KR101670364B1 - Method of manufacturing CID assembly for a secondary battery and CID assembly thereof - Google Patents

Abstract

The present invention discloses a method of manufacturing a CID assembly for a secondary battery and an assembly thereof.
A method of manufacturing a CID assembly and an assembly thereof according to the present invention includes a step of preparing a cap-down adhering material by thermally fusing one surface of an adhesive insulating member to a cap-down portion of a plate- A step S2 of manufacturing a thin safety band attaching member by aligning and fusing the projections of the thin safety band having a protrusion at the center in the form of a metal plate on the other side of the adhesive insulating member of the cap down attaching member, And a step S3 of manufacturing the CID module by attaching the protrusion and the subplate by ultrasonic welding. In this case, the structure retained by the frictional force only by fitting between the parts of the cap assembly is improved, And the 'Z' bending structure is removed to fundamentally reduce the thickness to increase structural stability and capacity of the secondary cell Is effective.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing a CID assembly for a secondary battery,

The present invention relates to a method of manufacturing a CID assembly for a secondary battery and an assembly thereof, and more particularly, to a method of manufacturing a CID assembly for a secondary battery by improving a structure retained only by frictional force between fittings of a cap assembly, The present invention relates to a method of manufacturing a CID assembly for a secondary battery and an assembly of the CID assembly for securing the structural stability and the capacity of the secondary battery by fundamentally reducing the thickness by removing the bending structure.

Conventional secondary batteries are classified as pouch-shaped batteries in which an electrode assembly is housed in a pouch-shaped case of an aluminum laminate sheet, and a cylindrical battery and a prismatic battery in which an electrode assembly is embedded in a cylindrical or rectangular metal can according to the shape of the battery case do.

In addition, the electrode assembly incorporated in the battery case is a chargeable / dischargeable power generation device formed of a lamination structure of a positive electrode / separator / negative electrode. The electrode assembly is a jelly-roll type electrode assembly in which a separator is interposed between a positive electrode and a negative electrode, Structure and a stacked structure in which a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked with a separator interposed therebetween. Among them, the jelly-roll type electrode assembly is most widely manufactured because it is easy to manufacture and has high energy density per weight, and the jelly-roll type electrode assembly is usually manufactured as a cylindrical battery.

However, the jelly-roll type electrode assembly tends to undergo repeated expansion and contraction during charging and discharging of the battery. In this process, the stress is concentrated to the central portion, and the electrode penetrates the separator and contacts the metal center pin, thereby causing an internal short circuit.

The organic solvent is decomposed by the heat generated due to the internal short circuit, so that gas is generated, and the battery can be ruptured by an increase in gas pressure in the cell. Such gas pressure rise inside the battery can occur even when an internal short circuit occurs due to an external impact.

In order to solve the safety problem of the battery, the cap assembly of the cylindrical battery includes a safety vent for discharging high-pressure gas, a PTC element for blocking current at high temperature, a current interruption Device: CID) and a top cap for forming protruding terminals for protecting the devices are fixed by a gasket.

The structure of the cap assembly essentially prevents the electrolyte in the battery from leaking to the outside by covering the outer peripheral surface of the safety vent, the PTC device, the CID, the top cap and the like. Therefore, if the electrolyte does not leak through the interface between the safety vest located at the innermost side of the battery and the gasket surrounding the outer periphery of the safety vent, the electrolyte can be prevented from leaking at the interface between the safety vent and the PTC device, Leakage does not occur.

However, some electrolytic solution leaks through the interface between the gasket and the safety vent due to the charging / discharging operation of the battery, dropping, external impact, etc., and the leaked electrolyte easily leaks out through the interface between the metal materials There is a problem. That is, since the interfacial region between the metal materials is relatively inferior in adhesion, the electrolyte introduced into the interface of the metal materials can easily leak to the outside relative to the interface portion of the gasket and the related elements, There is a high need for a technique capable of reducing the phenomenon that is caused by the presence of a foreign substance.

In this connection, Japanese Patent Application Laid-Open No. 2006-286561, Japanese Patent Application Laid-Open No. 2005-100927, Japanese Patent Application Laid-Open No. 2002-373711 and the like discloses a cap assembly provided with a gasket under the top cap. However, the cap assembly disclosed in these applications is not easy to manufacture because of the complicated shape of the gasket sealing the outer circumferential surface of the safety elements, There is a problem in that the thickness of the electrolyte membrane must be increased because the gasket is used several times.

In order to solve this problem, in Korean Patent Laid-Open Publication No. 2011-35625, as can be seen from FIG. 1, the cap assembly 400a includes a gasket 500a for mounting on the upper beading portion 210a of the can 200a (PTC device) 420a, a safety vent 430a for reducing the internal pressure, and a CID 440a are closely attached to the inside of the main cap 410a. The cylindrical rechargeable battery 100a is constructed such that the electrode assembly 110a is inserted into the can 200a and electrically connected to the cap assembly 400a through the lead tab 300a and the electrolyte 111a is injected into the cap assembly 400a and the lead tab 300a The cap assembly 400a is mounted on the open upper end of the can 200a and the end of the upper beading portion 210a is sealed so as to surround the cap assembly 400a. However, The structure is maintained, which may lead to defective or abnormal operation during vibration, and partially improves the structural stability by welding. However, since a plurality of gaskets are used, the thickness of the safety vent is increased by the Z bending shape, It is causing the rise.

Therefore, the first technical problem to be solved by the present invention is to improve the structure retained only by frictional force between fittings of the cap assembly, thereby greatly reducing defects due to vibration and eliminating the 'Z' bending structure, To provide a structural stability and to increase the capacity of the secondary battery, and to provide a method of manufacturing a CID assembly for a secondary battery.

The second technical problem to be solved by the present invention is to improve the structure retained only by the frictional force between the parts of the cap assembly to greatly reduce defects due to vibration and to eliminate the Z bending structure, To provide a CID assembly for a secondary battery that secures structural stability and increases the capacity of the secondary battery.

In order to solve the above-mentioned first technical problem, the present invention provides a cap-down attaching member by thermally fusing one surface of an adhesive insulating member to a plate-shaped cap-down portion provided with a center portion, A step S2 of manufacturing a thin safety band attaching member by aligning and fusing the projections of the thin safety band having a protrusion at the center in the form of a metal plate on the other side of the adhesive insulating member of the cap down attaching member, And attaching the protrusion and the sub-plate by ultrasonic welding to manufacture a CID module.

According to an embodiment of the present invention, the adhesive insulating member may have a hollow portion having a diameter equal to or larger than the diameter of the center portion.

According to another embodiment of the present invention, the recess may be disposed on the bottom of the recess protruding from the hole and thermally fused.

According to another embodiment of the present invention, the thermal fusion of step S1 or step S2 may be performed in a cap-down part or a thin safety vest.

According to another embodiment of the present invention, the temperature at the time of the heat fusion may be 160 to 250 ° C.

According to another embodiment of the present invention, the adhesive insulating member may include a thin safety vent attaching portion attached to the thin safety vent, a cap down attaching portion attached to the cap down portion, and a heat resistant portion having heat resistance.

According to another embodiment of the present invention, the thickness of the thin safety vest attaching portion or the cap down attaching portion may be 5 to 40% of the thickness of the adhesive insulating member.

According to another embodiment of the present invention, the thin safety vault attachment portion and the cap-down attachment portion may be a modified polyolefin-based resin.

According to another embodiment of the present invention, the modified polyolefin-based resin is a copolymer of ethylene or a monomer having a polar group with propylene and is selected from an ethylene / acrylic acid copolymer, an ethylene / methacrylic acid copolymer, an ethylene / ethyl acrylate, Ethylene / vinyl acetate copolymer, ethylene / itaconic acid copolymer, ethylene / monomethyl maleate copolymer, ethylene / maleic acid copolymer, ethylene / acrylic acid / methyl methacrylate copolymer, ethylene / Ethylene / acrylic acid / vinyl alcohol copolymers, ethylene / propylene / acrylic acid copolymers, ethylene / acrylic acid / vinyl acetate copolymers, ethylene / Ethylene / styrene / acrylic acid copolymer, ethylene / methacrylic acid / acrylonitrile copolymer, ethylene / PUMA Ethylene / vinyl chloride / acrylic acid copolymers, ethylene / chlorinated ethylene / methacrylic acid copolymers, ethylene / methacrylic acid sodium salt copolymers, ethylene / vinyl chloride / acrylic acid copolymers, ethylene / Acrylic acid copolymer, propylene / acrylic acid copolymer, propylene / methacrylic acid copolymer, propylene / ethyl acrylate, propylene / butyl acrylate copolymer Propylene / maleic acid copolymer, propylene / acrylic acid / methyl methacrylate copolymer, propylene / methacrylic acid / ethyl acrylate copolymer, propylene / vinyl acetate copolymer, propylene / itaconic acid copolymer, propylene / monomethyl maleate copolymer, Lt; / RTI > copolymer, propylene / monomethyl maleate / ethyl acrylate < RTI ID = Acrylic acid / vinyl alcohol copolymer, propylene / propylene / acrylic acid copolymer, propylene / styrene / acrylic acid copolymer, propylene / methacrylic acid / acrylonitrile copolymer, Propylene / vinylidene chloride / acrylic acid copolymer, propylene / chlorinated ethylene / methacrylic acid copolymer, propylene / methacrylic acid sodium salt copolymer, propylene / fumaric acid / vinyl methyl ether copolymer, propylene / vinyl chloride / acrylic acid copolymer, propylene / vinylidene chloride / Wherein the polyolefin resin is a substituted polyolefin resin wherein the polyolefin resin is a propylene / styrene sulfonate copolymer, a propylene / acrylic acid zinc salt copolymer, a propylene / styrenesulfonic acid sodium salt copolymer, a styrene-propylene-propylene copolymer, polyethylene maleic anhydride grafted polyethylene or polypropylene, High density polyethylene (m-HDPE), maleic anhydride graft It may be a propylene (m-PP), maleic anhydride grafted polyethylene / polypropylene copolymer (m-cpp), chlorinated polyethylene, polypropylene (CM), chlorosulfonated polyethylene or polypropylene (CSM).

According to another embodiment of the present invention, the heat-resistant portion includes a homopolypropylene resin, a mixed resin of polypropylene and PBT, a resin in which polypropylene and PBT are copolymerized, or a mixture of a modified propylene resin capable of electron beam crosslinking and a crosslinking assistant .

According to another embodiment of the present invention, the use of the PBT may be 10 to 50 wt% based on the total weight of polypropylene and PBT.

According to another embodiment of the present invention, the heat-resistant portion may include calcium carbonate, silica, clay, titanium oxide, aluminum hydroxide, magnesium hydroxide, talc, glass fiber or carbon fiber.

According to still another embodiment of the present invention, the step S3 may further include fixing a part of the sub-plate facing the cap down part by laser welding before or after the ultrasonic welding.

According to another embodiment of the present invention, the surface of the cap-down part or the thin safety vent of step S1 or step S2, which abuts on the adhesive insulating member, may have a concavo-convex part formed in advance.

According to another embodiment of the present invention, the surface of the cap down part or the thin safety vent of step S1 or step S2, which is in contact with the adhesive insulating member, is subjected to an etching treatment, a plasma treatment or a chromate treatment, .

According to another embodiment of the present invention, the end of the thin safety vest may be shaped to wrap the top cap.

According to another aspect of the present invention, there is provided a CID assembly for a secondary battery, which is manufactured by the manufacturing method described above.

According to an embodiment of the present invention, an adhesive insulating member is interposed between the thin safety vent and a plate-shaped cap down portion provided with a center portion, which is an opening for exposing the thin safety vent protrusion, The protrusion and the subplate may be a CID assembly for a secondary battery attached by ultrasonic welding.

According to the present invention, it is possible to improve the structure retained only by the frictional force between the parts of the cap assembly, thereby drastically reducing defects due to vibration, and substantially eliminating the 'Z' bending structure to fundamentally reduce the thickness, The capacity of the battery is increased.

FIG. 1 is a cross-sectional view of a conventional cap assembly mounted on a beading portion of a secondary battery can,
2 is a flowchart illustrating a method of manufacturing a CID assembly for a secondary battery according to an embodiment of the present invention,
3 is a cross-sectional view of a CID assembly according to an embodiment of the present invention mounted on a secondary battery,
Fig. 4 is an enlarged view of Fig. 3,
Fig. 5 is an enlarged view of Fig. 3B,
FIG. 6 is a cross-sectional view showing the bottom of the recessed portion protruding from the hole of the adhesive insulating member according to an embodiment of the present invention. FIG.
FIG. 7 is a cross-sectional view of a cap-down portion or a thin safety vent in a step of forming a hexahedral space opening of a concavo-convex portion according to an embodiment of the present invention,
8 is a cross-sectional view of an opening of a concavo-convex portion according to an embodiment of the present invention,
9 is a cross-sectional view showing a shape in which an end portion of a thin safety vault is wrapped around a top cap according to an embodiment of the present invention,
10 is a graph showing a result of evaluation of the adhesion of the CID assembly for a secondary battery according to the present invention,
11 is a graph showing a torque evaluation result for a CID assembly for a secondary battery according to the present invention.

Hereinafter, the present invention will be described in more detail.

While the present invention has been described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. . Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

FIG. 2 is a flowchart illustrating a method of manufacturing a CID assembly for a secondary battery according to an embodiment of the present invention, FIG. 3 is a cross-sectional view of a CID assembly mounted on a secondary battery according to an embodiment of the present invention, FIG. 4 is an enlarged view of FIG. 3, FIG. 5 is an enlarged view of FIG. 3, and FIG. 6 is a cross-sectional view illustrating a bottom of a recessed portion protruding from the hole of the adhesive insulating member according to an embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating the bottom of the recessed portion protruding from the hole of the adhesive insulating member according to the embodiment of the present invention. FIG. 7 is a cross- FIG. 8 is a cross-sectional view of an opening of a concave / convex portion according to an embodiment of the present invention. FIG. 9 is a cross-sectional view of a portion of a thin safety bolt according to an embodiment of the present invention. A cross-sectional view showing the shape of the wrapped tapkaep.

As shown in FIGS. 2 to 9, the method of manufacturing a CID assembly according to the present invention includes the steps of: covering one surface of an adhesive insulating member with a plate-shaped cap-down portion provided with a center portion as an opening for exposing a thin safety vent projection; A step of arranging a protruding portion of a thin safety vent having a protrusion at the center in the form of a metal plate on the other surface of the cap insulating material of the cap-down attaching member, And a step S3 of manufacturing a CID module by attaching the protrusion and the sub-plate by ultrasonic welding.

The protrusion 310 of the thin safety vent 300 is exposed at the central portion 340 of the cap down 330 and spaced apart from each other due to the interposition of the adhesive insulating member 350 The interposed width of the adhesive insulating member 350 is set to be wide so as to prevent mutual shorts even if the inner pressure of the adhesive insulating member 350 rises due to an abnormal operation and the bonding surface between the protruding portion 310 and the sub- The adhesive insulating member 350 may have a hollow portion H having a diameter equal to or larger than the diameter of the central portion 340 at the center thereof.

At least one notch 320 is provided concentrically around the protrusion 310 so that it is broken or deformed at abnormal high pressure so as to outgasse or break the contact surface between the protrusion and the subplate, The flow can be blocked.

In addition, the cap-down adhering material can prevent the adhesive insulating member 350 from sticking by applying heat to the cap down part 330, and can transmit uniform heat, can do.

When the thin safety vault 300, which is not the cap down 330, is first thermally fused, a thin safety vent assembly attached to the adhesive insulation member 350 is manufactured. Thereafter, A guiding jig is necessary for aligning to a fixed position and a small diameter should be located at the bottom and a large diameter should be located at the top, If the cap down portion is positioned at the lower portion and the thin safety vent assembly is positioned at the upper portion, there is a problem that heating is not possible from the upper portion.

That is, when heating is performed from the lower portion, there is a disadvantage that both the time for positioning and the time for pressing the guide jig are inconvenient.

On the other hand, if heating is performed at the upper portion, the process is advantageous because only the time for driving and contacting and pressing is lowered.

On the other hand, when the upper part and the lower part are simultaneously heated and adhered to each other, the lower part is overheated and overfused, which is very disadvantageous for maintaining the dimensional stability.

The adhesive insulating member 350 includes a thin safety vent attaching portion 351 attached to the thin safety vane, a cap down attaching portion 352 attached to the cap down portion, and a heat resistant portion 353 having heat resistance Since the attaching portions 351 and 352 require adhesive force, a modified polyolefin-based resin can be used. In the heat-resistant portion 353, due to abnormal operation inside the secondary battery, the internal pressure rises due to high temperature, It is preferable to use a material having heat resistance and being stable with respect to the electrolyte solution so as to prevent short-circuiting even if the adhesion surface of the sub-plate 360 and the sub-plate 360 is broken. For example, 353), a mixture of a homopolypropylene resin, a mixed resin of polypropylene and polybutylene terephthalate (PBT), a resin in which polypropylene and PBT are copolymerized, or a mixture of a modified propylene resin capable of crosslinking an electron beam and a crosslinking aid , The PBT mixing is preferably 10 to 50 wt% based on the total weight of polypropylene and PBT. If the blending amount is less than 10 wt%, the effect of securing a high melting temperature hardly occurs. On the other hand, if the blending amount exceeds 50 wt% Interfacial separation may occur.

Here, the modified polyolefin-based resin is a copolymer of ethylene or a monomer having a polar group with propylene and is preferably an ethylene / acrylic acid copolymer, an ethylene / methacrylic acid copolymer, an ethylene / ethyl acrylate, an ethylene-butyl acrylate copolymer, Vinyl acetate copolymer, ethylene / itaconic acid copolymer, ethylene / monomethyl maleate copolymer, ethylene / maleic acid copolymer, ethylene / acrylic acid / methyl methacrylate copolymer, ethylene / methacrylic acid / ethyl acrylate copolymer Acrylic acid / vinyl alcohol copolymer, ethylene / propylene / acrylic acid copolymer, ethylene / styrene / acrylic acid copolymer, ethylene / acrylic acid / vinyl acetate copolymer, ethylene / monomethyl maleate / ethyl acrylate copolymer, ethylene / methacrylic acid / vinyl acetate copolymer, , Ethylene / methacrylic acid / acrylonitrile copolymer, ethylene / fumaric acid / vinyl methyl ether Ethylene / vinyl chloride / acrylic acid copolymers, ethylene / chlorinated ethylene / methacrylic acid copolymers, ethylene / methacrylic acid sodium salt copolymers, ethylene / acrylic acid zinc salt copolymers, Ethylene / propylene copolymer, propylene / acrylic acid copolymer, propylene / methacrylic acid copolymer, propylene / ethyl acrylate, propylene-butyl acrylate copolymer, propylene-vinyl acetate copolymer Propylene / maleic acid copolymer, propylene / acrylic acid / methyl methacrylate copolymer, propylene / methacrylic acid / ethyl acrylate copolymer, propylene / maleic anhydride copolymer, propylene / Monomethyl maleate / ethyl acrylate copolymer, propylene / methacrylate copolymer Propylene / acrylic acid copolymer, propylene / styrene / acrylic acid copolymer, propylene / methacrylic acid / acrylonitrile copolymer, propylene / fumaric acid / acrylic acid copolymer, propylene / acrylic acid / vinyl alcohol copolymer, Vinyl acetate copolymer, propylene / vinyl chloride / acrylic acid copolymer, propylene / chlorinated ethylene / methacrylic acid copolymer, propylene / methacrylic acid sodium salt copolymer, propylene / acrylic acid copolymer, propylene / vinyl chloride / acrylic acid copolymer, Wherein the polyolefin resin is a substituted polyolefin resin in which a maleic anhydride is grafted, a high-density polyethylene (m-1) grafted with maleic anhydride, a polyolefin-based resin wherein the polyolefin resin is a polyolefin resin, a salt copolymer, a propylene / styrenesulfonic acid sodium salt copolymer, a styrene- HDPE), maleic anhydride grafted propylene (m-PP), anhydrous LES acid may be a grafted polyethylene / polypropylene copolymer (m-cpp), chlorinated polyethylene, polypropylene (CM), chlorosulfonated polyethylene or polypropylene (CSM).

The adhesive insulating member may be formed by previously co-extruding the thin-type safety vent attaching portion 351, the cap-down attaching portion 352 and the heat-resistant portion 353 or by forming the heat-resistant portion 353 on both sides thereof, Or may be provided as a laminating process by casting each of the films 351 and 352 or preparing them as a film.

The thin safety band attaching portion 351 or the cap down attaching portion 352 may be 5 to 40% of the thickness of the adhesive insulating member 350. If the adhesive insulating member is less than 5% The adhesive force of the attachment portions 351 and 352 may be weakened. On the contrary, when the adhesive strength exceeds 40%, the thickness of the heat-resistant portion may be thinned and the stability of the high-temperature dimension of the adhesive insulating member may be reduced.

The heat resistant portion 353 may contain calcium carbonate, silica, clay, titanium oxide, aluminum hydroxide, magnesium hydroxide, talc, glass fiber or carbon fiber to improve heat resistance and stability at high temperature.

The adhesive insulating member 350 may be disposed at the bottom of the concave portion S protruding from the hole H of the adhesive insulating member 350 and may be thermally fused. When heat is applied to the attaching portions 351 and 352 of the adhesive insulating member 350, The material of the attaching portions 351 and 352 may flow out into the exposed space and pin holes may be generated at the adhesive interface so that the outer surface O of the adhesive insulating member and the outer surface Can be thermally fused at the recessed bottom (S) having an outer wall portion (O ') abutting against the inner surface (I), and the inner wall portion (I') can be additionally provided according to design specifications and if necessary.

If the temperature is less than 160 ° C, it is difficult to sufficiently adhere to the bonding surface. On the contrary, if the temperature exceeds 250 ° C, thermal deformation may occur up to the heat-resistant portion, The stability can be reduced.

Meanwhile, the step S3 may further include a step of fixing the cap down part and a part of the facing sub plate by laser welding before or after the ultrasonic welding. At least one of the sub plates 360 So that the sub-plate 360 and the cap-down portion 330 are brought into contact with each other by laser welding and the contact between the sub-plate 360 and the thin safety vane 360. [ The lower safety bolt 300 is attached to the cap 300 by means of ultrasonic welding and attached to the cap down 330 for fixing, It is possible to prevent safety accidents due to occurrence of breakage or dropout at the time of occurrence of abnormally high temperature and pressure inside.

The surface of the thin safety vane 300 in the step S1 or S2 may be provided with a recessed portion 301 on a surface thereof in contact with the adhering insulating member, The concave and convex portions 301 and 331 may be formed by forging and the adhesive force of the concave and convex portions 301 and 331 to the adhesive insulating member 350 may be The adhesive force of the adhesive insulating member is weakened to prevent the interface from being separated. For this purpose, after the forging process in which the hexahedral space S is stamped with the punch, The opening S 'of the hexahedral space is narrowed so that the opening S' is smaller than the bottom surface width S '' of the concave portion.

In another embodiment of such concave and convex portions 301 and 331, the roughness of the surface is secured by using a wet or dry etching treatment or a plasma treatment for increasing the target of the adhesion interface to improve the adhesion / adhesion force Alternatively, the electrolytic resistance can be secured in addition to the adhesive force through the chromate treatment. Here, the wet or dry etching treatment, the plasma treatment, and the chromate treatment can be performed in advance by using a known method, and thus a detailed description thereof will be omitted.

Meanwhile, the CID assembly for a secondary battery manufactured by the above-described manufacturing method is provided with a gas discharge hole 412a, a cap cap 410a which is stacked with a top cap 410a forming a protruding terminal, A secondary battery can be constructed by including the conventional electrode assembly 110a, the electrolyte solution 111a and the lead tab 300a by being attached to the upper beading portion 210a of the can 200a, An adhesive insulating member is interposed and thermally fused between the thin safety bolt described above and a plate-shaped cap-down portion provided with a central portion serving as an opening for exposing the thin safety vent projection, and the protruding portion and the sub- May be a CID assembly for a secondary battery attached by welding.

Further, the PTC unit may further include a PTC unit between the top cap 410a and the thin safety vane 300. When the temperature of the secondary battery rises, the resistance of the PTC unit increases to trap the current of the secondary battery. It is possible to dispense with the safety feature that the protruding portion 310 and the sub-plate 360 and the attachment surface are broken by the internal pressure when the abnormal high temperature is generated.

In addition, the end portion 300 'of the thin safety vault 300 may be formed to surround the top cap 410a to improve the durability. In addition, the end portion 300' 410a. Alternatively, the upper end of the upper beading portion 210a may be bent and wrapped around the CID assembly so as to surround the CID assembly.

In addition, at least one second gas discharge hole (not shown) may be provided around the central portion 340 to smooth out the gas when the internal pressure rises.

Example

(Having a thickness of 30 mu m and a maleic anhydride grafted polypropylene film each of which has a thickness of 300 mu m and a thickness of 360 mu m) , A PBT with a weight ratio of 3: 7 and a polypropylene resin mixture) was placed on the recessed bottom portion protruding to the hole portion so as to face the cap down attachment portion of the adhesive insulating member on the cap down portion having a plate- And a protruding portion of a thin safety vent provided with a protrusion at the center is aligned with the central portion and thermally fused at 230 DEG C for 2 seconds to form a thin safety band attachment material, Were aligned on the protrusions, ultrasonic welding was performed, and four portions overlapping with the cap down portion were spot welded with a laser to manufacture a CID assembly for a secondary battery.

Comparative Example

In the prior art employing the "Z" bending structure, a safety vent or CID for internal pressure drop is closely adhered to the inside of the gasket for airtightness to be mounted on the upper beading portion of the can, and the bead end is bent to bend the CID assembly Assembled.

Experimental Example 1. Adhesion strength before and after the test

After impregnating the CID assembly according to the examples and the comparative examples for 1 month, 2 months and 3 months before impregnating the electrolyte solution, the thin safety bolt of each CID assembly was measured with a tensile strength measuring apparatus (SHIMPO, FGN -20B model) using a clamp, and a tension was applied by connecting a ring to the cap down portion to measure a change in tension applied until it was detached. The results are shown in FIG.

Referring to FIG. 10, it can be seen that the adhesion strength of the CID assembly according to the present invention remains excellent even after electrolyte solution impregnation.

Experimental Example 2: Electricity Before and after the test

Before impregnating the CID assembly according to the examples and the comparative example into the electrolyte solution, the thin safety bolt of each CID assembly was impregnated for 7 days from day 1, and then clamped on the stage of a rotational torque measuring device (model TOHNCHI, 503887T) And the rotation torque head is brought into close contact with the cap-down portion to measure a torque change applied until the cap-down portion is detached. The results are shown in Fig.

Referring to FIG. 11, it can be seen that the rotational torque of the CID assembly according to the present invention remains excellent even after electrolyte solution impregnation.

A thin safety vest 300, a protrusion 310,
The notch 320, the cap down portion 330,
A central portion 340, an adhesive insulating member 350,
Subplate 360

Claims (19)

delete delete A step S1 of preparing a cap-down adhering member by thermally fusing one side of the adhesive insulating member to a plate-shaped cap-down portion provided with a center portion as an opening for exposing the thin safety vent protrusion;
(S2) a step of aligning the projections of the thin safety vents having a protruding portion at the center in the form of a metal plate on the other surface of the cap insulating material of the cap-down attaching member, And
And attaching the protrusion and the sub-plate by ultrasonic welding to manufacture a CID module,
The surface of the cap-down portion or the thin safety vent in the step S1 or S2 is in contact with the adhesive insulating member,
Wherein the adhesive insulating member has a hollow portion having a diameter equal to or greater than the diameter of the center portion and disposed on the bottom of the recess portion protruding from the hole portion to be thermally fused.
The method of claim 3,
Wherein the step S1 or the step S2 is performed by a cap-down part or a thin safety bolt.
5. The method of claim 4,
Wherein the temperature at the time of the heat fusion is 160 to 250 ° C.
The method of claim 3,
Wherein the adhesive insulating member comprises a thin safety vault attachment portion attached to the thin safety vane, a cap down attachment portion attached to the cap down portion, and a heat resistant portion having heat resistance.
The method according to claim 6,
Wherein the thickness of the thin safety vest attaching portion or the cap down attaching portion is 8 to 40% of the thickness of the adhesive insulating member.
The method according to claim 6,
Wherein the thin safety vent attaching portion and the cap down attaching portion are modified polyolefin resin.
9. The method of claim 8,
The modified polyolefin-based resin is a copolymer of ethylene or a monomer having a polar group with propylene, and is preferably an ethylene / acrylic acid copolymer, an ethylene / methacrylic acid copolymer, an ethylene / ethyl acrylate, an ethylene-butyl acrylate copolymer, Ethylene / maleic acid copolymers, ethylene / acrylic acid / methyl methacrylate copolymers, ethylene / methacrylic acid / ethyl acrylate copolymers, ethylene / Ethylene / acrylic acid / vinyl alcohol copolymer, ethylene / propylene / acrylic acid copolymer, ethylene / styrene / acrylic acid copolymer, ethylene / acrylic acid / vinyl acetate copolymer, ethylene / acrylic acid / vinyl acetate copolymer, ethylene / monomethyl maleate / ethyl acrylate copolymer, ethylene / methacrylic acid / vinyl acetate copolymer, / Methacrylic acid / acrylonitrile copolymer, ethylene / fumaric acid / vinyl methyl ether copolymer, Ethylene / vinyl chloride / acrylic acid copolymer, ethylene / chlorinated ethylene / methacrylic acid copolymer, ethylene / methacrylic acid sodium salt copolymer, ethylene / acrylic acid zinc salt copolymer, ethylene / Propylene copolymer, a propylene / acrylic acid copolymer, a propylene / methacrylic acid copolymer, a propylene / ethyl acrylate, a propylene / butyl acrylate copolymer, a propylene / vinyl acetate copolymer, Propylene / maleic acid copolymer, propylene / acrylic acid / methyl methacrylate copolymer, propylene / methacrylic acid / ethyl acrylate copolymer, propylene / monomethyl maleate copolymer, propylene / Maleate / ethyl acrylate copolymer, propylene / methacrylic acid / vinyl Acrylic acid / vinyl alcohol copolymer, propylene / propylene / acrylic acid copolymer, propylene / styrene / acrylic acid copolymer, propylene / methacrylic acid / acrylonitrile copolymer, propylene / fumaric acid / vinyl methyl ether A propylene / vinyl chloride / acrylic acid copolymer, a propylene / chlorinated ethylene / methacrylic acid copolymer, a propylene / methacrylic acid sodium salt copolymer, a propylene / acrylic acid zinc salt copolymer (M-HDPE) in which maleic anhydride is grafted, a high-density polyethylene (m-HDPE) obtained by grafting maleic anhydride, a polyolefin-based resin such as a polypropylene resin, a propylene / styrene sulfonic acid sodium salt copolymer, a styrene- Propylene (m-PP) in which maleic anhydride grafted, maleic anhydride Wherein the grafted polyethylene / propylene copolymer (m-cpp), chlorinated polyethylene, polypropylene (CM), chlorosulfonated polyethylene or polypropylene (CSM) is used.
The method according to claim 6,
Wherein the heat-resistant portion includes a mixture of a homopolypropylene resin, a mixed resin of polypropylene and PBT, a resin in which polypropylene and PBT are copolymerized, or a modified propylene resin capable of crosslinking an electron beam, and a crosslinking assistant. Way.
11. The method of claim 10,
Wherein the use of the PBT is 10 to 50 wt% based on the total weight of polypropylene and PBT.
The method according to claim 6,
Wherein the heat-resistant portion includes calcium carbonate, silica, clay, titanium oxide, aluminum hydroxide, magnesium hydroxide, talc, glass fiber or carbon fiber.
The method of claim 3,
Further comprising the step of securing the cap down part and a part of the facing sub plate by laser welding before or after ultrasonic welding in step S3.
delete The method of claim 3,
Wherein the concavo-convex part is stamped to a hexagonal space, and after the forging process, the adjacent part is stamped secondarily to narrow the entrance part of the hexahedron space.
The method of claim 3,
Wherein the surface of the cap down portion or the thin safety vent in the step S1 or S2 is in contact with the adhesive insulating member is surface-processed by an etching treatment, a plasma treatment or a chromate treatment in advance .
The method of claim 3,
Wherein the end of the thin safety bolt is formed to wrap around the top cap.
A CID assembly for a secondary battery, which is manufactured by the method of any one of claims 3 to 13 or 15 to 17.
Which is produced by the production method of any one of claims 3 to 13 or 15 to 17,
An insulating insulating member is interposed between the thin safety vent and a cap-down portion having a central portion which is an opening for exposing the thin safety vent protrusion, and the protrusion and the sub-plate are attached by ultrasonic welding CID assembly for secondary battery.

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