KR102313058B1 - Secondary Battery Cell with Less Modification of External Form of Battery Case - Google Patents

Abstract

The present invention provides an electrode assembly including a main body including electrode plates and a separator having opposite polarities, an electrode terminal protruding from an end side of the main body, and the electrode terminal is a tab positioned inside the battery case together with the electrode assembly -It includes a lead coupling part and a terminal connection part protruding to the outside of the battery case, and the tab-lead coupling part is double bent in opposite directions in the inner space between the end of the body and the inner surface of the battery case facing the end to provide a secondary battery cell, characterized in that supporting the shape of the inner space.

Description

Secondary Battery Cell with Less Modification of External Form of Battery Case

The present invention relates to a battery cell in which the external deformation of the battery case is small.

Recently, rechargeable batteries capable of charging and discharging have been widely used as energy sources for wireless mobile devices. In addition, the secondary battery is an electric vehicle (EV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle that has been proposed as a solution to air pollution such as gasoline and diesel vehicles using fossil fuels. It is also attracting attention as a power source such as (Plug-In HEV).

While one or two or three battery cells are used per device in small mobile devices, medium-to-large battery modules electrically connecting a plurality of battery cells are used in mid-to-large devices such as automobiles due to the need for high output and large capacity.

As mobile devices become lighter and thinner, battery cells used therefor are also required to have a lighter and thinner structure. In addition, since it is preferable that the medium and large-sized battery module be manufactured as small as possible in size and weight, a battery cell capable of being charged with a high degree of integration and having a small weight to capacity is required.

In this regard, the usage of prismatic batteries, pouch-type batteries, and the like has recently increased. In particular, a pouch-type battery using an aluminum laminate sheet or the like as an exterior member has recently attracted a lot of attention due to advantages such as small weight, low manufacturing cost, and easy shape deformation.

1 is an exploded perspective view schematically showing a general structure of a conventional pouch-type secondary battery.

Referring to FIG. 1 , the pouch-type secondary battery 10 is welded to an electrode assembly 30 , a plurality of electrode tabs 32 and 34 extending from the electrode assembly 30 , and electrode tabs 32 and 34 . It is configured to include electrode leads 40 and 41, and a battery case 20 for accommodating the electrode assembly.

The electrode assembly 30 is a structure in which a separator is interposed between an anode and a cathode. The electrode tabs 32 and 34 extend from each electrode plate of the electrode assembly 30 , and the electrode leads 40 and 41 are formed with a plurality of electrode tabs 32 and 34 extending from each electrode plate, for example, by welding. are electrically connected to each other, and some are exposed to the outside of the battery case 20 . The battery case 20 provides a space for accommodating the electrode assembly 30 and has a pouch shape. In the case of the stacked electrode assembly 30 as in FIG. 1 , the plurality of positive electrode tabs 32 and the plurality of negative electrode tabs 34 may be coupled together to the electrode leads 40 and 41 , inside the battery case 20 . The upper end is spaced apart from the electrode assembly 30 .

The electrode assembly 30 is accommodated in the battery case 20 together with the electrolyte, and the battery case 20 is sealed through a vacuum process of removing air in the housing in which the electrode assembly 30 is built.

On the other hand, the plurality of electrode tabs 31 and 32 protruding from the electrode plate of the electrode assembly 30 are, for example, the electrode leads 40 and 41 in the form of a fusion joint integrally coupled by welding. are each connected to The electrode leads 40 and 41 have opposite ends to which the electrode tab fusion part is connected to the outside of the battery case 20 .

Here, since the electrode tabs 31 and 32 are integrally coupled to form a fusion portion, the inner upper end of the battery case 20 is spaced apart from the upper end surface of the electrode assembly 30 by a predetermined distance.

Therefore, when the battery is dropped toward its upper end, that is, toward the electrode leads 40 and 41 or a physical external force is applied to the upper surface of the secondary battery, the electrode assembly 300 moves to the upper end of the inner surface of the battery case 20 . or the top is crushed, so that the fusion part is broken or the electrode tabs 31 and 32 or the electrode leads 40 and 41 of the fusion part are pushed in the electrode assembly 30 direction and come into contact with opposite electrode plates to cause an internal short circuit can

In addition, when the battery case 20 performs a process of removing internal air by a vacuum process, the battery case is contracted into the inner upper space of the battery case 20 where the fusion part is located, and a plurality of wrinkles are formed on the battery case. can occur

The wrinkle of the battery case is contracted and stretched together in response to the contraction and expansion of the electrode assembly 30 according to the charging and discharging of the secondary battery. This may cause serious safety problems, such as leakage of electrolyte or introduction of foreign matter.

Accordingly, there is a high need for a technology capable of fundamentally solving these problems.

An object of the present invention is to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

Specifically, an object of the present invention is to provide a space between the end of the electrode assembly and the electrode assembly receiving portion of the battery case by having the tab-lead coupling portion positioned in the inner space of the battery case have a shape that is double bent in opposite directions. It is to provide a secondary battery cell supported by the bent portion of the tab-lead coupling portion to suppress the external deformation of the battery case.

The secondary battery cell of the present invention for achieving this object,

As a secondary battery cell in which an electrode assembly is embedded in a battery case together with an electrolyte,

The electrode assembly includes a body including electrode plates and a separator having opposite polarities, and an electrode terminal protruding from an end side of the body;

the electrode terminal includes a tab-lead coupling part positioned inside the battery case together with the electrode assembly and a terminal connection part protruding to the outside of the battery case;

The tab-lead coupling part is characterized in that it supports the shape of the inner space in a shape that is double bent in opposite directions in the inner space between the end of the main body and the inner space of the battery case facing the end.

In general, an internal short circuit caused by a fall of a secondary battery, application of an external shock, etc. can act as a main cause of explosion or ignition of the battery. This is because of the high resistance heat caused by the energized current in the contact resistance part. When the internal temperature of the battery rises above the critical value due to the resistance heat, the oxide structure of the positive electrode active material collapses to cause thermal runaway, which may cause ignition or explosion of the battery.

On the other hand, in the secondary battery cell according to the present invention, the tab-lead coupling portion supports the shape of the inner space in a shape that is double bent in opposite directions in the inner space between the end of the main body and the inner space of the battery case facing the end. As a result, even when the secondary battery cell moves due to a fall or impact, the movement of the electrode assembly is restricted on the battery case, so that the above-described problem can be solved.

Moreover, in the sealing process of the battery case, even when a vacuum process is performed, the tab-lead coupling portion prevents the portion of the battery case from being contracted, thereby preventing defects such as wrinkles from occurring.

In one specific example, the battery case may be a pouch-type battery case of a laminate sheet including a metal layer and a resin layer.

The battery case also includes a first cover having a first accommodating portion to be inserted into a portion of the main body, and a second cover having a second accommodating portion to be inserted into the remaining portion of the main body;

In a state in which the first cover and the second cover are coupled, the inner space includes a first space between an end of the main body and an inner surface of the first cover facing the end, and a first space between the end of the body and the second facing the end. It may include a second space between the two inner surfaces of the cover, and in the battery case having this structure, the tab-lead coupling part may be positioned over the first space and the second space.

In the present invention, the tab-lead coupling part is a concept including electrode tabs and an electrode lead defining an electrode terminal of a secondary battery cell, and means a portion of an electrode terminal positioned only in the first space and the second space. That is, since the electrode tabs are located in the battery case, they are included in the tab-lead coupling part, and a part of the electrode lead protrudes to the outside of the battery case as a terminal connection part, except for this, located in the first space and the second space. A part of the electrode lead is incorporated into a tab-lead coupling part according to the concept of the present invention.

In consideration of the above, the specific structure of the tab-lead coupling portion will be described in detail below.

The tab-lead coupling portion,

electrode tabs of the same polarity protruding outward from the electrode plates; and

it includes electrode leads positioned in the first space and the second space, and the electrode leads are coupled to the electrode tabs;

In a state in which the electrode tabs are bent from the bottom to the top of the body, the electrode leads are coupled to the ends of the bent electrode tabs from the bottom of the body to the top of the body, and a first bent part positioned in a first space; and

and a second bent part in which the electrode lead located in the second space is bent from the upper end of the main body to the lower end.

In the present invention, the electrode assembly has a structure in which electrode plates having opposite polarities are stacked with a separator therebetween, or a plurality of unit cells having a structure in which electrode plates of mutually opposite polarity are stacked with a separator therebetween are formed on a separation film In the arranged state, the separation film may have a wound structure.

The lower end of the main body of the electrode assembly means a portion located at the lowermost end of the surfaces having the largest area in the electrode assembly when each surface of the electrode assembly is positioned parallel to the ground.

In addition, the upper end of the body means a portion located at the uppermost portion of the surfaces having the largest area in the electrode assembly when the respective surfaces of the electrode assembly are positioned parallel to the ground.

For easy understanding of this structure, when it is assumed that the electrode assembly has a structure in which a plurality of electrode plates are stacked, the lowest electrode plate becomes the lower end of the body, and the electrode plate located at the uppermost end forms the upper end of the body. , If a separator is added on the electrode plates and is positioned at the outermost part, the separator forms the upper and lower ends of the body.

Similarly, in the electrode assembly of the wound structure after the unit cells are arranged on the separation film, in the unit cell located at the outermost part, a single electrode located at the outermost part or the separation film surrounding it forms the top and bottom of the body. can

In this structure, the first bent portion is adjacent to the inner surface of the first cover parallel to the lower end of the main body to support the shape of the first space, and the second bent portion is adjacent to the inner surface of the second cover parallel to the upper end of the main body. It can support the shape of 2 spaces.

The first bent part has a structure in which electrode tabs of the same polarity protruding outward from the electrode plates are assembled at a portion adjacent to the lower end of the body, and the assembled electrode tabs are bent at a first angle to face the upper end of the body, ;

It may include electrode tabs positioned in the first space and a portion of the electrode lead.

The first angle may be an angle of 0 degrees to 20 degrees with respect to the perpendicular to the ground, and if the angle is inclined more than 0 degrees, it may be directed toward the end of the body. This is to minimize the space occupied by the tab-lead coupling unit in the first space. However, if bent more rapidly than the angle of 20 degrees, there is a high possibility of contacting the end of the body, and since the electrode tabs are bent at a very large angle at the same time, there is a risk of the electrode tabs being damaged due to the low structural stability. .

In addition, when bending at the first angle, since the bent portions of the electrode tabs are adjacent to the inner surface of the battery case in the first space, it is preferable to bend to have a round shape rather than an angular shape.

The electrode lead may be bent at a second angle of 150 degrees to 180 degrees with respect to the first angle while extending to the upper end of the body along the bending direction of the electrode tabs to form a second bent part of the tab-lead coupling part. .

When the second angle is less than 150 degrees, it is undesirable because the space occupied by the electrode lead in the second space increases, and when it exceeds 180 degrees, the lead is excessively bent, and structural stability is low.

In addition, when bending at the second angle, since the bent portion of the electrode lead is adjacent to the inner surface of the battery case in the second space, it is preferable to be bent to have a round shape rather than an angular shape.

The electrode lead is integrally connected to the terminal connection part in a state in which it extends along the bending direction of the second bent part,

The second bent part is a part of the electrode lead positioned in the second space, and may include a part where bending of the electrode lead starts and a part connected to the terminal connection part.

In one specific example, a first insulating member is added over the first bent portion from the lower end of the main body so as to ensure insulation with respect to the inner surface of the first cover;

The first insulating member may be in close contact with the inner surface of the first cover parallel to the lower end of the main body in a bent state together with the first bent part.

In addition, a second insulating member is added from the upper end of the main body to the second bent portion so as to ensure the insulation of the inner surface of the second cover,

The second insulating member may be in close contact with the inner surface of the second cover parallel to the upper end of the main body in a bent state together with the second bent part.

The second insulating member may be additionally added to the electrode lead positioned between the first bent part and the second bent part.

The first insulating member and the second insulating member may be an insulating tape or a separation film.

The insulating tape may be an insulating tape made of a polymer material, a rubber tape, a black tape, or the like, but is not limited thereto.

The separation film may include an olefin-based polymer such as chemical-resistant and hydrophobic polypropylene; It may be a sheet or non-woven fabric made of glass fiber or polyethylene.

In addition, the separation film may be an organic/inorganic composite porous SRS (Safety-Reinforcing Separators) separator.

The SRS separator may have a uniform pore structure formed by an interstitial volume between inorganic particles, which is an active layer component, in addition to the pore structure included in the separator substrate itself, and the pores are the external impact applied to the electrode assembly. Not only can it be significantly alleviated, but also, the smooth movement of lithium ions through the pores is made, and a large amount of electrolyte is filled to indicate a high impregnation rate, so that the performance of the battery can be improved together.

On the other hand, the type of the battery cell of the present invention is not particularly limited, but as a specific example, a lithium ion (Li-ion) secondary battery, lithium polymer (Li) having advantages such as high energy density, discharge voltage, and output stability. -polymer), or a lithium secondary battery such as a lithium ion polymer (Li-ion polymer) secondary battery.

In general, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a lithium salt-containing non-aqueous electrolyte.

The positive electrode, for example, is prepared by coating a mixture of a positive electrode active material, a conductive material, and a binder on a positive electrode current collector and/or an extended current collector and then drying, and, if necessary, further adding a filler to the mixture do.

The positive electrode current collector and/or the extended current collector is generally made to have a thickness of 3 to 500 micrometers. The positive electrode current collector and the extended current collector are not particularly limited as long as they have high conductivity without causing a chemical change in the battery, and for example, stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum. A stainless steel surface treated with carbon, nickel, titanium, silver, or the like may be used. The positive electrode current collector and the extended current collector may form fine irregularities on the surface thereof to increase the adhesion of the positive electrode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a non-woven body are possible.

The cathode active material may _{include a layered compound such as lithium cobalt oxide (LiCoO 2} ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Formula Li _1+x Mn _2-x O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , and LiMnO _{2 ;} lithium copper oxide (Li ₂ CuO ₂ ); vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ , and Cu ₂ V ₂ O _{7 ;} Ni site-type lithium nickel oxide represented by the formula LiNi _1-x M _x O ₂ (wherein M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); Formula LiMn _2-x M _x O ₂ (where M = Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (where M = Fe, Co, lithium manganese composite oxide represented by Ni, Cu or Zn; _{LiMn 2} O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; disulfide compounds; And the like Fe ₂ (MoO _{4) 3,} but is not limited to these.

The conductive material is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive active material. Such a conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery. For example, graphite such as natural graphite or artificial graphite; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskeys such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; A conductive material such as a polyphenylene derivative may be used.

The binder is a component that assists in bonding between the active material and the conductive material and bonding to the current collector, and is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butyrene rubber, fluororubber, various copolymers, and the like.

The filler is optionally used as a component for inhibiting the expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. For example, an olipine-based polymer such as polyethylene or polypropylene; A fibrous material such as glass fiber or carbon fiber is used.

The negative electrode is manufactured by coating and drying the negative electrode active material on the negative electrode current collector and/or the extended current collector, and if necessary, the above-described components may be optionally further included.

The negative current collector and/or the extended current collector is generally made to have a thickness of 3 to 500 micrometers. Such a negative current collector and/or extended current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, Copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. may be used. In addition, like the positive electrode current collector, the bonding force of the negative electrode active material may be strengthened by forming fine irregularities on the surface, and may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a non-woven body.

Examples of the negative electrode active material include carbon such as non-graphitizable carbon and graphitic carbon; Li _x Fe ₂ O ₃ (0≤x≤1), Li _x WO ₂ (0≤x≤1), Sn _x Me _1-x Me' _y O _z (Me: Mn, Fe, Pb, Ge; Me' : metal composite oxides such as Al, B, P, Si, elements of Groups 1, 2, and 3 of the periodic table, halogen; 0<x≤1;1≤y≤3;1≤z≤8); lithium metal; lithium alloy; silicon-based alloys; tin-based alloys; SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ O ₄ , and metal oxides such as _{Bi 2} O _{5 ;} conductive polymers such as polyacetylene; A Li-Co-Ni-based material or the like can be used.

The separator is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 micrometers, and the thickness is generally 5 to 300 micrometers. As such a separation membrane, For example, olefin polymers, such as chemical-resistant and hydrophobic polypropylene; Sheets or non-woven fabrics made of glass fiber or polyethylene are used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

The electrolyte may be a lithium salt-containing non-aqueous electrolyte, and includes a non-aqueous electrolyte and a lithium salt. As the non-aqueous electrolyte, a non-aqueous organic solvent, an organic solid electrolyte, an inorganic solid electrolyte, and the like are used, but are not limited thereto.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxy methane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo An aprotic organic solvent such as a nate derivative, a tetrahydrofuran derivative, an ether, methyl pyropionate, or ethyl propionate can be used.

Examples of the organic solid electrolyte include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphoric acid ester polymers, poly agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, A polymer containing an ionic dissociation group or the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides, sulfates, etc. of Li such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS _{2 and the like may be used.}

The lithium salt is a material easily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

In addition, for the purpose of improving charge/discharge characteristics, flame retardancy, etc. in the nonaqueous electrolyte, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphate triamide, Nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, aluminum trichloride, etc. may be added. have. In some cases, in order to impart incombustibility, a halogen-containing solvent such as carbon tetrachloride and ethylene trifluoride may be further included, and carbon dioxide gas may be further included to improve high-temperature storage characteristics, and FEC (Fluoro-Ethylene) Carbonate), PRS (Propene Sultone), etc. may be further included.

In one specific example, LiPF ₆ , LiClO ₄ , LiBF ₄ , LiN(SO ₂ CF ₃ ) ₂ Lithium salt such as a cyclic carbonate of EC or PC and a low-viscosity solvent of DEC, DMC or EMC A lithium salt-containing non-aqueous electrolyte may be prepared by adding it to a mixed solvent of linear carbonate.

In one specific example, the battery case is made of a laminate sheet including a metal layer and a resin layer, and may be sealed by thermal fusion after the electrode assembly is mounted to the receiving part.

An insulating film is attached to the contact portion between the lead part and the battery case, and the insulating film may be heat-sealed together with the battery case.

The electrode assembly of the present invention has, for example, a stacked structure in which a plurality of electrode plates are stacked with a separator interposed therebetween, or a plurality of full-cell or bi-cell in which two or more electrode plates are stacked on a separation film. It may be a stack/folding type structure of a structure wound in an arranged state, but is not limited thereto.

The present invention also provides a battery pack including one or more of the battery cells and a device including the battery pack.

As described above, in the secondary battery cell according to the present invention, the tab-lead coupling portion is double bent in the direction opposite to each other in the inner space between the end of the body and the inner surface of the battery case facing the end of the inner space. Since the shape is supported, even if the secondary battery cell moves due to a fall or impact, the movement of the electrode assembly is limited on the battery case, and thus the problem is solved.

1 is a schematic diagram of a battery cell according to the prior art;
2 is a schematic side view of a battery cell according to an embodiment of the present invention;
3 is an enlarged schematic view of a vertical cross-section of a portion A of FIG. 2 .

Hereinafter, although described with reference to the drawings according to the embodiment of the present invention, this is for easier understanding of the present invention, and the scope of the present invention is not limited thereto.

FIG. 2 is a schematic side view of a battery cell according to an embodiment of the present invention, and FIG. 3 is an enlarged schematic view of a vertical cross-section of a portion A of FIG. 2 .

2 and 3 together, the secondary battery cell 100 has a structure in which the electrode assembly 110 is embedded in the battery case 200 together with the electrolyte.

The electrode assembly 110 includes a body 112 including electrode plates of opposite polarities and a separator, and an electrode terminal 130 protruding from an end side of the body 112 .

The electrode terminal 130 includes a tab-lead coupling part 114 positioned inside the battery case 200 together with the electrode assembly 110 and a terminal connection part 119 protruding to the outside of the battery case 200 .

Here, that the terminal connection part 119 protrudes to the outside of the battery case 200 means that it protrudes from the inner space of the battery case 200 in which the electrode assembly 110 is accommodated. It is a part of the electrode terminal 130 positioned outside the first space 212 and the second space 222 into which the main body 112 is inserted.

The tab-lead coupling part 114 is double bent in the opposite direction in the inner space between the end c of the main body 112 and the inner surface of the battery case 200 facing the end c. It supports the shape of the internal space.

The battery case 200 is a pouch-type battery case 200 of a laminate sheet including a metal layer and a resin layer, and a first cover in which a first housing part is formed so that a part of the body 112 is inserted. 210 and a second cover 220 having a second accommodating portion to be inserted into the rest of the main body 112 .

In a state in which the first cover 210 and the second cover 220 are coupled (facing state in FIG. 3 ), the inner space is a first facing end (c) and end (c) of the body 112 . The first space 212 between the inner surface of the cover 210, and the second space 222 between the end (c) of the main body 112 and the inner surface of the second cover 220 facing the end (c) contains

In the battery case 200 having this structure, the tab-lead coupling part 114 is positioned over the first space 212 and the second space 222 .

The tab-lead coupling part 114 is a concept including the electrode tabs 117 and the electrode lead 118 defining the electrode terminal 130 of the secondary battery cell 100 , the first space 212 . and a portion of the electrode terminal 130 positioned only in the second space 222 .

That is, since the electrode tabs 117 are located in the battery case 200 , the tab-lead coupling part 114 is included, and the electrode lead 118 is a part of the battery case 200 as the terminal connection part 119 . A part of the electrode lead 118 positioned in the first space 212 and the second space 222 except for this protrudes to the outside is integrated into the tab-lead coupling part 114 according to the concept of the present invention.

The tab-lead coupling portion 114 includes electrode tabs 117 of the same polarity protruding outwardly from the electrode plates and electrode leads 118 positioned in the first space 212 and the second space 222 . are doing In addition, the tab-lead coupling part 114 has a structure in which the electrode leads 118 are coupled to the electrode tabs 117 . Such bonding may be made, for example, by welding, soldering, or the like.

In the tab-lead coupling part 114 , in a state in which the electrode tabs 117 are bent from the bottom to the top of the body 112 , the electrode leads 118 are attached to the ends of the bent electrode tabs 117 in the body 112 . ) coupled to face the upper direction from the bottom and includes a first bent portion 101 located in the first space (212).

The tab-lead coupling part 114 also includes a second bending part 102 in which the electrode lead 118 located in the second space 222 is bent from the top to the bottom of the body 112 .

In the first bent part 101 , electrode tabs 117 of the same polarity protruding outward from the electrode plates are assembled at a portion adjacent to the lower end of the body 112 , and the assembled electrode tabs 117 are formed in the body 112 . ) is bent at a first angle to face the upper end, and includes electrode tabs 117 and a portion of the electrode lead 118 positioned in the first space 212 . Although not shown separately in the drawings, the first angle is approximately 15 degrees in FIG. 3 .

Here, since the bent portion of the first bent portion 101 is adjacent to the inner surface of the battery case 200 in the first space 212 , it is bent to have a round shape rather than an angular shape.

The electrode lead 118 is bent at a second angle of approximately 180 degrees based on the first angle in a state in which it extends to the upper end of the body 112 along the bending direction of the electrode tabs 117, and is bent to combine the tab-lead. The second bent portion 102 of the portion 114 is formed.

The electrode lead 118 is also integrally connected to the terminal connection part 119 in a state in which it extends along the bending direction of the second bent part 102 .

Accordingly, the second bent portion 102 may be understood as a part of the electrode lead 118 positioned in the second space 222 , and the portion where bending of the electrode lead 118 starts and the terminal connection portion 119 . ) is a concept that includes the part just before it is connected to.

In the above structure, the first bent portion 101 is adjacent to the inner surface of the first cover 210 parallel to the lower end of the main body 112 to support the shape of the first space 212 , and the second bent portion 102 ) is adjacent to the inner surface of the second cover 220 parallel to the upper end of the body 112 to support the shape of the second space 222 .

Therefore, in the secondary battery cell 100 according to the present invention, the tab-lead coupling portion 114 is opposite to each other in the inner space between the end of the body 112 and the inner surface of the battery case 200 facing the end. The double bent shape supports the shape of the inner space, and even if the secondary battery cell 100 moves due to a fall or an impact, the movement of the electrode assembly 110 on the battery case 200 is limited and thus the above-described problem can be resolved.

On the other hand, a first insulating member 310 is added from the lower end of the main body 112 to the first bent portion 101 so as to ensure the insulation of the inner surface of the first cover 210 .

The first insulating member 310 is in close contact with the inner surface of the first cover 210 parallel to the lower end of the main body 112 in a bent state together with the first bent portion 101 .

In addition, a second insulating member 320 is added from the upper end of the main body 112 to the second bent portion 102 so as to ensure the insulation of the inner surface of the second cover 220 .

The second insulating member 320 is in close contact with the inner surface of the second cover 220 parallel to the upper end of the main body 112 in a bent state together with the second bent portion 102 .

A second insulating member 320 is further added to the electrode lead 118 located between the first bent portion 101 and the second bent portion 102 , and according to the first bent portion 101 , the electrode In order to secure insulation at a portion where the lead 118 and the electrode tab 117 face each other, the electrode tab 117 facing the electrode lead 118 is also added.

Those of ordinary skill in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (15)

As a secondary battery cell in which an electrode assembly is embedded in a battery case together with an electrolyte,
The electrode assembly includes a body including electrode plates and a separator having opposite polarities, and an electrode terminal protruding from an end side of the body;
the electrode terminal includes a tab-lead coupling part positioned inside the battery case together with the electrode assembly and a terminal connection part protruding to the outside of the battery case;
The battery case includes a first cover in which a first accommodating part is formed so that a part of the main body is inserted, and a second cover in which a second accommodating part is formed so that the remaining part of the main body is inserted;
In a state in which the first cover and the second cover are coupled, the inner space includes a first space between an end of the main body and an inner surface of the first cover facing the end, and a first space between the end of the body and the second facing the end. a second space between the two inner surfaces of the cover;
The tab-lead coupling portion,
It is positioned over the first space and the second space, and supports the shape of the inner space in a shape double-folded in opposite directions in the inner space between the end of the main body and the inner space of the battery case facing the end,
electrode tabs of the same polarity protruding outward from the electrode plates; and
it includes electrode leads positioned in the first space and the second space, and the electrode leads are coupled to the electrode tabs;
In a state in which the electrode tabs are bent from the bottom to the top of the body, the electrode leads are coupled to the ends of the bent electrode tabs from the bottom of the body to the top of the body, and a first bent part positioned in a first space; and
a second bent part in which the electrode lead located in the second space is bent from the upper end of the main body to the lower end;
includes,
The first bent portion is adjacent to the inner surface of the first cover parallel to the lower end of the main body to support the shape of the first space, and the second bent portion is adjacent to the inner surface of the second cover parallel to the upper end of the main body to form the second space. A secondary battery cell, characterized in that supporting the shape. delete delete delete According to claim 1, wherein the first bent portion, the electrode tabs of the same polarity protruding outwardly from the electrode plates are collected at a portion adjacent to the lower end of the main body, the first angle so that the assembled electrode tabs face the upper end of the main body It is a structure that is bent with;
A secondary battery cell comprising electrode tabs positioned in the first space and a portion of the electrode lead. The method of claim 5, wherein the electrode lead is bent at a second angle of 150 degrees to 180 degrees with respect to the first angle in a state in which it extends to the upper end of the main body along the bending direction of the electrode tabs, so that the tab-lead coupling portion is second A secondary battery cell, characterized in that forming a bent part. The method according to claim 6, wherein the electrode lead is integrally connected to the terminal connection part while extending along the bending direction of the second bent part,
The second bent part is a part of the electrode lead positioned in the second space, and includes a part where the bending of the electrode lead starts and a part connected to the terminal connection part. The secondary battery cell according to claim 5, wherein the first angle is an angle of 0 degrees to 20 degrees with respect to the vertical to the ground. The method according to claim 1, wherein a first insulating member is added from the lower end of the main body to the first bent portion so as to ensure insulation to the inner surface of the first cover;
The first insulating member is a secondary battery cell, characterized in that in close contact with the inner surface of the first cover parallel to the lower end of the main body in a bent state together with the first bent portion. The method according to claim 1, wherein a second insulating member is added from the upper end of the main body to the second bent portion so as to ensure insulation of the inner surface of the second cover,
The second insulating member is a secondary battery cell, characterized in that in close contact with the inner surface of the second cover parallel to the upper end of the main body in a bent state together with the second bent portion. The secondary battery cell according to claim 10, wherein the second insulating member is additionally added to the electrode lead positioned between the first bent part and the second bent part. The secondary battery cell according to any one of claims 9 to 11, wherein the first insulating member and the second insulating member are an insulating tape or a separation film. According to claim 1, wherein the lower end of the main body, when each surface of the electrode assembly is positioned parallel to the ground, among the surfaces having the largest area in the electrode assembly, the lowermost portion;
The upper end of the main body, when each surface of the electrode assembly is positioned parallel to the ground, the secondary battery cell, characterized in that the uppermost portion of the surfaces having the largest area in the electrode assembly. According to claim 1, wherein the electrode assembly, a plurality of unit cells of a structure in which electrode plates of mutually opposite polarity are stacked with a separator interposed therebetween, or electrode plates of mutually opposite polarity are stacked with a separator therebetween are separated A secondary battery cell, characterized in that it has a structure in which a separation film is wound in a state arranged on a film. The secondary battery cell according to claim 1, wherein the battery case is a pouch-type battery case made of a laminate sheet including a metal layer and a resin layer.

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