WO2011115392A2 - Secondary battery - Google Patents

Secondary battery Download PDF

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Publication number
WO2011115392A2
WO2011115392A2 PCT/KR2011/001739 KR2011001739W WO2011115392A2 WO 2011115392 A2 WO2011115392 A2 WO 2011115392A2 KR 2011001739 W KR2011001739 W KR 2011001739W WO 2011115392 A2 WO2011115392 A2 WO 2011115392A2
Authority
WO
WIPO (PCT)
Prior art keywords
gasket
leakage preventing
cap assembly
case
secondary battery
Prior art date
Application number
PCT/KR2011/001739
Other languages
French (fr)
Korean (ko)
Other versions
WO2011115392A3 (en
Inventor
오경수
구자훈
최용수
김성종
이정아
장재동
김동명
정준용
황성민
김도균
남상봉
Original Assignee
주식회사 엘지화학
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020100023887A external-priority patent/KR20110029061A/en
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to US13/132,767 priority Critical patent/US8663837B2/en
Publication of WO2011115392A2 publication Critical patent/WO2011115392A2/en
Publication of WO2011115392A3 publication Critical patent/WO2011115392A3/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/171—Lids or covers characterised by the methods of assembling casings with lids using adhesives or sealing agents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/186—Sealing members characterised by the disposition of the sealing members
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/167—Lids or covers characterised by the methods of assembling casings with lids by crimping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/183—Sealing members
    • H01M50/184—Sealing members characterised by their shape or structure
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a secondary battery, and more particularly to a lithium ion / polymer secondary battery.
  • the secondary battery unlike the primary battery, means a battery that can be charged and discharged, and is widely used for power sources such as mobile phones, notebook computers, camcorders, electronic devices, electric vehicles, and the like.
  • the lithium secondary battery has an operating voltage of 3.6 V, and has a capacity of about three times or more than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for electronic equipment. Is rapidly increasing.
  • Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive electrode active materials and negative electrode active materials, respectively.
  • the lithium secondary battery may be classified into a square battery, a cylindrical battery, and a pouch type battery.
  • the lithium ion secondary battery includes an electrode assembly in which a positive electrode / separator / negative electrode is sequentially arranged, and a packaging material for sealingly storing the electrode assembly together with the electrolyte solution.
  • the packaging material of the rectangular or cylindrical secondary battery includes a case in which an open end is formed, and a cap assembly sealingly coupled to the open end of the case.
  • the electrode assembly is classified into a jelly-roll type wound by a separator between a sheet-shaped anode and a cathode coated with an active material, and a stack type sequentially laminated with a separator between a cathode and a cathode of a predetermined size.
  • the jelly-roll type electrode assembly is easy to manufacture and has a high energy density per weight, and in particular, the jelly-roll type electrode assembly is widely used because it is easy to store in a case of a cylindrical or rectangular battery.
  • a null is used for a pouch type battery as a stack type electrode assembly.
  • the electrode assembly tends to deform while undergoing repeated expansion and contraction.
  • stress is concentrated on the metallic center pin so that the electrodes are concentrated.
  • internal short circuits There is a tendency for internal short circuits to occur by drilling through the separator and contacting the metal center pin.
  • the internal short circuit of the secondary battery is connected to the heat generated by the battery, so that the organic solvent is decomposed to generate gas, and the external material may be ruptured by increasing the pressure inside the battery.
  • the increase in the gas pressure inside the battery may also be caused by an internal short circuit caused by an external impact.
  • a secondary battery basically includes a PTC element.
  • the cylindrical secondary battery forms safety devices such as a safety vent for discharging high pressure gas and a current interrupt device (CID) that blocks current when the internal pressure of the battery increases, and protruding terminals for protecting the devices.
  • a cap assembly including a top-cap, the cap assembly being hermetically coupled to the case by a gasket.
  • Korean Patent Laid-Open No. 10-2006-0037595 discloses a secondary battery in which at least one row of wrinkles of irregularities is formed on a surface of a gasket contacting a case and a cap assembly.
  • the secondary battery according to the related art also only forms the uneven structure only in the gasket made of plastic, and thus still does not solve the problem of deterioration of the sealability of the secondary battery. Because of the sealing structure of the gasket of the secondary battery of the prior art, the sealing property of the primary leakage of the electrolyte and / or gas, that is, the interface portion between the safety vent located in the bottom layer of the cap assembly and the gasket surrounding its outer peripheral surface. It was not focused.
  • the sealing method disclosed in the prior art seals at the final end of such an interface in the state where the electrolyte or the like leaks through the interface of the safety vent and the gasket surrounding its outer circumferential surface.
  • the sealing structure between the cap assembly and the gasket according to the prior art clearly had its limitations.
  • the present invention has been conceived to overcome the above problems, the structure so that the electrolyte and / or gas is leaked or leaked for the first time, that is to seal more completely between the interface of the cap assembly including the gasket and the safety vent
  • the purpose is to provide an improved secondary battery.
  • the electrode assembly is a positive electrode plate and a negative electrode plate disposed between the separator;
  • a case accommodating the electrode assembly;
  • a cap assembly capable of sealing the open end of the case;
  • a gasket interposed between the case and the cap assembly;
  • a leakage preventing part formed on at least one of one surface of the cap assembly or one surface of the gasket which is in contact with the gasket while facing the electrode assembly.
  • the cap assembly comprises: a top cap sealing an open end of the case;
  • the PTC device and one surface disposed to contact the top cap are in contact with the PTC device, and the other surface has a safety vent formed to contact the gasket and having the leakage preventing part formed thereon, and electrically connected to the electrode assembly.
  • the leakage preventing part includes at least one or more irregularities or at least one or more protrusions formed on the contact surface of the cap assembly.
  • the irregularities are triangular or square or round or round structure.
  • the protrusion is a triangular pyramid or a conical structure.
  • the uneven or the projection further comprises a barb.
  • the safety vent is a metal material.
  • the apparatus further includes a second leakage preventing part formed on a contact surface of the cap assembly facing the leakage preventing part and in contact with the gasket.
  • the apparatus further includes a third leakage preventing part formed on a contact surface of the can contacting the gasket.
  • At least one of the second leakage preventing part and the third leakage preventing part includes at least one or more irregularities or at least one or more protrusions.
  • At least one of the leakage preventing part and the third leakage preventing part includes at least one or more irregularities or at least one or more protrusions.
  • the cap assembly in which the electrolyte or the gas is leaked to the minimum that is, the cap assembly in which the top cap, the PTC element, and the safety vent are sequentially arranged, and one side of the gasket contacting the secondary battery
  • FIG. 1 is a cross-sectional view schematically showing the configuration of a secondary battery according to an exemplary embodiment of the present invention.
  • FIG. 2 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
  • FIG 3 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
  • FIG. 4 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
  • FIG. 5 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
  • FIG. 6 is a schematic cross-sectional view of a modification of the cap assembly of the embodiment of FIG. 5.
  • FIG. 7 is a schematic cross-sectional view of a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
  • a secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate are disposed between separators, a case in which the electrode assembly is housed, a cap assembly capable of sealing an open end of the case; And a gasket interposed between the case and the cap assembly, and a leakage preventing portion formed on at least one of one side of the cap assembly or one side of the gasket that is in contact with the gasket while facing the electrode assembly.
  • the cap assembly includes a top cap that seals the open end of the case, a PTC element disposed to contact the top cap, and one side of the cap element contacting the PTC element, and the other side of the cap assembly to be formed to contact the gasket, and the electrode assembly And a safety vent electrically connected to the.
  • the interface portion between the cap assembly and the gasket in particular the interface portion between the gasket and the safety vent, has a high possibility of leakage of electrolyte or gas or the like, as described above, the leakage preventing portion is formed, so that the safety vent is shorted until the safety vent is shorted. It is possible to greatly prevent the leakage of the electrolyte or gas at the interface, thereby greatly improving the safety of the battery.
  • the leakproof portion includes at least one or more irregularities or at least one or more protrusions formed on the contact surface of the cap assembly and the gasket.
  • the leakage preventing portion of the projection or the uneven structure improves the bonding force between the cap assembly and the gasket when the cap assembly is assembled with the case of the battery via the gasket by a mechanical pressing process (clamping process). This is because the protrusion or uneven leakage preventing part of the protrusion or uneven structure penetrates through a part of the surface of the plastic gasket, and the bonding force between the cap assembly and the gasket thus joined is very high.
  • the leakage preventing portion of the protrusion or the uneven structure may be formed on at least one of the surface of the cap assembly in contact with the gasket and the surface of the gasket in contact with the gasket.
  • corrugation is formed in the surface of all these in terms of bonding force.
  • the leakage preventing portion in the form of protrusions or irregularities may be a structure capable of solidifying the coupling force between the gasket and the cap assembly, and should not be particularly limited in its position, size, shape, and the like.
  • the leakage preventing portion of the uneven structure has a triangular or square or circular or round shape in cross section
  • the leakage preventing portion of the protrusion structure is a triangular pyramid or cone structure having a sharp point.
  • Pointed triangular pyramids or cone-shaped protrusions are mainly formed in safety vents, which can easily penetrate into the surface of the gasket, thus improving the cohesion, cohesion (fixability), and form occlusion between the interfaces in contact. You can.
  • the leakage preventing portion of the protrusion structure is preferably formed with a barbed portion in the form of a conventional fishing hook at the end of the protrusion to further improve the bonding force and / or adhesion between the interface.
  • the secondary battery according to another preferred embodiment of the present invention further includes a second leakage preventing portion formed on a surface of the cap assembly facing the leakage preventing portion of the aforementioned embodiment and in contact with the gasket.
  • the second leakage preventing part prevents leakage of the electrolyte solution or gas primarily from the leakage prevention part, and serves to prevent leakage of the gas or electrolyte solution if it is still insufficient.
  • the structure, shape, etc. of a 2nd leakage prevention part are the same as that of the above-mentioned leakage prevention part.
  • the secondary battery according to still another preferred embodiment of the present invention further includes a third leakage preventing part formed on any one surface of a case contacting the gasket and a surface of the gasket contacting the gasket.
  • the third leakage preventing part is for preventing the leakage of the electrolyte or gas through the interface between the case and the gasket separately from the leakage preventing part and the second leakage preventing part.
  • the safety vent is preferably a metal material.
  • the size of the safety vent may vary depending on the material and structure, and the like, and the size of the safety vent is not particularly limited as long as the safety vent may burst while generating a high pressure inside the battery.
  • the thickness of the safety vent may be approximately 0.2 to 0.6 mm.
  • the thickness of the PTC device may also vary depending on the material and structure, and may be preferably 0.2 to 0.4 mm. However, if the thickness of the PTC element is too thick, the internal resistance increases, and the size of the battery may be increased to reduce the capacity of the battery compared to the same standard. On the contrary, if the thickness of the PTC element is too thin, it is not preferable because it is difficult to exert a desired current interruption effect at a high temperature and can be destroyed by a weak external impact. Therefore, the thickness of the PTC element can be appropriately determined within the above-described thickness range in consideration of these points in combination.
  • the thickness of the top-cap portion in contact with the PTC device is not particularly limited as long as it can protect various components of the cap assembly from an externally applied pressure, and may be preferably 0.3 to 0.5 mm. If the thickness of the top-cap portion is too thin, it is difficult to exert a predetermined mechanical rigidity. On the contrary, if the thickness of the top-cap portion is too thick, the capacity of the battery may be reduced by increasing the size and weight, which is not preferable.
  • the gasket is made of an electrically insulating elastic material, and the material is not particularly limited as long as the material has electrical insulating property, impact resistance, elasticity, and durability.
  • the material is not particularly limited as long as the material has electrical insulating property, impact resistance, elasticity, and durability.
  • polyolefine and polypropylene (PP) may be used.
  • Can be used.
  • the positive electrode lead welded to the positive electrode foil of the jelly-roll type electrode assembly is electrically connected to the cap assembly and connected to the protruding terminal at the top of the top cap, and the negative electrode lead welded to the negative electrode foil.
  • the material of the case is not particularly limited and may be formed of any one of stainless steel, steel, aluminum, or equivalents thereof.
  • the secondary battery according to the preferred embodiments of the present invention may be a lithium (ion) secondary battery having high energy density, high discharge voltage, and high output stability.
  • the lithium secondary battery may be composed of a positive electrode, a negative electrode, a separator, a nonaqueous electrolyte containing lithium salt, and the like.
  • the positive electrode is prepared by, for example, applying a mixture of a positive electrode active material, a conductive material, and a binder on a positive electrode current collector, followed by drying, and, if necessary, may further include a filler.
  • the negative electrode is manufactured by coating and drying a negative electrode active material on a negative electrode current collector, and the above-described components may be further included as necessary.
  • the separator is interposed between the cathode and the anode, and an insulating thin film having high ion permeability and mechanical strength is used.
  • the lithium salt-containing non-aqueous electrolyte is composed of a nonaqueous electrolyte and a lithium salt, and the nonaqueous electrolyte is a liquid nonaqueous electrolyte, a solid electrolyte, an inorganic solid electrolyte, or the like.
  • a current collector, an electrode active material, a conductive material, a binder, a filler, a separator, an electrolyte, a lithium salt, and the like are known in the art, and thus detailed description thereof is omitted.
  • FIG. 1 is a cross-sectional view schematically showing the configuration of a secondary battery according to a preferred embodiment of the present invention.
  • the secondary battery 100 includes a cylindrical case 20 accommodating the electrode assembly 10 together with an electrolyte, and a cap assembly sealingly coupled to an open end of the case 20. 30, a gasket 40 interposed between the case 20 and the cap assembly 30, and a face (bottom of the drawing) of the cap assembly 30 facing the electrode assembly 10 and a gasket in contact with the face ( The liquid leakage prevention part 50 formed in all the surfaces of 40 is provided.
  • the electrode assembly 10 is interposed between two electrode plates 11 having different polarities from each other and having a wide plate shape in a roll shape and the electrode plates 11 to insulate the electrode plates 11 from each other. It is preferable to have a separator 12 disposed on the left side or the right side of the electrode plate 11 and wound in a so-called 'Jelly Roll' shape.
  • the positive electrode plate and the negative electrode plate of a predetermined standard may be stacked in such a manner that the separator is interposed therebetween.
  • the two electrode plates 11 have a structure in which an active material slurry is applied to a current collector in the form of a metal foil or a metal mesh each containing aluminum and copper.
  • the slurry is typically formed by stirring a granular active material, auxiliary conductor, binder, plasticizer, and the like in a state where a solvent is added. The solvent is removed in the subsequent process. In the direction in which the electrode plate 11 is wound, it is preferable that a non-coating portion where a slurry is not applied is present at the beginning and the end of the current collector. A pair of leads corresponding to each electrode plate 11 is attached to the uncoated portion.
  • the first lead 13 attached to the top of the electrode assembly 10 is electrically connected to the cap assembly 30, and the second lead (not shown) attached to the bottom of the electrode assembly 10 is the case 20. Is connected to the bottom of the. Of course, both the first lead 13 and the second lead may be drawn out toward the cap assembly 30.
  • the electrode assembly 10 may be disposed on a first insulating plate (not shown) installed at the bottom of the case 20, and the second insulating plate 14 may be disposed on the upper end of the electrode assembly 10.
  • the first insulating plate insulates between the electrode assembly 10 and the bottom of the case 20, and the second insulating plate 14 insulates between the electrode assembly 10 and the cap assembly 30.
  • the case 20 is made of a lightweight conductive metal material such as aluminum or an aluminum alloy, and has a cylindrical structure having an open upper end and a closed bottom opposite thereto.
  • the electrode assembly 10 and the electrolyte (not shown) are accommodated in the inner space of the case 20.
  • the electrolyte is to move lithium ions generated by the electrochemical reaction of the electrode plate 11 during charging and discharging of the secondary battery 100.
  • the electrolyte may be a polymer using a non-aqueous organic electrolyte or a polymer electrolyte which is a mixture of lithium salts and high purity organic solvents, but the type of electrolyte is not a problem.
  • a metallic center pin (not shown) which prevents the electrode assembly 10 wound in a jelly roll form from being released and serves as a gas passageway inside the secondary battery 100 is provided. It may be inserted.
  • An upper portion of the case 20, that is, an upper portion of the electrode assembly 10 is provided with a beading portion 24 formed to be bent from the outside to the inside to prevent the up and down flow of the electrode assembly 10.
  • the cap assembly 30 is assembled to the opening of the case 20 in a sealed state via the gasket 40, and includes a top cap 32, a PTC 34, a safety vent 36, and a current breaker. (38).
  • the top cap 32 has electrode terminals (not shown) formed to be electrically connected to the outside.
  • the PTC 34 is for blocking the flow of current inside the battery by overheating the battery 100.
  • the safety vent 36 protrudes convexly in the center and is welded with a current interrupt device (CID) 38.
  • the current breaker 38 may be deformed together with the safety vent 36 by the internal pressure of the secondary battery 100, and may be divided into a CID gasket and a CID filter.
  • the gasket 40 has a cylindrical shape with both ends open as a whole, and one end facing the inner surface of the case 20 is bent at a right angle toward the center so as to be placed at an open portion, that is, a clamping portion, of the case 20. Do.
  • the other end of the gasket 40 is straight in the initial stage of assembly and is oriented in the axial direction of the cylindrical gasket 40.
  • the gasket 40 is bent at a right angle toward the center during the pressing process with the case 20 so that the inner circumferential surface and the outer circumferential surface thereof are cap assemblies 30, respectively.
  • the top-cap is folded in close contact with the inner surface of the case 20.
  • the gasket 40 is made of a material such as polyolefine or polypropylene (PP) having electrical insulation, impact resistance, elasticity and durability.
  • the leakage preventing part 50 is formed on the lower surface of the safety vent 36 and the surface of the gasket 40 in contact with the safety vent 36 and has a concave-convex structure having a triangular side surface thereof. That is, the unevenness provided in the safety vent 36 and the unevenness provided in the gasket 40 are closely coupled while being engaged with each other during the clamping operation of the open end of the case 20 to provide a sealing coupling force between the cap assembly 30 and the gasket 40. It can be further strengthened. Therefore, the leakage preventing unit 50 prevents the electrolyte or gas from leaking to the upper portion of the cap assembly 30 until the safety vent 36 ruptures when internal pressure occurs in the secondary battery 100.
  • FIG. 2 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
  • the same components as those described in FIG. 1 are the same members with the same functions.
  • the secondary battery 100 includes a leakage preventing part 60 having a quadrangular shape.
  • the leakage preventing part 60 includes a quadrangular concave-convex structure formed at a contact portion between the safety vent 36 and the gasket 40, respectively.
  • the leakage preventing unit 60 increases the moving distance when the electrolyte or gas leaks from the leakage preventing unit 50 as described above, thereby greatly improving the airtightness between the interfaces even when the external shock or the internal pressure increases.
  • FIGS. 3 and 4 are cross-sectional views respectively illustrating cap assembly portions of a rechargeable battery according to another exemplary embodiment of the present invention.
  • the same components as those described in FIGS. 1 and 2 are the same members with the same functions.
  • the secondary battery 100 includes a circular leakage preventing part 70 and a round leakage preventing part 80, respectively.
  • the leakage preventing part 70 according to the embodiment of FIG. 3 is provided on the surface where the safety vent 36 and the gasket 40 are in contact with each other, and the semicircular recesses and the convex portions are continuously formed, respectively, and the recesses at the interface.
  • the convex portions are structures that respectively correspond to the corresponding convex portions and the recessed portions.
  • the leakage preventing part 80 according to the embodiment of FIG. 4 is provided on the surface where the safety vent 36 and the gasket 40 are in contact with each other, and has a structure in which a substantially round recessed part and an iron part are continuous.
  • the recessed portion and the convex portion are structures which are respectively joined to the corresponding convex portion and the recessed portion.
  • FIG. 5 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
  • the same components as those described in FIGS. 1 to 4 are the same members with the same functions.
  • the secondary battery 200 according to the present exemplary embodiment further includes a second leakage preventing unit 150 in addition to the leakage preventing unit 50 described above.
  • the second leakage preventing part 150 has a protrusion structure provided on the top surface of the top cap 32.
  • This protrusion structure may be in the form of a cone or a triangular pyramid.
  • the pointed portion of the protrusion penetrates the surface of the gasket 40 to be coupled to the gasket 40 and the top-cap.
  • the protrusion structure of the second leakage preventing part 150 may be deformed in the form of unevenness, in which case the unevenness may be formed on the surface of the corresponding gasket 40.
  • FIG. 6 is a schematic cross-sectional view of a modification of the cap assembly of the embodiment of FIG. 5.
  • the same components as those described in FIGS. 1 to 5 are the same members having the same functions.
  • the cap assembly 30 ′ of the secondary battery 200 may include a protrusion leakage preventing part 50 ′ and a top cap 32 formed on the bottom surface of the safety vent 36.
  • the projections 52 and 152 of each leakage preventing portion 50' and 150 ' are formed with a barb formed near the pointed portion ( 54) 154.
  • the barbs 54 and 154 may be formed by the protrusions 52 and 152 on the surface of the gasket 40 while the gasket 40 and the cap assembly 30 are coupled to each other by the case 20 during the clamping operation. To penetrate the barbs 54 and 154 more reliably into the gasket 40 when penetrating, it is to improve the bonding force and the sealing force.
  • FIG. 7 is a schematic cross-sectional view of a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
  • the same components as those described in FIGS. 1 to 6 are the same members with the same functions.
  • the secondary battery 300 according to the present exemplary embodiment further includes a third leakage preventing part 250 in addition to the leakage preventing part 50 and the second leakage preventing part 150 described above.
  • the third leakage preventing part 250 includes a protrusion or an uneven structure formed on an inner surface of the case 20 in contact with the gasket 40.
  • the concave-convex or convex may be provided on the surface of the gasket 40 so as to correspond to the convex or concave-convex structure of the case 20.
  • the third leakage preventing part 250 is a part other than the interface between the gasket 40 and the cap assembly 30 when the electrolyte or gas inside the battery is discharged to the outside due to an external shock or an increase in the internal pressure, that is, the case ( It is for the case of being discharged through the inner surface of 20).

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Sealing Battery Cases Or Jackets (AREA)
  • Gas Exhaust Devices For Batteries (AREA)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

The present invention relates to a secondary battery, comprising: an electrode assembly in which an anode plate and a cathode plate are arranged with a separator interposed therebetween; a cap assembly for sealing an open end of a case in which the electrode assembly is accommodated; a gasket interposed between the case and the cap assembly; and a leakage prevention portion formed on a surface of the cap assembly and/or on a surface of the gasket, wherein the surface of the cap assembly is directed toward the electrode assembly and contacts the gasket.

Description

이차 전지Secondary battery
본 발명은 본 발명은 이차 전지에 관한 것으로서, 보다 상세하게는 리튬 이온/폴리머 이차 전지에 관한 것이다.The present invention relates to a secondary battery, and more particularly to a lithium ion / polymer secondary battery.
일반적으로, 이차 전지는 일차 전지와 달리, 충,방전이 가능한 전지를 의미하며, 휴대폰, 노트북 컴퓨터, 캠코더 등의 전자기기 또는 전기 자동차 등의 전원에 널리 사용되고 있다. 특히, 리튬 이차 전지는 작동 전압이 3.6V로서, 전자 장비의 전원으로 많이 사용되는 니켈-카드뮴 전지 또는 니켈-수소 전지보다 약 3배 이상의 용량을 가지며, 단위 중량당 에너지 밀도가 높기 때문에 그 활용 정도가 급속도로 증가되는 추세에 있다.In general, the secondary battery, unlike the primary battery, means a battery that can be charged and discharged, and is widely used for power sources such as mobile phones, notebook computers, camcorders, electronic devices, electric vehicles, and the like. In particular, the lithium secondary battery has an operating voltage of 3.6 V, and has a capacity of about three times or more than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for electronic equipment. Is rapidly increasing.
이러한 리튬 이차 전지는 주로 리튬계 산화물과 탄소재를 각각 양극 활물질과 음극 활물질로 사용한다. 또한, 리튬 이차 전지는 각형 전지, 원통형 전지, 파우치형 전지로 구분될 수 있다. Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive electrode active materials and negative electrode active materials, respectively. In addition, the lithium secondary battery may be classified into a square battery, a cylindrical battery, and a pouch type battery.
리튬 이온 이차 전지는 양극/세퍼레이터/음극이 순차적으로 배치된 전극 조립체와, 전극 조립체를 전해액과 함께 밀봉 수납하는 외장재를 구비한다. 특히, 각형 또는 원통형 이차 전지의 외장재는 개방단이 형성된 케이스, 및 케이스의 개방단에 밀봉 결합되는 캡 조립체를 구비한다. The lithium ion secondary battery includes an electrode assembly in which a positive electrode / separator / negative electrode is sequentially arranged, and a packaging material for sealingly storing the electrode assembly together with the electrolyte solution. In particular, the packaging material of the rectangular or cylindrical secondary battery includes a case in which an open end is formed, and a cap assembly sealingly coupled to the open end of the case.
전극 조립체는 활물질이 각각 도포된 시트 형태의 양극과 음극 사이에 세퍼레이터를 개재시켜 권취한 젤리-롤 타입과, 소정 크기의 양극과 음극 사이에 세퍼레이터를 개재시켜 순차적으로 적층시킨 스택 타입으로 분류된다. 여기서, 젤리-롤 타입의 전극 조립체는 제조가 용이하고 중량당 에너지 밀도가 높은 장점이 있고, 특히, 원통형 또는 각형 전지의 케이스에 수납이 용이하므로 젤리-롤 타입의 전극 조립체가 널리 이용되고 있다. 한편, 스택 타입 전극 조립체는 파우치형 전지에 널이 이용되고 있다.The electrode assembly is classified into a jelly-roll type wound by a separator between a sheet-shaped anode and a cathode coated with an active material, and a stack type sequentially laminated with a separator between a cathode and a cathode of a predetermined size. Here, the jelly-roll type electrode assembly is easy to manufacture and has a high energy density per weight, and in particular, the jelly-roll type electrode assembly is widely used because it is easy to store in a case of a cylindrical or rectangular battery. On the other hand, a null is used for a pouch type battery as a stack type electrode assembly.
그런데, 이차 전지의 충,방전 시, 전극 조립체는 반복적인 팽창과 수축을 겪으면서 변형되는 경향이 있고, 이러한 과정에서, 젤리-롤 타입 전극 조립체의 경우, 금속성 센터 핀에 응력이 집중되어 전극들이 세퍼레이터를 뚫고 금속 센터 핀에 접촉됨으로써 내부 단락이 발생되는 경향이 있다. 이와 같은 이차 전지의 내부 단락은 전지의 발열로 연결되어, 유기 용매가 분해되어 가스를 발생시키게 되고, 전지 내부의 압력을 상승시켜 외장재가 파열될 수도 있다. 물론, 전지 내부의 가스 압력의 상승은 외부 충격에 의한 내부 단락에 의해서도 발생될 수도 있다.However, during charging and discharging of the secondary battery, the electrode assembly tends to deform while undergoing repeated expansion and contraction. In this process, in the case of the jelly-roll type electrode assembly, stress is concentrated on the metallic center pin so that the electrodes are concentrated. There is a tendency for internal short circuits to occur by drilling through the separator and contacting the metal center pin. The internal short circuit of the secondary battery is connected to the heat generated by the battery, so that the organic solvent is decomposed to generate gas, and the external material may be ruptured by increasing the pressure inside the battery. Of course, the increase in the gas pressure inside the battery may also be caused by an internal short circuit caused by an external impact.
이와 같은 전지의 안전성 문제를 해결하기 위해, 이차 전지는 기본적으로 PTC 소자를 구비한다. 특히, 원통형 이차 전지는, 고압 가스를 배출하는 안전 벤트, 전지의 내압 상승시 전류를 차단하는 전류차단소자(Current Interrupt Device:CID) 등의 안전 장치들과 이들 장치들을 보호하는 돌출형 단자를 형성하는 탑-캡(top-cap)을 포함하는 캡 조립체를 구비하고, 캡 조립체는 가스켓에 의해 케이스와 밀봉 결합된다. In order to solve the safety problem of such a battery, a secondary battery basically includes a PTC element. In particular, the cylindrical secondary battery forms safety devices such as a safety vent for discharging high pressure gas and a current interrupt device (CID) that blocks current when the internal pressure of the battery increases, and protruding terminals for protecting the devices. And a cap assembly including a top-cap, the cap assembly being hermetically coupled to the case by a gasket.
그런데, 종래의 이차 전지에 있어서, 가스켓을 매개로 캡 조립체와 케이스를 조립하는 과정에서, 가스켓과 캡 조립체 사이 또는 가스켓과 케이스 사이에 각각 틈새가 발생할 우려가 높다. 이러한 틈새는 전지의 기밀성을 저하시킨다. 즉, 케이스는 클램핑 공정 등을 거치는 동안, 가스켓이 케이스에 의해 눌려져 변형되면서 케이스와 캡 조립체 사이가 밀착된다. 그러나, 종래 구조에 따른 가스켓은 케이스와 캡 조립체 사이에 밀착되는 면이 단순한 평면 형태이므로 그 기밀성이 떨어지게 된다. 특히, 케이스의 클램핑 과정에서 가스켓의 클램핑 면이 고르게 가압되지 않는 경우에는 가스켓의 편평한 면이 불균일하게 변형되면서 가스켓의 일부가 케이스 또는 캡 조립체와 밀착되지 못하고 그 사이가 벌어지는 현상이 발생되어 케이스와의 기밀 특성을 저하시키게 된다. However, in the conventional secondary battery, there is a high possibility that a gap occurs between the gasket and the cap assembly or between the gasket and the case in the process of assembling the cap assembly and the case through the gasket. This gap reduces the airtightness of the battery. That is, while the case is subjected to the clamping process or the like, the gasket is pressed by the case and deformed to closely contact the case and the cap assembly. However, the gasket according to the conventional structure is inferior in airtightness since the surface closely contacted between the case and the cap assembly is a simple flat shape. In particular, when the clamping surface of the gasket is not evenly pressurized during the clamping of the case, a portion of the gasket does not come into close contact with the case or the cap assembly as the flat surface of the gasket is unevenly deformed, and a gap between them occurs. The airtightness is lowered.
이러한 문제점을 해결하기 위해, 한국특허공개번호 제10-2006-0037595호는, 케이스와 캡 조립체와 접하는 가스켓의 면에 요철 형태의 주름이 적어도 한 줄 이상 형성된 이차 전지를 개시하고 있다. 그러나, 이러한 종래기술에 따른 이차 전지 역시, 플라스틱 재질의 가스켓에만 요철 구조를 형성시킬 뿐이므로, 이차 전지의 밀봉성 저하의 문제점을 여전히 해결하지 못하고 있다. 왜냐하면, 이러한 종래 기술의 이차 전지의 가스켓의 밀봉 구조는, 전해액 및/또는 가스의 일차적인 누출 부위 즉, 캡 어셈블리의 최하층에 위치되는 안전 벤트와 그것의 외주면을 감싸는 가스켓 사이의 계면 부분의 밀봉성에 초점을 맞추지 않았기 때문이다. 즉, 종래기술에서 개시된 밀봉 방식은 안전 벤트와 그것의 외주면을 감싸는 가스켓의 계면을 통해 일단 전해액 등이 누출된 상태에서 그러한 계면의 최종단에서 밀봉을 하기 때문이다. 따라서, 종래기술에 따른 캡 조립체와 가스켓 사이의 밀봉 구조는 그 한계가 분명히 존재하였다.In order to solve this problem, Korean Patent Laid-Open No. 10-2006-0037595 discloses a secondary battery in which at least one row of wrinkles of irregularities is formed on a surface of a gasket contacting a case and a cap assembly. However, the secondary battery according to the related art also only forms the uneven structure only in the gasket made of plastic, and thus still does not solve the problem of deterioration of the sealability of the secondary battery. Because of the sealing structure of the gasket of the secondary battery of the prior art, the sealing property of the primary leakage of the electrolyte and / or gas, that is, the interface portion between the safety vent located in the bottom layer of the cap assembly and the gasket surrounding its outer peripheral surface. It was not focused. That is, the sealing method disclosed in the prior art seals at the final end of such an interface in the state where the electrolyte or the like leaks through the interface of the safety vent and the gasket surrounding its outer circumferential surface. Thus, the sealing structure between the cap assembly and the gasket according to the prior art clearly had its limitations.
본 발명은 상기와 같은 문제점을 극복하기 위해 착상된 것으로서, 전해액 및/또는 가스가 최초로 누액 또는 누설되는 부위 즉, 가스켓과 안전 벤트를 포함하는 캡 조립체의 계면 사이를 더욱 완벽하게 밀봉할 수 있도록 구조가 개선된 이차 전지를 제공하는데 그 목적이 있다.The present invention has been conceived to overcome the above problems, the structure so that the electrolyte and / or gas is leaked or leaked for the first time, that is to seal more completely between the interface of the cap assembly including the gasket and the safety vent The purpose is to provide an improved secondary battery.
상기와 같은 목적을 달성하기 위하여, 본 발명의 바람직한 예시적 실시예에 따른 이차 전지는, 양극판 및 음극판이 세퍼레이터를 사이에 두고 배치된 전극 조립체; 상기 전극 조립체가 수납되는 케이스; 상기 케이스의 개방단을 밀봉할 수 있는 캡 조립체; 상기 케이스와 상기 캡 조립체 사이에 개재되는 가스켓; 및 상기 전극 조립체를 향하면서 상기 가스켓과 접촉되는 상기 캡 조립체의 일면 또는 상기 가스켓의 일면 중 적어도 어느 하나의 면에 형성된 누액 방지부를 구비한다.In order to achieve the above object, a secondary battery according to an exemplary embodiment of the present invention, the electrode assembly is a positive electrode plate and a negative electrode plate disposed between the separator; A case accommodating the electrode assembly; A cap assembly capable of sealing the open end of the case; A gasket interposed between the case and the cap assembly; And a leakage preventing part formed on at least one of one surface of the cap assembly or one surface of the gasket which is in contact with the gasket while facing the electrode assembly.
바람직하게, 상기 캡 조립체는: 상기 케이스의 개방단을 밀봉하는 탑 캡(top cap); 상기 탑 캡에 접촉되도록 배치된 PTC 소자 및 일면은 상기 PTC 소자에 접촉되고 타면은 상기 누액 방지부가 형성되어 상기 가스켓에 접촉되도록 배치되고, 상기 전극 조립체에 전기적으로 연결된 안전 벤트를 구비한다. Preferably, the cap assembly comprises: a top cap sealing an open end of the case; The PTC device and one surface disposed to contact the top cap are in contact with the PTC device, and the other surface has a safety vent formed to contact the gasket and having the leakage preventing part formed thereon, and electrically connected to the electrode assembly.
바람직하게, 상기 누액 방지부는 상기 캡 조립체의 상기 접촉면에 형성된 적어도 하나 또는 그 이상의 요철들 또는 적어도 하나 또는 그 이상의 돌기들을 포함한다.Preferably, the leakage preventing part includes at least one or more irregularities or at least one or more protrusions formed on the contact surface of the cap assembly.
바람직하게, 상기 요철은 삼각형 또는 사각형 또는 원형 또는 라운드형 구조이다. Preferably, the irregularities are triangular or square or round or round structure.
바람직하게, 상기 돌기는 삼각뿔 또는 원뿔 구조이다. Preferably, the protrusion is a triangular pyramid or a conical structure.
바람직하게, 상기 요철 또는 상기 돌기는 미늘부를 더 포함한다. Preferably, the uneven or the projection further comprises a barb.
바람직하게, 상기 안전 벤트는 금속 재질이다. Preferably, the safety vent is a metal material.
바람직하게, 상기 누액 방지부와 대향되며 상기 가스켓과 접촉되는 상기 캡 조립체의 접촉면에 형성된 제2 누액 방지부를 더 구비한다. Preferably, the apparatus further includes a second leakage preventing part formed on a contact surface of the cap assembly facing the leakage preventing part and in contact with the gasket.
바람직하게, 상기 가스켓과 접촉되는 상기 캔의 접촉면에 형성된 제3 누액 방지부를 더 구비한다. Preferably, the apparatus further includes a third leakage preventing part formed on a contact surface of the can contacting the gasket.
바람직하게, 상기 제2 누액 방지부와 상기 제3 누액 방지부 중 적어도 어느 하나는 적어도 하나 또는 그 이상의 요철들 또는 적어도 하나 또는 그 이상의 돌기들을 포함한다.Preferably, at least one of the second leakage preventing part and the third leakage preventing part includes at least one or more irregularities or at least one or more protrusions.
바람직하게, 상기 누액 방지부와 상기 제3 누액 방지부 중 적어도 어느 하나는 적어도 하나 또는 그 이상의 요철들 또는 적어도 하나 또는 그 이상의 돌기들을 포함한다.Preferably, at least one of the leakage preventing part and the third leakage preventing part includes at least one or more irregularities or at least one or more protrusions.
본 발명에 따른 이차 전지는, 전해액 또는 가스 등이 최소로 누액되는 부위 즉, 탑-캡, PTC 소자, 및 안전 벤트가 순차적으로 배치된 캡 조립체의 일면과 이와 접촉되는 가스켓의 일면 중 적어도 어느 하나의 면에 요철 또는 돌기를 마련함으로써 그들 사이의 결합력을 높이고, 그 부분을 통한 가스 또는 전해액의 이동 거리를 증가시킴으로써 외부 충격 및 내압 증가 시에도 이차 전지의 기밀성이 크게 향상되는 효과가 있다.In the secondary battery according to the present invention, at least one of a portion of the cap assembly in which the electrolyte or the gas is leaked to the minimum, that is, the cap assembly in which the top cap, the PTC element, and the safety vent are sequentially arranged, and one side of the gasket contacting the secondary battery By providing irregularities or protrusions on the surface thereof, the bonding force therebetween is increased, and by increasing the moving distance of the gas or the electrolyte through the portion, the airtightness of the secondary battery is greatly improved even when the external shock and the internal pressure are increased.
본 명세서에 첨부되는 다음의 도면들은 본 발명의 바람직한 예시적 실시예들을 예시하는 것이며, 전술된 발명의 상세한 설명과 함께 본 발명의 기술사상을 더욱 이해시키는 역할을 하는 것이므로, 본 발명은 그러한 도면에 기재된 사항에만 한정되어 해석되지 않아야 한다.The following drawings, which are attached to this specification, illustrate exemplary embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the spirit of the present invention, the present invention is directed to such drawings. It should not be construed as limited to only what is stated.
도 1은 본 발명의 바람직한 예시적 실시예에 따른 이차 전지의 구성을 개략적으로 도시한 단면도이다. 1 is a cross-sectional view schematically showing the configuration of a secondary battery according to an exemplary embodiment of the present invention.
도 2는 본 발명의 바람직한 다른 바람직한 예시적 실시예에 따른 이차 전지의 캡 조립체 부위를 도시한 단면도이다. 2 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
도 3은 본 발명의 또 다른 바람직한 예시적 실시예에 따른 이차 전지의 캡 조립체 부위를 도시한 단면도이다.3 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
도 4는 본 발명의 또 다른 바람직한 예시적 실시예에 따른 이차 전지의 캡 조립체 부위를 도시한 단면도이다.4 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
도 5는 본 발명의 또 다른 바람직한 예시적 실시예에 따른 이차 전지의 캡 조립체 부위를 도시한 단면도이다. 5 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
도 6은 도 5의 실시예의 캡 조립체의 변형예를 개략적으로 도시한 단면도이다. 6 is a schematic cross-sectional view of a modification of the cap assembly of the embodiment of FIG. 5.
도 7은 본 발명의 또 다른 바람직한 예시적 실시예에 따른 이차 전지의 캡 조립체 부위를 개략적으로 도시한 단면도이다.7 is a schematic cross-sectional view of a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention.
본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 아니되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다. 따라서, 본 명세서에 기재된 실시예와 도면에 도시된 구성은 본 발명의 가장 바람직한 일 실시예에 불과하고 본 발명의 기술적 사상을 모두 대변하는 것은 아니므로, 본 출원시점에 있어서 이들을 대체할 수 있는 다양한 균등물과 변형예들이 있을 수 있음을 이해하여야 한다.The terms or words used in this specification and claims are not to be construed as being limited to their ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.
본 발명의 바람직한 예시적 실시예에 따른 이차 전지는, 양극판 및 음극판이 세퍼레이터를 사이에 두고 배치된 전극 조립체와, 전극 조립체가 수납되는 케이스와, 케이스의 개방단을 밀봉할 수 있는 캡 조립체와, 케이스와 캡 조립체 사이에 개재되는 가스켓, 및 전극 조립체를 향하면서 가스켓과 접촉되는 캡 조립체의 일면 또는 가스켓의 일면 중 적어도 어느 하나의 면에 형성된 누액 방지부를 구비한다.According to an exemplary embodiment of the present invention, a secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate are disposed between separators, a case in which the electrode assembly is housed, a cap assembly capable of sealing an open end of the case; And a gasket interposed between the case and the cap assembly, and a leakage preventing portion formed on at least one of one side of the cap assembly or one side of the gasket that is in contact with the gasket while facing the electrode assembly.
캡 조립체는 케이스의 개방단을 밀봉하는 탑-캡과, 탑-캡에 접촉되도록 배치된 PTC 소자, 및 일면은 PTC 소자에 접촉되고 타면은 누액 방지부가 형성되어 가스켓에 접촉되도록 배치되고, 전극 조립체에 전기적으로 연결된 안전 벤트를 구비한다. The cap assembly includes a top cap that seals the open end of the case, a PTC element disposed to contact the top cap, and one side of the cap element contacting the PTC element, and the other side of the cap assembly to be formed to contact the gasket, and the electrode assembly And a safety vent electrically connected to the.
캡 조립체와 가스켓 사이의 계면 부위, 특히 가스켓과 안전 벤트 사이의 계면 부위는, 전술한 바와 같이, 전해액 또는 가스 등의 누출 가능성이 높기 때문에, 누액 방지부가 형성됨으로써, 안전 벤트가 단락될 때까지 그들의 계면에서 전해액 또는 가스 등이 누출되는 것을 방지하여 전지의 안전성을 크게 향상시킬 수 있다.Since the interface portion between the cap assembly and the gasket, in particular the interface portion between the gasket and the safety vent, has a high possibility of leakage of electrolyte or gas or the like, as described above, the leakage preventing portion is formed, so that the safety vent is shorted until the safety vent is shorted. It is possible to greatly prevent the leakage of the electrolyte or gas at the interface, thereby greatly improving the safety of the battery.
누액 방지부는 캡 조립체와 가스켓의 접촉면에 형성된 적어도 하나 또는 그 이상의 요철들 또는 적어도 하나 또는 그 이상의 돌기들을 포함한다. 한편, 돌기 또는 요철 구조의 누액 방지부는, 기계적 프레스 공정(크램핑 공정)에 의해 캡 조립체가 가스켓을 개재시켜 전지의 케이스와 조립될 때, 캡 조립체와 가스켓 사이의 결합력을 향상시킨다. 왜냐하면, 돌기 또는 요철 구조의 누액 방지부는 금속성의 안전 벤트의 돌기 또는 요철이 플라스틱 재질의 가스켓의 표면 중 일 부분을 뚫고 들어가게 되고, 이렇게 결합된 캡 조립체와 가스켓 사이의 결합력이 매우 높아지기 때문이다.The leakproof portion includes at least one or more irregularities or at least one or more protrusions formed on the contact surface of the cap assembly and the gasket. On the other hand, the leakage preventing portion of the projection or the uneven structure improves the bonding force between the cap assembly and the gasket when the cap assembly is assembled with the case of the battery via the gasket by a mechanical pressing process (clamping process). This is because the protrusion or uneven leakage preventing part of the protrusion or uneven structure penetrates through a part of the surface of the plastic gasket, and the bonding force between the cap assembly and the gasket thus joined is very high.
돌기 또는 요철 구조의 누액 방지부는 가스켓에 접촉되는 캡 조립체의 면과이와 접촉되는 가스켓의 면 중 적어도 어느 하나의 면에 형성될 수 있다. 그런데, 결합력 측면에서 이들 모두의 면에 돌기 또는 요철이 형성되는 것이 바람직하다. 전술한 바와 같이, 돌기 또는 요철 형태의 누액 방지부는 가스켓과 캡 조립체 사이의 결합력을 공고히 할 수 있는 구조이면 되고, 그 위치, 크기, 형상 등에 특별한 제한을 두어서는 아니된다. 다만, 요철 구조의 누액 방지부는 단면이 삼각형 또는 사각형 또는 원형 또는 라운드형인 것이 바람직하고, 돌기 구조의 누액 방지부는 끝이 뾰족한 삼각뿔 또는 원뿔 구조인 것이 바람직하다. 끝이 뾰족한 삼각뿔 또는 원뿔 형상의 돌기는 주로 안전 벤트에 형성되어, 돌기가 가스켓의 표면 속으로 무리없이 파고 들어 갈 수 있으므로, 접촉되는 계면 사이의 결합력, 밀착성(고정성), 형태 교합성을 향상시킬 수 있다. 또한, 돌기 구조의 누액 방지부는 계면 사이의 결합력 및/또는 밀착성을 더욱 향상시키기 위해 돌기의 끝 부분에 통상의 낚시 바늘 형태의 미늘부가 형성되는 것이 바람직하다. The leakage preventing portion of the protrusion or the uneven structure may be formed on at least one of the surface of the cap assembly in contact with the gasket and the surface of the gasket in contact with the gasket. By the way, it is preferable that protrusion or unevenness | corrugation is formed in the surface of all these in terms of bonding force. As described above, the leakage preventing portion in the form of protrusions or irregularities may be a structure capable of solidifying the coupling force between the gasket and the cap assembly, and should not be particularly limited in its position, size, shape, and the like. However, it is preferable that the leakage preventing portion of the uneven structure has a triangular or square or circular or round shape in cross section, and the leakage preventing portion of the protrusion structure is a triangular pyramid or cone structure having a sharp point. Pointed triangular pyramids or cone-shaped protrusions are mainly formed in safety vents, which can easily penetrate into the surface of the gasket, thus improving the cohesion, cohesion (fixability), and form occlusion between the interfaces in contact. You can. In addition, the leakage preventing portion of the protrusion structure is preferably formed with a barbed portion in the form of a conventional fishing hook at the end of the protrusion to further improve the bonding force and / or adhesion between the interface.
본 발명의 다른 바람직한 실시예에 따른 이차 전지는, 전술한 실시예의 누액 방지부와 대향되며 가스켓과 접촉되는 캡 조립체의 면에 형성된 제2 누액 방지부를 더 구비한다. 이러한 제2 누액 방지부는 누액 방지부에서 일차적으로 전해액 또는 가스의 누출을 방지하고, 그래도 부족한 경우 2차적으로 가스 또는 전해액의 누출을 방지하는 기능을 한다. 제2 누액 방지부의 구조, 형상 등은 전술한 누액 방지부의 그것과 동일하다.The secondary battery according to another preferred embodiment of the present invention further includes a second leakage preventing portion formed on a surface of the cap assembly facing the leakage preventing portion of the aforementioned embodiment and in contact with the gasket. The second leakage preventing part prevents leakage of the electrolyte solution or gas primarily from the leakage prevention part, and serves to prevent leakage of the gas or electrolyte solution if it is still insufficient. The structure, shape, etc. of a 2nd leakage prevention part are the same as that of the above-mentioned leakage prevention part.
본 발명의 또 다른 바람직한 실시예에 따른 이차 전지는, 가스켓과 접촉되는 케이스의 면과 이에 접촉되는 가스켓의 면 중 어느 하나의 면에 형성된 제3 누액 방지부를 더 구비한다. 이러한 제3 누액 방지부는 전술한 누액 방지부 및 제2 누액 방지부와 별도로 케이스와 가스켓 사이의 계면을 통해 전해액 또는 가스가 누출되는 것을 방지하기 위한 것이다. The secondary battery according to still another preferred embodiment of the present invention further includes a third leakage preventing part formed on any one surface of a case contacting the gasket and a surface of the gasket contacting the gasket. The third leakage preventing part is for preventing the leakage of the electrolyte or gas through the interface between the case and the gasket separately from the leakage preventing part and the second leakage preventing part.
안전 벤트는 금속 재질인 것이 바람직하다. 안전 벤트의 사이즈는 소재 및 구조 등에 따라 달라질 수 있으며, 전지 내부의 소정의 고압 발생시 파열되면서 가스 등을 배출할 수 있다면 특별히 제한되는 것은 아니다. 특히, 안전 벤트의 두께는 대략 0.2 내지 0.6mm일 수 있다. The safety vent is preferably a metal material. The size of the safety vent may vary depending on the material and structure, and the like, and the size of the safety vent is not particularly limited as long as the safety vent may burst while generating a high pressure inside the battery. In particular, the thickness of the safety vent may be approximately 0.2 to 0.6 mm.
PTC 소자의 두께 역시 소재 및 구조 등에 따라 달라질 수 있으며, 바람직하게는 0.2 내지 0.4mm일 수 있다. 다만, PTC 소자의 두께가 너무 두꺼우면 내부 저항이 상승하고, 전지의 크기를 증가시켜 동일 규격 대비 전지의 용량을 감소시킬 수 있다. 반대로, PTC 소자의 두께가 너무 얇으면, 고온에서 소망하는 전류 차단 효과를 발휘하기 어렵고 약한 외부 충격에 의해서도 파괴될 수 있으므로 바람직하지 않다. 따라서, PTC 소자의 두께는 이러한 점들을 복합적으로 고려하여 전술한 두께 범위 내에서 적절히 결정될 수 있다. The thickness of the PTC device may also vary depending on the material and structure, and may be preferably 0.2 to 0.4 mm. However, if the thickness of the PTC element is too thick, the internal resistance increases, and the size of the battery may be increased to reduce the capacity of the battery compared to the same standard. On the contrary, if the thickness of the PTC element is too thin, it is not preferable because it is difficult to exert a desired current interruption effect at a high temperature and can be destroyed by a weak external impact. Therefore, the thickness of the PTC element can be appropriately determined within the above-described thickness range in consideration of these points in combination.
PTC 소자와 접촉되는 탑-캡 부위의 두께는, 외부로부터 인가되는 압력으로부터 캡 조립체의 여러 구성 요소들을 보호할 수 있는 범위라면 특별히 제한되는 것은 아니며, 바람직하게는 0.3 내지 0.5mm일 수 있다. 탑-캡 부위의 두께가 너무 얇으면 소정의 기계적 강성을 발휘하기 어렵고, 반대로 너무 두꺼우면 크기 및 중량 증가에 의해 동일 규격 대비 전지의 용량을 감소시킬 수 있으므로 바람직하지 않다.The thickness of the top-cap portion in contact with the PTC device is not particularly limited as long as it can protect various components of the cap assembly from an externally applied pressure, and may be preferably 0.3 to 0.5 mm. If the thickness of the top-cap portion is too thin, it is difficult to exert a predetermined mechanical rigidity. On the contrary, if the thickness of the top-cap portion is too thick, the capacity of the battery may be reduced by increasing the size and weight, which is not preferable.
가스켓은 전기 절연성의 탄력적인 소재로 구성되며, 이러한 소재는 전기 절연성과, 내충격성, 탄력성 및 내구성을 가진 소재라면 특별히 제한되는 것은 아니며, 예를 들어, 폴리올레핀(polyolefine), 폴리프로필렌(PP)이 사용될 수 있다. The gasket is made of an electrically insulating elastic material, and the material is not particularly limited as long as the material has electrical insulating property, impact resistance, elasticity, and durability. For example, polyolefine and polypropylene (PP) may be used. Can be used.
일반적으로, 원통형 이차 전지에 있어서, 젤리-롤 타입의 전극 조립체의 양극 포일에 용접된 양극 리드는 캡조립체와 전기적으로 연결되어 탑-캡 상단의 돌출 단자에 연결되며, 음극 포일에 용접된 음극 리드는 케이스의 밀폐단에 용접되어 케이스 자체가 음극 단자를 구성한다. 케이스의 소재는 특별히 제한되지 않으며 스테인리스 스틸, 스틸, 알루미늄 또는 그 등가물 중 어느 하나로 형성될 수 있다. 전극 조립체가 케이스에 수납된 상태에서 전해액이 주입되고, 케이스의 개방단에 캡 조립체를 장착하여 밀봉시키면 이차 전지의 조립이 완성된다. In general, in the cylindrical secondary battery, the positive electrode lead welded to the positive electrode foil of the jelly-roll type electrode assembly is electrically connected to the cap assembly and connected to the protruding terminal at the top of the top cap, and the negative electrode lead welded to the negative electrode foil. Is welded to the closed end of the case and the case itself constitutes the negative terminal. The material of the case is not particularly limited and may be formed of any one of stainless steel, steel, aluminum, or equivalents thereof. The electrolyte is injected while the electrode assembly is stored in the case, and the cap assembly is attached to the open end of the case to seal the assembly of the secondary battery.
본 발명의 바람직한 실시예들에 따른 이차 전지는 높은 에너지 밀도, 방전 전압, 및 출력 안정성이 높은 리튬(이온) 이차 전지일 수 있다. 이러한 리튬 이차전지는 양극, 음극, 세퍼레이터, 리튬염을 함유한 비수 전해액 등으로 구성될 수 있다. 양극은 예를 들어, 양극 집전체 상에 양극 활물질, 도전재 및 바인더의 혼합물을 도포한 후 건조하여 제조되며, 필요에 따라서는, 충진제를 더 참가하기도 한다. 음극은 음극 집전체 상에 음극 활물질을 도포, 건조하여 제작되며, 필요에 따라 전술한 성분들이 더 포함될 수도 있다. 세퍼레이터는 음극과 양극 사이에 개재되며, 높은 이온 투과도와 기계적 강도를 가진 절연성의 얇은 박막이 사용된다. 리튬염 함유 비수계 전해액은, 비수 전해액과 리튬염으로 구성되며, 비수 전해액은 액상 비수 전해액, 고체 전해질, 무기 고체 전해질 등이 사용된다. 여기서, 집전체, 전극 활물질, 도전재, 바인더, 충진제, 세퍼레이터, 전해액, 리튬염 등은 당업계에 널이 알려져 있으므로, 그에 대한 상세한 설명은 생략한다.The secondary battery according to the preferred embodiments of the present invention may be a lithium (ion) secondary battery having high energy density, high discharge voltage, and high output stability. The lithium secondary battery may be composed of a positive electrode, a negative electrode, a separator, a nonaqueous electrolyte containing lithium salt, and the like. The positive electrode is prepared by, for example, applying a mixture of a positive electrode active material, a conductive material, and a binder on a positive electrode current collector, followed by drying, and, if necessary, may further include a filler. The negative electrode is manufactured by coating and drying a negative electrode active material on a negative electrode current collector, and the above-described components may be further included as necessary. The separator is interposed between the cathode and the anode, and an insulating thin film having high ion permeability and mechanical strength is used. The lithium salt-containing non-aqueous electrolyte is composed of a nonaqueous electrolyte and a lithium salt, and the nonaqueous electrolyte is a liquid nonaqueous electrolyte, a solid electrolyte, an inorganic solid electrolyte, or the like. Here, a current collector, an electrode active material, a conductive material, a binder, a filler, a separator, an electrolyte, a lithium salt, and the like are known in the art, and thus detailed description thereof is omitted.
이하, 첨부된 도면을 참조하여 본 발명의 바람직한 실시예에 따른 이차 전지 를 상세히 설명한다.Hereinafter, a secondary battery according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
도 1은 본 발명의 바람직한 실시예에 따른 이차 전지의 구성을 개략적으로 도시한 단면도이다. 1 is a cross-sectional view schematically showing the configuration of a secondary battery according to a preferred embodiment of the present invention.
도 1을 참조하면, 본 실시예에 따른 이차 전지(100)는, 전극 조립체(10)를 전해액과 함께 수납하는 원통형 케이스(20)와, 케이스(20)의 개방단에 밀봉 결합되는 캡 조립체(30), 케이스(20)와 캡 조립체(30) 사이에 개재되는 가스켓(40), 및 전극 조립체(10)를 향하는 캡 조립체(30)의 면(도면의 하면)과 이러한 면에 접촉되는 가스켓(40)의 면 모두에 형성된 누액 방지부(50)를 구비한다.Referring to FIG. 1, the secondary battery 100 according to the present embodiment includes a cylindrical case 20 accommodating the electrode assembly 10 together with an electrolyte, and a cap assembly sealingly coupled to an open end of the case 20. 30, a gasket 40 interposed between the case 20 and the cap assembly 30, and a face (bottom of the drawing) of the cap assembly 30 facing the electrode assembly 10 and a gasket in contact with the face ( The liquid leakage prevention part 50 formed in all the surfaces of 40 is provided.
전극 조립체(10)는 서로 극성이 다르고 롤 형태의 넓은 판형을 가진 두 개의 전극판들(11)과 이러한 전극판들(11)을 상호 절연시키기 위해 전극판들(11) 사이에 개재되거나 어느 하나의 전극판(11)의 좌측 또는 우측에 배치되는 세퍼레이터(12)를 구비하고, 이른바 '젤리롤(Jelly Roll)' 형태로 권취된 구조가 바람직하다. 물론, 소정 규격의 양극판과 음극판이 세퍼레이터를 사이에 두고 적층된 형태일 수도 있다. 두 개의 전극판들(11)은 각각 알루미늄과 구리를 포함하는 금속 포일 또는 금속 메쉬 형태의 집전체에 활물질 슬러리가 도포된 구조이다. 슬러리는 통상적으로 입상의 활물질, 보조도체, 바인더 및 가소제 등이 용매가 첨가된 상태에서 교반되어 형성된다. 용매는 후속 공정에서 제거된다. 전극판(11)이 감기는 방향으로 집전체의 시작단과 끝단에는 슬러리가 도포되지 않는 무지부가 존재하는 것이 바람직하다. 무지부에는 각각의 전극판(11)에 대응되는 한 쌍의 리드가 부착된다. 전극 조립체(10)의 상단에 부착되는 제1 리드(13)는 캡 조립체(30)에 전기적으로 연결되고, 전극 조립체(10)의 하단에 부착되는 제2 리드(미도시)는 케이스(20)의 바닥에 연결된다. 물론, 제1 리드(13)와 제2 리드는 모두 캡 조립체(30) 방향으로 인출될 수도 있다. The electrode assembly 10 is interposed between two electrode plates 11 having different polarities from each other and having a wide plate shape in a roll shape and the electrode plates 11 to insulate the electrode plates 11 from each other. It is preferable to have a separator 12 disposed on the left side or the right side of the electrode plate 11 and wound in a so-called 'Jelly Roll' shape. Of course, the positive electrode plate and the negative electrode plate of a predetermined standard may be stacked in such a manner that the separator is interposed therebetween. The two electrode plates 11 have a structure in which an active material slurry is applied to a current collector in the form of a metal foil or a metal mesh each containing aluminum and copper. The slurry is typically formed by stirring a granular active material, auxiliary conductor, binder, plasticizer, and the like in a state where a solvent is added. The solvent is removed in the subsequent process. In the direction in which the electrode plate 11 is wound, it is preferable that a non-coating portion where a slurry is not applied is present at the beginning and the end of the current collector. A pair of leads corresponding to each electrode plate 11 is attached to the uncoated portion. The first lead 13 attached to the top of the electrode assembly 10 is electrically connected to the cap assembly 30, and the second lead (not shown) attached to the bottom of the electrode assembly 10 is the case 20. Is connected to the bottom of the. Of course, both the first lead 13 and the second lead may be drawn out toward the cap assembly 30.
전극 조립체(10)는 케이스(20)의 바닥부에 설치된 제1 절연판(미도시) 위에 배치되고, 전극 조립체(10)의 상단에는 제2 절연판(14)이 배치되는 것이 바람직하다. 제1 절연판은 전극 조립체(10)와 케이스(20)의 바닥부 사이를 절연시키고, 제2 절연판(14)은 전극 조립체(10)와 캡 조립체(30) 사이를 절연시킨다.The electrode assembly 10 may be disposed on a first insulating plate (not shown) installed at the bottom of the case 20, and the second insulating plate 14 may be disposed on the upper end of the electrode assembly 10. The first insulating plate insulates between the electrode assembly 10 and the bottom of the case 20, and the second insulating plate 14 insulates between the electrode assembly 10 and the cap assembly 30.
상기 케이스(20)는 알루미늄 또는 알루미늄 합금과 같은 경량의 전도성 금속 재질로 구성되며, 상단이 개방된 개방부와 그와 대향되는 밀폐된 바닥부를 가진 원통 구조를 가진다. 케이스(20)의 내부 공간에는 전극 조립체(10)와 전해액(미도시)이 수용된다. 상기 전해액은 이차 전지(100)의 충, 방전 시 전극판(11)의 전기 화학적 반응에 의해 생성되는 리튬 이온을 이동시키기 위한 것이다. 이러한 전해액은 리튬염과 고순도 유기 용매류의 혼합물인 비수질계 유기전해액 또는 고분자 전해질을 이용한 폴리머일 수도 있으나, 전해액의 종류는 문제되지 않는다. The case 20 is made of a lightweight conductive metal material such as aluminum or an aluminum alloy, and has a cylindrical structure having an open upper end and a closed bottom opposite thereto. The electrode assembly 10 and the electrolyte (not shown) are accommodated in the inner space of the case 20. The electrolyte is to move lithium ions generated by the electrochemical reaction of the electrode plate 11 during charging and discharging of the secondary battery 100. The electrolyte may be a polymer using a non-aqueous organic electrolyte or a polymer electrolyte which is a mixture of lithium salts and high purity organic solvents, but the type of electrolyte is not a problem.
한편, 케이스(20)의 중앙에는 젤리롤 형태로 권취된 전극 조립체(10)가 풀리는 것을 방지하고 이차 전지(100) 내부의 가스의 이동 통로의 역할을 수행하는 금속성의 센터 핀(미도시)이 삽입될 수도 있다. 케이스(20)의 상부 즉, 전극 조립체(10)의 상부에는 외부에서 내측으로 가압 절곡 형성된 비딩부(24)가 마련되어 전극 조립체(10)의 상, 하 방향의 유동을 방지한다.Meanwhile, at the center of the case 20, a metallic center pin (not shown) which prevents the electrode assembly 10 wound in a jelly roll form from being released and serves as a gas passageway inside the secondary battery 100 is provided. It may be inserted. An upper portion of the case 20, that is, an upper portion of the electrode assembly 10 is provided with a beading portion 24 formed to be bent from the outside to the inside to prevent the up and down flow of the electrode assembly 10.
캡 조립체(30)는 가스켓(40)을 개재시켜 밀폐된 상태에서 케이스(20)의 개방부에 조립되는 것으로서, 탑-캡(32), PTC(34), 안전 벤트(36), 및 전류차단기(38)를 포함한다. 탑-캡(32)은 외부와 전기적으로 접속되도록 형성된 전극 단자(미도시)를 갖는다. PTC(34)는 전지(100)의 과열에 의해 전지 내부의 전류의 흐름을 차단하기 위한 것이다. 안전 벤트(36)는 중앙에 볼록하게 돌출되어 전류차단기(CID: current Interrupt Device)(38)와 용접된다. 전류차단기(38)는 이차 전지(100)의 내부 압력에 의해 안전 벤트(36)와 함께 변형될 수 있는 것으로서, CID 가스켓 및 CID 필터로 구분될 수도 있다. The cap assembly 30 is assembled to the opening of the case 20 in a sealed state via the gasket 40, and includes a top cap 32, a PTC 34, a safety vent 36, and a current breaker. (38). The top cap 32 has electrode terminals (not shown) formed to be electrically connected to the outside. The PTC 34 is for blocking the flow of current inside the battery by overheating the battery 100. The safety vent 36 protrudes convexly in the center and is welded with a current interrupt device (CID) 38. The current breaker 38 may be deformed together with the safety vent 36 by the internal pressure of the secondary battery 100, and may be divided into a CID gasket and a CID filter.
상기 가스켓(40)은 전체적으로 양단이 개방된 원통 형태를 이루며, 케이스(20)의 내면을 향하는 일단은 케이스(20)의 개방부 즉, 클램핑 부위에 놓여지도록 중심부를 향해 직각으로 절곡된 구조가 바람직하다. 가스켓(40)의 타단은 조립 초기에는 직선으로 펴져 원통형 가스켓(40)의 축방향으로 향하고 있으며, 케이스(20)와의 가압 공정시 중심부를 향해 직각으로 절곡되어 내주면과 외주면이 각각 캡 조립체(30)의 탑-캡과 케이스(20)의 내측면에 밀착된 상태로 접히게 된다. 가스켓(40)은 전기 절연성과, 내충격성, 탄력성 및 내구성을 가진 소재 예를 들어, 폴리올레핀(polyolefine) 또는 폴리프로필렌(PP)으로 제조된다. The gasket 40 has a cylindrical shape with both ends open as a whole, and one end facing the inner surface of the case 20 is bent at a right angle toward the center so as to be placed at an open portion, that is, a clamping portion, of the case 20. Do. The other end of the gasket 40 is straight in the initial stage of assembly and is oriented in the axial direction of the cylindrical gasket 40. The gasket 40 is bent at a right angle toward the center during the pressing process with the case 20 so that the inner circumferential surface and the outer circumferential surface thereof are cap assemblies 30, respectively. The top-cap is folded in close contact with the inner surface of the case 20. The gasket 40 is made of a material such as polyolefine or polypropylene (PP) having electrical insulation, impact resistance, elasticity and durability.
상기 누액 방지부(50)는 안전 벤트(36)의 하면과 안전 벤트(36)와 접촉되는 가스켓(40)의 면에 형성되고 그 측면이 삼각 형태인 요철 구조를 나타낸다. 즉, 안전 벤트(36)에 마련된 요철과 가스켓(40)에 마련된 요철은 케이스(20)의 개방단의 클램핑 작업시 서로 맞물리면서 밀착 결합되어 캡 조립체(30)와 가스켓(40) 사이의 밀봉 결합력을 더욱 강화시킬 수 있다. 따라서, 이러한 누액 방지부(50)는 이차 전지(100)에서 내압이 발생할 경우 안전 벤트(36)가 파열될 때까지 전해액 또는 가스가 캡 조립체(30)의 상부로 누출되는 것을 방지한다. The leakage preventing part 50 is formed on the lower surface of the safety vent 36 and the surface of the gasket 40 in contact with the safety vent 36 and has a concave-convex structure having a triangular side surface thereof. That is, the unevenness provided in the safety vent 36 and the unevenness provided in the gasket 40 are closely coupled while being engaged with each other during the clamping operation of the open end of the case 20 to provide a sealing coupling force between the cap assembly 30 and the gasket 40. It can be further strengthened. Therefore, the leakage preventing unit 50 prevents the electrolyte or gas from leaking to the upper portion of the cap assembly 30 until the safety vent 36 ruptures when internal pressure occurs in the secondary battery 100.
도 2는 본 발명의 바람직한 다른 실시예에 따른 이차 전지의 캡 조립체 부위를 도시한 단면도이다. 도 1에서 설명된 참조부호와 동일한 구성요소는 동일한 기능을 가진 동일부재이다. 2 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention. The same components as those described in FIG. 1 are the same members with the same functions.
도 2를 참조하면, 본 발명의 변형된 실시예에 따른 이차 전지(100)는 4각 형태의 누액 방지부(60)를 구비한다. 누액 방지부(60)는 안전 벤트(36)와 가스켓(40)의 계면 사이에 각각 그 접촉 부위에 형성된 4각 형태의 요철 구조를 포함한다. 이러한 누액 방지부(60)는 전술한 누액 방지부(50)보다 전해액 또는 가스의 누액 시 그 이동 거리를 증가시켜 외부 충격 또는 내압 증가 시에도 계면 사이의 기밀성을 크게 향상시킬 수 있다.Referring to FIG. 2, the secondary battery 100 according to the modified embodiment of the present invention includes a leakage preventing part 60 having a quadrangular shape. The leakage preventing part 60 includes a quadrangular concave-convex structure formed at a contact portion between the safety vent 36 and the gasket 40, respectively. The leakage preventing unit 60 increases the moving distance when the electrolyte or gas leaks from the leakage preventing unit 50 as described above, thereby greatly improving the airtightness between the interfaces even when the external shock or the internal pressure increases.
도 3 및 도 4는 본 발명의 또 다른 바람직한 실시예에 따른 이차 전지의 캡 조립체 부위를 각각 도시한 단면도들이다. 도 1 및 도 2에서 설명된 참조부호와 동일한 구성요소는 동일한 기능을 가진 동일부재이다. 3 and 4 are cross-sectional views respectively illustrating cap assembly portions of a rechargeable battery according to another exemplary embodiment of the present invention. The same components as those described in FIGS. 1 and 2 are the same members with the same functions.
도 3 및 도 4를 참조하면, 본 실시예에 따른 이차 전지(100)는 각각 원형의 누액 방지부(70) 및 라운드형 누액 방지부(80)를 구비한다. 도 3의 실시예에 따른 누액 방지부(70)는 안전 벤트(36)와 가스켓(40)이 접촉되는 면에 마련되는 것으로서, 각각 반원형의 요부와 철부가 연속되도록 형성되며, 계면에서 각각의 요부와 철부는 그 대응되는 철부와 요부에 각각 형합되는 구조이다. 도 4의 실시예에 따른 누액 방지부(80)는 안전 벤트(36)와 가스켓(40)이 접촉되는 면에 마련되는 것으로서, 실질적으로 라운드 진 요부와 철부가 연속되는 구조이며, 계면에서 각각의 요부와 철부는 그 대응되는 철부와 요부에 각각 형합되는 구조이다.3 and 4, the secondary battery 100 according to the present embodiment includes a circular leakage preventing part 70 and a round leakage preventing part 80, respectively. The leakage preventing part 70 according to the embodiment of FIG. 3 is provided on the surface where the safety vent 36 and the gasket 40 are in contact with each other, and the semicircular recesses and the convex portions are continuously formed, respectively, and the recesses at the interface. And the convex portions are structures that respectively correspond to the corresponding convex portions and the recessed portions. The leakage preventing part 80 according to the embodiment of FIG. 4 is provided on the surface where the safety vent 36 and the gasket 40 are in contact with each other, and has a structure in which a substantially round recessed part and an iron part are continuous. The recessed portion and the convex portion are structures which are respectively joined to the corresponding convex portion and the recessed portion.
도 5는 본 발명의 또 다른 바람직한 실시예에 따른 이차 전지의 캡 조립체 부위를 도시한 단면도이다. 도 1 내지 도 4에서 설명된 참조부호와 동일한 구성요소는 동일한 기능을 가진 동일부재이다. 5 is a cross-sectional view illustrating a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention. The same components as those described in FIGS. 1 to 4 are the same members with the same functions.
도 5를 참조하면, 본 실시예에 따른 이차 전지(200)는 전술한 누액 방지부(50) 이외에 제2 누액 방지부(150)를 더 구비한다. Referring to FIG. 5, the secondary battery 200 according to the present exemplary embodiment further includes a second leakage preventing unit 150 in addition to the leakage preventing unit 50 described above.
제2 누액 방지부(150)는 탑-캡(32)의 상면에 마련된 돌기 구조를 구비한다. 이러한 돌기 구조는 원뿔 또는 삼각뿔 형태일 수 있다. 제2 누액 방지부(150)는 케이스(20)와 캡 조립체(30)의 크램핑 작업 시, 돌기의 뾰족한 부분이 가스켓(40)의 면을 뚫고 들어가 결합됨으로써, 가스켓(40)과 탑-캡(32) 사이의 결합력 및 밀봉력을 증가시키기 위한 것이다. 물론, 제2 누액 방지부(150)의 돌기 구조는 요철 형태로 변형될 수도 있고, 이 경우 대응되는 가스켓(40)의 면에 요철이 형성될 수 있다.The second leakage preventing part 150 has a protrusion structure provided on the top surface of the top cap 32. This protrusion structure may be in the form of a cone or a triangular pyramid. When the second leakage preventing part 150 clamps the case 20 and the cap assembly 30, the pointed portion of the protrusion penetrates the surface of the gasket 40 to be coupled to the gasket 40 and the top-cap. To increase the bonding force and sealing force between the (32). Of course, the protrusion structure of the second leakage preventing part 150 may be deformed in the form of unevenness, in which case the unevenness may be formed on the surface of the corresponding gasket 40.
도 6은 도 5의 실시예의 캡 조립체의 변형예를 개략적으로 도시한 단면도이다. 도 1 내지 도 5에서 설명된 참조부호와 동일한 구성요소는 동일한 기능을 가진 동일부재이다.6 is a schematic cross-sectional view of a modification of the cap assembly of the embodiment of FIG. 5. The same components as those described in FIGS. 1 to 5 are the same members having the same functions.
도 6을 참조하면, 본 실시예에 따른 이차 전지(200)의 캡 조립체(30')는 안전 벤트(36)의 하면에 형성된 돌기 형태의 누액 방지부(50') 및 탑-캡(32)의 상면에 형성된 돌기 형태의 제2 누액 방지부(150')에 있어서, 각각의 누액 방지부(50')(150')의 돌기들(52)(152)이 뾰족부 근방에 형성된 미늘부(54)(154)를 더 구비한다. 이러한 미늘부(54)(154)는 클램핑 작업시 케이스(20)에 의해 가스켓(40)과 캡 조립체(30)가 결합되는 과정에서 돌기들(52)(152)이 가스켓(40)의 표면을 뚫고 들어갈 때 미늘부(54)(154)가 가스켓(40)에 더욱 확실하게 박히게 됨으로써 결합력 및 밀봉력을 향상시키기 위한 것이다. Referring to FIG. 6, the cap assembly 30 ′ of the secondary battery 200 according to the present exemplary embodiment may include a protrusion leakage preventing part 50 ′ and a top cap 32 formed on the bottom surface of the safety vent 36. In the projection-shaped second leakage preventing portion 150 ', the projections 52 and 152 of each leakage preventing portion 50' and 150 'are formed with a barb formed near the pointed portion ( 54) 154. The barbs 54 and 154 may be formed by the protrusions 52 and 152 on the surface of the gasket 40 while the gasket 40 and the cap assembly 30 are coupled to each other by the case 20 during the clamping operation. To penetrate the barbs 54 and 154 more reliably into the gasket 40 when penetrating, it is to improve the bonding force and the sealing force.
도 7은 본 발명의 또 다른 바람직한 실시예에 따른 이차 전지의 캡 조립체 부위를 개략적으로 도시한 단면도이다. 도 1 내지 도 6에서 설명된 참조부호와 동일한 구성요소는 동일한 기능을 가진 동일부재이다.7 is a schematic cross-sectional view of a cap assembly portion of a rechargeable battery according to another exemplary embodiment of the present invention. The same components as those described in FIGS. 1 to 6 are the same members with the same functions.
본 실시예에 따른 이차 전지(300)는 전술한 누액 방지부(50) 및 제2 누액 방지부(150) 이외에 제3 누액 방지부(250)를 더 구비한다.The secondary battery 300 according to the present exemplary embodiment further includes a third leakage preventing part 250 in addition to the leakage preventing part 50 and the second leakage preventing part 150 described above.
제3 누액 방지부(250)는 가스켓(40)과 접촉되는 케이스(20)의 내측면에 형성된 돌기 또는 요철 구조를 포함한다. 물론, 본 실시예의 변형에 따르면, 케이스(20)의 돌기 또는 요철 구조에 대응되도록 가스켓(40)의 면에도 요철 또는 돌기가 마련될 수도 있다. 이러한 제3 누액 방지부(250)는 전지 내부의 전해액 또는 가스 등이 외부 충격 또는 내압 상승에 의해 외부로 배출될 때 가스켓(40)과 캡 조립체(30) 부분의 계면 이외의 부분 즉, 케이스(20)의 내측면을 통해 배출되는 경우를 대비하기 위한 것이다. The third leakage preventing part 250 includes a protrusion or an uneven structure formed on an inner surface of the case 20 in contact with the gasket 40. Of course, according to the modification of the present embodiment, the concave-convex or convex may be provided on the surface of the gasket 40 so as to correspond to the convex or concave-convex structure of the case 20. The third leakage preventing part 250 is a part other than the interface between the gasket 40 and the cap assembly 30 when the electrolyte or gas inside the battery is discharged to the outside due to an external shock or an increase in the internal pressure, that is, the case ( It is for the case of being discharged through the inner surface of 20).
낙하 실험Drop test
가스켓에만 요철이 형성된 이차 전지(비교예1)의 샘플 10개를 제작하고, 가스켓과 안전 벤트 모두에 요철이 형성된 이차 전지(실험예1)의 샘플 20개를 제작하여 각각 1m의 높이에서 콘크리트 바닥면으로 10회씩 자유 낙하시키는 실험을 실시하였다. 실험결과, 비교예의 샘플들은 평균 2.1회의 낙하시 전해액이 누설되는 것을 확인할 수 있었고, 실험예1의 샘플 20개 모두는 연속하여 10회의 낙하 실험에 의하더라도 전해액의 누출이 발견되지 않았다. 이를 정리하면 다음 표 1과 같다.Ten samples of the secondary battery (Comparative Example 1) with irregularities formed only in the gasket were made, and 20 samples of the secondary battery (Experimental Example 1) with the irregularities formed in both the gasket and the safety vents were made. An experiment was conducted in which the surface was freely dropped ten times. As a result of the experiment, the samples of the comparative example was confirmed that the electrolyte leaked when the average of 2.1 drops, all 20 samples of Experimental Example 1 was not found leakage of the electrolyte even after 10 successive drop experiments. This is summarized in Table 1 below.
표 1
Figure PCTKR2011001739-appb-T000001
 Table 1
Figure PCTKR2011001739-appb-T000001
압력 실험Pressure experiment
이차 전지 샘플들의 바닥면에 구멍을 형성하고 그 구멍을 통해 질소 가스를 각각의 셀의 내부로 가압하는 실험을 하였다. 실험 결과, 가스켓에만 요철이 형성된 이차 전지(비교예2)의 샘플 20개 중 CID가 단락되기 전에 누액되는 경우는 없었고, CID가 단락되는 압력 즉, 12kgf/cm2 부근에서 3개의 샘플에서 누출이 발견되었다. 가스켓과 안전 벤트 모두에 요철이 형성된 이차 전지(실험예2)의 샘플 20개는 CID가 단락된 후 16kgf/cm2까지 압력을 높이더라도 누액 현상이 발견되지 않았다. 이를 정리하면 다음 표 2와 같다.An experiment was performed in which a hole was formed in the bottom surface of the secondary battery samples and the nitrogen gas was pressurized into the inside of each cell through the hole. Result, there was the case that leakage before CID is short circuit of the 20 samples of the secondary battery (Comparative Example 2) A concave-convex is formed only gasket, pressure CID is short-that is, leakage from the three samples in the vicinity of 12kgf / cm 2 is Found. In 20 samples of the secondary battery (Experimental Example 2) in which unevenness was formed in both the gasket and the safety vent, no leakage was found even if the pressure was increased to 16 kgf / cm 2 after the CID was shorted. This is summarized in Table 2 below.
표 2
Figure PCTKR2011001739-appb-T000002
 TABLE 2
Figure PCTKR2011001739-appb-T000002
이상에서, 본 발명은 비록 한정된 실시예들과 도면들에 의해 설명되었으나, 본 발명은 이것에 의해 한정되지 않으며 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에 의해 본 발명의 기술사상과 아래에 기재될 특허청구범위의 균등범위 내에서 다양한 수정 및 변형이 가능함은 물론이다.In the above, although the present invention has been described by means of limited embodiments and drawings, the present invention is not limited by this and the technical spirit of the present invention and the following by those skilled in the art to which the present invention pertains. Various modifications and variations are possible, of course, within the scope of equivalents of the claims to be described.

Claims (11)

  1. 양극판 및 음극판이 세퍼레이터를 사이에 두고 배치된 전극 조립체;An electrode assembly in which a positive electrode plate and a negative electrode plate are disposed with the separator interposed therebetween;
    상기 전극 조립체가 수납되는 케이스;A case accommodating the electrode assembly;
    상기 케이스의 개방단을 밀봉할 수 있는 캡 조립체;A cap assembly capable of sealing the open end of the case;
    상기 케이스와 상기 캡 조립체 사이에 개재되는 가스켓; 및A gasket interposed between the case and the cap assembly; And
    상기 전극 조립체를 향하면서 상기 가스켓과 접촉되는 상기 캡 조립체의 일면 또는 상기 가스켓의 일면 중 적어도 어느 하나의 면에 형성된 누액 방지부를 구비하는 것을 특징으로 하는 이차 전지.And a leakage preventing part formed on at least one of one surface of the cap assembly or one surface of the gasket facing the electrode assembly and in contact with the gasket.
  2. 제1항에 있어서,The method of claim 1,
    상기 캡 조립체는:The cap assembly is:
    상기 케이스의 개방단을 밀봉하는 탑 캡(top cap);A top cap sealing an open end of the case;
    상기 탑 캡에 접촉되도록 배치된 PTC 소자; 및A PTC element disposed to contact the top cap; And
    일면은 상기 PTC 소자에 접촉되고 타면은 상기 누액 방지부가 형성되어 상기 가스켓에 접촉되도록 배치되고, 상기 전극 조립체에 전기적으로 연결된 안전 벤트를 구비하는 것을 특징으로 하는 이차 전지.The second battery is characterized in that the one surface is in contact with the PTC element and the other surface is formed so that the leakage preventing portion is formed to contact the gasket, and has a safety vent electrically connected to the electrode assembly.
  3. 제1항 또는 제2항에 있어서,The method according to claim 1 or 2,
    상기 누액 방지부는 상기 캡 조립체의 상기 접촉면에 형성된 적어도 하나 또는 그 이상의 요철들 또는 적어도 하나 또는 그 이상의 돌기들을 포함하는 것을 특징으로 하는 이차 전지.The leakage preventing unit includes at least one or more irregularities or at least one or more protrusions formed on the contact surface of the cap assembly.
  4. 제3항에 있어서,The method of claim 3,
    상기 요철은 삼각형 또는 사각형 또는 원형 또는 라운드형 구조인 것을 특징으로 하는 이차 전지.The unevenness is a secondary battery, characterized in that the triangular or square or round or round structure.
  5. 제3항에 있어서,The method of claim 3,
    상기 돌기는 삼각뿔 또는 원뿔 구조인 것을 특징으로 하는 이차 전지.The protrusion is a secondary battery, characterized in that the triangular pyramid or conical structure.
  6. 제3항에 있어서,The method of claim 3,
    상기 요철 또는 상기 돌기는 미늘부를 더 포함하는 것을 특징으로 하는 이차 전지.The uneven or the protrusion further comprises a barb portion.
  7. 제2항에 있어서,The method of claim 2,
    상기 안전 벤트는 금속 재질인 것을 특징으로 하는 이차 전지.The safety vent is a secondary battery, characterized in that the metal material.
  8. 제1항에 있어서,The method of claim 1,
    상기 누액 방지부와 대향되며 상기 가스켓과 접촉되는 상기 캡 조립체의 접촉면에 형성된 제2 누액 방지부를 더 구비하는 것을 특징으로 하는 이차 전지.And a second leakage preventing part formed on a contact surface of the cap assembly facing the leakage preventing part and in contact with the gasket.
  9. 제1항에 있어서,The method of claim 1,
    상기 가스켓과 접촉되는 상기 캔의 접촉면에 형성된 제3 누액 방지부를 더 구비하는 것을 특징으로 하는 이차 전지.And a third leakage preventing part formed on a contact surface of the can contacting the gasket.
  10. 제8항 또는 제9항에 있어서,The method according to claim 8 or 9,
    상기 제2 누액 방지부와 상기 제3 누액 방지부 중 적어도 어느 하나는 적어도 하나 또는 그 이상의 요철들 또는 적어도 하나 또는 그 이상의 돌기들을 포함하는 것을 특징으로 하는 이차 전지.At least one of the second leakage preventing part and the third leakage preventing part includes at least one or more unevennesses or at least one or more protrusions.
  11. 제1항에 있어서,The method of claim 1,
    상기 누액 방지부와 상기 제3 누액 방지부 중 적어도 어느 하나는 적어도 하나 또는 그 이상의 요철들 또는 적어도 하나 또는 그 이상의 돌기들을 포함하는 것을 특징으로 하는 이차 전지.At least one of the leakage preventing unit and the third leakage preventing unit includes at least one or more irregularities or at least one or more protrusions.
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