KR20130063709A - Pouch for secondary battery and secondary battery using the same - Google Patents

Abstract

PURPOSE: A pouch exterior for a secondary battery is provided to prevent corrosion by preventing oxidation of a thin metal film even when microcracks are formed on an internal resin layer. CONSTITUTION: A pouch exterior for a secondary battery comprises an inner resin layer(110), a thin metal layer(130), and an external resin layer(140). A buffer layer with a smaller reactivity than the thin metal layer is formed on the side which is in contact with the thin metal layer. The thin metal layer is formed of aluminum metal. The buffer layer consists of one or more metals selected from copper, silver, platinum, and gold and has a thickness of 100 nm - 10 micron. A secondary battery includes the pouch exterior.

Description

Pouch exterior material for secondary battery and secondary battery using same {Pouch for secondary battery and secondary battery using the same}

The present invention relates to a pouch exterior material for a secondary battery and a secondary battery using the same.

As the use of portable electric products such as video cameras, portable telephones and portable PCs is activated, the importance of secondary batteries mainly used as driving power thereof is increasing. In particular, lithium secondary batteries have higher energy density per unit weight and can be rapidly charged compared to other lead-acid batteries and other secondary batteries such as nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. It is actively underway.

Unlike primary batteries that are not normally rechargeable, rechargeable batteries that are capable of charging and discharging are being actively researched by the development of high-tech fields such as digital cameras, cellular phones, notebook computers, and hybrid cars. Examples of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and lithium secondary batteries. Among these, lithium secondary battery is used as a power source for portable electronic devices with an operating voltage of 3.6V or more, or used in high-power hybrid vehicles by connecting several in series, which operates compared to nickel-cadmium batteries or nickel-metal hydride batteries. The voltage is three times higher and the energy density per unit weight is also excellent and is being used rapidly.

The lithium secondary battery may be classified into a lithium ion battery using a liquid electrolyte and a lithium ion polymer battery using a polymer solid electrolyte according to the type of electrolyte. Lithium ion polymer batteries can be classified into fully solid lithium ion polymer batteries containing no electrolyte solution and lithium ion polymer batteries using gel polymer electrolyte containing electrolyte solution, depending on the type of polymer solid electrolyte.

In the case of a lithium ion battery using a liquid electrolyte, it is usually used in a form in which a cylinder or a rectangular metal can is used as a container and welded and sealed. Since the can type secondary battery using the metal can as a container has a fixed shape, there is a disadvantage in restricting the design of the electric product using the power source, and it is difficult to reduce the volume. Therefore, a pouch type secondary battery that uses two electrodes, a separator, and an electrolyte in a pouch made of a film and is sealed is used.

The pouch of a lithium ion polymer battery which is commonly used has an inner resin layer which sequentially has a thermal adhesiveness and acts as a sealing material, and acts as a metal foil layer, a substrate and a protective layer which serves as a barrier layer of water and oxygen while maintaining mechanical strength. It consists of a multilayer film structure laminated | stacked by the outer resin layer.

Pouch type secondary battery has the advantage that can be flexible in form and to implement a secondary battery of the same capacity with a smaller volume and mass. However, unlike the can type, the pouch type has a problem that the metal foil layer is easily oxidized in case of damage such as micro cracks in the inner resin layer, and the pouch exterior of the battery is easily eroded. It is a required situation.

The present invention provides a battery pouch packaging material including an inner resin layer, a metal foil layer, and an outer resin layer, wherein a buffer layer having a smaller reactivity than the metal foil layer is formed on a surface where the inner resin layer and the metal foil layer are in contact with each other. To provide a pouch exterior material.

However, the technical problem to be solved by the present invention is not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

The present invention provides a battery pouch packaging material including an inner resin layer, a metal foil layer, and an outer resin layer, wherein a buffer layer having a smaller reactivity than the metal foil layer is formed on a surface where the inner resin layer and the metal foil layer are in contact with each other. Pouch exterior material.

In one embodiment of the present invention, a secondary battery including a pouch exterior of the battery is provided.

In another embodiment of the present invention, there is provided a medium-large battery module or a battery pack comprising a plurality of the secondary battery electrically connected.

The present invention relates to a pouch packaging material for a secondary battery and a secondary battery using the same. The pouch packaging material of the battery according to the present invention additionally forms a buffer layer having a smaller reactivity than the metal foil layer, thereby causing micro cracks in the inner resin layer. Even if it is damaged, the corrosion of the pouch packaging material of the battery can be prevented by preventing the oxidation reaction of the metal foil layer.

1 is a structure of a pouch case of a conventional battery composed of an inner resin layer, a metal foil layer, and an outer resin layer.
Figure 2 is a structure of a pouch packaging material of a battery according to an embodiment of the present invention consisting of an inner resin layer, a buffer layer, a metal foil layer, and an outer resin layer.
Figure 3 illustrates a secondary battery including a pouch case of the battery according to an embodiment of the present invention.

Conventionally, no attempt has been made to introduce a buffer layer to prevent corrosion in a pouch packaging material of a battery. Accordingly, the present inventors have confirmed that by further forming a buffer layer having a smaller reactivity than the metal foil layer in the pouch packaging material of the battery, it is possible to prevent corrosion of the pouch packaging material of the battery and completed the present invention.

Specifically, in the pouch packaging material of the battery consisting of the inner resin layer, the metal foil layer, the outer resin layer, a buffer layer having a less reactive than the metal foil layer is formed on the surface where the inner resin layer and the metal foil layer abut. A pouch packaging material for a battery is provided.

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

While the invention allows for various modifications and variations, specific embodiments thereof are illustrated by way of example in the drawings and will be described in detail below. However, it is not intended to be exhaustive or to limit the invention to the precise forms disclosed, but rather the invention includes all modifications, equivalents, and alternatives consistent with the spirit of the invention as defined by the claims.

1 is a structure of a pouch case of a conventional battery composed of an inner resin layer, a metal foil layer, and an outer resin layer.

As shown in FIG. 1, the pouch packaging material 100 of a conventional battery has a structure including an inner resin layer 110, a metal foil layer 130, and an outer resin layer 140. In addition, a tape may be formed between the inner resin layer 110 and the metal foil layer 130, between the metal foil layer 130 and the outer resin layer 140, or both, to improve adhesion, and the battery pouch exterior material 100 ) Is generally 40 to 180㎛, the inner resin layer 110 and the outer resin layer 140 is 10 to 40㎛, metal foil layer 130 is preferably 20 to 100㎛, but is not limited thereto. Do not.

The inner resin layer 110 constituting the pouch exterior material of the battery serves as a sealing material having a heat-adhesive layer, and modified propylene or polypropylene-butylene-ethylene terpolymer such as unstretched polypropylene (CPP). And the like can be used. In this case, the inner resin layer 110 may be formed on the lower surface of the metal foil layer 130 by coating or laminating to a thickness of approximately 10 to 40 μm.

The metal foil layer 130 constituting the pouch packaging material of the battery serves as a barrier layer for preventing moisture and oxygen from penetrating from the outside while maintaining mechanical strength by maintaining an appropriate thickness. ) Is preferably made of at least one metal selected from iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), and aluminum (Al), but is not limited thereto. However, when the metal foil layer 130 is made of aluminum (Al), the flexibility is maintained while maintaining mechanical strength, and the metal foil layer 130 is more preferably made of aluminum (Al) metal. In this case, the metal foil layer 130 may be formed by coating or laminating a thickness of approximately 20 to 100 μm on the bottom surface of the outer resin layer 140.

The outer resin layer 140 constituting the pouch packaging material of the battery serves as a substrate and a protective layer, and may be generally nylon or polyethylene terephthalate. In this case, the outer resin layer 140 may be formed to a thickness of approximately 10 to 40 ㎛.

However, when the internal resin layer 110 is damaged such as micro cracks, the metal foil layer 130 is directly exposed to the electrolyte, so that the oxidation reaction of the metal foil layer 130 proceeds, and the lithium-aluminum alloy ( As the Li-Al alloy continues to grow, micro pores are formed in the pouch packaging material 100 of the battery, and moisture and oxygen penetrate from the outside, thereby causing corrosion of the pouch packaging material 100 of the battery.

Figure 2 is a structure of a pouch packaging material of a battery according to an embodiment of the present invention consisting of an inner resin layer, a buffer layer, a metal foil layer, and an outer resin layer.

As shown in Figure 2, the pouch packaging material 100 of the battery according to an embodiment of the present invention is a battery pouch packaging material consisting of the inner resin layer 110, the metal foil layer 130, the outer resin layer 140. In (100), a buffer layer 120 having a smaller reactivity than the metal foil layer 130 is further formed on a surface where the inner resin layer 110 and the metal foil layer 130 contact each other.

The buffer layer 120 constituting the pouch packaging material of the battery is characterized in that it is made of a metal less reactive than the metal foil layer (130). The term "small reactive metal" used in the present invention refers to a "metal having a low tendency to ionize," and a metal having low reactivity is a metal which is relatively easy to obtain electrons. Accordingly, when the internal resin layer 110 is damaged, such as micro cracks, the metal foil layer 130 is prevented from being oxidized by the metal foil layer 130 exposed to the electrolyte, thereby preventing the pouch packaging material of the battery. It serves to prevent corrosion of the (100).

The buffer layer 120 is preferably made of at least one metal selected from copper, silver, platinum, and gold, which is less reactive than the metal foil layer 130, but is not limited thereto. At this time, the thickness of the buffer layer 120 is not particularly limited, but the buffer layer 120 is preferably 100 nm to 10 ㎛ thickness. When the thickness of the buffer layer 120 is less than 100 nm, there is a problem in that it does not effectively prevent the oxidation reaction of the metal foil layer 130 and thus does not properly perform the role of the buffer layer 120, and the thickness of the buffer layer 120 exceeds 10 μm. The disadvantage is that it becomes difficult to form the pouch case.

In addition, the present invention provides a secondary battery comprising a pouch case of the battery.

Figure 3 illustrates a secondary battery including a pouch case of the battery according to an embodiment of the present invention.

As shown in FIG. 3, the secondary battery 10 including the pouch sheathing material of the battery is composed of the pouch sheathing material 100 of the battery in which the electrode assembly 200 and the electrolyte are added and sealed by heat fusion. It can have flexibility, and there is an advantage that can implement a secondary battery of the same capacity with a smaller volume and mass. In particular, the buffer layer 120, which is a component of the pouch packaging material 100 of the battery, prevents oxidation of the metal foil layer 130, thereby preventing corrosion of the pouch packaging material 100 of the battery.

In addition, the pouch packaging material 100 of the battery is for accommodating the electrode assembly 200, characterized in that the pouch packaging material front portion of the battery and the pouch packaging material rear portion of the battery, characterized in that the form is not particularly limited. In FIG. 3, although the groove for accommodating the electrode assembly 200 is formed only in the rear portion of the pouch sheath of the battery, the groove for accommodating the electrode assembly 200 is formed in both the front pouch sheath of the battery and the rear portion of the pouch sheath of the battery. It may have a formed shape.

The electrode assembly 200 according to the present invention includes a cathode 210 including a cathode active material, a cathode 220 including a cathode active material, and a separator 230.

Specifically, the positive electrode 210 is manufactured by, for example, applying a mixture of a positive electrode active material, a conductive agent, and a binder onto a positive electrode current collector, followed by drying. If necessary, a filler may be further added to the mixture. . The cathode 220 is fabricated by applying an anode material on an anode current collector and drying the cathode material, and if necessary, may further include the components as described above. The separator 230 for separating the electrodes from each other between the anode and the cathode may be a known polyolefin separator or a composite separator having an organic-inorganic hybrid layer formed on the olefin-based substrate.

In addition, the electrode assembly 200 may further include a positive electrode tab connected to the anode 210 and a negative electrode tab connected to the cathode 220. In FIG. 3, the electrode assembly 200 in which the positive electrode tab and the negative electrode tab are formed in the same direction. ), The positive electrode tab and the negative electrode tab may be formed in opposite directions to each other.

In addition, the electrolyte according to the present invention is a lithium salt-containing non-aqueous electrolyte, which consists of a non-aqueous electrolyte and lithium. As the nonaqueous electrolyte, a nonaqueous electrolyte, a solid electrolyte, an inorganic solid electrolyte, and the like are used.

In addition, the present invention provides a medium-large battery module or a battery pack, characterized in that it comprises a plurality of the secondary battery electrically connected.

The medium-large battery module or battery pack includes an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV); Electric trucks; Electric commercial vehicle; Or it can be used as a power source for any one or more of the system for power storage.

As described above, the buffer layer applied to the secondary battery according to the present invention is characterized in that the metal is made of less reactive than the metal foil layer. Accordingly, even when the internal resin layer is damaged, such as micro cracks, the metal foil layer is prevented from being oxidized by exposure of the metal foil layer to the electrolyte, thereby preventing corrosion of the pouch packaging material of the battery.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

10: secondary battery
100: battery pouch packaging material
110: inner resin layer
120: buffer layer
130: metal foil layer
140: outer resin layer
200: electrode assembly
210: anode
220: cathode
230: separator

Claims (9)

In the pouch packaging material of the battery consisting of an inner resin layer, a metal foil layer, an outer resin layer,
And a buffer layer having a smaller reactivity than the metal foil layer is formed on a surface where the inner resin layer and the metal foil layer are in contact with each other.
The method of claim 1,
The metal foil layer is a pouch case of a battery, characterized in that the aluminum metal.
The method of claim 1,
The buffer layer is a battery pouch packaging material, characterized in that made of at least one metal selected from copper, silver, platinum, and gold.
The method of claim 1,
The buffer layer is a pouch packaging material, characterized in that the thickness of 100 nm to 10 ㎛.
Secondary battery comprising a pouch case of the battery according to claim 1.
A medium-large battery module comprising a plurality of secondary batteries according to claim 5 electrically connected to each other.
The method according to claim 6,
The medium-large battery module includes an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV); Electric trucks; Electric commercial vehicle; Or medium to large battery module, characterized in that used as a power source for any one or more of the medium or large power storage system.
A medium to large battery pack comprising a plurality of secondary batteries according to claim 5 electrically connected.
The method of claim 8,
The medium-large battery pack may include an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV); Electric trucks; Electric commercial vehicle; Or medium-large battery pack, characterized in that used as a power source for any one or more of the system for power storage.

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