KR101894449B1 - Cell pouch and method of preparing the same - Google Patents

Abstract

The cell pouch includes a sealant layer, a barrier layer formed on the sealant layer, and an outer layer formed on the barrier layer. At this time, the sealant layer has a multi-layer structure including a first skin layer, a core layer, and a second skin layer which are sequentially stacked. The first skin layer includes random polypropylene (random PP) having a melting temperature (T _m ) of 140 ° C to 150 ° C and a slip agent. The core layer includes a block polypropylene (block PP) having a melting temperature (T _m ) of 155 to 165 ° C and a slipping agent. The second skin layer includes random PP having a melting temperature ( _Tm ) of 140 ° C to 150 ° C.

Description

≪ Desc / Clms Page number 1 > CELL POUCH AND METHOD OF PREPARING THE SAME [

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell pouch for a secondary battery and a method of manufacturing the same. More particularly, the present specification relates to a cell pouch for a lithium ion secondary battery and a method for manufacturing the same.

Generally, a cell such as a lithium ion secondary battery is embedded (stored) in a cell pouch. Such a cell pouch may have a multi-layer structure including a sequentially stacked sealant layer, a barrier layer and an outer layer, and may be manufactured by bonding the layers individually.

In order to improve the adhesion between the layers, it is possible to carry out the processes accompanied by the high temperature in the production of the cell pouch, and in particular, to improve the adhesion between the sealant layer and the barrier layer, / L (solvent dry lamination) process can be performed. However, since the conventional sealant layer includes a resin having low heat resistance and is fragile at high temperatures, a cell pouch having a greatly reduced surface slip property due to such high-temperature aging can be produced.

Korean Patent Publication No. 10-2016-0070468 Korean Patent No. 10-1537399 Korean Patent Publication No. 10-2015-0114470

It is an object of the present invention to provide a cell pouch which is excellent in heat resistance and does not cause a decrease in surface slip due to high temperature, but has an improved surface slip property, and further has excellent blocking resistance and moldability, and a method for producing the cell pouch.

A cell pouch according to exemplary embodiments for achieving an object of the present invention includes a sealant layer, a barrier layer formed on the sealant layer, and a barrier layer formed on the barrier layer. And includes an outer layer. At this time, the sealant layer has a multi-layer structure including a first skin layer, a core layer, and a second skin layer which are sequentially stacked. The first skin layer includes random polypropylene (random PP) having a melting temperature (T _m ) of 140 ° C to 150 ° C and a slip agent. The core layer includes a block polypropylene (block PP) having a melting temperature (T _m ) of 155 to 165 ° C and a slipping agent. The second skin layer includes random PP having a melting temperature ( _Tm ) of 140 ° C to 150 ° C.

In exemplary embodiments, the slip agent may be a fatty acid amide slip agent selected from oleamide, erucamide, behenamide, and stearamide. The first skin layer may include at least one of the slip agents. The core layer may include two or more of the slip agents.

The core layer may comprise, as a slip agent, one selected from behenamide and stearamide, and erucamide. Based on the total weight of the slip agent contained in the core layer, one selected from among behenamide and stearamide may be included in an amount of about 77 to 95% by weight, and erucamide may be contained in about 5 to 23% by weight.

In exemplary embodiments, the first skin layer may further comprise an anti-blocking agent (AB agent). Wherein the first skin layer comprises, based on the total weight of the first skin layer, about 80-90 wt% of the random polypropylene; About 3 to 5% by weight of the antiblocking agent; And about 5 to 15% by weight of the slip.

In exemplary embodiments, the core layer may further comprise an elastomer. Wherein the core layer comprises, based on the total weight of the core layer, from about 39 to about 49 weight percent of the block polypropylene; About 50 to 60% by weight of said elastomer; And about 1 to 11% by weight of the slip agent.

In exemplary embodiments, the second skin layer may further comprise an elastomer and an anti-blocking agent. Wherein the second skin layer comprises, based on the total weight of the second skin layer, about 60-90 wt% of the random polypropylene; About 5 to about 30 weight percent of said elastomer; And about 3 to 5% by weight of the anti-blocking agent.

In exemplary embodiments, the barrier layer may include one or more metals having gas barrier properties and moisture barrier properties.

In exemplary embodiments, the outer layer may comprise at least one selected from a polyamide-based resin and a polyester-based resin.

In exemplary embodiments, the first skin layer may contact a cell embedded in the cell pouch as an innermost layer of the cell pouch. The outer layer may be exposed to the outside as an outermost layer of the cell pouch. The barrier layer may be formed on and contacted with the second skin layer.

In exemplary embodiments, the cell pouch may be a cell pouch for a secondary cell.

In exemplary embodiments, the secondary battery may be a lithium ion secondary battery.

A cell pouch according to exemplary embodiments for achieving an object of the present invention can be manufactured by performing the following processes: a multi-layered structure including a first skin layer, a core layer and a second skin layer which are sequentially stacked Forming a sealant layer of the structure; Forming a barrier layer on the sealant layer; And forming an outer layer on the barrier layer. The first skin layer is formed to include random polypropylene (random PP) having a melting temperature (T _m ) of 140 ° C to 150 ° C and a slip agent. The core layer is formed to include block polypropylene (block PP) having a melting temperature ( _Tm ) of 155 占 폚 to 165 占 폚 and a slipping agent. The second skin layer is formed so as to include random PP having a melting temperature (T _m ) of 140 ° C to 150 ° C.

In exemplary embodiments, the sealant layer may be formed by extruding the first skin layer, the core layer, and the second skin layer using an extruder.

As described above, the cell pouches according to the exemplary embodiments of the present invention include a sealant layer comprising a sealing resin having a melting temperature ( _Tm ) of about 140 DEG C or higher and having a multi-layer structure, . Accordingly, the cell pouch may not suffer from problems such as a decrease in surface slip property due to a high temperature and a decrease in interlayer adhesion force.

Further, in addition to the sealing resin, the sealant layer may further comprise a slip agent, an antiblocking agent, and an elastomer. More specifically, the first skin layer constituting the sealant layer may further comprise at least one slip agent and an anti- Layer further comprises at least two slip agents and an elastomer and the second skin layer further comprises an elastomer and an antiblocking agent so that the cell pouch not only has excellent surface slip property but also has anti- It can be excellent.

Therefore, the secondary battery, specifically, the lithium ion secondary battery can be effectively packaged using the cell pouch.

1 illustrates a cross-sectional view of a cell pouch according to exemplary embodiments of the present invention.

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

It is to be understood that the invention is not to be limited to the specific forms disclosed, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention, As will be understood by those skilled in the art.

As used herein, the term 'cell' refers to a battery, and has the broadest meaning including all kinds of batteries such as a secondary battery and a portable battery, such as a lithium ion battery and a lithium polymer battery.

The term 'cell pouch' as used herein refers to a cell pouch capable of packaging cell components such as an anode, a cathode, and a separator impregnated in an electrolyte, and has a gas barrier property, a water barrier property, The film having the laminated structure in consideration of the shape and the like is processed into a bag shape or a box shape so that the cell component can be embedded therein.

In the present specification, "barrier property" means a property of blocking water vapor (moisture) or air from the outside of the cell and gas generated in the inside of the cell.

In the present specification, "excellent formability of cell pouch" means that a laminated film having gas barrier properties, water barrier properties, electrolyte resistance, thermal adhesiveness, and the like is easily damaged to a predetermined shape without being damaged or broken . At this time, the energy density of the secondary battery (the cell built in the cell pouch) can be increased as the depth at which the cell pouch can be formed is greater.

The term " anti-blocking property " as used herein refers to a property in which undesirable adhesion between the laminated films can be prevented when the films laminated in a multi-layer structure are wound after extrusion to constitute the cell pouch . When the blocking resistance is secured, for example, the polypropylene-containing film and the polypropylene-containing film or the polypropylene-containing film and the nylon-containing film may not stick to each other when they are roll-to-roll . In general, when cell pouches have improved slip properties, their blocking resistance is also excellent.

Cell pouch

A cell pouch according to exemplary embodiments of the present invention can be used as a cell pouch for a secondary battery, specifically, as a cell pouch for a lithium ion secondary cell.

1 illustrates a cross-sectional view of a cell pouch according to exemplary embodiments of the present invention.

1, the cell pouch 100 includes a sequentially laminated sealant layer 10, a barrier layer 20 and an outer layer 30, wherein the sealant layer 10, Layer structure including the first skin layer 11, the core layer 13, and the second skin layer 15 which are sequentially stacked, as shown in Fig.

The sealant layer 10 can be sealed (heat-sealed) by heat after the cells are embedded (packaged). The sealant layer 10 may have a total thickness of about 20 to 80 um for good heat bond strength, i.e., sealability, as well as improved heat resistance. If the total thickness of the sealant layer 10 is too small, less than about 20 μm, the electrolyte may leak due to lack of sealing property, or the packed cells may not be sufficiently insulated, and furthermore, it may be difficult to ensure a sufficient degree of heat resistance. In addition, when the thickness of the sealant layer 10 is too thick to be greater than about 80 um, it is difficult for other layers provided above the sealant layer 10 to have a sufficient thickness, Etc. may be degraded. In one embodiment, the sealant layer 10 may have a thickness of about 20 um, 30 um, 40 um, 50 um or 80 um.

The first skin layer 11 is the innermost layer of the cell pouch 100 and can contact the cell built in the cell pouch 100. The first skin layer 11 may comprise a sealing resin capable of withstanding a high temperature of at least about 60 DEG C, specifically a temperature in excess of about 120 DEG C to about 130 DEG C, and the surface slip of the cell pouch 100 A slip agent may be included to improve the stability of the resin.

The sealing resin can be melted and sealed by heat (having thermal adhesiveness) and can be selected from resins having heat resistance at such high temperatures as described above. It is preferable that the sealing resin has not only thermal adhesiveness and heat resistance but also insulating property, electrolytic solution resistance, cold resistance and the like. Accordingly, in exemplary embodiments, the sealing resin may be random polypropylene (random PP) having a melting temperature ( _Tm ) of about 140 ° C to about 150 ° C.

The slip agent may be at least one selected from fatty acid amide slip agents oleamide, erucamide, behenamide, and stearamide. In exemplary embodiments, the first skin layer 11 may comprise one type of slip agent, wherein the slip agent may be erucamide.

The first skin layer 11 may further include an anti-blocking agent (AB agent) as an additive in addition to the sealing resin and the slip agent. The anti-blocking agent is not particularly limited as long as it can impart blocking resistance to the first skin layer 11 and the cell pouch 100 including the first skin layer 11, and any antiblocking agent may be used.

In the exemplary embodiments, the first skin layer 11, based on the total weight of the first skin layer 11, is about 80 to 90 percent of the random polypropylene, taking into account both improved heat resistance, surface slip properties, weight%; About 5 to 15% by weight of the slip; And about 3 to 5% by weight of the anti-blocking agent. In one embodiment, the first skin layer 11 comprises, based on its total weight, about 84 weight percent of the random polypropylene; About 13% by weight of the slip; And about 3% by weight of the antiblocking agent.

On the other hand, the first skin layer 11 may have a thickness of more than about 5 [mu] m to 7 [mu] m. When the thickness of the first skin layer 11 is about 5 μm or less, the first skin layer 11 and the cell pouch 100 including the first skin layer 11 may not have surface slipperiness.

The core layer 13 may be provided between the first skin layer 11 and the second skin layer 15 to form the sealant layer 10. The core layer 10 may include a sealing resin capable of withstanding a high temperature of about 60 캜 or more, specifically, a temperature in excess of a temperature of about 120 캜 to 130 캜, to improve the surface slip property of the cell pouch 100 The slip agent may be included.

The sealing resin may be selected from among resins having thermal adhesiveness and heat resistance such as a sealing resin included in the first skin layer 11, and in particular, the heat resistance of the sealant layer 10 and the cell pouch 100 including the sealant layer 10 It may be selected from resins having higher heat resistance than the sealing resin included in the first skin layer 11 for further improvement. In addition, in the exemplary embodiments, the sealing resin has a melting temperature ( _Tm ) of about 155 DEG C, preferably not more than < RTI ID = 0.0 & To about 165 < 0 > C (block polypropylene, block PP).

The slip agent may be at least two selected from fatty acid amide slip agents oleamide, erucamide, behenamide, and stearamide.

Unlike the first skin layer 11, which may include one or more slip agents, two or more kinds of slip agents may be blended in the core layer 13, so that the core layer 13 and the cells The pouch 100 can have a further improved surface slip property and further can be improved anti-blocking property and moldability.

In exemplary embodiments, the core layer 13 may comprise a total of two slip agents, including one selected from behenamide and stearamide, and erucamide. have. At this time, considering the difference in characteristics of each of the slip agents with respect to the implementation and maintenance of the surface slip property, behenamide and stearamide (based on the total weight of the slip agent included in the core layer 13) ) May be included in an amount of about 77 to 95% by weight, and erucamide may be included in an amount of about 5 to 23% by weight.

Most preferably, in one embodiment, the core layer 13 may comprise behenamide and erucamide as two slip agents, wherein the core layer 13 contains Based on the total weight of the slip agent, behenamide and erucamide may be included at a ratio of about 91 wt% and about 9 wt%, respectively, i.e. about 10: 1.

Since behenamide has a strong heat and oxidation-resistant property, the cell pouch 100 is deteriorated or damaged even if a high-temperature treatment process (for example, an aging process at about 60 ° C or more) is carried out for a considerable period of time And can have improved surface slip properties. In addition, since behenamide requires a longer time than erucamide for forming a coating film for surface slip property implementation, as a result, a material containing behenamide as a slip agent is used as a slip agent, It may be much more advantageous to implement and maintain the long-term slip properties of the pouch 100. However, when the first skin layer 11 and / or the core layer 13 includes only behenamide as a slip agent, it may take a long time to realize surface slip property, There is a restriction on the improvement of the surface slip property of the cell pouch 100.

Further, the core layer 13 may further include an elastomer. The elastic polymer is not particularly limited as long as it can impart elasticity to the core layer 13 to improve elongation of the cell pouch 100, and any of them can be used. The elastic polymer not only improves the elongation of the cell pouch 100 but also improves the properties of the cell pouch 100 such as the heat bonding strength and the seal sealing strength when heat is applied to the cell pouch 100 .

In the exemplary embodiments, considering all of the improved heat resistance, surface slip resistance, blocking resistance and moldability, the core layer 13 comprises 39 to 49% by weight of the block polypropylene, based on the total weight thereof; 1 to 11 wt% of the slip; And 50 to 60% by weight of the elastomer.

In one embodiment, the core layer 13 comprises, based on its total weight, about 39 wt% of the block polypropylene; About 11% by weight of the slip; And about 50% by weight of the elastomer. Most preferably, in one embodiment, the core layer 13 comprises, based on its total weight, about 39 wt.% Of the block polypropylene; About 10% by weight behenamide; About 1% by weight of erucamide; And about 50% elastomer by weight.

On the other hand, the core layer 13 may have a thickness of about 6 to 66 μm. The thickness range is a value obtained by subtracting the achievable thickness of the first skin layer 11 and the achievable thickness of the second skin layer 15, which will be described later, from the total achievable thickness of the sealant layer 10. In one embodiment, when the sealant layer 10 has a thickness of about 20 um, the core layer 13 may have a thickness of about 6 to 10 um. In one embodiment, when the sealant layer 10 has a thickness of about 50 um, the core layer 13 may have a thickness of about 36 to 40 um. As the core layer 13 has a thicker thickness, the heat bonding strength and heat resistance of the sealant layer 10 can be further improved.

The second skin layer 15 may be provided on the core layer 13 to form the sealant layer 10. The second skin layer 15 may comprise a sealing resin capable of withstanding a high temperature of at least about 60 DEG C, specifically greater than about 120 DEG C to about 130 DEG C, and an elastomer and anti-blocking agent AB agent.

The sealing resin is selected from among resins having thermal adhesiveness and heat resistance as well as insulating properties, electrolytic solution resistance and cold resistance, as well as sealing resins included in the first skin layer 11 and the core layer 13 . Thus, in exemplary embodiments, the sealing resin may be a sealing resin that is substantially the same as the first skin layer 11, i.e. a random polypropylene with a melting temperature (T _m ) of about 140 ° C to about 150 ° C polypropylene, random PP).

The elastic polymer is not particularly limited as long as it can impart elasticity to the second skin layer 15 to improve elongation of the cell pouch 100, and any of them can be used. The antiblocking agent is not particularly limited as long as it can impart blocking resistance to the second skin layer 15 and the cell pouch 100 including the antiblocking agent. Any antiblocking agent may be used. In the exemplary embodiments, the elastomer may be the same as the elastic polymer of the core layer 13, and the antiblocking agent may be the same as the antiblocking agent of the first skin layer 11. The elastic polymer can contribute to the improvement of the elongation of the cell pouch 100, the heat bonding strength, the sealing strength of the impurities and the like, as well as the elongation of the second skin layer 15 which can be in direct contact with the barrier layer 20 , Adhesion (laminating) properties, and the like.

In the exemplary embodiments, the second skin layer 15, based on the total weight of the second skin layer 15, is about 60 to 90% of the random polypropylene, taking into account both improved heat resistance, surface slip property, weight%; About 5 to about 30 weight percent of said elastomer; And about 3 to 5% by weight of the anti-blocking agent.

In particular, when the elastomer is included in an amount of about 5 to 20% by weight, the second skin layer 15 may not show a change with time and may have improved electrolyte resistance. However, when the elastomer is contained in an amount of about 20% by weight or more, the electrolyte may slowly change over time, and electrolyte resistance may deteriorate. When the elastomer is contained in an amount exceeding about 30% by weight, And the electrolytic solution resistance may be greatly deteriorated. As a result, the performance of the cell pouch 100 may be adversely affected.

In one embodiment, the second skin layer 15 comprises about 77 wt% of the random polypropylene, based on its total weight; About 20% elastomer; And about 3% by weight of an antiblocking agent.

On the other hand, the second skin layer 15 may have a thickness of more than about 5 [mu] m to 7 [mu] m. The second skin layer 15 and the cell pouch 100 including the second skin layer 15 may be difficult to have surface slippery property, and in particular, when the thickness of the second skin layer 15 is less than about 5 μm, The second skin layer 15 can be easily damaged due to its thin thickness when the second skin layer 15 is corona treated.

The barrier layer 20 is provided on the sealant layer 10 and can be in contact with the second skin layer 15 to prevent moisture and air from the outside and gases generated therein from being blocked. The barrier layer 20 may include a metal having gas barrier properties and water barrier properties and may be formed of a metal such as aluminum (Al), iron (Fe), copper (Cu), nickel (Ni), tin (A single metal or a mixture of single metals) selected from the group consisting of zinc (Zn), indium (In), tungsten (W) and the like, or two or more alloys selected therefrom. In exemplary embodiments, the barrier layer 20 may comprise aluminum (Al) or an aluminum alloy, taking into account moisture barrier properties, gas barrier properties, and formability.

The barrier layer 20 may have a thickness of about 25 to 45 um for a sufficient degree of gas barrier and water barrier properties. However, the thickness of the barrier layer 20 is not limited to this, but may be a thin-film cell pouch implemented with a cell pouch to be implemented, i.e., a total thickness of about 90 um, A pouch, or a middle- or large-sized cell pouch implemented with a total thickness of about 153 um.

On the other hand, in one embodiment, for the corrosion resistance, the barrier layer 20 may be surface treated with phosphoric acid, chromium, or the like.

The outer layer 30 is an outermost layer of the cell pouch 100 which is provided on the barrier layer 20 and can be exposed to the outside. The outer layer 30 is formed of a material having excellent wear resistance, heat resistance, cold resistance, Insulating property, chemical resistance, moldability, and the like. Thus, in exemplary embodiments, the outer layer 30 may comprise a polyamide-based resin and / or a polyester-based resin. The polyamide-based resin may be nylon having a high elongation and favorable molding. The polyester resin may be polybutylene terephthalate (PBT) or polyethylene terephthalate (PET) which can realize high chemical resistance, pinhole property, insulation property, mechanical strength and the like, May be polybutylene terephthalate (PBT) having a higher elongation than polyethylene terephthalate (PET).

The outer layer 30 may have a thickness of about 15 to 30 탆 in consideration of sufficient abrasion resistance, heat resistance, pinhole resistance, chemical resistance, moldability, and insulation. If the thickness of the outer layer 30 is too thin, the moldability of the cell pouch 100 may be deteriorated due to the lack of strength of the outer layer 30. On the other hand, if it is too thick, the sealant layer 10 (i.e., the first skin layer 11, the core layer 13, and the second skin layer 15) and the barrier layer 20 provided under the outer layer 30 The thickness of the cell pouch 100 must be reduced to a relatively small thickness, which may cause problems such as a decrease in the heat bonding strength and a decrease in the peeling strength between the layers. However, the thickness of the outer layer 30 is not limited to the above range, but may be a thin-film cell pouch implemented with a cell pouch to be used, that is, a cell with a total thickness of about 90 um, A cell pouch, or a medium or large cell pouch implemented with a total thickness of about 153 um.

As described above, the cell pouches according to the exemplary embodiments of the present invention include a sealant layer comprising a sealing resin having a melting temperature ( _Tm ) of about 140 DEG C or higher and having a multi-layer structure, . Accordingly, the cell pouch may not suffer from problems such as a decrease in surface slip property due to a high temperature and a decrease in interlayer adhesion force.

Further, in addition to the sealing resin, the sealant layer may further comprise a slip agent, an antiblocking agent, and an elastomer. More specifically, the first skin layer constituting the sealant layer may further comprise at least one slip agent and an anti- Layer further comprises at least two slip agents and an elastomer and the second skin layer further comprises an elastomer and an antiblocking agent so that the cell pouch not only has excellent surface slip property but also has anti- It can be excellent.

Therefore, the secondary battery, specifically, the lithium ion secondary battery can be effectively packaged using the cell pouch.

Method of manufacturing cell pouch

A cell pouch according to exemplary embodiments of the present invention may be manufactured by performing the following processes.

A multi-layered sealant layer is formed in which the first skin layer, the core layer and the second skin layer, which are the same as described above, are sequentially laminated.

The first skin layer is formed by mixing random polypropylene (random PP) having a melting temperature ( _Tm ) of about 140 DEG C to 150 DEG C and at least one kind of slip described above in a reactor and reacting the same in the same manner as described above For example, by performing a die casting process using the first mixed resin after forming the first mixed resin by adding an inhibitor. The first skin layer may have a thickness of, for example, greater than about 5 micrometers to about 7 micrometers.

The core layer is formed by mixing and reacting block polypropylene (block PP) having a melting temperature (T _m ) of about 155 ° C to 165 ° C, at least two kinds of the same slip as described above, and an elastomer in a reactor to form a second mixed resin And then performing a die casting process using the second mixed resin, for example. In exemplary embodiments, the core layer is formed to comprise, as a slip agent, one selected from behenamide and stearamide, and erucamide at a ratio of 10: 1, respectively, can do. Most preferably, in one embodiment, the core layer may be formed to include behenamide and erucamide at a ratio of 10: 1 as a slip agent. The core layer may be formed to a thickness of, for example, about 6 to 66 μm.

The second skin layer is prepared by mixing and reacting a random PP having a melting temperature ( _Tm ) of about 140 ° C to 150 ° C and the same elastomer as described above in a reactor and adding the same anti- Forming a third mixed resin, and then performing a die casting process using the third mixed resin. The second skin layer may be formed to have a thickness of, for example, greater than about 5 micrometers to about 7 micrometers.

In exemplary embodiments, the sealant layer may be formed by extruding the first skin layer, the core layer, and the second skin layer using an extruder such as a T-die multilayer extruder. The sealant layer may be formed to a thickness of, for example, about 20 to 80 μm, specifically about 20 μm, 30 μm, 40 μm, 50 μm, or 80 μm.

The same barrier layer as described above is formed on the sealant layer using a metal having moisture barrier property and gas barrier property. At this time, the barrier layer is provided on the second skin layer and can directly contact the barrier layer.

In exemplary embodiments, the barrier layer may be formed by depositing a metal, such as aluminum (Al) or an aluminum alloy, as described above to form a metal layer deposited layer, or a metal such as aluminum ) Or a metal foil including an aluminum alloy (Al alloy). The barrier layer may be formed to have a thickness of, for example, about 25 to 45 μm.

The same outer layer as described above is formed on the barrier layer.

In the exemplary embodiments, the outer layer is formed using a polyamide-based resin and / or a polyester-based resin, for example, to have a thickness of about 15 to 30 um can do.

As described above, the cell pouches according to the exemplary embodiments are formed in a multi-layered structure using a sealing resin having a melting temperature ( _Tm ) of about 140 ° C or higher, thereby exhibiting excellent heat resistance. Therefore, even if a process accompanied by a high temperature such as an SD / L process requiring high-temperature aging of about 60 ° C or more is performed during and / or after the production, the cell pouch may not deteriorate or be damaged, The surface slip property may not be lowered and the product can be manufactured so as to have an improved interlayer adhesion.

In addition, since a slip agent, an antiblocking agent and an elastomer are used in addition to the heat resistant resin, a cell pouch having a further improved slipping property and further excellent blocking resistance and moldability can be easily produced.

The present invention will be described in more detail through the following embodiments. It should be understood, however, that the embodiments of the present invention disclosed herein are for illustrative purposes only, and that the embodiments of the present invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein Can not be done.

 [Example 1]

A first mixed resin comprising propylene-ethylene random PP with a T _m of 142 占 폚, plastics and erucamide as a PDB-1121T of people, and AB305 was prepared and used The first skin layer was formed to a thickness of 6 mu m. A second mixed resin comprising a propylene-ethylene block PP, Tm having a T _m of 159.4 ° C, a plastics and erucamide (erucamide) of human PDB-1121T, and a PN series elastomer of Mitsui Chemicals And a core layer having a thickness of 28 micrometers was formed on the first skin layer. (Random PP) having a T _m of 142 ° C, a PN-based elastomer of Mitsui Chemicals Co., Ltd., and a third mixed resin containing AB305 were prepared, and a second skin Layer was formed to a thickness of 6 탆. A barrier layer containing aluminum (Al) was formed on the second skin layer to a thickness of 40 um. Using nylon resin, an outer layer was formed to a thickness of 25 mu m on the barrier layer. Thus, a cell pouch including a first skin layer (random PP + erucamide), a core layer (block PP + erucamide), a second skin layer (random PP), a barrier layer, .

[Example 2]

The same processes as described in Example 1 were carried out except that the first skin layer was formed to further contain behenamide as a slip agent other than erucamide. Thus, a first skin layer (random PP + erucamide + behenamide), a core layer (block PP + erucamide), a second skin layer (random PP), a barrier layer and an outer layer, A cell pouch was fabricated.

[Example 3]

The same processes as described in Example 1 were carried out except that the core layer was formed to further contain behenamide as a slipping agent other than erucamide. Thus, the first and second skin layers (random PP + erucamide), the core layer (block PP + erucamide + behenamide), the second skin layer (random PP), the barrier layer and the outer layer, A cell pouch was fabricated.

[Comparative Example 1]

Except that the core layer was formed so as to contain only a block ethylene-based block polypropylene (block PP) having a T _m of 159.4 ° C without using a slip agent, and a PN-based elastomer of Mitsui Chemicals. The same processes as described above were performed. Thus, a cell pouch including a first skin layer (random PP + erucamide), a core layer (block PP), a second skin layer (random PP), a barrier layer and an outer layer sequentially stacked and having a total thickness of 105 mu was manufactured .

[Comparative Example 2]

(Random PP) having a T _m of 142 占 폚 or a propylene-ethylene block polypropylene (block PP) having a T _m of 159.4 占 폚 and having a melt temperature (T _m ) of 120 Except that the first skin layer, the core layer, and the second skin layer were formed using ter-polypropylene (ter PP) at a temperature of -30 ° C to 130 ° C. Respectively. Thus, a cell pouch having a total thickness of 105 um and including a first skin layer (ter PP + erucamide), a core layer (ter PP + erucamide), a second skin layer (ter PP) .

Characterization of cell pouches

In order to evaluate the characteristics of the cell pouches according to the exemplary embodiments of the present invention, the cell pouches prepared according to Examples 1 to 3 and Comparative Examples 1 and 2 were subjected to surface treatment using the method described in [Table 1] Slip property, moldability and blocking resistance were tested. The results are shown in [Table 1].

Item How to measure unit Comparative Example 2 Comparative Example 1 Example 1 Example 2 Example 3 Sealant layer thickness ASTM-374 um 40 40 40 40 40 Slipperiness Labthink Friction / Peel
Tester The second skin layer /
The second skin layer mS 0.106 0.114 0.077 0.125 0.053 mD 0.102 0.098 0.054 0.107 0.041 The second skin layer /
The first skin layer mS 0.127 0.119 0.64 0.111 0.045 mD 0.105 0.105 0.055 0.087 0.039 The first skin layer /
The first skin layer mS 0.283 0.101 0.069 0.85 0.049 mD 0.111 0.087 0.033 0.062 0.004 Formability YCC Method mm 4.5 to 5.0 5.0 to 5.5 6.0 to 6.5 5.0 to 5.5 7.0 to 7.5 My blocking ability Sheet lamination method - △ △ ○ ○ ◎

Excellent (◎) Good (○) Average (△) Dissatisfied (X)

Referring to [Table 1], the cell pouches prepared according to Examples 1 to 3 were excellent in surface slip property, moldability and blocking resistance. Particularly, the cell pouch prepared according to Example 3, in which the first skin layer contains one kind of slip agent and the core layer contains two kinds of slip agents, has the best surface slip property, formability and blocking resistance .

Thus, a sealant layer having a multi-layer structure is formed using a sealing resin having improved heat resistance, wherein the first skin layer of the sealant layer is formed to include at least one slip agent, and the core layer includes two or more slip agents It is possible to easily manufacture a cell pouch capable of effectively packaging a secondary battery, specifically, a lithium ion secondary battery.

10: sealant layer
11: First skin layer
13: core layer
15: Second skin layer
20: barrier layer
30: outer layer
100: cell pouch

Claims (13)

1. A cell pouch comprising:
A multi-layered sealant layer comprising a first skin layer, a core layer and a second skin layer which are sequentially stacked;
A barrier layer formed on the sealant layer; And
And an outer layer formed on the barrier layer,
Wherein the first skin layer comprises random polypropylene (random PP) and a slip agent having a melting temperature ( _Tm ) of 140 ° C to 150 ° C,
Wherein the core layer comprises a block polypropylene (block PP) having a melting temperature ( _Tm ) of 155 DEG C to 165 DEG C and a slipping agent,
Wherein the second skin layer comprises random PP having a melting temperature (T _m ) of 140 ° C to 150 ° C,
The slip agent is a fatty acid amide slip agent selected from oleamide, erucamide, behenamide, and stearamide,
Wherein the first skin layer includes at least one slip agent,
Wherein the core layer comprises, as a slip agent, one selected from behenamide and stearamide, and erucamide. delete The method according to claim 1,
Based on the total weight of the slip agent contained in the core layer,
One selected from among behenamide and stearamide is included in an amount of 77 to 95% by weight,
And erucamide in an amount of 5 to 23% by weight. The method according to claim 1,
The first skin layer
Further comprising an anti-blocking agent (AB agent)
Based on the total weight of the first skin layer
80 to 90 wt% of the random polypropylene;
3 to 5% by weight of the antiblocking agent; And
And 5 to 15% by weight of the slip. The method according to claim 1,
The core layer
Further comprising an elastomer,
Based on the total weight of the core layer
39 to 49% by weight of the block polypropylene;
50 to 60% by weight of said elastomer; And
And 1 to 11% by weight of the slip. The method according to claim 1,
The second skin layer
Further comprising an elastomer and an anti-blocking agent,
Based on the total weight of the second skin layer
60 to 90% by weight of the random polypropylene;
5 to 30% by weight of the elastomer; And
And 3 to 5% by weight of the antiblocking agent. The method according to claim 1,
Wherein the barrier layer comprises at least one metal having gas barrier properties and moisture barrier properties. The method according to claim 1,
Wherein the outer layer comprises at least one selected from a polyamide-based resin and a polyester-based resin. The method according to claim 1,
Wherein the first skin layer is in contact with a cell embedded in the cell pouch as an innermost layer of the cell pouch,
The outer layer is exposed to the outside as an outermost layer of the cell pouch,
Wherein the barrier layer is formed on and in contact with the second skin layer. The method according to claim 1,
Wherein the cell pouch is a cell pouch for a secondary battery. 11. The method of claim 10,
Wherein the secondary battery is a lithium ion secondary battery. A method of manufacturing a cell pouch according to any one of claims 1 and 3 to 11,
Forming a multi-layered sealant layer including a sequentially sequentially stacked first skin layer, a core layer, and a second skin layer;
Forming a barrier layer on the sealant layer; And
Forming an outer layer on the barrier layer,
The first skin layer is formed to include a random polypropylene (random PP) having a melting temperature (T _m ) of 140 ° C to 150 ° C and a slip agent,
The core layer is formed to include a block polypropylene (block PP) having a melting temperature ( _Tm ) of 155 DEG C to 165 DEG C and a slipping agent,
Wherein the second skin layer is formed to include random PP having a melting temperature (T _m ) of 140 ° C to 150 ° C. 13. The method of claim 12,
The formation of the sealant layer
And extruding the first skin layer, the core layer and the second skin layer using an extruder.

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