KR20180130892A - Pouch Type Lithium Secondary Battery comprising Lead Wing having External Force Properties - Google Patents

Abstract

The present invention relates to a secondary battery. The secondary battery includes a lead-wing-type CID which maintains battery safety from overcharge or volume expansion such as swelling, etc. caused by gas generated in the abnormal state of a pouch type battery cell, and disperses external force when vibration occurs in a device including the battery cell. According to the present invention, it is possible to prevent current from flowing into the pouch type secondary battery due to overcharging as well as in the abnormal state. The secondary battery includes an electrode assembly, an electrode tab, an electrode lead and a lead film.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pouch type secondary battery including a lead wing having external force characteristics,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pouch type secondary battery including a lead blade having external force characteristics, and more particularly, To a pouch type secondary battery including a lead blade having external force characteristics for maintaining safety.

In general, the secondary battery includes a nickel cadmium battery, a nickel metal hydride battery, a lithium ion battery, and a lithium ion polymer battery. Such a secondary battery is not only a compact product such as a digital camera, a P-DVD, an MP3P, a mobile phone, a PDA, a portable game device, a power tool and an e-bike, but also a large product requiring high output such as an electric car or a hybrid car, Power storage devices for storing power generation and renewable energy, and backup power storage devices.

The lithium secondary battery generally comprises a cathode, a separator, and an anode. These materials are selected in consideration of battery life, charge / discharge capacity, temperature characteristics, stability, etc. In general, The lithium secondary battery has a three-layered structure of a cathode / separator / cathode or a five-layer structure of anode / separator / cathode / separator / anode or cathode / separator / anode / separator / cathode. The unit cells are assembled into one electrode assembly or a secondary battery.

The lithium secondary battery is charged and discharged while repeating a process in which lithium ions are intercalated and deintercalated from the lithium metal oxide in the positive electrode to the graphite electrode in the negative electrode.

These secondary batteries have various problems that threaten the safety of the secondary battery such as internal short circuit due to external shock, overheating due to overcharge, overheating, electrolyte decomposition due to this, and thermal runaway phenomenon. Particularly, the explosion of the secondary battery is caused by various reasons, but the increase of the gas pressure inside the secondary battery due to the decomposition of the electrolyte is also one cause. Specifically, when the secondary battery is repeatedly charged and discharged, gas is generated due to an electrochemical reaction between the electrolyte and the electrode active material. At this time, the generated gas raises the internal pressure of the secondary battery, causing problems such as weakening of the fastening between the parts, breakage of the outer case of the secondary battery, early operation of the protection circuit, deformation of the electrode, internal short circuit, explosion and the like.

In the case of such a battery, overcharge is prevented by overcurrent shutdown through control of electronic components for battery safety in case of overcharging. A protection circuit such as a PCM (Protection Circuit Module) is exemplified as a method in which such a method is applied to a battery. However, even if an overcharge protection circuit such as a PCM is applied, safety is not ensured sufficiently, and in particular, in a pouch type battery, a stronger protection circuit structure needs to be applied in order to more accurately grasp the swelling of the pouch cell.

In addition, a mechanical interrupter (CID) that physically disconnects the series connection of the battery is applied by using the pressure generated by thermal expansion of the battery during overcharging in consideration of the malfunction of the electronic component. Generally, a current interrupting device of a battery pack is widely used as a method of disconnecting a current by physically disconnecting a series connection of a battery pack through a battery pack mechanism using only the inflation pressure of a battery generated in an overcharged state. However, a CID capable of breaking the current through the volume expansion of the pouch-shaped battery has not been proposed.

Korean Patent Publication No. 1601135 discloses a configuration in which a polymer material is inserted between lead-leads in the coupling between two lead plates of a pouch-type secondary battery. When the internal pressure of the secondary battery is higher than a certain level, The first and second sealants inserted between the lead plates are configured to have a feature of insulating and heat-sealing property that does not allow electricity to flow, and a structure in which the first and second sealants Discloses a structure in which electrical insulation and heat-sealability are not provided. However, the configuration in which the conductive polymer is inserted between the electrode lead-lead or the lead-tab and the notch portion in the film surrounding the electrode lead-lead or the lead-tab are not confirmed.

In Korean Patent Laid-Open Publication No. 2016-0125920, both electrode assemblies; And a pouch type outer shell which is made up of a first pouch portion and a second pouch portion, and in which the first pouch portion and the second pouch portion are bonded to each other by sealing portions of the pouch type secondary battery, A first electrode lead extending from the electrode assembly and attached to the first pouch portion; A second electrode lead attached to the second pouch portion and protruding to the outside of the pouch outer case; A first sealing member interposed between the first electrode lead and the second electrode lead to prevent the first electrode lead and the second electrode lead from contacting each other; And a film type connection member electrically connecting the first electrode lead and the second electrode lead to each other. However, the configuration in which the sealing member has no conductivity is different from the present invention.

Korean Patent Registration No. 1192077 discloses an electrode assembly including a first electrode and a second electrode, and a separator positioned between the first electrode and the second electrode, a case in which the electrode assembly is accommodated, And a lead tab extending from the case to the outside of the case and electrically connected to the first electrode through the electrode terminal, wherein the lead tab is in contact with the case Further comprising an adhesive member formed to be separated from at least a part of the electrode terminal so as to be electrically disconnected from the first electrode when the case is deformed in a state that the lead tab is deformed, Wherein the adhesive member has a through hole, and the lead tab is electrically connected to the electrode terminal through the through hole, Being formed so as to be connected to, it discloses a secondary battery according to claim. However, there is a difference in the configuration in which the insulating polymer is inserted between the electrode lead-lid or the lead-tab.

Korean Patent Registration No. 1447064 discloses a battery cell in which an electrode assembly having a positive electrode / separator / negative electrode structure is embedded in a housing portion of a battery case. In each of the electrode plates constituting the electrode assembly, And an electrode lead for electrically connecting the electrode tabs is disposed at one end of the electrode tabs where the electrode tabs are stacked. In the electrical connection between the electrode tabs and the electrode leads, the electrode leads are deformed Wherein the battery cell has a physical connection introduced into the electrode tabs. However, the configuration in which the conductive polymer is inserted between the electrode lead-lead or the lead-tab and the notch portion in the film surrounding the electrode lead-lead or the lead-tab are not confirmed.

Accordingly, the secondary battery technology including the lead wing, which is characterized in that the secondary battery is short-circuited through the internal pressure increase and the volume expansion of the pouch-shaped battery due to the gas generation, such as an abnormal state such as overcharge and abnormal gas generation, There is no bar.

Korean Patent Registration No. 1601135 Korean Patent Laid-Open Publication No. 2016-0125920 Korean Patent Registration No. 1192077 Korean Patent Registration No. 1447064

SUMMARY OF THE INVENTION It is a primary object of the present invention to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a pouch type battery cell in which, in order to maintain battery safety due to volume expansion or overcharge of swelling due to gas generated in an abnormal state, The present invention provides a pouch type secondary battery including a lead wing for ensuring safety in overcharging with a lead wing physically disconnected.

Another object of the present invention is to provide a pouch-type secondary battery including a simple lead wing capable of maintaining the energy density of the battery cell, rather than a complicated additional device capable of breaking current in an abnormal state such as a volume expansion of the battery cell.

It is another object of the present invention to provide a pouch type secondary battery including a lead wing for disconnecting an electrode lead using an external force applied to an electrode lead through a change in shape of a lead wing when a volume expansion occurs in a device to which the battery cell is applied .

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a pouch type secondary battery which is housed in a pouch including an electrode assembly, an electrode tab, an electrode lead, and a lead film in which an anode and a cathode are stacked with a separator interposed therebetween The battery may include a pouch type secondary battery including a lead wing having one surface in contact with the pouch and the other surface in contact with the electrode lead.

In addition, the lead vane may be more strongly coupled to the pouch than the electrode lead.

A first adhesive layer may be formed between the lead wing and the pouch.

The first adhesive layer may be further formed on one surface of the lead wing that is not in contact with the pouch and the electrode lead.

Further, a second adhesive layer may be formed on the electrode lead, which is connected to the first adhesive layer.

The second adhesive layer may be formed in the electrode tab direction.

A notch may be formed in the electrode lead between the lead wing and the lead film.

The thickness (W _t ) of the lead wing is a thickness at which disconnection occurs in the notch portion of the electrode lead, preferably 200 to 4000 μm.

Further, the length (W _L ) of the lead wing is an area attached to the pouch, and may be preferably 1 to 10 mm.

The lead wing may be formed on both sides of the electrode lead.

In addition, when the pouch expands due to an internal pressure rise of the pouch type secondary battery, the lead vane may open the lead vane in the direction perpendicular to the electrode tab to cut off the energization of the electrode lead.

Further, it may be a device including a pouch type secondary battery.

In addition, the device may be selected from the group consisting of an electronic device, an electric vehicle, a hybrid vehicle, and a power storage device.

According to the pouch type secondary battery including the lead wing having the external force characteristics according to the present invention, it is possible to prevent a current from flowing into the pouch type secondary battery due to an abnormal condition as well as overcharge.

In addition, the present invention has the effect of eliminating the lowering of the energy density when a complicated apparatus is carried out in addition to the pouch type secondary battery.

In addition, the present invention has the effect of shorting the electrode leads through gas expansion of the pouch type secondary battery.

1 is a view showing an exemplary conventional pouch-shaped battery cell.
Fig. 2 is a diagram showing an example of pouch-shaped battery cell showing gas evolution due to volume expansion. Fig.
3 is a view showing a pouch type secondary battery in which a lead wing is formed on an electrode lead according to an embodiment of the present invention.
4 is a cross-sectional view illustrating a short circuit of an electrode lead by a lead blade according to an internal expansion according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the detailed description of known functions and configurations incorporated herein will be omitted when it may unnecessarily obscure the subject matter of the present invention.

The same reference numerals are used for portions having similar functions and functions throughout the drawings. Throughout the specification, when a part is connected to another part, it includes not only a case where it is directly connected but also a case where the other part is indirectly connected with another part in between. In addition, the inclusion of an element does not exclude other elements, but may include other elements, unless specifically stated otherwise.

The present invention will be described in detail with reference to the drawings.

1 is a view showing an exemplary conventional pouch-shaped battery cell.

Generally, in manufacturing a lithium secondary battery, a positive electrode current collector and a negative electrode current collector are first coated with a mixture of an active material, a binder and a plasticizer to prepare a positive electrode plate and a negative electrode plate, and the positive electrode plate and the negative electrode plate are laminated on both sides of the separator, The battery cell is inserted into the battery case, and the electrolyte solution is injected and sealed to complete the battery pack.

The structure of an electrode lead connected to a conventional electrode assembly is such that one end is connected to the electrode assembly and the other end is exposed to the outside of the battery case, And the battery case which is present and encapsulates has an electrode lead structure in which the electrode lead is sealed by an adhesive layer by a sealant at a portion extending to the outside of the battery case.

Further, the electrode assembly is provided with an electrode tab. The current collecting plate of the electrode assembly is composed of a portion coated with an electrode active material and a terminal portion (hereinafter referred to as "plain portion ") to which no electrode active material is applied, and the electrode tab is formed by cutting a non- Or may be a separate conductive member connected by welding or the like. The electrode tabs may protrude unidirectionally or may protrude in both directions so as to be aligned with the electrode assembly so as to face each other as shown in the figure.

The electrode tab serves as an electron transfer path inside and outside the battery, and the electrode lead is connected to the electrode tab by spot welding or the like. The electrode leads may extend in the same direction or in opposite directions depending on the formation positions of the positive electrode tab and the negative electrode tab. The positive electrode lead and the negative electrode lead may have different materials from each other. That is, the positive electrode lead may be made of the same aluminum (Al) material as the positive electrode plate, and the negative electrode lead may be made of the same copper material as the negative electrode plate or a copper material coated with nickel (Ni). Finally, the electrode lead is electrically connected to the external terminal through the terminal portion.

The pouch exterior member accommodates and seals the electrode assembly so that a part of the electrode leads, that is, the terminal portions, is exposed. Between the electrode lead and the pouch exterior member, an adhesive layer such as the sealant described above is interposed. The pouch outer sheath has a sealing area at the rim and the horizontal slit of the electrode lead is spaced from the sealing area toward the junction. That is, when the electrode lead is inverted T-shaped, the leg portion of the T-shaped protrusion protrudes to the outside of the pouch exterior member, and a part of the T-shaped head is formed in the sealing region.

Usually, the anode lead plate is made of aluminum material and the anode current collector plate is made of copper material. When the swelling phenomenon occurs, the copper foil tends to rupture rather than the aluminum foil. Therefore, the cathode lead is more likely to break than the cathode lead. . In such a case, it may be desirable to form the negative electrode lead with such a breakable electrode lead

In the normal state of the secondary battery, the electrode assembly is shielded from the outside by the adhesive layer, and when the internal pressure of the battery rises due to overcharging, high temperature, or the like, expansion of the battery case may be caused. However, The weak junction of the element will rupture and the gas inside the cell will be exhausted.

However, since the current from the battery will continue to flow as long as the electrode assembly and the electrode lead are electrically connected, it is very difficult to secure the stability of the battery. In order to solve such a problem, a method of adjusting the amount of electrolyte injected into the secondary battery or adjusting the short circuit pressure of the current blocking member (CID) is used. However, there is a problem that the safety of the battery is deteriorated when the battery is overcharged. In other words, it is not practical to simultaneously solve the safety of the battery during overcharging and the stability of use due to the use of the battery in a high temperature environment.

(Comparative Example)

Fig. 2 is a diagram showing an example of pouch-shaped battery cell showing gas evolution due to volume expansion. Fig.

The pouch includes a gas barrier layer and a sealant layer. The gas barrier layer may further include a surface protective layer as an outermost layer formed on the gas barrier layer. The gas barrier layer is for blocking gas entry, and it is mainly made of an aluminum foil. The sealant layer is located in the innermost layer and contacts the contents, i. E. The cell. The surface protective layer is mainly made of nylon resin in consideration of abrasion resistance and heat resistance. The pouch is fabricated by processing the film of the laminated structure as a bag, and the cell component such as an anode, a cathode, and a separator is impregnated with the electrolytic solution and then embedded. After the cell components are built in, the sealant layers are thermally adhered to each other at the inlet of the pouch and sealed. At this time, since the sealant layer is in contact with the cell component, it must have insulation property and electrolytic solution resistance and should have high sealing property for sealing with the outside. In other words, the sealant areas where the sealant layers are thermally adhered to each other must have excellent heat bonding strength. Generally, a polyolefin resin such as polypropylene (PP) or polyethylene (PE) is used as the sealant layer. Particularly, polypropylene (PP) is excellent in mechanical properties such as tensile strength, rigidity, surface hardness and impact strength, and electrolyte resistance and is mainly used as a sealant layer of a pouch.

However, the pouch type secondary battery according to the related art has a problem in that there is no stability against explosion risk. Generally, in a cell, heat and pressure are generated in the process of generating / releasing (charging / discharging) electricity (redox reaction, etc.). In this case, high heat and pressure may occur due to overcharging or short- have. The conventional pouch-type secondary battery can not exploit the technical means to prevent the explosion, and thus it is exposed to the risk of explosion.

(Example)

3 is a view showing a pouch type secondary battery in which a lead wing is formed on an electrode lead according to an embodiment of the present invention.

1. A pouch type secondary battery accommodated in a pouch including an electrode assembly, an electrode tab, an electrode lead, and a lead film in which an anode and a cathode are stacked with a separator interposed therebetween, wherein one surface is in contact with the pouch and the other surface is in contact with the electrode lead It is possible to provide a pouch-type secondary battery including a lead wing.

In addition, the lead vane may be more strongly coupled to the pouch than the electrode lead.

A first adhesive layer may be formed between the lead wing and the pouch.

The first adhesive layer may be further formed on one surface of the lead wing that is not in contact with the pouch and the electrode lead.

Further, a second adhesive layer may be formed on the electrode lead, which is connected to the first adhesive layer.

The second adhesive layer may be formed in the electrode tab direction.

A notch may be formed in the electrode lead between the lead wing and the lead film.

The thickness (W _t ) of the lead wing is a thickness at which disconnection occurs in the notch portion of the electrode lead, preferably 200 to 4000 μm.

Further, the length (W _L ) of the lead wing is an area attached to the pouch, and may be preferably 1 to 10 mm.

The lead wing may be formed on both sides of the electrode lead.

In addition, when the pouch expands due to an increase in the internal pressure of the pouch type secondary battery, the lead vane may open the lead vane in the direction of the electrode tab to cut off the energization of the electrode lead.

The lead wing of FIG. 3 is formed to connect the electrode tab and the electrode lead.

1. A pouch type secondary battery accommodated in a pouch including an electrode assembly, an electrode tab, an electrode lead, and a lead film in which an anode and a cathode are stacked with a separator interposed therebetween, wherein one surface is in contact with the pouch and the other surface is in contact with the electrode lead It is possible to provide a pouch-type secondary battery including a lead wing.

In addition, the lead vane may be more strongly coupled to the pouch than the electrode lead.

A first adhesive layer may be formed between the lead wing and the pouch.

The first adhesive layer may be further formed on one surface of the lead wing that is not in contact with the pouch and the electrode lead.

Further, a second adhesive layer may be formed on the electrode lead, which is connected to the first adhesive layer.

One surface of the lead wing contacts one surface of the electrode lead, and the other surface touches the pouch. The lead wing is strongly coupled to the pouch and weakly coupled to the electrode lead. The lead wing and the pouch may be thermally fused. Preferably, the lead flyer is bonded to the pouch with a polymer resin.

The adhesive layer made of the polymer resin is in contact with the lead wing on one side and the pouch on the other side. The adhesive layer is strongly bonded to the pouch. The adhesive layer, the lead wing, and the pouch may be thermally fused. Preferably, it can be bonded with a polymer resin.

The adhesive layer may be formed so as to surround at least one of the electrode lead and the lead wing.

The first adhesive layer is preferably formed between the lead wing and the pouch, and the first adhesive layer may be further formed on one surface of the lead wing that is not in contact with the pouch and the electrode lead. Preferably, the first adhesive layer may be formed on a side surface of the lead wing.

The first adhesive layer formed between the lead wing and the pouch, and the first adhesive layer formed on one side of the pouch and the electrode lead, which are not in contact with the pouch and the electrode lead, can be continuously connected to each other.

The thickness of the adhesive layer may be 10 to 500 mu m, preferably 15 to 300 mu m. Normal insulation performance can not be maintained beyond the above-mentioned thickness range.

Further, the thickness of the lead wing may be 5 to 5000 mu m.

The thickness of the lead wing may be 100 to 4000 mu m, preferably 150 to 3000 mu m. Exceeding the thickness range may adversely affect normal conduction performance, heat dissipation performance, and energy density.

The thickness and length of the lead wing can be changed according to operating conditions such that the internal lead of the pouch battery cell is short-circuited at a pressure of 1.5 to 3 atm.

The lead wing may be made of platinum (Pt), gold (Au), palladium (Pd), iridium (Ir), silver (Ag), ruthenium (Ru), nickel (Ni), stainless steel ), Copper (Cu), molybdenum (Mo), chromium (Cr), carbon (C), titanium Ti, tin Sn, tungsten W, ITO (C), nickel (Ni), titanium (Ti), or silver (Ag) can be surface-treated on the surface of aluminum (Al), copper (Cu), or stainless steel.

Further, the lead blade may be a polymer resin, preferably a thermosetting resin.

The adhesive layer may be made of any one of thermoplastic, thermosetting and photocurable resins having electric insulation properties or two or more resins.

4 is a cross-sectional view illustrating a short circuit of an electrode lead connection part by a lead blade according to an internal expansion according to an embodiment of the present invention.

The secondary battery is short-circuited in accordance with the expansion of the pouch due to the generation of the internal gas, the temperature rise, and the pressure increase, which are abnormal states of the secondary battery.

When a short circuit of the secondary battery is examined in a time-wise manner, the pouch expands due to gas generation due to an abnormal state of the secondary battery and internal pressure increase, and the insulating layer strongly coupled to the pouch is deformed according to the expansion of the pouch At this time, the lead wing is opened in the direction of the electrode tab while the lead wing relatively moves toward the coupling, and the short circuit is physically progressed in the notch portion of the electrode lead.

The pouch type secondary battery may further include an adhesive layer. The adhesive layer is attached at a predetermined position in contact with the lead wing, the electrode lead, and the pouch. Since the pressure of the pouch is relatively high at a portion contacting the lead wing during the sealing process, the possibility of damaging the casted polypropylene (CPP) layer of the pouch film is increased. Therefore, when the pouch is fused and sealed under heat and pressure, the inner layer of the adhesive layer imparts mechanical strength and heat resistance to maintain the shape of the adhesive layer so that the adhesion between the pouch and the lead blade is maintained.

The adhesive layer may be made of any one of thermoplastic, thermosetting and photocurable resins or two or more polymer resins.

In addition, the adhesive layer may include at least one of polypropylene (PP), polyethylene (PE), polyimide (PI), and polyamide.

Examples of the polymer resin include thermoplastic, thermosetting and photocurable resins. Examples of the resin include styrene / butadiene resin, styrene resin, epoxy resin, urethane resin, acrylic resin, phenol resin, amide resin, acrylate resin, May be selected and used. If necessary, two or more of them may be mixed and used. The thermoplastic resin in the polymer resin is an elastomer serving as a matrix for supporting film formation, and preferably has a softening point of about 100 to 180 ° C, and may be used in an amount of 20 to 80% by volume of the entire part of the polymer resin.

In addition, a lead film may be formed between the electrode lead and the pouch. The inner layer of the lead film prevents the aluminum thin film of the pouch from being electrically contacted with the electrode tab even when the aluminum thin film is partially exposed during the sealing process, thereby maintaining the insulation property. The outer layer of the lead film may provide an adhesive force between the pouch and the electrode tab to maintain the sealing even if the shape of the outer film is partially deformed under the heating and pressing conditions. Therefore, in the sealing process of the pouch, the casted polypropylene (CPP) layer of the pouch is deformed by heating and pressing, so that the sealing can be maintained even if the aluminum foil is partially exposed.

In addition, the lead film may be made of any one of thermoplastic, thermosetting, and photo-curing resins having electrical insulation or two or more resins.

The lead film may include at least one of polypropylene (PP), polyethylene (PE), polyimide (PI), and polyamide.

Examples of the polymer resin include thermoplastic, thermosetting and photocurable resins having electrical insulation, and examples thereof include styrene-butadiene resin, styrene resin, epoxy resin, urethane resin, acrylic resin, phenol resin, amide resin, And modified resins thereof, and they may be used in combination of two or more as necessary. The thermoplastic resin in the polymer resin is an elastomer serving as a matrix for supporting film formation, and preferably has a softening point of about 100 to 180 ° C, and may be used in an amount of 20 to 80% by volume of the entire part of the polymer resin.

Wherein the polymer resin is at least one of an acrylic resin, an epoxy resin, an EPDM resin, a CPE (chlorinated polyethylene) resin, a silicone, a polyurethane, a urea resin, a melamine resin, a phenol resin and an unsaturated ester resin as a thermosetting polymer resin One or more.

Most preferably, an acrylic resin is used as the thermosetting polymer resin.

The notch may be formed at a portion where the electrode lead is disconnected according to the deformation force of the lead wing due to the abnormal state of the battery cell.

The depth of the notch is not limited to the depth of the electrode lead if it can be broken according to the deformation force of the lead wing. In addition, if the flow of current can be stably performed in the steady state of the battery cell, it is not limited to the depth.

The depth of the notch may preferably be 10 to 500 mu m, and preferably 15 to 300 mu m. If the depth value is large, the steady-state conduction characteristic may be deteriorated. If the depth value is small, the electrode lead is not broken in an abnormal state, and normal insulation performance can not be maintained.

Wherein the cathode active material is at least one selected from the group consisting of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium cobalt-nickel oxide, lithium cobalt-manganese oxide, lithium manganese-nickel oxide, lithium cobalt- , A lithium manganese oxide having a spinel structure, and oxides in which the ternary element (s) are substituted or doped with one or more lithium-containing metal oxides. The other element may be any one or two or more elements selected from the group consisting of Al, Mg, Mn, Ni, Co, Cr, V and Fe.

The negative electrode active material may be lithium metal, a lithium alloy (for example, an alloy of lithium and aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium or indium), amorphous carbon, crystalline carbon, SnO _2, or the like may be used, but the present invention is not limited thereto.

Further, it may be a device including a pouch type secondary battery.

In addition, the device may be selected from the group consisting of an electronic device, an electric vehicle, a hybrid vehicle, and a power storage device.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the above teachings. It is to be understood that such modified embodiments are also within the scope of protection of the present invention as defined by the appended claims.

100: Battery cell
110: upper pouch
120: electrode assembly
120a: cathode
120b: anode
120c:
121: positive electrode tab
122: cathode tab
123: lead film
124: positive lead
125: cathode lead
126: lead wing
127: adhesive layer
127a: first adhesive layer
127b: second adhesive layer
128: Notch
130: Lower pouch

Claims (13)

1. A pouch type secondary battery accommodated in a pouch including an electrode assembly, an electrode tab, an electrode lead, and a lead film in which an anode and a cathode are stacked with a separator interposed therebetween,
And a lead wing having one surface abutting the pouch and the other surface abutting the electrode lead.
The method according to claim 1,
Wherein the lead wing is firmly coupled to the pouch more than the electrode lead.
The method according to claim 1,
Wherein a first adhesive layer is formed between the lead wing and the pouch.
The method of claim 3,
Wherein the first adhesive layer is formed on one surface of the lead wing that is not in contact with the pouch and the electrode lead.
5. The method of claim 4,
And a second adhesive layer is formed on the electrode lead, the second adhesive layer being connected to the first adhesive layer.
6. The method of claim 5,
And the second adhesive layer is formed in the electrode tab direction.
The method according to claim 1,

And a notch is formed in the electrode lead between the lead wing and the lead film.

8. The method of claim 7,
Wherein the thickness (W _t ) of the lead wing is a thickness at which disconnection occurs in the notch portion of the electrode lead, preferably 200 to 4000 μm.
8. The method of claim 7,
The length (W _L ) of the lead wing is an area attached to the pouch, and is preferably 1 to 10 mm.
The method according to claim 1,
Wherein the lead wing is formed on both surfaces of the electrode lead.
The method according to claim 1,
Wherein when the pouch expands due to an increase in the internal pressure of the pouch type secondary battery, the lead vane opens the lead vane in the direction perpendicular to the electrode tab to cut off the energization of the electrode lead.
A method according to any one of claims 1 to 11,
And the pouch type secondary battery.
13. The method of claim 12,
Wherein the device is selected from the group consisting of an electronic device, an electric vehicle, a hybrid vehicle, and a power storage device.

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