KR102169375B1 - Battery Cell Including Spacer Being Disposed Between Connection Member and Washer - Google Patents

Abstract

The present invention is a cylindrical battery cell constituting a battery module or battery pack in which a plurality of battery cells are electrically connected, and a jelly-roll type having a structure in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound. Electrode assembly; A cylindrical can in which the electrode assembly is embedded together with an electrolyte, and an upper outer peripheral portion is bent inward to form a clamping portion; A cap assembly coupled to the open upper end of the cylindrical can; A gasket interposed between the upper inner surface of the cylindrical can and the outer surface of the cap assembly so as to electrically insulate the cylindrical can and the cap assembly; A washer mounted on the cap assembly while the top cap of the cap assembly is exposed so as to prevent contact between the connecting member coupled to the upper end of the cap assembly for electrical connection and the clamping portion of the cylindrical can; And a spacer interposed between the connection member and the washer so as to secure an additional separation distance between the end portion of the connection member and the gasket.

Description

Battery Cell Including Spacer Being Disposed Between Connection Member and Washer {Battery Cell Including Spacer Being Disposed Between Connection Member and Washer}

The present invention relates to a battery cell including a spacer between a connection member and a washer.

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing, and among such secondary batteries, a lot of research has been conducted on lithium secondary batteries with high energy density and discharge voltage. Is being used.

Depending on the shape of the battery case, secondary batteries are classified into cylindrical and prismatic batteries in which the electrode assembly is embedded in a cylindrical or rectangular metal can, and pouch-type batteries in which the electrode assembly is embedded in a pouch-shaped case of an aluminum laminate sheet. . Among them, the cylindrical battery has the advantage of being relatively large in capacity and structurally stable.

The electrode assembly built in the battery case is an electric device capable of charging and discharging consisting of a stacked structure of a positive electrode/separator/cathode, and a jelly-roll type wound with a separator interposed between a long sheet-shaped positive electrode and a negative electrode coated with an active material, It is classified as a stack type in which a plurality of positive and negative electrodes of a predetermined size are sequentially stacked with a separator interposed therebetween. Among them, the jelly-roll type electrode assembly is easy to manufacture and has the advantage of high energy density per weight.

In this regard, Fig. 1 schematically shows a vertical cross-sectional view of a conventional cylindrical battery.

Referring to FIG. 1, the battery cell 10 includes a positive electrode, a negative electrode, and an electrode assembly 11 having a structure in which a separator is interposed between the positive electrode and the negative electrode, and is embedded in a cylindrical can 12 together with an electrolyte. The upper end of 12) has a structure in which the cap assembly 13 is coupled, and a gasket 14 is interposed between the cap assembly 13 and the cylindrical can 12 for electrical insulation.

The battery cell 10 having such a structure includes a plurality of battery cells connected to the upper end of the cap assembly 13 and/or a cylindrical can by a connection member 15 in order to configure a high capacity/high output battery module or battery pack. Connect at the bottom of 12).

At this time, a washer between the connecting member 15 and the cylindrical can 12 to prevent a short circuit due to contact between the connecting member 15 coupled to the upper end of the cap assembly 13 and the cylindrical can 12. (16) is interposed.

However, the battery cell 10 having such a structure generates high temperature from the connection member 15 connected to the upper portion of the cap assembly 13 when an external short circuit occurs, and the generated heat affects the gasket 14. Go crazy, the gasket 14 can be melted. Accordingly, the clamping portion 17 of the cylindrical can 12 contacts the cap assembly 13 to the molten gasket 14, thereby causing a short circuit.

Therefore, there is a very need for a battery cell capable of solving the above problems.

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

Specifically, an object of the present invention is to prevent the gasket from melting due to the high temperature generated from the connecting member by an external short circuit affecting the gasket, and thereby preventing the occurrence of a short circuit between the cylindrical can and the cap assembly. It is to provide this improved battery cell.

The battery cell according to the present invention for achieving this purpose,

As a cylindrical battery cell constituting a battery module or battery pack consisting of a plurality of battery cells are electrically connected,

A jelly-roll type electrode assembly having a structure in which an anode, a cathode, and a separator interposed between the anode and the cathode are wound;

A cylindrical can in which the electrode assembly is embedded together with an electrolyte, and an upper outer peripheral portion is bent inward to form a clamping portion;

A cap assembly coupled to the open upper end of the cylindrical can;

A gasket interposed between the upper inner surface of the cylindrical can and the outer surface of the cap assembly so as to electrically insulate the cylindrical can and the cap assembly;

A washer mounted on the cap assembly while the top cap of the cap assembly is exposed so as to prevent contact between the connecting member coupled to the upper end of the cap assembly for electrical connection and the clamping portion of the cylindrical can; And

A spacer interposed between the connection member and the washer so as to secure an additional separation distance between the end of the connection member and the gasket;

It may be composed of a structure including.

Therefore, the battery cell according to the present invention includes a spacer interposed between the connection member and the washer so as to secure an additional separation distance between the end of the connection member and the gasket, even if a high temperature occurs from the connection member due to an external short circuit. Since such heat does not affect the gasket and the gasket is melted, it is possible to prevent the clamping unit and the cap assembly from contacting the gasket to be short-circuited.

In one embodiment of the present invention, the gasket, washers and spacers may be made of an electrically insulating material. Specifically, the insulating material may be made of polyethylene, polypropylene, a polymer compound, or the like.

In one embodiment of the present invention, the spacer may be interposed on an inner end of the washer on a vertical surface. That is, the spacer may be interposed on the inner circumferential surface on the horizontal surface of the washer.

The spacer may have a width of 10% to 20% of the width of the washer on a vertical section. A structure in which the thickness of the washer is increased to secure an additional separation distance between the connection member and the gasket may be considered, but this increases the manufacturing cost of the washer, thereby increasing the cost of manufacturing the battery cell.

Accordingly, the battery cell according to the present invention is a minimum configuration capable of securing an additional separation distance between the connection member and the gasket, and may include a spacer having a width of 10% to 20% of the width of the washer. have.

When the width of the spacer on the vertical cross-section is less than 10% of the width of the washer, the spacer may not be able to sufficiently support the load at the end of the connecting member positioned at the upper end thereof. On the other hand, when the width on the vertical cross-section of the spacer exceeds 20% of the width of the washer, the manufacturing cost of the spacer may be increased, and there may be a problem in that the spacer on the horizontal plane is exposed from the connection member.

In addition, the spacer may have a thickness of 80% to 120% of the thickness of the washer on a vertical section. When the spacer has a size of less than 80% of the thickness of the washer, there may be a problem in that a sufficient separation distance between the connection member and the gasket is not secured. On the other hand, when the spacer has a size exceeding 120% of the thickness of the washer, there may be a problem of increasing the volume of the battery due to excessive distance between the connecting member and the gasket.

As a specific example of the spacer, the spacer may have an emboss shape. The shape of the spacer is not limited thereto as long as it can sufficiently secure a separation distance between the connection member and the gasket.

In addition, the spacer may be made of an electrically insulating elastic material.

The clamping part may be inwardly bent to a size of 50% to 80% of the width of the upper end of the gasket to surround the upper part of the gasket. When the clamping part is bent to a size of 50% of the width of the upper end of the gasket, the gasket may not be sufficiently fixed by the clamping part. On the other hand, when the upper end of the gasket is bent to a size of 80% of the width, there is a possibility that the clamping part comes into contact with the cap assembly through the melted part of the gasket when the gasket is melted due to high temperature from the connecting member It can be high.

In one embodiment of the present invention, the cylindrical can may be made of a metal can. The negative electrode tab of the electrode assembly is in contact with and connected to the lower end of the cylindrical can, so that the cylindrical can may be made of a negative electrode.

The type of the battery cell is not particularly limited, but as a specific example, it may be a lithium secondary battery such as a lithium ion battery or a lithium ion polymer battery having advantages such as high energy density, discharge voltage, and output stability.

In general, 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, followed by drying, and if necessary, a filler may be further added to the mixture.

The positive electrode active material may include a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; Lithium manganese oxides such as chemical formula Li1+xMn2-xO4 (wherein x is 0 to 0.33), LiMnO3, LiMn2O3, and LiMnO2; Lithium copper oxide (Li2CuO2); Vanadium oxides such as LiV3O8, LiFe3O4, V2O5, and Cu2V2O7; Ni site-type lithium nickel oxide represented by the formula LiNi1-xMxO2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); Formula LiMn2-xMxO2 (here, M = Co, Ni, Fe, Cr, Zn or Ta, x = 0.01 ~ 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn) Lithium manganese composite oxide; LiMn2O4 in which Li in the formula is partially substituted with alkaline earth metal ions; Disulfide compounds; Fe2(MoO4)3 etc. can be mentioned, but it is not limited only to these.

The conductive material is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive electrode active material. Such a conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; Carbon blacks such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; Conductive fibers such as carbon fibers and metal fibers; 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 may be used.

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

The filler is selectively used as a component that suppresses the expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing chemical changes in the battery, and examples thereof include olivine polymers such as polyethylene and polypropylene; Fibrous materials such as glass fiber and carbon fiber are used.

The negative electrode is manufactured by coating and drying a negative electrode active material on a negative electrode current collector, and if necessary, components as described above may be optionally further included.

Examples of the negative active material include carbon such as non-graphitized carbon and graphite-based carbon; LixFe2O3 (0≤x≤1), LixWO2 (0≤x≤1), SnxMe1-xMe'yOz (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, Group 1 of the periodic table, Metal complex oxides such as Group 2 and Group 3 elements, halogen, 0<x≦1; 1≦y≦3; 1≦z≦8); Lithium metal; Lithium alloy; Silicon-based alloys; Tin-based alloys; Metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separator and the separation film are interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 μm, and the thickness is generally 5 to 130 μm. Examples of such separation membranes include olefin-based polymers such as polypropylene having chemical resistance and hydrophobicity; Sheets or non-woven fabrics made of glass fiber or polyethylene are used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

In addition, in one specific example, in order to improve the safety of the battery, the separator and/or the separation film may be an organic/inorganic composite porous SRS (Safety-Reinforcing Separators) separator.

The SRS separator is manufactured by using inorganic particles and a binder polymer as active layer components on a polyolefin-based separator substrate, and at this time, the pore structure included in the separator substrate itself and the interstitial volume between inorganic particles as the active layer component It has a uniform pore structure formed.

In the case of using such an organic/inorganic composite porous separator, compared to the case of using a conventional separator, there is an advantage in that it is possible to suppress an increase in the thickness of the battery due to swelling during the formation process. When a polymer that can be gelled when impregnated with a liquid electrolyte is used, it can be used as an electrolyte at the same time.

In addition, since the organic/inorganic composite porous separator can exhibit excellent adhesion characteristics by controlling the content of inorganic particles and binder polymers as active layer components in the separator, the battery assembly process can be easily performed.

The inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as the oxidation and/or reduction reaction does not occur in the operating voltage range (eg, 0 to 5V based on Li/Li+) of the applied battery. Particularly, in the case of using inorganic particles having ion transfer capability, it is possible to improve the performance by increasing the ionic conductivity in the electrochemical device, so it is preferable that the ion conductivity is as high as possible. In addition, when the inorganic particles have a high density, it is difficult to disperse during coating, as well as a problem of weight increase during battery manufacturing, so it is preferable that the density is as small as possible. Further, in the case of an inorganic material having a high dielectric constant, the ionic conductivity of the electrolyte may be improved by contributing to an increase in the degree of dissociation of an electrolyte salt, such as a lithium salt, in a liquid electrolyte.

The lithium salt-containing non-aqueous electrolyte is composed of a polar organic electrolyte and a lithium salt. As the electrolyte, a non-aqueous liquid electrolyte, an organic solid electrolyte, an inorganic solid electrolyte, or the like is used.

As the non-aqueous liquid electrolyte, for example, N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc (franc), 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolone, formamide, dimethylformamide, dioxolone , Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid tryster, trimethoxymethane, dioxolone derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo Aprotic organic solvents such as nate derivatives, tetrahydrofuran derivatives, ethers, methyl pyropionate and ethyl propionate may be used.

As the organic solid electrolyte, for example, a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, a poly agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, A polymer or the like containing an ionic dissociating group may be used.

Examples of the inorganic solid electrolyte include Li such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, and Li3PO4-Li2S-SiS2. Nitrides, halides, sulfates, and the like can be used.

The lithium salt is a material that is soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2) 2NLi, lithium chloroborane, lithium lower aliphatic carboxylic acid, lithium tetraphenylborate, imide, and the like can be used.

In addition, non-aqueous electrolytes include pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, and hexaphosphate triamide for the purpose of improving charge/discharge properties and flame retardancy. , Nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxy ethanol, aluminum trichloride, etc. May be. In some cases, in order to impart non-flammability, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further included, and carbon dioxide gas may be further included in order to improve high-temperature storage characteristics.

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

The present invention also provides a device comprising the battery pack as a power source.

The device may be selected from a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a wearable electronic device, a notebook computer, an electric vehicle, or a power storage device.

Since the structure of these devices and a method of manufacturing them are known in the art, detailed descriptions thereof will be omitted in the present specification.

As described above, the battery cell according to the present invention includes a spacer interposed between the connection member and the washer so as to secure an additional distance between the end of the connection member and the gasket, from the connection member by an external short circuit. Even if a high temperature occurs, the heat does not affect the gasket and thus the gasket is prevented from being melted, so that the clamping portion and the cap assembly contact the portion where the gasket is melted to prevent a short circuit.

1 is a vertical cross-sectional view of a conventional cylindrical battery cell;
2 is a vertical cross-sectional view of a battery cell according to an embodiment of the present invention.

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

2 schematically illustrates a vertical cross-sectional view of a battery cell according to an embodiment of the present invention.

Referring to FIG. 2, the battery cell 100 includes an electrode assembly 110, a cylindrical can 120, a cap assembly 130, a gasket 140, a washer 150, and a spacer 160.

The electrode assembly 110 is a jelly-roll type electrode assembly having a structure in which an anode, a cathode, and a separator interposed between the anode and the cathode are wound, and is embedded in the cylindrical can 120 together with an electrolyte (not shown). , The cap assembly 130 is coupled to the upper end of the cylindrical can 120.

The cylindrical can 120 has an upper outer peripheral portion bent inward to form a clamping portion 121.

A gasket 140 is interposed between the upper inner surface of the cylindrical can 120 and the outer surface of the cap assembly 130 so as to electrically insulate the cylindrical can 120 and the cap assembly 130.

The washer 150 may prevent contact between the connection member 170 coupled to the upper end of the cap assembly 130 for electrical connection and the clamping portion 121 of the cylindrical can 120, so that the cap assembly 130 ) Of the top cap 131 is mounted on the cap assembly 130 in an exposed state.

In addition, the spacer 160 is interposed between the connection member 170 and the washer 150 to secure an additional separation distance between the end of the connection member 170 and the gasket 140.

The spacer 160 is interposed on the inner end of the washer 150, and the width W1 of the spacer 160 is made of 20% of the width W2 of the washer 150, and the spacer 160 The thickness T1 of the washer 150 is 100% of the thickness T2 of the washer 150, and the shape of the spacer 160 is made of an embossed shape.

The clamping portion 121 is bent inward to a size W3 of 80% of the width W4 of the upper end portion of the gasket 140 to surround the upper portion of the gasket.

The gasket 140, the washer 150, and the spacer 160 are made of an electrically insulating material, and the cylindrical can 120 is made of a metal can.

Those of ordinary skill in the field to which the present invention belongs will be able to make various applications and modifications in the scope of the present invention based on the above contents.

Claims (9)

As a cylindrical battery cell constituting a battery module or battery pack consisting of a plurality of battery cells are electrically connected,
A jelly-roll type electrode assembly having a structure in which an anode, a cathode, and a separator interposed between the anode and the cathode are wound;
A cylindrical can in which the electrode assembly is embedded together with an electrolyte, and an upper outer peripheral portion is bent inward to form a clamping portion;
A cap assembly coupled to the open upper end of the cylindrical can;
A gasket interposed between the upper inner surface of the cylindrical can and the outer surface of the cap assembly so as to electrically insulate the cylindrical can and the cap assembly;
A washer mounted on the cap assembly while the top cap of the cap assembly is exposed so as to prevent contact between the connecting member coupled to the upper end of the cap assembly for electrical connection and the clamping portion of the cylindrical can; And
A spacer interposed between the connection member and the washer so as to secure an additional separation distance between the end of the connection member and the gasket;
The spacer is interposed on the inner end of the washer on a vertical surface, has a width of 10% to 20% of the width of the washer on a vertical cross-section, and has a thickness of 80% to 120% of the thickness of the washer on a vertical cross-section. It has, characterized in that the battery cell comprising the one consisting of an emboss (emboss) shape .
delete delete delete delete The battery cell according to claim 1, wherein the spacer is made of an electrically insulating elastic material. The battery cell according to claim 1, wherein the clamping part is bent inward to a size of 50% to 80% of the width of the upper end of the gasket to surround the upper part of the gasket. The battery cell according to claim 1, wherein the cylindrical can is a metal can. A battery pack comprising at least one battery cell according to claim 1.

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