KR20060059699A - Pouch type lithium secondary battery and method of using the same - Google Patents

Abstract

The pouch type lithium secondary battery of the present invention and a manufacturing method using the same include a core pack having a protective element and an external terminal installed in a bare cell in which an electrode assembly is accommodated in a pouch, a hard cover covering at least a portion of the core pack, and a hard cover. Since it includes a molding material for molding the core pack portion and the hard cover peripheral portion that is not protected by the cover, there is an advantage that the portion to apply the molding material to receive the pouch by applying the molding material to only the side of the hard cover to minimize.

Description

Pouch type secondary battery and manufacturing method using same {Pouch type Lithium Secondary Battery and Method of using the same}

1 is a view illustrating a state in which an electrode assembly is accommodated in a pouch according to the present invention;

2 is an exploded perspective view of a pouch type secondary battery according to the present invention;

3 is a perspective view of a pouch type secondary battery according to the present invention;

4 is a view illustrating a method of manufacturing a pouch type secondary battery according to the present invention.

<Brief Description of Major Codes in Drawings>

150: electrode assembly 170: protection device

180: external terminal 200: pouch

210: drawing unit 220: molding material

300: hard cover 320: first hard cover

321,331: Side cover part 323,333: Notch

330: second hard cover

The present invention relates to a pouch type secondary battery, and more particularly, to a pouch type lithium secondary battery in which an electrode assembly including a positive electrode, a negative electrode, and a separator is accommodated in a pouch, and a manufacturing method using the same.

Recently, compact and lightweight electric / electronic devices such as cellular phones, notebook computers, camcorders, etc. have been actively developed and produced. These portable electric / electronic devices have a battery pack that can be operated in a place where no separate power source is provided. The built-in battery pack includes at least one battery therein for outputting a predetermined level of voltage for driving the portable electric / electronic device for a period of time.

In consideration of economical aspects, battery packs employ secondary batteries that can be charged and discharged in recent years. Typical secondary batteries include nickel secondary batteries such as nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni-MH) batteries, lithium (Li) batteries, and lithium ion (Li-ion) batteries.

In particular, the lithium secondary battery has an operating voltage of 3.6 V, which is three times higher than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for portable electronic equipment, and is rapidly expanding in terms of high energy density per unit weight. to be.

Such lithium secondary batteries mainly use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials. In general, a battery is classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of electrolyte, and a battery using a liquid electrolyte is called a lithium ion battery, and a battery using a polymer electrolyte is called a lithium polymer battery. Moreover, although a lithium secondary battery is manufactured in various shapes, typical shapes include cylindrical shape, square shape, and pouch type.

In general, a lithium secondary battery is positioned between a positive electrode plate coated with a positive electrode active material, a negative electrode plate coated with a negative electrode active material, and a positive electrode plate and a negative electrode plate to prevent a short and to move only lithium ions (Li-ion). The electrode assembly which enables the separator to be wound up, the lithium secondary battery case which accommodates an electrode assembly, and the electrolyte solution injected into the lithium secondary battery case inside, and enable movement of lithium ion etc. are comprised.

When the lithium secondary battery is classified according to the type of electrolyte, the lithium secondary battery may be classified into a lithium metal battery using a liquid electrolyte, a lithium ion battery, and a lithium ion polymer battery using a polymer solid electrolyte.

In the case of a fully solid lithium ion polymer battery, there is no problem of leakage of the organic electrolyte, and even in the case of a gel type lithium ion polymer battery containing the organic electrolyte, the problem of leakage of the electrolyte is simpler than that of the lithium ion battery using the liquid electrolyte. Can be prevented. For example, a lithium ion polymer cell may use a pouch instead of a metal can as the container of the electrode assembly.

The pouch is usually composed of a metal foil layer and a multilayered film covering the synthetic resin layer. When the pouch is used, the weight of the battery can be significantly reduced than when using a metal can. Aluminum is usually used as the metal forming the foil in the multilayer film pouch. The polymer membrane, which constitutes the pouch membrane inner layer, protects the metal foil from the electrolyte and prevents short circuits between the positive and negative electrodes and the electrode tabs.

In order to form a pouch-type lithium secondary battery, an electrode assembly formed by first stacking or winding a cathode, a separator, and a cathode is placed in a pouch in a sealed state. When the upper and lower pouch membranes are heat-sealed at the open edge of the pouch, a sealed pouch-type bare cell battery is formed.

A core pack battery is formed by attaching an accessory or a structure such as a protective corrugated mold (PCM) or a positive temperature coefficient (PTC) to a bare cell battery.

Bonding the core pack battery into the hard case forms a completed pouch-type lithium secondary battery.

Here, the hard case is to be installed on the outer surface of the pouch to protect the outer surface of the soft pouch, the bonding is bonded by melting the binder by applying a binder melted by heat between the pouch and the hard case.

However, such a conventional pouch has a problem in that the electrode assembly housed in the pouch is deformed due to heat melting the binder as the binder melted by the heat is applied to the pouch. That is, the electrode assembly may be deformed by high heat to cause a failure of the battery or to explode to cause a safety accident.

In addition, since the hard case is formed larger than the size of the pouch for accommodating the pouch therein, the size of the hard case is increased.

The present invention has been made to solve the problems described above, an object of the present invention is to manufacture a pouch-type lithium secondary battery and minimize the application of the binder to secure the combination of the hard cover and the pouch to protect the pouch and manufacturing using the same To provide a way.

The present invention for achieving the above object is a core pack having a protective element and an external terminal installed in the bare cell formed by receiving the electrode assembly in the pouch, a hard cover to cover at least a portion of the core pack, and the hard cover The present invention provides a pouch type lithium secondary battery including a core pack portion which is not protected and a molding material for molding the hard cover peripheral portion.

The molding material is an insulator, and may be hot melt or silicon, epoxy, or urethane.

Preferably, the hard cover covers the maximum area of the bare cell.

The pouch may be formed by the drawing portion on one side and covered by the other side bent.

The hard cover may be installed on a surface on which the drawing portion of the pouch is formed and a surface covering the drawing portion.

The hard cover may be divided into a first hard cover and a second hard cover.

The long side edge portion of the hard case may have a side cover portion covering the side of the pouch.

Preferably, the side cover portion is formed with a notch.

The molding material is preferably applied to the side cover portion of the hard cover.

The electrode assembly is accommodated in a pouch to form a bare cell, a protective element and an external terminal are coupled to the bare cell by molding to form a core pack, and a hard cover coupled to the core pack is formed by a molding material. It provides a pouch-type lithium secondary battery manufacturing method comprising the step of being combined.

Hereinafter, a pouch-type lithium secondary battery according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view illustrating a state in which an electrode assembly is accommodated in a pouch according to the present invention, FIG. 2 is an exploded perspective view of the pouch type secondary battery according to the present invention, and FIG. 3 is a perspective view of the pouch type secondary battery according to the present invention. to be.

Referring to these drawings, the pouch-type lithium secondary battery includes an electrode assembly 150 including the first and second electrode plates 110 and 120 and the separator 130, and the electrode assembly 150 to form a bare cell. A protective device 170 electrically connected to the pouch 200 and the electrode assembly 150 and forcibly blocking the flow of current when an abnormality occurs, an external terminal 180 electrically connected to the protective device 170, and a bare Combining the hard cover 300 and the core pack and the hard cover 300 to cover at least a portion of the core pack formed by connecting the protective element 170 and the external terminal 180 to the cell and protected by the hard cover 300 It comprises a molding material 220 for molding the periphery of the hard cover 300 is not.

The electrode assembly 150 is disposed between the first and second electrode plates 110 and 120 coated with the first and second electrode active material layers, and the first and second electrode plates 110 and 120 to form the first and second electrode plates 110 and 120. The separator 130 is wound around the short circuit to prevent the short circuit and to allow the movement of lithium ions. The first and second electrode tabs 141 and 143 are drawn out to the first and second electrode plates 110 and 120, respectively.

In this case, the first electrode plate 141 may be an anode, and the second electrode plate 143 may be a cathode.

Herein, a chalcogenide compound is used as the cathode active material, and complex metal oxides such as LiCo02, LiMn204, LiNi02, LiNi1-xCox02 (0 <x <1), and LiMn02 are used. As the negative electrode active material, carbon (C) -based materials, Si, Sn, tin oxides, composite tin alloys, transition metal oxides, and lithium metal oxides are used. In addition, in general, the anode electrode plate is made of aluminum (Al), the cathode electrode plate is made of copper (Cu), and the separator 130 generally uses polyethylene (PE) or polypropylene (PP). It is not limited to the above materials.

The pouch 200 may have a substantially rectangular shape, and a drawing portion 210 having a predetermined depth may be formed at one side so that the electrode assembly 150 may be accommodated, and the other side may be bent to correspond to the drawing portion 210. It is made to cover 210. The material of the pouch 200 includes a core made of a metal material such as aluminum (Al), a heat seal layer formed on the top surface of the core, and an insulating film formed on the bottom surface of the core. The heat-sealing layer serves as an adhesive layer using a modified polypropylene, for example, a polymer resin, such as CPP (Casted Polypropylene), and the insulating film may be a resin material such as nylon or polyethylene terephthalate (PET), but the material of the pouch 200 may be It is not limited.

On the other hand, the first and second electrode tabs 141 and 143 drawn to the outside of the pouch 200 are connected with the insulating member 160 therebetween, and the protection device 170 to block the flow of current in the event of an abnormal battery, such as a short circuit. Is installed.

The protection element 170 is connected to the external terminal 180 exposed to the outside by the connection lead 171. The external terminal 180 is a portion directly connected to an external electrical terminal during charging.

The hard cover 300 may accommodate the pouch 200 and the protection element 170 and the external terminal 180 installed to be connected to the pouch 200 and cover at least a part surface of the pouch 200 but have a maximum area. It is preferable to cover the surface to protect the outer surface of the pouch 200.

In addition, the hard cover 300 is divided into a first hard cover 320 and a second hard cover 330.

When the drawing unit 210 is formed on one side of the pouch 200, the first hard cover 320 is coupled to the surface on which the drawing unit 210 is formed in the pouch 200, and the second hard cover 330 is drawing. It is coupled to the surface located to correspond to the portion (210). In this case, the side cover parts 321 and 331 are formed at the edges of the long sides of the first and second hard covers 320 to cover the sides of the pouch 200, and the side cover parts 321 and 331 have side surfaces of the hard cover 300. A plurality of notches 323 and 333 in which the side cover parts 321 and 331 are partially cut off are formed to facilitate coupling of overlapping portions of the cover parts 321 and 331.

That is, when the hard cover 300 is installed to surround the pouch 200, the side cover parts 321 and 331 positioned at the side of the pouch 200 flow by the notches 323 and 333, and thus, the first hard cover 320 of the first hard cover 320. The side cover part 321 and the side cover part 331 of the second hard cover 330 overlap.

The molding material 220 may typically be used as an insulator that may insulate the pouch 200 from the outside. In addition, any one of silicone, epoxy, and urethane may be used. However, the kind is not limited here.

The molding material 220 molds the protective element 170 and the external electrons 180 connected to the bare cell and couples them to the upper side of the pouch 200. In addition, the molding member 220 is applied to the side cover parts 231 and 331 of the hard cover 300 to cover the core pack portion and the hard cover 300 peripheral portion which are not protected by the hard cover 300, and the first hard cover ( 320 and the second hard cover 330 are combined.

Hereinafter, a method of manufacturing the pouch type lithium secondary battery made as described above will be described.

First, the electrode assembly 150 is accommodated in one side drawing part 210 of the pouch 200.

The other side of the pouch 200 in which the electrode assembly 150 is accommodated is bent to cover the drawing part 210 of the pouch 200 at a position corresponding to the drawing part 210. At this time, in the pouch 200, the first and second electrode tabs 141 and 143 connected to the first and second electrode plates 110 and 120 of the electrode assembly 150 are drawn out of the pouch 200. The other side of the pouch 200 is bent to cover the drawing portion 210 to seal the edge of the pouch 200 to form a bare cell. (S310)

Next, the protection element 170 and other structures are disposed around the first and second electrode tabs 141 and 143 drawn out of the pouch 200, and the first and second electrode tabs 141 and 143 are disposed around the first and second electrode tabs 141 and 143. It is electrically connected to the two electrode tabs 141 and 143. The protection device 170 is electrically connected to the external terminal 180 exposed to the outside to form a core pack. (S320)

First and second hard covers 320 and 330 are installed on the wide surface of the core pack, that is, the surface on which the drawing portion 210 of the pouch 200 is formed and the outer surface of the pouch 200 corresponding to the drawing portion 210. At this time, the side cover portion 321 of the first hard cover 320 and the side cover portion 331 of the second hard cover 330 flow by the notches 323 and 333 at the side portions of the pouch 200 and overlap. To be installed. Therefore, the core pack is accommodated in the hard cover 300. (S330)

Next, a molding material 220 is coated on the side cover parts 321 and 331 of the hard cover 300. Here, the protection element 170 and the external terminal 180 forming the core pack are also formed by the molding material 220. Molded. (S340)

Accordingly, the pouch 200 is accommodated in the hard cover 300 by the molding material 220, and the molding material 220 is applied only to the side of the hard cover 300.

As described above, the pouch-type lithium secondary battery of the present invention has an advantage of minimizing a portion of the molding material since the molding material is applied to only the side of the hard cover to accommodate the pouch.

In addition, since the hard cover is separated into a first hard cover and a second hard cover to be in contact with the surface of the pouch, there is an advantage of minimizing the size of the hard cover.

Claims (12)

A core pack in which a protective element and an external terminal are installed in a bare cell formed by accommodating an electrode assembly in a pouch; A hard cover covering at least a portion of the core pack; And a molding material for molding the core pack portion and the hard cover peripheral portion which are not protected by the hard cover. The method of claim 1, The molding material is a pouch type lithium secondary battery, characterized in that the insulator. The method of claim 2, The molding material is a pouch type lithium secondary battery, characterized in that the hot melt. The method of claim 2, The molding material is a pouch type lithium secondary battery, characterized in that any one of silicon, epoxy, urethane. The method of claim 1, The hard cover is a pouch type lithium secondary battery, characterized in that for covering the maximum surface area of the bare cell. The method of claim 5, The pouch is a pouch type lithium secondary battery, characterized in that the drawing portion is formed on one side and covered by the other side bent. The method of claim 6, The hard cover is a pouch-type lithium secondary battery, characterized in that installed on the surface formed with the drawing portion of the pouch and the surface covering the drawing portion. The method of claim 7, wherein The hard cover is a pouch type lithium secondary battery, characterized in that divided into a first hard cover and a second hard cover. The method of claim 8, Pouch-type lithium secondary battery, characterized in that the long side edge portion of the hard case is formed with a side cover portion covering the side of the pouch. The method of claim 9, The side cover portion is a pouch type lithium secondary battery, characterized in that the notch (Notch) is formed. The method of claim 9, The molding material is a pouch type lithium secondary battery, characterized in that applied to the side cover portion of the hard cover. Receiving an electrode assembly in a pouch to form a bare cell; Forming a core pack by coupling a protective element and an external terminal to the bare cell by molding; And The hard cover is coupled to the core pack is bonded by a molding material; pouch type lithium secondary battery manufacturing method comprising a.

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