KR102055853B1 - Pouch type lithium secondary battery with improved safety - Google Patents

Abstract

In the present invention, the electrode lead is formed with a notch; Lead films for attaching the pouch case is located outside the notch portion and applied to both sides of the electrode lead; And a pouch-type lithium secondary battery is provided between the lead film and the connection portion of the electrode tab-electrode lead and includes a lead film for disconnection induction applied by varying the surface applied to the electrode lead around the notch.

Description

Pouch type lithium secondary battery with improved safety}

The present invention relates to a pouch type lithium secondary battery having improved safety, and more particularly, to a pouch type lithium secondary battery in which lead disconnection is induced when an internal gas is generated.

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.

Unlike primary batteries that are not normally rechargeable, rechargeable batteries can be charged with advanced technologies such as digital cameras, cellular phones, laptop computers, power tools, electric bicycles, electric cars, hybrid cars, and large-capacity power storage devices. Active research is in progress.

In particular, lithium secondary batteries have a higher energy density per unit weight and can be rapidly charged compared to other secondary batteries such as lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries, thereby increasing their use actively. It's going on.

Lithium secondary battery has a working voltage of 3.6V or higher, which is used as a power source for portable electronic devices, or by connecting multiple batteries in series or in parallel to high-power electric vehicles, hybrid vehicles, power tools, electric bicycles, power storage devices, UPS, etc. Used.

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, a cylindrical or rectangular metal can is used as a container by welding sealing. Since the can-type secondary battery using such a metal can as a container is fixed in shape, there is a disadvantage in restricting the design of an electric product using the same as a power source, and it is difficult to reduce the volume. Therefore, a pouch type secondary battery using an electrode assembly and an electrolyte in a pouch packaging material made of a film and sealing it has been developed and used.

When charging and discharging are repeatedly performed in the secondary battery, gas is generated due to the electrochemical reaction between the electrolyte and the electrode active material. At this time, the generated gas increases the internal pressure of the secondary battery, which may cause problems such as weakening of the coupling between parts, damage to the outer case of the secondary battery, premature operation of the protection circuit, deformation of the electrode, internal short circuit, and explosion.

When gas is generated inside the pouch type secondary battery, an event such as venting or explosion may occur while the pouch is inflated. In this situation, disconnection does not occur in a cell stored in the pouch case, such as a folded cell, and charging and discharging continuously occur. As such, if the current continuously flows inside the exhausted cell, the battery temperature rises due to the influence of internal resistance, and if such a situation continues, fire or additional events may occur, which may threaten user safety. have.

1 is a top view schematically illustrating a conventional embodiment in which a lead film is applied to an electrode lead for use in a pouch type secondary battery.

Referring to FIG. 1, the lead film 120 is applied to both surfaces of the electrode lead 110 at substantially the same shape and position, and the lead film 120 is positioned at a sealing portion of a pouch case (not shown). Done. To this end, the lead film 120 is applied to the electrode lead 110 at a predetermined distance from the connection portion W of the electrode tab-electrode lead.

2 is a schematic cross-sectional view of a conventional embodiment in which an electrode lead is applied to a pouch case in a pouch type secondary battery.

2, one end of the electrode lead 210 is connected to an electrode tab (not shown) extending from the electrode assembly 250 to form a connection portion 280, and the other end of the electrode lead 210 is a pouch. The case 260 is exposed to the outside. In addition, in order for the electrode lead 210 to be more easily heat-sealed with the pouch case 260, the lead film 220 may be spaced apart from the connection portion 280 with the electrode tab by a predetermined distance. Applied to, the electrode lead 210 is attached to the pouch case 260 via the lead film 220 to form the sealing portion S. That is, the lead film 220 is positioned to be limited to the sealing portion S in which the upper pouch case and the lower pouch are heat-sealed to attach the electrode lead 210 to the pouch case. For this reason, even if internal pressure arises and pouch case expands, lead disconnection cannot be induced easily.

On the other hand, in the pouch-type secondary battery has been proposed to secure the safety of the secondary battery by causing some components to physically deform when the breakdown voltage occurs. However, this method has a problem in that the safety of the secondary battery is limited because the current is cut off only when the manufacturing process of the secondary battery is complicated or when the internal pressure of the pouch case reaches a considerable level.

Accordingly, it is an object of the present invention to provide a pouch type secondary battery in which lead disconnection may be easily induced when an internal gas is generated in the pouch type secondary battery.

In another aspect, the present invention is to provide a pouch-type secondary battery that can lead to lead disconnection at a lower withstand voltage than in the prior art.

Another object of the present invention is to provide a pouch-type secondary battery in which lead disconnection is induced with excellent sensitivity to breakdown voltage generation compared to the prior art.

In order to solve the above technical problem, in one aspect of the present invention, there is provided an electrode lead including a notch portion; A pouch case attachment lead film positioned outside the notch and applied to both sides of the electrode lead; And a lead film for disconnection induction, which is positioned between the lead film for attaching the pouch case and the connection portion of the electrode tab-electrode lead, and is applied to the upper or lower surface of the electrode lead with a different surface applied to the notch. A secondary battery is provided.

 The pouch case attachment lead film may be heat-sealed to constitute a sealing portion of the pouch case.

The disconnection induction lead film may be applied to an electrode lead part positioned inside the sealing part of the pouch case.

The disconnection induction lead film applied to the upper surface of the electrode lead may be attached to the upper surface of the pouch case, and the disconnection induction lead film applied to the lower surface of the electrode lead may be attached to the lower surface of the pouch case.

The notch part may be formed at an electrode lead part positioned inside the sealing part of the pouch case.

The notch may have a thickness corresponding to 10 to 90% of the thickness of the electrode lead.

The notch may be formed in a V-shape, a bottom V-shape, a U-shape, an ellipse, or a wavy shape in the electrode lead.

When the pouch is inflated due to internal gas generation, the lead disconnection may be induced while the lead film for disconnection induction, which is attached to the other surface around the notch part, is led in opposite directions.

According to another aspect of the present invention, there is provided a secondary battery module comprising the pouch type secondary battery as a unit cell.

In addition, there is provided a battery pack comprising the secondary battery module.

The battery pack may be used as a power source for a medium and large device, and the medium and large device may be an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for power storage.

In the pouch type secondary battery according to an aspect of the present invention, when the pouch case is expanded by the generation of internal gas, lead disconnection by the lead film may be more easily induced. Therefore, in the pouch type secondary battery, since no current flows inside by disconnection before venting of the internal gas occurs, the secondary battery may be stabilized, and no further heat generation or explosion may occur. do.

In addition, in the pouch type secondary battery according to an embodiment of the present invention, some disconnection of the lead may occur even at a lower internal pressure than in the related art. When a part of the lead is disconnected, current flow is interrupted, and thus, a high resistance is applied to the lead part, resulting in heat generation. As a result, complete disconnection of the lead is induced, thereby inducing safety of the lithium secondary battery. Therefore, it can have a significantly improved safety compared to the pouch type secondary battery which is secured only by the complete disconnection of the lead.

In addition, in the battery pack including the pouch type secondary battery according to an aspect of the present invention, when a breakdown voltage is generated due to an abnormal situation, some disconnection occurs in a specific cell, thereby increasing the resistance and increasing the width of the voltage variation. There is an advantage that can be sensed more reliably.

1 is a top view schematically showing a conventional embodiment in which a lead film is applied to an electrode lead for use in a pouch type secondary battery.
2 is a schematic cross-sectional view of a conventional embodiment in which an electrode lead, a lead film, and a pouch case are assembled in a pouch type secondary battery.
3A is a top view schematically illustrating an embodiment of the present invention in which a lead film is attached to an electrode lead for use in a pouch type secondary battery, and FIG. 3B is a lead film on an opposite side of the electrode lead shown in FIG. 3A. This is a bottom view schematically showing the attached mode.
4 is a schematic cross-sectional view of an embodiment of the present invention in which an electrode lead, a lead film, and a pouch case are assembled in a pouch type secondary battery.
5A and 5B are views schematically showing, in a side view, an embodiment in which disconnection occurs when internal gas is generated in an electrode lead (FIG. 5A) to which a lead film is applied, according to one embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

A pouch type secondary battery according to an aspect of the present invention includes an electrode assembly, an electrode lead, a lead film, and a pouch case, and more specifically, an electrode lead having a notch portion; A lead film for attaching the pouch case positioned outside the notch and applied to both sides of the electrode lead; And a lead film for disconnection induction, which is positioned between the lead film for attaching the pouch case and the connection portion of the electrode tab-electrode lead, and is applied with a different surface applied to the electrode lead around the notch.

As the electrode assembly used in the present invention, an electrode assembly commonly used in the art may be used, and includes an anode, a cathode, a separator, and an electrolyte, and an electrode tab, which is a portion where an active material is not coated on the cathode and the anode, The electrode tab is attached to and connected to the electrode lead.

The electrode leads have a thin plate or rod shape and are made of metal for conductivity. In general, the electrode leads are composed of a conductive metal selected from aluminum (Al), nickel (Ni), copper (Cu), alloys thereof, and the like which are advantageous in conductivity. The electrode leads are attached to the electrode tabs by welding, riveting, or the like and extend outwardly of the electrode assembly. The electrode lead includes a positive electrode lead directly or indirectly connected to the positive electrode tab, and a negative electrode lead directly or indirectly connected to the negative electrode tab. The positive electrode lead and the negative electrode lead may extend in opposite directions to each other or may extend in the same direction. A lead film for sealing is interposed between the electrode lead and the pouch case to attach the electrode lead and the pouch case.

An embodiment in which a lead film is applied to an electrode lead according to the present invention will be described with reference to FIGS. 3A and 3B.

3A and 3B show top and bottom surfaces of one electrode lead, respectively. 3A and 3B, the lead film 320 for attaching the pouch case for sealing the pouch case is applied to both surfaces of the electrode lead 310, and the upper and lower surfaces of the electrode lead 310 are respectively provided. The lead wires 320 'and 320 " for sealing the upper surface of the pouch case and the lower surface of the pouch case are applied to each other. A notch portion for easily inducing lead disconnection when internal pressure is generated ( N) is formed in the electrode lead 310.

The location of the notch is not particularly limited as long as lead disconnection can be easily induced during overcurrent or internal gas generation. However, when the notch portion is located outside the sealing portion or the sealing portion formed by thermal fusion of the upper pouch case and the lower pouch case (not shown), induction of lead breakage does not occur. That is, it is preferably formed in the portion to be located in the electrode assembly accommodating portion.

Notches may be formed over the entire lead width or only a portion of the lead width, taking into account factors such as lead width, lead thickness, desired overcurrent sensitivity. In addition, it may be formed on both sides of the electrode lead or only on one surface.

In addition, the notch portion may be formed in the electrode lead in a shape such as V shape, bottom V shape, U shape, ellipse or wave shape. In addition, the notch may be formed in the form of a dotted line or in the form of a continuous inscribed line, depending on the formation method thereof.

The method for forming the notch is not particularly limited as long as it can be used conventionally in the art. As a non-limiting example, the notches may be formed by methods such as laser, cutting, punching or sawing. When notches are formed by perforation, the perforated through holes may have any shape, such as circles, rectangles, squares, and triangles.

In addition, the notch may be formed to have a thickness corresponding to 10 to 90% or 20 to 80% of the electrode lead thickness. The notch part serves as a sort of perforation line for inducing lead disconnection, which is induced when the lead film for disconnection induction, which is bonded to the other surface of the notch part, is generated in an opposite direction when the pouch is inflated. If the electrode is disconnected by adjusting only the thickness of the notch without the lead film for disconnection induction, the notch part should be formed to have a thinner thickness than the present invention. In this case, the electrode lead has high resistance and There is a problem that the output loss in the operating state becomes large and becomes inefficient.

For example, in FIGS. 3A and 3B, the notch portion is formed in a V-shaped shape having a bottom over the entire width of the lead at a portion corresponding to the lower surface of the lead films 320 and 320 ′ and the electrode lead.

The electrode lead 310 may include a pouch case attaching lead film 320 positioned outside the notch and applied to both sides of the electrode lead; And a lead wire 320 ′ for induction of wire disconnection, which is positioned between the lead film for attaching the pouch case and the connection portion W of the electrode tab-electrode lead and is applied by varying a surface applied to the electrode lead around the notch part.

As used herein, the term 'outside of the notch' refers to an outer side of the pouch case (not the electrode tab side) based on the notch of the electrode leads when the electrode lead is connected to the electrode tab and disposed toward the outside of the pouch case. I understand that.

In the present specification, the terms 'pouch case attach lead film' and 'break wire lead film' are used for convenience of reference, and the function and use of the lead film are understood to be limited to 'pouch case attach' or 'break induction', respectively. It should not be. In addition, the lead film for attaching the pouch case and the lead film for disconnection may be formed of one lead film integrally formed according to necessity or convenience, or may be formed of two or more lead films separately formed. Can be configured.

3A and 3B, the lead film for disconnection induction is not applied to the lower surface of the electrode lead 310 corresponding to the part to which the disconnection lead film 320 'is applied among the top surfaces of the electrode lead 310. The lead film for disconnection induction is not applied to the upper surface of the electrode lead 310 corresponding to the portion to which the disconnection induction lead film 320 ″ is applied among the lower surfaces of the electrode lead 310. Meanwhile, the pouch case is illustrated in FIG. 3A. The lead film 320 for attachment and the lead film 320 'for disconnection induction are marked by marks (M), which are for convenience of description, and the lead film for attaching the pouch case and the lead film for disconnection induction The 320 and 320 'may be formed of a single piece of lead film formed in one piece, or may be two pieces of lead film formed separately.

In addition, referring to FIGS. 4, 5A, and 5B to further illustrate an embodiment in which a lead film is applied to an electrode lead and a pouch case in an aspect of the present invention.

Referring to FIG. 4, the pouch case attachment lead film 420 is applied to both sides of the electrode lead 410 to be thermally fused to both sides of the pouch case 460 to form a sealing part. In addition, each of the lead films for disconnection induction is applied only to each of the upper and lower surfaces of the electrode lead and thermally fused only to one surface of the pouch case 460. When the lead film for disconnection induction is located in the pouch case sealing part, even if an overcurrent occurs, it is not cut and cannot open in the opposite direction, that is, since lead disconnection cannot be induced, that is, inside the sealing part of the pouch case, that is, It shall be applied to the electrode leads on the electrode assembly receiving space side. Thus, the lead film according to the present invention can be applied to the electrode leads as a whole closer to or closer to the connection of the electrode tab-electrode leads.

5A, the lead films 520 ′ and 520 ″ for disconnection induction are attached to the electrode leads 510 at different positions on the both sides before the breakdown voltage is generated. Thereafter, a breakdown voltage is generated and stress is applied to the electrode leads. In case of loss, as shown in FIG. 5B, the stress is concentrated in the notch portion N, and each of the disconnection induction lead films 520 ′ and 520 ″ attached to the electrode lead 510 is attached thereto. While moving in the expansion direction of the upper or lower pouch case, that is, the electrode lead 510 is opened in the opposite direction about the notch portion N, and disconnection occurs in the electrode lead 510.

Even if the pouch case expansion does not occur to the extent that the electrode lead is completely disconnected, if some breakage of the electrode lead is caused by the breakdown voltage, ultimately, the electrode lead can be completely disconnected. This is made possible by interruption of current flow by some disconnection of the electrode lead, thereby causing the electrode lead to have high resistance, thereby generating heat, thereby inducing safety of the lithium secondary battery.

The lead film for attaching the pouch case and the lead film for disconnection induction are not particularly limited in terms of the material, as long as they can exhibit the desired functions, and may be formed of the same or different materials.

For example, the lead film for attaching the pouch case and the lead film for disconnection induction may be each independently composed of a polypropylene (PP) or polyethylene (PE) film for thermal adhesiveness with the pouch case. Alternatively, the lead film for attaching the pouch case and the lead film for disconnection induction may be each independently configured as a multilayer structure of two layers or three layers. For example, the inner layer may be composed of a mixed resin layer including polystyrene (PS) having excellent electrical insulation and the like in ethylene vinyl acetate resin (EVA) capable of maintaining excellent thermal adhesion with a metal. The outer layer is not particularly limited as long as it has a thermal adhesive force with the pouch case of the secondary battery. Such an outer layer may be formed including one or two or more selected from a mixture of EVA and PS, polyethylene (PE), polypropylene (PP), cast polypropylene (CPP) and ethylene-propylene copolymers. . In addition, by including an intermediate layer having a lower melt index (MFI) than the inner layer and the outer layer, it is possible to maintain the shape of the lead film during thermal bonding. The interlayers include, but are not limited to, polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN) and stretched polypropylene (OPP) films And the like.

Although the lead wire for disconnection induction may be attached to the pouch case and the electrode lead by thermal fusion, an adhesive layer is further formed on one or both surfaces of the lead wire for disconnection induction, if necessary, so that the adhesive strength to the pouch case or the electrode lead is increased. Can be adjusted or differentiated. For example, the adhesive layer may be formed only on one surface of the both sides of the lead film for disconnection induction, and the other adhesive layer may not be formed on the other surface of the lead film. The adhesive layer is not particularly limited as a material providing adhesiveness without reacting with the electrolyte solution inside the battery cell, and may be formed of, for example, an acrylic resin.

The pouch case is sealed by forming a sealing portion by heat-sealing the edge region with the electrode assembly accommodated so that the electrode lead is drawn out. The pouch case may have a multi-layered structure to ensure both excellent heat sealability, shape, and rigidity and insulation for protecting the electrode assembly. For example, the pouch case may have a multilayer structure including an innermost layer facing the electrode assembly, an outermost layer directly exposed to the external environment, and a metal layer interposed between the two layers, but is not limited thereto. . The innermost layer may be made of a material having corrosion resistance, insulation, and heat adhesion to an electrolyte solution, such as polypropylene (PP), for example, and the outermost layer is rigid to maintain shape, such as polyethylene terephthalate (PET). And an insulating material, and the metal layer may be made of a metal material such as aluminum (Al).

The electrode assembly accommodated in the pouch case is not particularly limited as long as it can be used in the art, and may have a structure including a positive electrode, a negative electrode, and a separator interposed therebetween as is well known in the art.

The positive electrode and the negative electrode are not particularly limited and may be prepared in the form of the electrode active material bound to the electrode current collector in accordance with conventional methods known in the art.

Non-limiting examples of the positive electrode active material of the electrode active material may be a conventional positive electrode active material that can be used for the positive electrode of the conventional electrochemical device, in particular lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide or a combination thereof It is preferable to use a lithium composite oxide.

Non-limiting examples of the negative electrode active material may be a conventional negative electrode active material that can be used for the negative electrode of the conventional electrochemical device, in particular lithium metal or lithium alloys, carbon, petroleum coke, activated carbon, Lithium adsorbents such as graphite or other carbons are preferred. Non-limiting examples of the positive electrode current collector is a foil produced by aluminum, nickel or a combination thereof, and non-limiting examples of the negative electrode current collector is manufactured by copper, gold, nickel or copper alloy or a combination thereof Foil and the like.

As the separator, any porous polymer substrate used in an electrochemical device such as a porous membrane or a nonwoven fabric formed of various polymers can be used. For example, a polyolefin-based porous membrane or a nonwoven fabric made of polyethylene terephthalate fiber, which is used as an electrochemical device, in particular, a separator of a lithium secondary battery, may be used, and the material and shape thereof may be variously selected as desired. For example, the polyolefin-based porous membrane may form polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, and polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, and ultra high molecular weight polyethylene, alone or in combination thereof. The nonwoven fabric may also be made of a polyolefin-based polymer or a fiber using a polymer having higher heat resistance. The thickness of the porous polymer substrate is not particularly limited, but is preferably about 1 to about 100 μm, more preferably about 5 to about 50 μm, and the pore size and pore present in the porous polymer substrate are also not particularly limited. Preferably from about 0.001 to about 50 μm and from about 10 to about 95%

The pouch case may contain an electrolyte solution together with the electrode assembly. As salts of the structure, such as A + B- electrolyte that may be used in the electrode assembly of the present invention, A ⁺ comprises Li ^+, Na ^+, an alkali metal cation or an ion composed of a combination thereof, such as K ⁺ and B ^- It is _{^{PF 6 -, BF 4 -,}} Cl -, Br -, I -, ClO 4 -, AsF 6 -, CH 3 CO 2 -, CF 3 SO 3 -, N (CF 3 SO 2) 2 -, C ( Salts containing ions consisting of anions such as CF ₂ SO ₂ ) ₃ ^- or a combination thereof are propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethylcarbonate (EMC), gamma butyrolactone (γ- Butyrolactone) or a mixture thereof, or dissolved in an organic solvent, but is not limited thereto. The electrolyte injection may be performed at an appropriate step of the battery manufacturing process, depending on the manufacturing process and the required physical properties of the final product. That is, it may be applied before battery assembly or at the final stage of battery assembly.

The present invention also provides a medium-large battery module including the lithium secondary battery as a unit cell and a battery pack including the battery module.

The battery pack may be used in a variety of medium-large and large devices that require high rate characteristics and high temperature safety, for example, a power tool that is driven by an electric motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); Electric two-wheeled vehicles including E-bikes and E-scooters; It can be used as a power source, such as an electric golf cart (electric golf cart), can be used in the power storage system, but is not limited thereto.

On the other hand, the embodiments of the present invention disclosed herein are not intended to limit the scope of the present invention only presented a specific example to facilitate understanding. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

Claims (12)

An electrode lead having a notch formed therein;
Lead films for attaching the pouch case is located outside the notch portion and applied to both sides of the electrode lead; And
Included between the lead film for attaching the pouch case and the connection portion of the electrode tab-electrode lead, the lead film for disconnection induction applied to the upper or lower surface of the electrode lead;
The notch portion is formed in the electrode lead portion which is located inside the sealing portion of the pouch case,
The notch portion is formed in a V-shape, a bottom V-shape, a U-shape, an oval or a wavy shape over the entire width of the lead
The lead film for disconnection induction is applied to the upper surface, the lower surface or both of the electrode leads, and is located inside the sealing portion of the pouch case,
When one surface of the lead wire for disconnection is applied to the top surface of the electrode lead, the other surface of the lead wire for lead disconnection is attached to the top surface of the pouch case, and one surface of the lead wire for lead disconnection is applied to the bottom surface of the electrode lead. When applied, the other surface of the lead film for disconnection induction is attached to the lower surface of the pouch case,
The notch part serves as a cutting line of the electrode lead when gas is generated inside the pouch-type secondary battery, and disconnection of the electrode lead occurs as the electrode lead opens in the opposite direction toward each of the upper pouch and the lower pouch with respect to the notch part. Characterized
Pouch type secondary battery.
The method of claim 1,
A pouch type secondary battery, wherein the pouch case and the lead film for attaching the pouch case to each of the electrode leads are formed by thermal fusion.
The method of claim 1,
In the lead film for disconnection induction, an adhesive layer is formed on one surface bonded to the pouch case, and no adhesive layer is formed on the other surface bonded to the electrode lead.
The method of claim 1,
The lead wire for disconnection induction pouch type secondary battery, characterized in that consisting of a polypropylene or polyethylene film.
The method of claim 3,
A pouch type secondary battery, wherein the adhesive layer is an adhesive layer composed of an acrylic resin material.
The method of claim 1,
A pouch type secondary battery, wherein the notch has a thickness corresponding to 10 to 90% of an electrode lead thickness.
The method of claim 1,
The pouch case attachment lead film and the lead wire for disconnection induction are pouch type secondary batteries, characterized in that one lead film formed integrally.
The method of claim 1,
The pouch type secondary battery, wherein the notch portion is formed at a portion corresponding to an interface between the lead film for attaching the pouch case and the electrode lead.
A secondary battery module comprising the pouch type secondary battery according to any one of claims 1 to 8 as a unit cell.
A battery pack comprising the secondary battery module according to claim 8.
The method of claim 10,
The battery pack is a battery pack, characterized in that used as a power source for medium and large devices.
The method of claim 11,
The medium and large device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a battery pack, characterized in that the system for power storage.

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