KR101798926B1 - Secondary Battery Having Insulative Member with Improved Structural Stability against External Force - Google Patents

Abstract

The present invention relates to an electrode assembly in which an electrode assembly having a cathode, a cathode, and a separator interposed between an anode and a cathode is inserted into a rectangular metal can together with an electrolyte, an insulating member is mounted on an upper end of the electrode assembly, Wherein the insulating member includes a plate-like body having a shape corresponding to a horizontal cross-sectional structure of the metal can, wherein the body has a first end which is in close contact with both inner surfaces of the metal can, And a first side and a second side which are in close contact with the inner front and rear surfaces of the metal can, respectively, wherein the first side and the second side are provided with one or more support portions projecting upward from the upper surface of the body And a buffer member for preventing breakage of the insulating member due to external force is attached to the outer peripheral surface of the first end portion and the second end portion, respectively It provides a rechargeable battery with.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery including an insulative member having improved structural stability against an external force,

The present invention relates to a secondary battery including an insulating member having improved structural stability against an external force.

As technology development and demand for mobile devices have increased, the demand for secondary batteries as energy sources has been rapidly increasing, and accordingly, a lot of researches on batteries that can meet various demands have been conducted.

Lithium secondary batteries such as lithium ion polymer batteries having high energy density, discharge voltage, and output stability in terms of the material of the battery are high in demand. The lithium ion secondary battery can be applied to products such as mobile phones with a thin thickness in terms of shape, There is a high demand for a prismatic battery and a pouch-type battery which can be used as a battery of a battery module manufactured by stacking the battery module.

One of the major research tasks in these cells is to improve safety. For example, a lithium secondary battery can be operated at a high temperature within the battery, which can be caused by an abnormal operating state of the battery, such as an internal short circuit, an overcharged state exceeding an allowable current and a voltage, exposure to a high temperature, And the explosion of the battery may be caused by the high pressure.

In particular, a secondary battery including a positive electrode, a negative electrode, and a jelly-roll type electrode assembly having a structure in which a separator is disposed between the positive electrode and the negative electrode is wound due to an external force such as a drop, An internal short circuit is more likely to occur.

Such a prismatic battery is characterized in that a jelly-roll type electrode assembly composed of an anode, a cathode and a separator is mounted inside a rectangular metal can, and an insulating member is mounted on the open upper end thereof, The electrolyte is injected into the battery case through the electrolyte injection hole, sealed with a metal ball, a safety element and a protection circuit are mounted on the electrolyte, and then sealed with a housing (outer case).

In this structure, a schematic view of an insulating member mounted on the top of a jelly-roll type electrode assembly of a prismatic battery for preventing contact between a metal cap and an electrode tab is shown in Fig.

Referring to FIG. 1, the insulating member 50 has a plate-shaped body corresponding to a horizontal inner surface structure of a battery case (not shown) and an upward protruding support portion 55 formed at both side end portions thereof. The plate-shaped body 52 is provided with a pair of openings 54 through which the positive electrode and the negative electrode of the electrode assembly (not shown) can be respectively inserted.

The insulating member 50 is mounted on the upper end of the electrode assembly so that the protruding support portions 55 at both side ends face upward, and after inserting the jelly-roll type electrode assembly into the square can, do. The protruding support portion 55 is formed at a height that can be brought into close contact with the lower end surface of the top cap, thereby preventing the electrode assembly from deviating from the correct position due to external force.

However, when an inertial force or a centrifugal force is applied to the electrode assembly by applying a strong external force due to drop or rotation, as the electrode assembly moves inside the metal can, an external force is applied also to the insulating member 50 fixed inside the metal can A strong tensile force is applied to both end portions of the insulating member 50 by the protruding and supporting portions 55 that are in close contact with the inner surface of the metal can and the end portions are broken or bent to break the insulating member 50 have.

In addition, when the insulating member is broken, the upper end portion of the electrode assembly is pressed, thereby causing the electrode to be damaged, resulting in a short circuit between the can and the electrode.

Therefore, there is a high need for a technique that can prevent internal shorting of the electrode assembly by external force by simply changing the structure of the insulating member, thereby further improving the safety of the battery.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

Specifically, an object of the present invention is to provide a secondary battery improved in stability through an insulating member to which a buffer member for preventing breakage of the insulating member due to external force is added.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a rechargeable battery including a positive electrode, a negative electrode, and an electrode assembly having a separator interposed between the positive electrode and the negative electrode, And a top cap is coupled to an open upper end of the metal can,

Wherein the insulating member includes a plate-like body having a shape corresponding to a horizontal cross-sectional structure of the metal can,

The main body includes a first side and a second side which are in close contact with inner side surfaces and a rear side of the metal can, respectively,

The first side portion and the second side portion being formed with one or more supporting portions protruding upward from the upper surface of the main body,

And a cushioning member for preventing breakage of the insulating member due to an external force is added to the outer peripheral surfaces of the first end and the second end.

Generally, the insulating member is disposed between the electrode assembly and the top cap by being mounted on the top of the electrode assembly, and serves as an insulating member to prevent undesirable electrical contact between the electrodes of the electrode assembly and the top cap. On the other hand, since the insulating member of the present invention includes the cushioning members at the first end and the second end, which are both end portions, in addition to the above-mentioned basic role, the external impact on the electrode assembly is mitigated to prevent the electrode from being damaged , And preventing the occurrence of a short circuit between the can and the electrode, thereby enhancing the safety of the battery.

Specifically, in the secondary battery according to the present invention, the insulating member is provided at the first end and the second end, which are in close contact with the inner surface on both sides of the metal can, respectively, on the outer circumferential surface thereof, Even when the electrode assembly moves, the buffer member absorbs an external force or an impact applied to the first end and the second end of the insulating member which are in close contact with the inner surfaces on both sides of the metal can, respectively, . As a result, the secondary battery according to the present invention has a high structural stability because it prevents safety problems caused by breakage of the insulating member.

Further, the insulating member is formed with a supporting portion on only the first side and the second side which are in close contact with the front surface of the metal can, except for the first end and the second end, which is the end of the insulating member most vulnerable to breakage by external force It should be noted that it is a structure.

This minimizes the contact area between the first end and the second end of the metal can that are in close contact with the inner surfaces of both sides of the metal can so that the tension applied to the first end and the second end Can be reduced, and the above-described structure can improve the problems of the first end and the second end that are liable to breakage as the electrode assembly moves.

The buffer member may be a porous structure made of silicone, a polymer resin, or a natural rubber or a synthetic rubber, though not limited as long as it is a resilient material so as to mitigate impact.

The porous structure of the polymer resin may be, for example, a polyethylene sponge or a polyurethane sponge having electrical insulation and excellent chemical resistance to an electrolytic solution.

In one specific example, the buffer member may be added to the outer peripheral surface of the first end and the second end to a thickness of 30% to 100% of the thickness of the metal can.

When the thickness of the buffer member is less than 30% of the thickness of the metal can, it is not preferable because the external force can not be sufficiently mitigated. If the thickness is more than 100% of the thickness of the metal can, An excessive external force may be applied to the member, and thus the buffer member may be separated from the outer peripheral surface of the first end and the second end of the insulating member. In addition, when the buffer member is formed thick as described above, the insulating member can move inside the metal can due to excessive elasticity, whereby the insulating member is inverted or the first end or the second end of the insulating member So that it can be separated from the inner surfaces of both sides of the metal can.

The total length of the length from the first end to the second end and the thickness of the cushioning member may be 95% to 105% of the length between the inner and the inner sides of the metal can.

When the total length is less than 95% of the length between the inner and both side surfaces of the metal can, the first end and the second end are not firmly fixed to the inner surfaces of both sides of the metal can, It is not preferable since the end portion or the second end portion can be separated from the inner surface on both sides of the metal can. If the length is longer than 105%, excessive tension is applied to the first end portion and the second end portion of the insulating member, It is not preferable because the risk increases.

The buffer member may be further attached to the upper surface and / or the lower surface of the body adjacent to the outer circumferential surface of the first end and the second end as well as the outer circumferential surface of the first end and the second end to improve the stability of the insulating member .

Such a structure has a structure in which the body of the plate-like structure has a shape corresponding to the inner surface of the metal can, while covering the upper part of the electrode assembly as a whole, and also has an impact on the upper surface and / or the lower surface of the body adjacent to the outer peripheral surfaces of the first end and the second end. The insulating member can stably support between the top cap and the electrode assembly, and as a result, the stability of the secondary battery can be further improved.

In one specific example, the main body may further include at least two liquid injection ports through which the electrolyte solution can be injected, and the main liquid injection ports may be formed by injecting the air inside the metal can, As shown in FIG.

The body may also be perforated with one or more openings of a shape corresponding to the horizontal cross-sectional structure of the electrode tab so that the electrode tab projecting from the top surface of the electrode assembly can be connected to the top cap through the body, The electrode tab may be bent to protrude through the opening and the bent surface may be electrically connected to the lower end of the protruding terminal of the top cap.

In general, the prismatic secondary battery has an electrode assembly in which one electrode tab can be connected to the lower end of the protruding terminal of the top cap, another electrode tab opposite to the electrode tab is electrically connected to the metal can, As such, an electrode can be formed.

At this time, when the electrode tab connected to the top cap is severely bent during the manufacturing process or use of the battery, a part of the electrode tab may come into contact with the metal can to cause a short circuit.

In order to solve such a short circuit problem, in the secondary battery according to the present invention, the first side and / or the second side adjacent to the opening are provided with insulation for preventing the electrode tab protruding through the opening from coming into contact with the inner surface of the metal can. An insulative wall may be formed upwardly and the insulating wall may be formed in such a manner that during the process of connecting the electrode tabs from the electrode assembly to corresponding portions of the top cap or during use of the battery in such a connection state, It is possible to prevent contact with the battery cap and to prevent a short circuit.

The insulating wall has a structure in which the first side and / or the second side of the body extend to a predetermined width and length. The length of the insulating wall is not particularly limited as long as it is a size that can prevent the bending protruding portion of the electrode tab from being connected to the metal can and is not limited to a distance L equal to or less than the distance L between the insulating member and the top cap May be small in size and may be formed upwardly from the top surface of the body at the first side and / or the second side with a length of 90% to 100% of the distance L between the insulating member and the top cap have.

However, if the length of the insulation wall is greater than the separation distance L, it may not be easy to mount the insulation member having the insulation wall at a predetermined position on the upper surface of the electrode assembly. On the other hand, It may be undesirable for prevention.

The width of the insulating wall is not particularly limited as long as the bending protruding portion of the electrode tab can be prevented from being connected to the metal can. And may be 100% to 120% of the width of the electrode tabs. The width of the openings may be 100% to 120% of the width of the electrode tabs.

On the other hand, in one specific example, the support portion may be formed in the vicinity of the first side and the second side adjacent to the buffer member added to the outer peripheral surfaces of the first end and the second end, And a portion extending from the side and the second side to the first end and the second end.

This support serves as a guide for inserting the insulating member in the correct position along the inner surface of the metal can when inserting the insulating member into the metal can and is provided on the inner surface of the metal can corresponding to the first side and the second side The insulating member can be prevented from being turned upside down.

The length of the support portion is not particularly limited as long as it is a size that facilitates mounting the insulation member on the metal can, and more specifically, it may protrude to a length of 200% to 400% of the thickness of the insulation member. When the support portion protrudes to a length less than the above range, the effect of the support portion described above can not be exhibited. If the support portion protrudes beyond the above range, the support portion may be greatly vulnerable to external force, .

The supporting portion may be formed to have a width of 5% to 10% of the length of the first side portion or the second side portion. If the supporting portion has a width less than the above range, it may be highly vulnerable to external force, When the above range is exceeded, a strong tensile force is applied to the first side, the second side, and the second side adjacent to the first end, the second end, and the end, which are the ends of the insulating member in which the support portion is formed, So that the insulating member may be damaged.

Meanwhile, the secondary battery according to the present invention is not particularly limited in its kind, but specific examples thereof include a lithium ion (Li-ion) secondary battery having advantages of high energy density, discharge voltage and output stability, lithium polymer Li-polymer secondary batteries, or lithium-ion polymer secondary batteries.

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

The positive electrode is prepared, for example, by coating a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode current collector, and then drying the mixture. Optionally, a filler may be further added to the mixture.

The cathode current collector is generally made to have a thickness of 3 to 500 micrometers. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery, and may be formed of a material such as stainless steel, aluminum, nickel, titanium, sintered carbon, or a surface of aluminum or stainless steel Treated with carbon, nickel, titanium, silver or the like may be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

The cathode active material may be 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 Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ and the like; 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 ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where 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, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, 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; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes 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 fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the cathode 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 butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode is manufactured by applying and drying a negative electrode active material on a negative electrode collector, and if necessary, the above-described components may be selectively included.

The negative electrode collector is generally made to have a thickness of 3 to 500 micrometers. Such an anode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and may be formed of a material such as copper, stainless steel, aluminum, nickel, titanium, fired carbon, surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite 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 complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x < Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{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 Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane 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 membrane is generally 0.01 to 10 micrometers, and the thickness is generally 5 to 300 micrometers. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The electrolytic solution may be a non-aqueous electrolytic solution containing a lithium salt, and is composed of a non-aqueous electrolytic solution and a lithium salt. As the non-aqueous electrolyte, non-aqueous organic solvents, organic solid electrolytes, inorganic solid electrolytes, and the like are used, but the present invention is 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 -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and 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 and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily 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.

For the purpose of improving the charge-discharge characteristics and the flame retardancy, the nonaqueous electrolytic solution is preferably a solution prepared by dissolving or dispersing in a solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, hexaphosphoric triamide, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like may be added have. In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (Fluoro-Ethylene Carbonate, PRS (Propene sultone), and the like.

In one specific _{example, LiPF 6, LiClO 4, LiBF} 4, LiN (SO 2 CF 3) 2 , such as a lithium salt, a highly dielectric solvent of DEC, DMC or EMC Fig solvent cyclic carbonate and a low viscosity of the EC or PC of And then adding it to a mixed solvent of linear carbonate to prepare a lithium salt-containing non-aqueous electrolyte.

The electrode assembly may be a jelly-roll type electrode assembly having a structure in which an anode, a separator, and a cathode are sequentially stacked.

The present invention also provides a secondary battery pack including the secondary battery, a battery module including at least one secondary battery pack, and a device including the battery module as a power source.

The device may be one selected from a cell phone, a portable computer, a smart phone, a smart pad, a tablet PC, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, . The structure of these devices and their fabrication methods are well known in the art, and a detailed description thereof will be omitted herein.

As described above, the secondary battery according to the present invention includes the insulating member provided with the cushioning member for relieving the external force on the outer peripheral surfaces of the first end and the second end of the secondary battery, Even when an external force is applied to the secondary battery to move the electrode assembly, the buffer member absorbs an external force or an impact applied to the first end and the second end of the insulating member, , Breakage of the insulating member can be prevented. As a result, the secondary battery according to the present invention has a high structural stability because it prevents safety problems caused by breakage of the insulating member.

1 is a schematic view of an insulating member according to this prior art;
2 is a schematic diagram of a secondary battery according to an embodiment of the present invention;
3 is a schematic view of the insulating member of Fig. 2;
4 is a schematic view of an insulating member according to another embodiment;
5 is a side schematic view of a secondary battery according to the present invention;
Fig. 6 is an enlarged schematic view of the upper portion of the secondary battery of Fig. 5;

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

Fig. 2 schematically shows a secondary battery according to the present invention, and Fig. 3 schematically shows the insulating member of Fig.

Referring to these figures together, the secondary battery 100 has an electrode assembly 102 and an electrolytic solution (not shown) inserted into the metal can 104, and an insulating member 110 is mounted on the upper end of the electrode assembly 102 And the top cap 106 is coupled to the open upper end of the metal can 104. [ An insulating tape 108 is attached to the lower portion of the metal can 104 and the lower end of the electrode assembly 102 and the metal can 104 can be electrically insulated by the insulating tape 108.

The insulating member 110 includes a plate-like body 112, a first end 136 and a second end 138 which are the outer peripheral ends of the body 112, and a first side 134 and a second side 132, .

The main body 112 is provided with electrode tabs 12 and 14 so that the electrode tabs 12 and 14 protruding from the top surface of the electrode assembly 102 can be connected to the top cap 106 through the main body 112. [ And a plurality of liquid injecting cavities 119 capable of injecting the electrolytic solution at positions adjacent to the openings 114 and 115 are formed so as to penetrate downwardly .

The first end portion 136 and the second end portion 138 are located on both inner side surfaces of the metal can and the first side portion 134 and the second side portion 132 are in close contact with the inner front surface and the rear surface of the metal can 104, do.

A cushioning member 120 is attached to the outer circumferential surfaces of the first end 136 and the second end 138 and the cushioning member 120 is in close contact with the inner surface of the metal can.

The cushioning member 120 is pressed against the metal can 104 in the direction of the first end 136 or the second end 138 or the secondary battery 100 rotates, The external force applied to the first end 136 and the second end 138 of the insulating member 110 is absorbed by the elastic force so that the end portion of the insulating member 110, The first end 136 and the second end 138 can be protected from external forces.

4, the buffer member 120a may be disposed on the lower surface of the main body 112a adjacent to the outer peripheral surfaces of the first end portion 136a and the second end portion 138a of the insulating member 110a, The insulating member 110a can stably support the gap between the top cap 106 and the electrode assembly 102 through the buffer member 120a.

Referring again to Figures 2 and 3, a first side 134 and a second side 132 adjacent to the cushioning member 120, which are attached to the outer circumferential surface of the first end 136 and the second end 138, The supporting portions 118 and 118 'are protruded upward to a length approximately twice the thickness of the insulating member 110 in the adjacent portion.

The supporting portions 118 and 118 'serve as guides to insulate the insulating member 110 along the inner surface of the metal can when the insulating member 110 is inserted into the metal can, And is in close contact with the inner surface of the metal can 104 corresponding to the first side portion 136 and the second side portion 138. Therefore, the supporting portions 118 and 118 'can prevent the insulating member 110 from turning upside down or from flaming.

The negative electrode tab 14 protrudes through the opening 114 and is bent in a state in which the negative electrode tab 14 protrudes through the opening 114. The negative electrode tab 14 protrudes through the opening 114, Is electrically connected to the lower end of the protruding terminal 10 at the lower end of the top cap 106 electrically connected to the negative electrode terminal 11 formed on the top cap 106. The protruding terminals 10 are insulated from the top cap 106 and the metal can 104 by an insulating plate (not shown) on the top cap 106. Here, the top cap 106 and the metal can 104 are electrically connected to each other.

The positive electrode tab 14 is electrically connected to the top cap 106 while protruding through the opening 115 and is electrically connected to the conductive metal can 104 by the top cap 106, 104 form a positive terminal by itself.

The first side 136 adjacent to the opening 114 where the negative electrode tab 12 protrudes is provided with a plurality of through holes 114 for preventing the negative electrode tab 12 protruding through the opening 114 from coming into contact with the inner surface of the metal can 104 And the insulating wall 116 is formed upward.

The structure of the insulating wall 116 is shown in detail in FIGS. 5 and 6, and will be described later with reference to FIGS. 5 and 6. FIG.

2 to 6, the top cap 106 includes a gasket 24, a protruding terminal 10 mounted to the bottom of the top cap 106, an insulating plate 22, and a gasket 24 And an electrode terminal 11 mounted on the top cap 106 in an insulated state. The lower end of the electrode terminal 11 is inserted through the opening formed in the insulating plate 22 and inserted through the opening formed in the protruding terminal 10, The insulating plate 22 and the protruding terminal 10 are pressed against the top cap 106 and fixed.

An insulating member 110 is mounted on an upper end of the electrode assembly 102 and an insulating wall 116 is formed on a first side 136 of the insulating member 110. This insulating wall 116 is formed in such a manner that the negative electrode tab 12 of the electrode assembly 102 is drawn upward through the opening 114 formed in the insulating member 110, 104 so that the negative electrode tab 12 is prevented from coming into contact with the metal can 100, thereby preventing a short circuit therebetween.

The end portion of the negative electrode tab 12 is welded to the projecting terminal 10 so that an electrical connection is made between the negative electrode tab 12, the projecting terminal 10, and the electrode terminal 11. The insulating plate 22 prevents the protruding terminal 10 from contacting the top cap 106.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (21)

An electrode assembly having an anode, a cathode, and a separator interposed between an anode and a cathode is inserted into a rectangular metal can together with an electrolytic solution, an insulating member is mounted on an upper end of the electrode assembly, A secondary battery having a cap coupled thereto,
Wherein the insulating member includes a plate-like body having a shape corresponding to a horizontal cross-sectional structure of the metal can,
The main body includes a first side and a second side which are respectively in close contact with inner side surfaces and a rear side of the metal can,
The first side portion and the second side portion being formed with one or more supporting portions protruding upward from the upper surface of the main body,
And a buffer member for preventing breakage of the insulating member due to an external force is attached to the outer peripheral surface of the first end portion and the second end portion,
The buffer member is in close contact with the inner surface of the metal can while being positioned between the insulating member main body and the metal can so as to surround the outer circumferential surface of the first end and the second end and a part of the bottom surface of the insulating member main body,
The body is formed with one or more openings of a shape corresponding to the horizontal cross-sectional structure of the electrode tab so that the electrode tab protruding from the top surface of the electrode assembly can be connected to the top cap through the body,
Wherein the electrode tab is bent in a protruded state through the opening, the bent surface of the electrode tab is electrically connected to the lower end of the protruded terminal of the top cap,
And an insulative wall for preventing the electrode tab protruding through the opening from contacting the inner surface of the metal can is formed upward in the first side portion and / or the second side portion adjacent to the opening portion. Secondary battery. The secondary battery according to claim 1, wherein the buffer member is a porous structure made of a polymer resin, or a porous structure made of natural rubber or synthetic rubber. The secondary battery according to claim 2, wherein the porous structure is a polyethylene sponge or a polyurethane sponge. The secondary battery according to claim 1, wherein the buffer member is added to the outer peripheral surface of the first end and the second end to a thickness of 30% to 100% of the thickness of the metal can. The secondary battery according to claim 1, wherein the total length of the length from the first end to the second end and the thickness of the cushioning member is 95% to 105% of the length between both inner sides of the metal can. delete The secondary battery according to claim 1, wherein the body further comprises at least two inlets, through which the electrolyte solution can be injected. delete delete delete The battery pack according to claim 1, characterized in that the insulating wall is formed upward from the upper surface of the main body in the first side portion and / or the second side portion with a length of 90% to 100% . The secondary battery according to claim 1, wherein a width of the insulating wall is 100% to 120% of a width of the electrode tab. 2. The secondary battery according to claim 1, wherein the support portion is formed at an adjacent portion of the first side portion and the second side portion adjacent to the cushioning member added to the outer peripheral surface of the first end portion and the second end portion. 14. The secondary battery according to claim 13, wherein the adjacent portion is a portion extending from the first side portion and the second side portion to the first end portion and the second end portion. 14. The secondary battery according to claim 13, wherein the support portion protrudes to a length of 200% to 400% of the thickness of the insulating member. 14. The secondary battery according to claim 13, wherein the support portion is formed to have a width of 5% to 10% of a length of the first side portion or the second side portion. The secondary battery according to claim 1, wherein the secondary battery is a lithium secondary battery. The secondary battery according to claim 1, wherein the electrode assembly is a jelly-roll type electrode assembly having a structure in which an anode, a separator, and a cathode are sequentially stacked. A secondary battery pack comprising the secondary battery according to claim 1. 20. A battery module comprising at least one secondary battery pack according to claim 19. A device comprising the battery module according to claim 20 as a power source.

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