removed. Applying an electrode active material; further includes.

In an exemplary embodiment, the cell pouch film may have an electrolyte resistance peel strength of 10 to 20 N/15 mm between the metal layer and the sealant film, as described below.

In one exemplary embodiment, the cell pouch film may have a puncture strength of 30N or more, 31N or more, 32N or more, 33N or more, 34N or more, 35N or more, or 36N, as described below.

5 is a schematic diagram showing a state in which a cell pouch film having electrodes of an exemplary embodiment of the present invention is applied to a thin film battery.

As shown in FIG. 5 , welding is performed directly on a battery using a cell pouch film in which electrodes are formed on a metal layer. That is, since there is no film corresponding to the outer layer in the cell pouch film design, the outer layer in the battery module can be welded so that it directly contacts the conductor. Accordingly, battery operation is possible with one tap.

The electrode active material formed on the metal layer of the cell pouch film may be a negative electrode or a positive electrode active material according to design, and thus may form a negative electrode or a positive electrode.

On the other hand, in exemplary embodiments of the present invention, as an adhesive protective film used in the thin film battery manufacturing method, a first base film, a first pressure-sensitive adhesive layer, a second base film, a second pressure-sensitive adhesive layer, and a third base film are sequentially laminated. An adhesive protective film is provided.

In exemplary embodiments of the present invention, as an adhesive protective film used in the thin film battery manufacturing method, a window frame-shaped sealant layer fabric in which an area corresponding to a cover layer is removed from a region on which an electrode active material on a metal layer is to be applied is provided.

Exemplary embodiments of the present invention are described in more detail through the following examples. Embodiments disclosed herein are illustrated for purposes of explanation only, and embodiments of the present invention may be implemented in various forms and should not be construed as being limited to the embodiments described herein.

<Manufacture>

Manufacturing example of SUS laminate using adhesive protective film

As shown in FIG. 1A, an adhesive protective film in which a PET film (10 μm) as a first base film, a first adhesive layer, a PET film (15 μm) as a second base film, a second adhesive layer, and a PET film (95 μm) as a third base film are laminated is prepared.

As the metal layer (barrier layer), SUS SUS316L having a thickness of 15 μm was used.

First, the adhesive properties of the adhesive protective film to be attached to the SUS surface were evaluated and selected. It can be used only when there is little transfer of adhesive residues, and a level close to 0% transfer rate is required. To this end, the degree of transfer rate of the adhesive was evaluated.

[Adhesive transfer rate test (CKP-5000)]

Since there should be no residual adhesive on the SUS surface, the adhesive transfer rate was measured as follows. Untreated PET is a reference (Ref.) sample, and since untreated PET is in a state without adhesive, the peel strength is measured after being attached with a standard tape, and this peel strength is the standard.

On the other hand, after coating each adhesive (silicone adhesive, urethane adhesive, acrylic adhesive) on PET, it was pressed and attached to untreated PET.

After 20 hours, the PET coated with the adhesive was removed from the untreated PET. After removal, the untreated PET (surface to which the adhesive film was attached) was peeled off by attaching a standard tape to measure the peel strength. The more the residual adhesive transfers to the untreated PET surface, the lower the peel strength. In the case of acrylic, since it is similar to the strength of reference (Ref.) PET, it can be said to be excellent in terms of transition rate because there is almost no transition.

The prepared sample was compressed by reciprocating twice at a speed of 10 mm/sec using a FINAT test roller (load of 2 kg), and then stored at 23±2° C. for 20 hours.

After removing the attached sample, a standard tape (NITTO 31B) with a width of 25 mm and a length of 250 mm was lightly attached to the surface. (The standard is measured by peeling the standard tape from the untreated PET of Comparative Example 1.) After compressing the standard tape by reciprocating twice at a speed of 10 mm/sec using a FINAT test roller (load of 2 kg), the test sample is fixed to the jig, and the standard tape is peeled in the direction of 180 ° at a rate of 300 mm/min to measure the peel strength, and the measurement results are shown in [Table 1] below. As shown in the table below, the peel strength is preferably 1000 gf / inch, and in the case of the example, since it has the same level of peel strength as the untreated Comparative Example 1, it can be seen that the adhesive hardly transfers.

[Table 1]

- Excellent (◎) Good (○) Normal (△) Unsatisfactory (X) - Comparative Example 1: Untreated PET Cotton (Ref.)

- Comparative Example 2: PET sample removal surface using silicone-based adhesive

- Comparative Example 3: PET sample removal surface using urethane-based adhesive

- Example: PET sample removal surface using acrylic adhesive

From the comparison of the above Examples and Comparative Examples, it can be seen that the most advantageous pressure-sensitive adhesive is the acrylic pressure-sensitive adhesive (transition rate of the acrylic pressure-sensitive adhesive is 0.2% or less).

On the other hand, it is necessary to set the optimal adhesive strength in order to attach the adhesive protective film to the SUS surface in the form of a window. That is, since the first base film is peeled off from the second base film and attached to the surface of the SUS, the adhesive strength of the pressure-sensitive adhesive layer should be set accordingly. To this end, the optimal adhesive strength was derived by changing the adhesive strength of the acrylic adhesive.

The adhesive strength test and visual evaluation of adhesive adhesion were performed as follows.

[Adhesive strength test test (CKP-5000) & SUS surface adhesion protective film adhesion state evaluation]

The adhesive protective film was cut into a width of 25 mm × length of 250 mm in the machine direction, and the release peel force was measured while peeling at a peel speed of 300 m / min in a 180 ° Peel Test method using an adhesive force measuring device (CKP-5000).

The specimen subjected to the release peel test was laminated to the washed and dried glass (or SUS plate) using an automatic laminator (load of 2 kg) and stored at 25 ± 2 ° C for 30 minutes. The adhesive strength was measured while peeling at a peeling speed of 300 mm/min in a 180° Peel Test method using an adhesive force measuring device (CKP-5000) (check the adhesive strength for each glass part).

On the other hand, the adhesion state of the adhesive protective film on the SUS surface was evaluated as follows.

A window was removed from a portion of the first base film and a partially punched adhesive protective film was prepared in a size of about 20x30 mm (size can be changed).

The partially punched adhesive film on the SUS alloy was laminated using an automatic laminator (2kg load). After confirming that the first adhesive in the window area is in close contact with the SUS foil and laminated, the third base film is slowly peeled off. Accordingly, only the cover layer remains and the remaining adhesive protective film falls off. Check the condition with the naked eye to see if the cover layer is adhered to the SUS alloy accurately.

[Table 2] shows the results of each adhesive force measurement and visual evaluation of adhesion.

[Table 2]

- Excellent (◎) Good (○) Normal (△) Unsatisfactory (X)

In the case of Comparative Example 1, the adhesion was good, but after attaching the CPP film, which is a sealant film, the adhesive protective film had to be finally removed, but the adhesive strength was too high, so it was difficult to remove.

Comparative Example 2 showed a shape that adhered well to SUS or remained attached to the second base film. In the case of Comparative Example No. 3, the first base film adhered to the second base film and did not adhere well to the SUS.

On the other hand, in the case of the examples, it adhered to the SUS surface most excellently. In addition, when removing the adhesive protective film, it was removed without any problems (when the cut adhesive film is laminated by applying a load to SUS and then slowly removed, only the adhesive protective film of the cover layer portion remains and the rest is removed). Through the examples, it was confirmed that it is appropriate for the first pressure-sensitive adhesive layer to have an adhesive strength of at least 100 gf/inch, and the second pressure-sensitive adhesive layer preferably has an adhesive strength difference of about 40 to 50 gf/inch from the first pressure-sensitive adhesive layer.

[Pretreatment test to improve electrode coating properties of SUS fabric]

In the embodiment of the present invention, since the electrode active material is coated on the metal layer SUS, cleaning and degreasing are performed to improve coating properties. In order to evaluate the effect, the following experiment was conducted.

First, a detergent for SUS and a degreaser were prepared.

The detergent was used as a stock solution, and the degreaser was diluted with water (3% by volume of the degreaser + 97% by volume of water).

For cleaning, the SUS fabric was immersed in the cleaning solution for 10 seconds, washed with water, and dried at 60 ° C. for 5 minutes.

For degreasing, the SUS fabric was impregnated in the diluted degreasing liquid for 10 seconds, washed with water, and dried at 60 degrees for 5 minutes.

The surface tension of each pretreated SUS fabric was measured using a Dyne pen from Arcrotest and shown in [Table 3] below.

[Table 3]

- Excellent (◎) Good (○) Normal (△) Unsatisfactory (X) - Comparative Example 1: Untreated (Ref.)

- Comparative Example 2: Washing treatment (Citric acid based pH 6.8)

- Comparative Example 3: Degreasing treatment (NaOH-based pH 12)

- Example: Degreasing (NaOH based pH 12) treatment after washing (Citric acid based pH 6.8)

In the case of Comparative Example 1, the level was 48 dyne in the basic state without any treatment, and each of cleaning and degreasing showed a certain degree of improvement in surface tension. A dramatic increase in surface tension was confirmed during the first and second pretreatments of cleaning and degreasing in Examples. Therefore, it was confirmed that the degreasing treatment after the cleaning (rinsing) operation of the SUS fabric is advantageous. In relation to the surface tension, it is preferable to have a surface tension of 60 dyne or more.

Sealant film manufacturing example

A CPP film (thickness of the film of 20 μm) having a window frame shape with the window shape removed was prepared. A two-component epoxy adhesive was applied to the cut CPP film. In order to attach to the SUS, which is a metal layer later, an epoxy adhesive that can be dried at a low temperature was used, and dried at 50 ° C or higher for 20 seconds or more.

In this regard, it is advantageous for lamination to remove the tacky property by overrunning the drying time. When drying for 20 seconds under basic drying conditions at 50° C. or higher, some tacky properties are maintained. Therefore, it was possible to remove the tacky property by doubling the drying time from 20 seconds to 40 seconds.

On the other hand, the CPP film must be accurately positioned and laminated, and if the tacky property remains, the laminate becomes very difficult.

Cell pouch film manufacturing example

As described above, the cover window portion was removed from the SUS surface to which the cover window was attached, and the CPP film, which is a sealant film, was laminated on the SUS surface by 80° C. thermal lamination. next. It was aged for 3 days at a temperature of 60 ° C or higher.

6 is a photograph showing a completed cell pouch film according to an embodiment of the present invention.

Example of electrode coating and thin film cell configuration

FIG. 7A is an exemplary photograph showing that graphite is coated on the completed cell pouch film as an electrode active material, and FIG. 7B is a photograph showing manufacturing a thin film battery by folding the graphite-coated cell pouch film of FIG. 7A in half.

As shown in FIGS. 7A and 7B, a graphite-coated window-type cell pouch film is folded in half so that two windows face each other, a cathode with a tab coated on both sides and a separator are inserted, and an electrolyte is injected to form a thin film battery.

8 is a photograph showing a completed thin film battery.

As shown in FIG. 8 , the cell pouch film may be directly welded to the thin film battery.

<Physical property test of cell pouch film>

The electrolyte resistance and puncture strength of the cell pouch film were evaluated as follows.

Cell pouch film electrolyte test

The cell pouch films of Comparative Examples and Examples shown in the table below were impregnated with an electrolyte (1M LiPF6 carbonate-based electrolyte), left in an oven at 85 ° C, and then the peel strength of the barrier layer (metal layer) // sealant layer was measured with a universal tester (UTM). The width of the measurement sample was 15 mm, the gauge length was 300 mm, and the speed was 200 mm/min. It is judged that the higher the peel strength, the better the electrolyte resistance. The results are shown in [Table 4] below.

[Table 4]]

-Excellent (◎) Good (○) Normal (△) Unsatisfactory (X)- Excellent (above 10 N/15mm), Good (8~9 N/15mm), Normal (6~7 N/15mm), Unsatisfactory (below 5 N/15mm)

-Comparative Example 1: Nylon // Al (aluminum) 40㎛ // Sealant film 20㎛

-Comparative Example 2: Nylon // Al (aluminum) 40㎛ // Sealant film 50㎛

-Example: SUS316L (stainless steel) 15㎛ // Sealant film 20㎛

In general, when the thickness of the CPP film, which is the sealant layer, is lowered, the electrolyte resistance is lower than that of CPP with a high thickness. As a result of this test, it was confirmed that the same level of electrolyte resistance was shown compared to the existing aluminum (AL) type cell pouch.

Cell pouch film puncture strength test

The puncture strength of the cell pouch film was measured at regular intervals at 5 points in the TD direction. When measuring, the sample width was 30 mm, the speed was 200 mm/min, and the punch diameter was Ø. The higher the puncture strength, the better the durability. The measurement results are shown in [Table 5] below.

[Table 5]

-Excellent (◎) Good (○) Fair (△) Unsatisfactory (X)- Excellent (over 35N), Good (20~30 N), Normal (15~20 N), Unsatisfactory (less than 10 N)

-Comparative Example 1: Nylon // Al (aluminum) 40㎛ // Sealant film 20㎛

-Comparative Example 2: Nylon // Al (aluminum) 40㎛ // Sealant film 50㎛

-Example: SUS316L (stainless steel) 15㎛ // Sealant film 20㎛

As can be seen from the above results, it can be seen that the case of Example has the best puncture strength and excellent durability. In particular, durability is excellent even without the SUS outer layer film.

Although non-limiting and exemplary embodiments of the present invention have been described above, the technical spirit of the present invention is not limited to the accompanying drawings or the above description. It is obvious to those skilled in the art that various types of modifications are possible within the scope of the technical spirit of the present invention, and also, these types of modifications will fall within the scope of the claims of the present invention.

Claims (18)

A method for manufacturing a cell pouch film for a window type thin film battery to which an electrode active material can be applied,
Preparing an adhesive protective film in which a first base film, a first pressure-sensitive adhesive layer, a second base film, a second pressure-sensitive adhesive layer, and a third base film are sequentially laminated;
Partially punching out from the first base film of the adhesive protective film to a part of the third base film;
partially removing the first base film from the partially cut-out adhesive protective film so that the first base film has one or more window portions;
laminating the adhesive protective film from which the window portion of the first base film is partially removed with the metal layer so that the side of the first base film faces the metal layer;
forming a cover layer on a portion of the metal layer to be coated with an electrode active material by removing the adhesive protective film while leaving a partially punched area including the window portion of the adhesive protective film on the metal layer after the lamination;
coating a resist on a portion of the metal layer except for the cover layer;
removing the cover layer from the metal layer; and
Laminating a sealant layer film having a window frame shape corresponding to the resist-coated region to the resist-coated region; A method of manufacturing a cell pouch film for a window-type thin film battery to which an electrode active material can be applied, comprising: According to claim 1,
The thickness of the first base film is 10 to 20 μm,
The thickness of the second base film is 10 to 20 μm,
The method of manufacturing a cell pouch film for a window-type thin film battery to which an electrode active material can be applied, characterized in that the thickness of the third base film is 90 to 100 μm. According to claim 2,
The adhesive strength of the first adhesive is 100 gf / inch or more,
The adhesive strength of the second adhesive is smaller than that of the first adhesive,
A method for manufacturing a cell pouch film for a window type thin film battery to which an electrode active material can be applied, characterized in that the difference in adhesive strength between the first adhesive and the second adhesive is 40 to 50 gf / inch. According to claim 3,
The method of manufacturing a cell pouch film for a window type thin film battery to which an electrode active material can be applied, characterized in that the first adhesive is an acrylic adhesive. According to claim 1,
The method of manufacturing a cell pouch film for a window-type thin film battery to which an electrode active material can be applied, characterized in that the metal layer is an austenitic SUS alloy. According to claim 5,
A cell pouch film manufacturing method for a window-type thin film battery to which an electrode active material can be applied, characterized in that SUS 316L is used as the austenitic SUS alloy. According to claim 1,
Method for manufacturing a cell pouch film for a window-type thin film battery to which an electrode active material can be applied, characterized in that the metal layer is subjected to cleaning and degreasing treatment. According to claim 7,
The method of manufacturing a cell pouch film for a window type thin film battery to which an electrode active material can be applied, characterized in that the metal layer has a surface tension of 60 dyne or more. According to claim 1,
The method of manufacturing a cell pouch film for a window type thin film battery to which an electrode active material can be applied, characterized in that the resist coating is a chromium coating. According to claim 1,
The step of laminating a sealant layer film having a window frame shape corresponding to the resist-coated region to the resist-coated region,
removing or reducing the tackiness of the epoxy adhesive by applying an epoxy adhesive to the sealant layer film and drying at 50° C. or higher for 40 seconds or more; and
After removing or reducing the tackiness of the epoxy adhesive, thermally laminating the sealant layer film with the metal layer; A method of manufacturing a cell pouch film for a window-type thin film battery to which an electrode active material can be applied, characterized in that it comprises. As a thin film battery manufacturing method,
A method for manufacturing a cell pouch film for a window type thin film battery to which the electrode active material of any one of claims 1 to 10 can be applied,
Thin film battery manufacturing method characterized in that it further comprises; applying an electrode active material to the metal layer from which the cover layer is removed. delete A cell pouch film for a window type thin film battery capable of applying an electrode active material,
The cell pouch film is made of a metal layer and a sealant layer film in the form of a window frame laminated to the metal layer and does not have an outer layer,
The metal layer is exposed at the window portion of the sealant layer film in the form of a window frame,
The metal layer of the exposed window portion is an electrode active material application area,
The metal layer thickness is 15 ~ 30㎛,
The sealant layer film thickness is 20 to 50 μm,
The cell pouch film for a window type thin film battery capable of applying an electrode active material, characterized in that the cell pouch film thickness is 35 ~ 85㎛. A cell pouch film for a window type thin film battery capable of applying an electrode active material,
The cell pouch film is made of a metal layer and a sealant layer film in the form of a window frame laminated to the metal layer and does not have an outer layer,
The metal layer is exposed at the window portion of the sealant layer film in the form of a window frame,
The metal layer of the exposed window portion is an electrode active material application area,
A cell pouch film for a window type thin film battery capable of applying an electrode active material, characterized in that the electrolytic solution peel strength between the metal layer and the sealant layer film of the cell pouch film is 1 kgf / 15 mm or more. A cell pouch film for a window type thin film battery capable of applying an electrode active material,
The cell pouch film is made of a metal layer and a sealant layer film in the form of a window frame laminated to the metal layer and does not have an outer layer,
The metal layer is exposed at the window portion of the sealant layer film in the form of a window frame,
The metal layer of the exposed window portion is an electrode active material application area,
A cell pouch film for a window type thin film battery capable of applying an electrode active material, characterized in that the puncture strength of the cell pouch film is 35N or more. A cell pouch film for a window-type thin film battery capable of applying the electrode active material of any one of claims 13 to 15; and
A thin film battery comprising an electrode formed on a metal layer of the cell pouch film for a thin film battery. An adhesive protective film used for manufacturing a cell pouch film for a window-type thin film battery capable of applying electrode active materials,
It is used in a method for manufacturing a cell pouch film for a window type thin film battery to which the electrode active material of any one of claims 1 to 10 can be applied,
A first base film, a first pressure-sensitive adhesive layer, a second base film, a second pressure-sensitive adhesive layer, and a third base film are sequentially laminated, characterized in that a window-type thin film battery cell pouch film capable of applying an electrode active material Adhesive protective film used for manufacturing. A sealant layer film for a cell pouch film for a window type thin film battery capable of applying an electrode active material,
It has a window frame shape in which the region corresponding to the region on which the electrode active material is applied on the metal layer of the cell pouch is removed,
The cell pouch film is made of a metal layer and a sealant layer film in the form of a window frame laminated to the metal layer and does not have an outer layer,
The metal layer is exposed at the window portion of the sealant layer film in the form of a window frame,
The metal layer of the exposed window portion is an electrode active material application area,
The metal layer thickness is 15 ~ 30㎛,
The sealant layer film thickness is 20 to 50 μm,
The cell pouch film thickness is 35 ~ 85㎛, a cell pouch sealant layer film for a window type thin film battery capable of applying an electrode active material.