KR102301518B1 - Cell pouch with heat dissipation property comprising non-metal type barrier and the method for prodicng the same - Google Patents

Abstract

In the present specification, a non-metal barrier layer comprising a fluorine-containing polymer resin; and a heat dissipation layer disposed on the non-metal barrier layer and comprising a polyimide-based resin; including, a cell pouch is provided.

Description

Cell pouch including a non-metal barrier layer and having heat dissipation properties, and a method for manufacturing the same

The present specification discloses a cell pouch having heat dissipation properties, which includes a non-metal barrier layer and is capable of being lightweight/thin film.

Recently, various electronic products such as laptops and mobile phones are progressing at a remarkable speed in terms of performance and miniaturization. BACKGROUND ART With the increase in performance and miniaturization of electronic products, the capacity and integration of the battery components built therein are progressing, whereby a lot of heat is generated in the electronic products. In addition, the problem of heat generation due to the enlargement and high performance of pouch-type batteries used in EVs and ESSs is gradually emerging. In particular, the heat generated from the battery shortens the lifespan of the product or causes malfunction or malfunction, and in severe cases, it may cause an explosion or fire.

The structure of the conventional cell pouch is generally divided into an outermost layer, a metal barrier layer, and an inner layer. The metal barrier layer is divided into Al and SUS depending on the type, and the inner layer is composed of a sealant layer and the outermost layer is composed of nylon and PET layers. In particular, a metal barrier layer is widely used because it has excellent heat dissipation properties, but research to replace it with a non-metal-based barrier is in progress as the demand for light weight/thin film has increased recently.

PCTFE is widely used in various industrial fields (semiconductor, high-pressure gasket, medical packaging, etc.) can In addition, by replacing the existing metal barrier layer with a non-metal-based film, it can be expected to improve the energy density by reducing the weight and reducing the thickness.

However, since the metal barrier has superior heat dissipation properties compared to the non-metal-based film, if it is replaced with a non-metal barrier layer, the heat dissipation performance deteriorates, which causes a problem. Due to the recent high performance/miniaturization of secondary batteries, a lot of heat may be generated, which may shorten the lifespan of the product, expose it to failure, and risk of fire.

Accordingly, there is a growing need for a cell pouch having heat dissipation properties as well as heat resistance, chemical resistance, barrier properties, flame retardancy, and the like of a non-metal barrier.

Embodiments of the present invention are to solve the problem that the heat dissipation performance of the non-metallic barrier in the cell pouch is inferior to that of the metal barrier, and the product to which it is applied is exposed to the risk of shortened life, failure, and fire.

Embodiments of the present invention are to solve the problem of low energy density because the conventional cell pouch having a metal barrier layer is not suitable for weight reduction and thinning flow.

In one embodiment of the present invention, a non-metal barrier layer comprising a fluorine-containing polymer resin; and a heat dissipation layer disposed on the non-metal barrier layer and comprising a polyimide-based resin; including, a cell pouch is provided.

In an exemplary embodiment, the fluorine-containing polymer resin may include at least one resin selected from the group consisting of CTFE, PCTFE, PTFE, PVDF, PVF, PFA, ETFE, ECTFE, and FEP.

In an exemplary embodiment, the polyimide-based resin may include a polyamide resin alone.

In an exemplary embodiment, the heat dissipation layer may further include an organic filler.

In an exemplary embodiment, the organic filler is modified graphite, and the modified graphite may be graphite modified with one or more selected from the group consisting of silica, magnesium oxide, zinc oxide, aluminum hydroxide, titanium dioxide, and titanium hydroxide.

In an exemplary embodiment, the organic filler is a core composed of graphite; and a cell comprising at least one selected from the group consisting of silica, magnesium oxide, zinc oxide, aluminum hydroxide, titanium dioxide, and titanium hydroxide; a core consisting of- It may be modified graphite having a cell structure.

In an exemplary embodiment, the average diameter of the organic filler may be 500 nm to 5 μm.

In an exemplary embodiment, the organic filler may be included in an amount of 25 to 55% by weight based on the total weight of the heat dissipation layer.

In an exemplary embodiment, the thickness of the non-metal barrier layer may be 20 to 50 μm.

In an exemplary embodiment, the thickness of the heat dissipation layer may be 2 to 5 μm.

In an exemplary embodiment, the cell pouch includes a sealant layer; and an adhesive layer positioned between the non-metal barrier layer and the sealant layer.

In an exemplary embodiment, the cell pouch may have moisture permeability, electrolyte resistance, chemical resistance, heat dissipation and thermal diffusion properties.

In one embodiment of the present invention, there is provided a method of manufacturing a cell pouch according to an embodiment of the present invention, comprising: coating a heat dissipation composition on a non-metal barrier layer to form a heat dissipation layer; wherein the cell pouch is a fluorine-containing polymer A method for manufacturing a cell pouch is provided, comprising: a non-metal barrier layer including a resin; and a heat dissipation layer disposed on the non-metal barrier layer and including a polyimide-based resin.

In an exemplary embodiment, the heat dissipation composition includes a polyimide-based resin and a solvent, and the solvent is one or more solvents selected from the group consisting of N-Methyl-2-Pyrrolidone (NMP), DMAC, DMF, and NMP/DMAC. may include.

In an exemplary embodiment, the heat dissipation composition may further include modified graphite.

In an exemplary embodiment, the method may further include forming a sealant layer on one surface of the non-metal barrier layer.

The cell pouch according to the embodiment of the present invention may have excellent heat resistance, chemical resistance, barrier properties, flame retardancy, etc. as well as heat dissipation properties.

The cell pouch according to the embodiment of the present invention may have a light weight/thin film reduction by introducing a non-metal-based barrier layer, and may have an effect of improving energy density. Therefore, it is possible to efficiently manage the heat generated due to the recent high performance/miniaturization of secondary batteries, thereby reducing the lifespan of the product, preventing failure, and preventing the risk of fire.

1 shows a configuration diagram showing a stacked structure of a cell pouch according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail.

The embodiments of the present invention disclosed in the text are illustrated for the purpose of explanation only, and the embodiments of the present invention may be embodied in various forms and should not be construed as being limited to the embodiments described in the text. .

The present invention is not intended to limit the present invention to a specific disclosed form, but is not intended to limit the present invention to a specific disclosed form, as various changes may be made and may have various forms, and all changes, equivalents or substitutes included in the spirit and scope of the present invention should be understood as including

cell pouch

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a configuration diagram showing a stacked structure of a cell pouch according to an embodiment of the present invention. Referring to FIG. 1 , in one embodiment of the present invention, a non-metal barrier layer 20 including a fluorine-containing polymer resin; and a heat dissipation layer (10) located on the non-metal barrier layer and including a polyimide-based resin; including, a cell pouch is provided.

In an exemplary embodiment, the fluorine-containing polymer resin may include at least one resin selected from the group consisting of CTFE, PCTFE, PTFE, PVDF, PVF, PFA, ETFE, ECTFE, and FEP. Preferably, the fluorine-containing polymer resin may be PCTFE. The fluorine-containing polymer resin may have excellent moisture permeability required for the barrier layer.

In an exemplary embodiment, the polyimide-based resin may include a polyamide resin alone, and the polyimide-based resin has heat resistance, chemical resistance, electrical insulation, flame retardancy, and low temperature characteristics compared to conventional materials such as nylon resin. , dimensional stability, etc. may be more excellent.

In an exemplary embodiment, the heat dissipation layer 10 may further include an organic filler. The organic filler may be a conductive material having high thermal conductivity.

In an exemplary embodiment, the organic filler is modified graphite, and the modified graphite may be graphite modified with one or more selected from the group consisting of silica, magnesium oxide, zinc oxide, aluminum hydroxide, titanium dioxide, and titanium hydroxide. The modified graphite can obtain non-conductivity having insulating properties while maintaining the high thermal conductivity properties of graphite through modification.

In an exemplary embodiment, the organic filler is a core composed of graphite; and a cell comprising at least one selected from the group consisting of silica, magnesium oxide, zinc oxide, aluminum hydroxide, titanium dioxide, and titanium hydroxide; a core consisting of- It may be modified graphite having a cell structure.

For example, the modified graphite may be manufactured by coating silica on the graphite surface by a chemical method through the sol-gel method, and as a result, it retains the intrinsic property of high thermal conductivity and is new to the existing non-conductive type graphite that does not conduct electricity. Characteristics may be added.

In an exemplary embodiment, the average diameter of the organic filler may be 500 nm to 5 μm. Preferably, the average particle size of the organic filler may be 500 nm to 3 μm, or 500 nm to 1 μm. By using an organic filler having an average particle size in the above range, it is possible to prevent agglomeration and non-uniform mixing with each other and smooth mixing of the process.

In general, as for the particle size of the organic filler added to the heat dissipation layer 10, if the particle size of graphite is doubled, the number of interfaces with the polymer is halved. If it exceeds ㎛, it may be difficult to form a film (film formation) in the process of extruding the film, or the equipment may be damaged due to the graphite particles being caught in the T-die part of the extrusion machine.

In an exemplary embodiment, the organic filler may be included in an amount of 25 to 55% by weight based on the total weight of the heat dissipation layer. Specifically, the organic filler may be included in 25-40 wt%, 30-50 wt%, 30-45 wt%, or 30-40 wt% based on the total weight of the heat dissipation layer. Preferably, the organic filler may be included in an amount of 35 to 45 wt% based on the total weight of the heat dissipation layer. When the organic filler exceeds 55% by weight based on the total weight of the heat dissipation layer, it may be difficult to coat the barrier layer, and when it is less than 25% by weight based on the total weight of the heat dissipation layer, the heat dissipation performance may be poor. In general, the heat dissipation performance is determined according to the addition amount of the modified graphite to be filled, and the heat dissipation performance is excellent as the addition amount increases.

In an exemplary embodiment, the thickness of the non-metal barrier layer 20 may be 20 to 50 μm. When the thickness of the non-metal barrier layer 20 is less than 20 μm, the thickness of the barrier layer is too thin, and the moisture permeability may be lowered and the moldability may be poor. advantage may be diminished.

In an exemplary embodiment, the thickness of the heat dissipation layer 10 may be 2 to 5 μm. For example, it may have a thickness of 2 to 3 μm, 3 to 4 μm, or 3 to 5 μm. If the thickness of the heat dissipation layer 10 is less than 3 μm, physical/chemical resistance may be deteriorated, and if it is more than 5 μm, the coating property may be deteriorated, whereas there may be a problem in that the cost increases due to an increase in the amount of application. In general, the heat dissipation layer may be coated to a thickness of 3 to 4 μm, and when coated to a thickness of 2 to 3 μm, a similar level of physical properties may be exhibited.

In an exemplary embodiment, the cell pouch includes a sealant layer 40; and an adhesive layer 30 positioned between the non-metal barrier layer and the sealant layer. For example, the sealant layer 40 is attached (heat-sealed) by heat after the cell is accommodated (embedded) to provide sealing properties. It may include a sealing resin for thermal bonding. can For example, the sealing resin may be a resin having thermal adhesive properties, insulation, electrolyte resistance, and/or cold resistance, and the like. In addition, the adhesive layer 30 has a mechanism of adhering the sealant layer to the barrier layer, and the material thereof is not limited as long as it has adhesive properties.

In an exemplary embodiment, the cell pouch may have moisture permeability, electrolyte resistance, chemical resistance, heat dissipation and thermal diffusion properties.

How to make a cell pouch

In one embodiment of the present invention, there is provided a method of manufacturing a cell pouch according to an embodiment of the present invention, comprising: coating a heat dissipation composition on a non-metal barrier layer to form a heat dissipation layer; wherein the cell pouch is a fluorine-containing polymer A method for manufacturing a cell pouch is provided, comprising: a non-metal barrier layer including a resin; and a heat dissipation layer disposed on the non-metal barrier layer and including a polyimide-based resin.

In an exemplary embodiment, the heat dissipation composition includes a polyimide-based resin and a solvent, and the solvent is one or more solvents selected from the group consisting of N-Methyl-2-Pyrrolidone (NMP), DMAC, DMF, and NMP/DMAC. may include.

In an exemplary embodiment, the viscosity of the heat dissipation composition may be 100 to 3,000 cps. It may be easy to coat the heat dissipation layer as the outermost layer in the above viscosity range.

In an exemplary embodiment, the heat dissipation composition may further include modified graphite. Specific modified graphite may be the same as described above.

In an exemplary embodiment, the method may further include forming a sealant layer on one surface of the non-metal barrier layer.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not to be construed as being limited by these examples.

Example 1: Cell Pouch

A poly-chloro-trifluoro-ethylene (PCTFE) film having a thickness of 20 μm was used as a barrier layer film, and polyimide was coated on the PCTFE film.

Specifically, for polyimide, a coating agent with a solid content of 25 to 30%, modified graphite (particle size of 500 nm to 5 μm) and NMP (N-Methyl-2-Pyrrolidone) as a solvent was used, and the viscosity was 100 cps to 3,000 cps. was adjusted with The coating agent was coated as the outermost layer on the PCTFE film using a comma coater. Then, a CPP film, which is a sealant film, was laminated on the opposite side of the PCTFE film with an adhesive to prepare a cell pouch.

Comparative Example 1: Metal barrier cell pouch

A metal barrier cell pouch was prepared in the same manner as in Example 1, except that aluminum (Al) was used instead of the PCTFE film as the barrier layer film, and a nylon resin was used instead of polyimide.

Comparative Example 2: Metal barrier cell pouch

A metal barrier cell pouch was prepared in the same manner as in Example 1, except that stainless steel (SUS) was used as the barrier layer film instead of the PCTFE film, and a nylon resin was used instead of polyimide.

Experimental Example 1: Test for resistant electrolyte

After impregnating the cell pouch in the electrolyte, measure the peel strength of the barrier layer// sealant layer at regular time intervals. When measuring, the width of the sample is 15mm, the gage distance is 300mm, and the speed is 200mm/min. The higher the peel strength, the better the electrolyte resistance, and the results are shown in Table 1 below. Here, excellent (◎), good (○), average (Δ), and dissatisfied (X) are respectively.

note Comparative Example 1 Comparative Example 2 Example 1 Electrolyte resistance
peel strength
(kgf/15mm) Initial strength before impregnation ◎ ◎ ◎ 24 hours after impregnation ◎ ◎ ○ 48 hours after impregnation ◎ ◎ ○ 72 hours after impregnation ○ ○ ○

As a result of the experiment, it was confirmed that the cell pouch to which the non-metal barrier layer was applied had excellent or equivalent level of electrolyte resistance compared to the cell pouch having a conventional metal barrier layer.

Experimental Example 2: Chemical resistance test

After dropping 1 drop of electrolyte on the outermost layer (heat dissipation) of the cell pouch, wipe the surface at regular intervals to check the surface condition. The higher the chemical resistance, the higher the surface state maintains the original shape, and it is judged that the chemical resistance is excellent, and the results are shown in Table 2 below. Here, excellent (◎), good (○), average (Δ), and dissatisfied (X) are respectively.

note nylon PET heat dissipation PI coating
(Example 1) chemical resistance
surface condition initial surface state ◎ ◎ ◎ 5 minutes X ◎ ◎ 10 minutes X ◎ ○ 30 minutes X ◎ ○

As a result of the experiment, it was confirmed that the PI heat dissipation coating layer had excellent chemical resistance compared with the conventional outermost coating layer such as nylon or PET. In particular, it was confirmed that the chemical resistance of the surface of nylon rapidly decreased when 5 minutes or more elapsed, whereas, in the case of the heat dissipation layer (PI coating) applied to the present invention, excellent chemical resistance was maintained over time.

Experimental Example 3: Heat dissipation and thermal diffusivity test

The heat dissipation performance was confirmed by attaching each cell pouch to the heat source based on 60℃ and testing the temperature change over time to confirm the lowered temperature. After a period of time, thermal diffusivity was checked with a thermal imaging camera. The results are shown in Table 3 below. Here, excellent (◎), good (○), average (Δ), and dissatisfied (X) are respectively.

Comparative Example 1 Comparative Example 2 Example 1 heat dissipation performance ◎ △ ○ heat diffusivity ◎ △ ○

As a result of the experiment, it was confirmed that the cell pouch according to the embodiment of the present invention has excellent heat dissipation performance and heat diffusivity. In particular, it was confirmed that it had better performance compared to Comparative Example 2, and therefore, it was confirmed that the cell pouch according to the embodiment of the present invention had excellent moisture permeability, electrolyte resistance, chemical resistance, heat dissipation and thermal diffusion properties at the same time.

Experimental Example 4: PI/Modified Graphite Coating Test

In the cell pouch of Example 1, PI resin (PI varnish) and modified graphite were mixed to confirm the coatability of the cell pouch of Example 1, which was coated on the outermost layer. The modified graphite particle size used was mixed differently (500nm, 1㎛, 3㎛, 5㎛) and then coated on the outermost layer of the PCTFE film with a comma coater. After coating, the coatability of the surface was visually observed. The results are shown in Table 4 below. Here, excellent (◎), good (○), average (Δ), and dissatisfied (X) are respectively.

Example 1-1
(500nm) Example 1-2
(1um) Examples 1-3
(3um) Examples 1-4
(5um) coatability ◎ △ X X

As a result of the experiment, it was confirmed that the PI coating, which is the outermost layer, had good coating properties in the cell pouch according to the embodiment of the present invention. In particular, it was confirmed that when the particle diameter of the modified graphite included in the heat dissipation layer (outermost layer) was 500 nm to 1 μm, it had excellent coating properties.

The embodiments of the present invention described above should not be construed as limiting the technical spirit of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can improve and change the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the protection scope of the present invention as long as they are apparent to those of ordinary skill in the art.

Claims (15)

a non-metal barrier layer comprising a fluorine-containing polymer resin; and
and a heat dissipation layer disposed on the non-metal barrier layer and comprising a polyimide-based resin;
A cell pouch having moisture permeability, electrolyte resistance, chemical resistance, heat dissipation and thermal diffusion properties. According to claim 1,
The fluorine-containing polymer resin is characterized in that it comprises one or more resins selected from the group consisting of CTFE, PCTFE, PTFE, PVDF, PVF, PFA, ETFE, ECTFE, and FEP, cell pouch. According to claim 1,
The heat dissipation layer is characterized in that it further comprises an organic filler, cell pouch. 4. The method of claim 3,
The organic filler is modified graphite, and the modified graphite is graphite modified with at least one selected from the group consisting of silica, magnesium oxide, zinc oxide, aluminum hydroxide, titanium dioxide, and titanium hydroxide, Cell pouch. 4. The method of claim 3,
The organic filler is a core composed of graphite; and
A cell comprising at least one selected from the group consisting of silica, magnesium oxide, zinc oxide, aluminum hydroxide, titanium dioxide, and titanium hydroxide; core-consisting of a cell pouch, characterized in that it is a modified graphite having a cell structure. 4. The method of claim 3,
The average diameter of the organic filler is characterized in that 500 nm to 5㎛, cell pouch. 4. The method of claim 3,
The organic filler is characterized in that 25 to 55% by weight based on the total weight of the heat dissipation layer is included, the cell pouch. According to claim 1,
The non-metal barrier layer has a thickness of 20 to 50 μm, characterized in that the cell pouch. According to claim 1,
The heat dissipation layer has a thickness of 2 to 5 μm, characterized in that the cell pouch. According to claim 1,
The cell pouch may include a sealant layer; and
Cell pouch, characterized in that it further comprises an adhesive layer positioned between the non-metal barrier layer and the sealant layer. delete 11. The method for manufacturing a cell pouch according to any one of claims 1 to 10,
Including; coating the heat dissipation composition on the non-metal barrier layer to form a heat dissipation layer;
The cell pouch includes a non-metal barrier layer comprising a fluorine-containing polymer resin and a heat dissipation layer disposed on the non-metal barrier layer and comprising a polyimide-based resin. 13. The method of claim 12,
The heat dissipation composition includes a polyimide-based resin and a solvent,
Wherein the solvent comprises at least one solvent selected from the group consisting of N-Methyl-2-Pyrrolidone (NMP), DMAC, DMF, and NMP/DMAC. 13. The method of claim 12,
The heat dissipation composition is characterized in that it further comprises modified graphite, cell pouch manufacturing method. 13. The method of claim 12,
Forming a sealant layer on one surface of the non-metal barrier layer; characterized in that it further comprises a cell pouch manufacturing method.

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