KR101211217B1 - Pouch type secondary battery capable of preventing short between electrode lead - Google Patents

Abstract

PURPOSE: A pouch type secondary battery is provided to prevent a short circuit between electrode leads because each of the electrode leads are not contacted to each other even if an external material is expanded due to abnormal circumstances such as an increase of inner pressure of a battery, physical impacts from outside, etc. CONSTITUTION: A pouch type secondary battery comprises: an electrode assembly(100) which comprises a positive electrode coated with a positive electrode active material, a negative electrode coated with a negative electrode active material, and a separator interposed between the positive and negative electrodes; external material(200) accepting the electrode assembly; a positive electrode lead(110) and negative electrode lead(120) which protrude in a same direction from the external material by being connected to the positive electrode and negative electrode respectively; and an insulating unit(300) interposed between the positive electrode lead and the negative electrode lead. The insulating unit has a thickness corresponding with a separate distance between the positive electrode lead and negative electrode lead.

Description

Pouch type secondary battery capable of preventing short between electrode lead}

The present invention relates to a pouch type secondary battery capable of preventing a short circuit between electrode leads.

In general, a battery is capable of supplying electrical energy including a cathode or a positive electrode and an anode or a negative electrode separated from each other by a separator and an electrolyte that enables ion transfer between the two electrodes. will be.

Such a battery is classified into a primary battery (general battery), which is discarded after one use, and a secondary battery, which can be reused through charging.

Recently, the demand for rechargeable batteries that can be recharged and miniaturized and large-capacity is rapidly increasing due to the spread of portable electronic devices such as mobile phones, laptops, PDAs, etc. As a result, secondary battery performance is gradually improved and mass-produced.

Examples of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and lithium secondary batteries. Among these, lithium secondary batteries are used as power sources for portable electronic devices with an operating voltage of 3.6 V or higher, or used in high-power hybrid vehicles by connecting several in series, compared to nickel-cadmium batteries or nickel-metal hydride batteries. The operating voltage is three times higher and the energy density per unit weight is also excellent and is being used rapidly.

Lithium secondary batteries may be classified into lithium ion batteries using liquid electrolytes and lithium ion polymer batteries using polymer electrolytes according to electrolyte types. The lithium ion polymer battery may be classified into a fully solid lithium ion polymer battery containing no electrolyte solution and a lithium ion polymer battery using a gel polymer electrolyte containing an electrolyte solution, depending on the type of polymer 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 an electrical product using the same as a power source, and it is difficult to reduce the volume. Therefore, a pouch type secondary battery using two electrodes, a separator and an electrolyte in a pouch made of a film and being sealed is developed and used.

The pouch type secondary battery is sealed in a state in which an electrode assembly capable of charging and discharging is embedded in an exterior material made of a laminate sheet including a resin layer and a metal layer, and an electrode lead (anode lead / anode lead) electrically connected to the electrode assembly is an exterior material. Is partially protruded to the outside of the sealing portion, and is connected to an external terminal.

In such a pouch-type secondary battery, when an exterior material is swollen or an impact is applied from the outside of the battery, the positive lead and the negative electrode lead are likely to contact each other, thereby causing an electrical short circuit (short). Specifically, when gas is generated due to abnormal reaction inside the battery and the internal pressure is increased, the pouch sheathing material made of a laminate sheet of a polymer resin layer and a thin aluminum metal layer swells, and in this case, the anode lead and the cathode lead are inclined in a direction facing each other. When they come into contact with each other, a short circuit occurs.

In order to reduce the possibility of short-circuit between the anode lead and the cathode lead, there is a method of protruding the electrode lead in both directions, but in this case, two laminate sheets (double cups) must be sealed on four sides where the upper and lower surfaces are in contact with each other. After bending using (Single Cup), the efficiency of battery manufacturing is less than that of sealing only on three sides.

The present invention is an electrode assembly having a cathode coated with a cathode active material, a cathode coated with an anode active material, and a separator interposed between the anode and the cathode; An exterior material containing the electrode assembly; An anode lead and a cathode lead electrically connected to the anode and the cathode, respectively, protruding from the exterior material in the same direction; And to provide a pouch-type secondary battery comprising an insulating member interposed between the positive lead and the negative lead.

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 is an electrode assembly having a cathode coated with a cathode active material, a cathode coated with an anode active material, and a separator interposed between the anode and the cathode; An exterior material containing the electrode assembly; An anode lead and a cathode lead electrically connected to the anode and the cathode, respectively, protruding from the exterior material in the same direction; And it provides a pouch-type secondary battery comprising an insulating member interposed between the positive lead and the negative lead.

In one embodiment of the present invention, there is provided a medium-large battery module or a battery pack, characterized in that it comprises a plurality of pouch-type secondary battery electrically connected.

The pouch type secondary battery according to the present invention can prevent a short circuit between the electrode leads by interposing an insulating member between the positive electrode lead and the negative electrode lead protruding in the same direction from the outer packaging material, thereby increasing the internal pressure of the battery or abnormal physical shocks such as external physical shocks. Even if the packaging material expands due to the occurrence of the situation, the electrode leads do not come into contact with each other, and thus a short circuit between the electrode leads can be prevented.

1 is a schematic view of a pouch type secondary battery according to an embodiment of the present invention.

Conventional pouch-type secondary batteries, when an abnormal situation such as an increase in the internal pressure of the battery or an external physical shock occurs, the outer material expands and the positive and negative lead protruding out of the outer material are inclined to face each other. The contact may occur between the bars may cause a short circuit between the electrode leads, the present invention is to prevent this.

Specifically, the present invention includes an electrode assembly having a cathode coated with a cathode active material, an anode coated with an anode active material, and a separator interposed between the anode and the cathode; An exterior material containing the electrode assembly; An anode lead and a cathode lead electrically connected to the anode and the cathode, respectively, protruding from the exterior material in the same direction; And it provides a pouch-type secondary battery comprising an insulating member interposed between the positive lead and the negative lead.

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 schematic view of a pouch type secondary battery according to an embodiment of the present invention.

As shown in FIG. 1, the pouch type secondary battery of the present invention includes an electrode assembly 100 having a cathode coated with a cathode active material, an anode coated with an anode active material, and a separator interposed between the cathode and the anode; An exterior member 200 in which the electrode assembly 100 is accommodated; An anode lead 110 and a cathode lead 120 electrically connected to the anode and the cathode and protruding in the same direction from the exterior member 200; And an insulating member 300 interposed between the positive lead 110 and the negative lead 120.

The electrode assembly 100 is characterized in that the positive electrode is coated with a positive electrode active material, the negative electrode is coated with a negative electrode active material, and a separator interposed between the positive electrode and the negative electrode.

The positive electrode is a part of the positive electrode active material is coated on the positive electrode current collector, the positive electrode current collector is usually formed to a thickness of 3 to 500 ㎛. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, the positive electrode current collector may be formed on the surface of stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel. The surface-treated with carbon, nickel, titanium, silver, etc. can be used. The positive electrode current collector may increase the adhesion of the positive electrode active material by forming minute unevenness on its surface, and may be in various forms such as film, sheet, foil, net, porous body, foam, and nonwoven fabric. At the end of the positive electrode current collector, a positive electrode non-coating portion to which the positive electrode active material is not applied is formed. The positive electrode non-coating portion is formed with a positive electrode terminal electrically connected to the external circuit so that the electrons collected in the positive electrode current collector can flow to the external circuit. The positive electrode terminal is normally attached to the positive electrode non-coating portion by means of welding or conductive adhesive such as laser welding or ultrasonic welding, and then additionally, a tape may be attached to prevent separation of the positive electrode terminal.

The negative electrode is produced by coating and drying a negative electrode active material on the negative electrode current collector, the negative electrode current collector is usually made of a thickness of 3 to 500 ㎛. Such a negative electrode current collector is not particularly limited so long as it has conductivity without causing chemical change in the battery. For example, the negative electrode current collector may be formed on the surface of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper, or stainless steel. Surface-treated with carbon, nickel, titanium, silver and the like, aluminum-cadmium alloy and the like can be used. The negative electrode current collector may also form fine irregularities on its surface to increase the adhesion of the negative electrode active material.

The exterior material 200 is formed of a laminate sheet of a metal layer and a resin layer to stably accommodate the electrode assembly 100 described above. The exterior member 200 is integrally formed with an accommodating part in which an inner space corresponding to the thickness and area of the electrode assembly 100 is formed, and a plate-shaped cover part for closing an upper opening of the accommodating part.

Meanwhile, the anode lead 110 and the cathode lead 120 electrically connected to the electrode assembly 100 protrude in the same direction at predetermined intervals to the outside of the exterior member 200. That is, the two electrode leads 110 and 120 are electrically connected to the electrode terminals extending from the electrode plates of the electrode assembly 100 by welding or the like, and a part thereof is exposed to the outside of the exterior member 200. will be.

In addition, an insulating member 300 is interposed between the positive lead 110 and the negative lead 120 to prevent a short circuit between the positive lead 110 and the negative lead 120 protruding to the outside of the exterior member 200. Of course, in order to reduce the possibility of short circuit between the anode lead and the cathode lead, there is a method of protruding the electrode lead in both directions, but as described above, two laminate sheets (double cups) must be sealed on the four sides where the upper and lower surfaces contact each other. Since the manufacturing efficiency of the battery is lower than the case of bending using one laminate sheet (single cup) after sealing only on three sides, the present invention will be described in the case where the electrode leads 110 and 120 protrude in the same direction. .

The insulating member 300 may be formed of an electrically insulating polymer resin to prevent electrical short between the electrode leads 110 and 120. The electrically insulating polymer resin is preferably made of one or more selected from polyethylene, polypropylene, polystyrene, polyurethane, epoxy resin, phenol resin and melamine resin, and more preferably made of polypropylene in consideration of mechanical properties and price. However, the present invention is not limited thereto.

In order for the insulating member 300 to be provided in the exterior material 200, no special method is required. For example, a simple method such as forming a fastening groove in the exterior member 200 between the positive lead 110 and the negative electrode lead 120 and press-fitting the fastening groove or attaching to the exterior member 200 using an adhesive member may be applied. Can be.

In addition, the thickness of the insulating member 300 need not be particularly limited. That is, the thickness may be such that the contact between the positive electrode lead 110 and the negative electrode lead 120 may be prevented when an abnormal situation such as an internal pressure rise of the battery or an external physical shock occurs. However, in the case of having a thickness corresponding to the separation distance between the anode lead 110 and the cathode lead 120, it is possible to prevent the possibility of a short circuit between the anode lead 110 and the cathode lead 120.

In addition, in the present invention, an insulating film (not shown) may be further included in each electrode lead. In other words, the insulating film may be attached or coated on the entire surface of each lead in order to prevent a short circuit between the positive lead and the negative lead, but since each electrode lead must be electrically connected to the external terminal, the insulating film is not connected to the external terminal. It is preferable to be formed in the part. In addition, an insulating film may be formed on both inner surfaces of the anode lead and the cathode lead that face each other. However, in order to reduce material costs, an insulating member may be attached to only one of the inner surfaces of the anode lead and the cathode lead which face each other. It is also possible to coat.

Here, the material of the insulating film may be made of an electrically insulating polymer resin similarly to the above-described insulating member. The electrically insulating polymer resin is preferably made of one or more selected from polyethylene, polypropylene, polystyrene, polyurethane, epoxy resin, phenol resin and melamine resin, and more preferably made of polypropylene in consideration of mechanical properties and price. However, the present invention is not limited thereto.

In addition, the insulating film is preferably formed to a thickness of 1㎛ 100㎛. In other words, when the thickness is less than 1 µm, the insulation effect is insufficient, and when the thickness is greater than 100 µm, the volume of the battery is increased. As such, by adding an insulating film to the positive lead and the negative lead, it is possible to more surely reduce the possibility of electrical short circuit therebetween, thereby increasing the overall safety 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.

100: electrode assembly
110: positive lead
120: cathode lead
200: Outer material
300: insulation member

Claims (10)

An electrode assembly having a cathode coated with an anode active material, an anode coated with an anode active material, and a separator interposed between the anode and the cathode;
An exterior material containing the electrode assembly;
An anode lead and a cathode lead electrically connected to the anode and the cathode, respectively, protruding from the exterior material in the same direction; And
A pouch type secondary battery comprising an insulating member interposed between the positive lead and the negative lead.
The method of claim 1,
The insulating member has a pouch type secondary battery having a thickness corresponding to the separation distance between the positive lead and the negative lead.
The method of claim 1,
The insulating member is a pouch type secondary battery, characterized in that made of an electrically insulating polymer resin.
The method of claim 3,
The electrically insulating polymer resin is a pouch type secondary battery comprising at least one selected from polyethylene, polypropylene, polystyrene, polyurethane, epoxy resin, phenol resin and melamine resin.
The method of claim 1,
Pouch-type secondary battery, characterized in that the insulating film is coated on the non-connected portion of the protruding positive electrode lead and negative electrode lead.
The method of claim 1,
A pouch type secondary battery, characterized in that an insulating film is coated on at least one of the protruding positive and negative lead surfaces.
The method according to claim 5 or 6,
The insulating film is a pouch type secondary battery, characterized in that made of an electrically insulating polymer resin. 8. The method of claim 7,
The electrically insulating polymer resin is a pouch type secondary battery comprising at least one selected from polyethylene, polypropylene, polystyrene, polyurethane, epoxy resin, phenol resin and melamine resin.
Medium-large battery module or battery pack comprising a plurality of pouch-type secondary batteries according to claim 1 electrically connected.
The method of claim 9,
The medium-large battery module or battery pack includes a power tool; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); Electric trucks; Electric commercial vehicle; Or medium or large battery module or battery pack, characterized in that used as a power source for any one or more of the medium or large power storage system.

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