WO2019164369A1 - Gasket anticorrosive, secondary battery gasket comprising same, and secondary battery comprising secondary battery gasket - Google Patents

Abstract

The present invention relates to: a gasket anticorrosive, which comprises an anticorrosive material and a polymer resin, wherein the polymer resin comprises a polyethylene and/or a copolymer, which comprises two or more derived units selected from the group consisting of an ethylene-derived unit, a propylene-derived unit, a butylene terephthalate-derived unit, an ethylene terephthalate-derived unit and a methyl acrylate-derived unit, and the anticorrosive material comprises a compound of the following formula 1; a secondary battery gasket comprising same; and a secondary battery. [Formula 1] (A)_m-R In formula 1, R is any one of a C5-C20 saturated or unsaturated aliphatic hydrocarbon group and a C6-C18 aromatic hydrocarbon group, A is a functional group comprising at least any one of an oxygen atom, a nitrogen atom and a fluorine atom, the functional group is substituted at the hydrogen atom position of R, and m is 1-3.

Description

Anti-corrosive agent for gasket, Secondary battery gasket comprising same, Secondary battery comprising gasket for secondary battery

Citation with Related Applications

This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0022064, filed February 23, 2018, and all content disclosed in the literature of that Korean Patent Application is incorporated as part of this specification.

Technical Field

The present invention relates to a secondary battery comprising a rust inhibitor for a gasket, a secondary battery gasket comprising the same, and a secondary battery gasket.

In general, a secondary battery means a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and is widely used for a power source of an electronic device such as a mobile phone, a notebook computer, a camcorder, or an electric vehicle. In particular, the lithium secondary battery has an operating voltage of 3.6 V, and has a capacity of about three times that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for electronic equipment, and has a high energy density per unit weight. 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. In addition, 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 an anode, a separator, and an anode are sequentially disposed, and an exterior member that seals and houses the electrode assembly together with the electrolyte solution. In particular, the packaging material has a can formed with an open end and a cap assembly sealingly coupled to the open end of the can.

In general, a gasket is interposed between the can and the cap assembly to seal the battery. As the gasket of the battery, polymer resin layers such as polypropylene have been used. However, there is a problem that rust occurs in a crimping part of a battery, for example, a trimming part in which Fe is exposed in a high temperature and high humidity atmosphere, and there is a need for improvement.

One problem to be solved by the present invention is to minimize the occurrence of rust in the crimping part of the battery in a high temperature, high humidity atmosphere, the anti-corrosive material for the gasket that can improve the sealing properties of the gasket, a secondary battery gasket comprising the same, and To provide a secondary battery.

According to an embodiment of the present invention, an antirust material and a polymer resin are included, and the polymer resin is polyethylene; And a copolymer comprising at least two derived units selected from the group consisting of ethylene derived units, propylene derived units, butylene terephthalate derived units, ethylene terephthalate derived units, and methyl acrylate derived units. The rust preventive substance is provided with a rust preventive agent for a gasket comprising a compound of the following Formula 1.

[Equation 1]

In Formula 1,

R is any one of a saturated or unsaturated aliphatic hydrocarbon group having 5 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 18 carbon atoms,

A is a functional group containing at least one of an oxygen atom, a nitrogen atom, and a fluorine atom, wherein the functional group is substituted at the hydrogen atom site of R;

M is 1 to 3.

According to another embodiment of the present invention, the gasket anti-rust agent; And there is provided a gasket for a secondary battery comprising a base resin.

According to another embodiment of the present invention, an electrode assembly including an anode and a cathode; A can including a top opening; A cap assembly formed on an upper circumferential surface of the can and coupled to the can by a crimping portion formed by bending a portion of the upper opening inwardly; The secondary battery gasket is provided, and the secondary battery gasket is provided with a secondary battery interposed between the can and the cap assembly.

The anti-corrosive agent for the gasket according to the embodiment of the present invention includes a specific anti-corrosive material, and the anti-corrosive material is vaporized to be adsorbed to the exposed portion of Fe in the crimping unit, especially the upper opening of the can, so that Fe is in direct contact with water and oxygen Can be prevented. Accordingly, it is possible to minimize the occurrence of rust in the crimping portion of the battery in a high temperature, high humidity atmosphere. In addition, since the specific rust-preventing material is dispersed in a small size at the level of omstrong and is present in the gasket, the voids generated in the gasket during vaporization are formed to a negligible level. Therefore, the sealing property of the gasket can be maintained when using the rust inhibitor for the gasket of the present invention as compared with the case of using the conventional rust preventing materials dispersed in the micro (μm) level and present in the gasket.

1 is a cross-sectional view showing one side of a secondary battery in which a gasket for a secondary battery including a gasket rust inhibitor according to an embodiment of the present invention is introduced.

2 is a cross-sectional view illustrating a secondary battery in which a gasket for a secondary battery including a gasket rust inhibitor according to an embodiment of the present invention is introduced.

3 is a cross-sectional view illustrating a secondary battery in which a gasket for a secondary battery including a gasket rust inhibitor according to another embodiment of the present invention is introduced.

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

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.

The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

As used herein, the terms "comprise", "comprise" or "have" are intended to indicate that there is a feature, number, step, component, or combination thereof, that is, one or more other features, It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

Anticorrosive for gaskets according to an embodiment of the present invention includes an antirust material and a polymer resin, the polymer resin is polyethylene; And a copolymer comprising at least two derived units selected from the group consisting of ethylene derived units, propylene derived units, butylene terephthalate derived units, ethylene terephthalate derived units, and methyl acrylate derived units. The rust preventive substance includes a compound represented by the following Formula 1.

[Equation 1]

In Formula 1,

R is any one of a saturated or unsaturated aliphatic hydrocarbon group having 5 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 18 carbon atoms,

A is a functional group containing at least one of an oxygen atom, a nitrogen atom, and a fluorine atom, wherein the functional group is substituted at the hydrogen atom site of R;

M is 1 to 3.

The gasket rust inhibitor is a rust inhibitor included in a gasket, specifically, the gasket is a gasket used for a battery, and more specifically, the battery may be a secondary battery.

The gasket rust inhibitor may be a vaporizable rust inhibitor (VCI; Volatile Corrosion Inbibitor). The gasket rust preventive agent may be vaporized and adsorbed to a trimming part in which Fe is exposed at a crimping part, particularly at the top opening of the can, to prevent Fe from directly contacting water and oxygen.

The gasket rust inhibitor may be present dispersed in a molecular unit in the base resin of the gasket.

The rust preventive material may include a compound of Formula 1 below.

[Equation 1]

In Formula 1,

R is any one of a saturated or unsaturated aliphatic hydrocarbon group having 5 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 18 carbon atoms,

A is a functional group containing at least one of an oxygen atom, a nitrogen atom, and a fluorine atom, wherein the functional group is substituted at the hydrogen atom site of R;

M is 1 to 3.

The functional group A can be electrically and / or chemically adsorbed to the crimped part, in particular the exposed part of Fe at the top opening of the can, in particular the trimming part. That is, when the gasket rust inhibitor is vaporized, the rust preventive material may be disposed in a portion where Fe is exposed by the presence of the functional group. In addition, R except for the functional group among the rust preventive materials may form a hydrophobic layer to prevent Fe from directly contacting with moisture and oxygen. Through this, it is possible to minimize the occurrence of rust in the crimping portion of the battery even under high temperature, high humidity conditions.

Specifically, the rust preventing material may include at least one of the compound of Formula 1-1 and the compound of Formula 1-2.

Equation 1-1

Formula 1-2

R ₁ is selected from the group consisting of a linear alkyl group having 8 to 20 carbon atoms, a branched alkyl group having 8 to 20 carbon atoms, an alkenyl group having 8 to 20 carbon atoms, alkynyl group having 8 to 20 carbon atoms, and an aryl group having 8 to 18 carbon atoms. Which one,

R ₂ is a linear alkylene group having 8 to 20 carbon atoms, a branched alkylene group having 8 to 20 carbon atoms, an alkenylene group having 8 to 20 carbon atoms, an alkenylene group having 8 to 20 carbon atoms, and an arylene group having 8 to 18 carbon atoms. Any one selected from the group consisting of,

A ₁ and A ₂ are each independently any one selected from the group consisting of a carboxyl group, an amino group, a nitro group, a hydroxyl group, and a fluorine group.

When using the compounds according to Equations 1-1 and 1-2 above, A ₁ and / or A ₂ are electrically and / or chemically adsorbed to the crimping section, especially the trimming section where Fe is exposed at the top opening of the can. , R ₁ and / or R ₂ may form a hydrophobic layer to prevent Fe from directly contacting water and oxygen. Through this, it is possible to minimize the occurrence of rust in the crimping portion of the battery even under high temperature, high humidity conditions.

On the other hand, the gasket for secondary batteries of the present invention is manufactured by the method of injecting the base resin and the gasket rust inhibitor at a high temperature. The injection temperature of the base resin is a high temperature, but when using the compounds according to the formula 1-1 and formula 1-2 as the rust preventive material, the rust preventive material may not collapse even at the injection temperature. Therefore, the antirust effect by the antirust material can be maintained even in the finally manufactured gasket.

More specifically, the rust preventing material may include at least one of the compound of Formula 1-3 and the compound of Formula 1-4.

[Equation 1-3]

[Equation 1-4]

In Equation 1-3 and Equation 1-4,

A ₁ is the same as A ₁ of Formulas 1-1 and 1-2,

P is 4 to 10,

Q may be 3 to 6.

The rust preventive materials of Equation 1-3 and Equation 1-4 may exhibit the rust preventive effect described above, and do not deform the structure at the injection temperature of the base resin. In addition, it is possible to minimize the deterioration of the sealing properties of the gasket for the following reasons.

Conventionally, materials such as NaNO ₂ and NaNO ₃ , which are used as rust preventive materials, are dispersed and present in a large unit at a micro (μm) level in the resin, so that when the materials are vaporized, large voids are generated in the resin constituting the gasket. . As a result, external moisture and oxygen can penetrate into the battery through the pores, and thus the sealing property of the gasket may be degraded, thereby degrading battery performance. On the other hand, since the rust preventive materials of Equation 1-3 and Equation 1-4 are dispersed in a small size at the Omstrong level and present in the gasket, the voids generated in the gasket during vaporization are formed to a negligible level. . Therefore, the fall of the sealing characteristic which a gasket has can be minimized.

More specifically, the rust preventing material may include at least one selected from the group consisting of decanoic acid, lauric acid, and myristic acid. When using the rust preventive material, it can exhibit the above-described rust preventive effect, the structure is not deformed at the injection temperature of the base resin. In addition, the deterioration of the sealing property of the gasket can be minimized.

The polymer resin may be mixed with the rust preventive material to serve to disperse the rust preventive material in the base resin. The material constituting the polymer resin may be different from the material constituting the base resin.

The polymer resin is polyethylene (PE); And ethylene derived units, propylene derived units, butylene terephthalate derived units, ethylene terephthalate derived units, and methyl acrylate derived units. Copolymers comprising two or more derived units; It may include at least one of. Specifically, the above materials may be mixed and used. The polymer resin is preferable in that it is easy to mix with the rust-preventing material and easy to mix with the base resin. In addition, the antirust property of the gasket can be further improved. Specifically, the polymer resin may be a copolymer including an ethylene-derived unit and a methyl acrylate-derived unit in consideration of a manufacturing process and mixing with the base resin.

The weight ratio of the polymer resin and the rust preventing material may be 99: 1 to 80:20, specifically 99: 1 to 85:15, and more specifically 99: 1 to 90:10. If the above range is satisfied, the rust preventive effect may be more effective.

The rust preventive agent may be in the form of pellets. Specifically, the rust preventive agent may be in the form of pellets formed through the pelletization process after mixing the polymer resin and the rust preventive material. Through this, the rust preventive agent can be smoothly dispersed in the base resin. If only the rust preventing material is mixed with the base resin in a non-pellet form (i.e., without a polymer resin), the rust preventing function is sharply degraded because the rust preventing material is not smoothly dispersed in the base resin.

A secondary battery gasket according to another embodiment of the present invention is a gasket rust inhibitor; And a base resin. The gasket rust preventive agent is the same as the gasket rust preventive agent of the above-mentioned embodiment, and therefore description is omitted.

The base resin may include at least one selected from the group consisting of polypropylene, polybutylene terephthalate and polyphenylene sulfide. The base resin is suitable for sealing batteries, especially cylindrical batteries, and is preferable in view of excellent heat resistance. Specifically, the base resin may be polybutylene terephthalate. Since the polybutylene terephthalate has high heat resistance and low oxygen and moisture permeability, it is more preferable as the base resin of the gasket.

Furthermore, in the case where the base resin is polybutylene terephthalate, when the antirust material included in the anticorrosive for the gasket is used, there are advantages as follows. In the case of conventionally used rust-preventing materials such as NaNO ₂ and NaNO ₃ , the polybutylene terephthalate is degraded by weakening the C═O bonds contained in the polybutylene terephthalate, thereby deteriorating the physical properties of the gasket. Specifically, the ductility of the polybutylene terephthalate is lowered, and cracks are likely to occur in the gasket due to external force. On the other hand, the rust preventive material of the present invention can minimize the weakening of the C═O bonds contained in the polybutylene terephthalate or have no influence on the bonds, so that the physical properties of the gasket can be maintained. In addition, the polybutylene terephthalate has a high injection temperature of 280 ℃, the anti-rust material of the present invention injected with the polybutylene terephthalate does not collapse the structure even at the high temperature, so that the final gasket Antirust properties can be maintained.

The rust preventive agent may be included in the secondary battery gasket 2 wt% to 15 wt%, specifically 2 wt% to 10 wt%, and more specifically 5 wt% to 10 wt%. When the above range is satisfied, the above-described antirust property can be further improved.

A secondary battery according to another embodiment of the present invention comprises an electrode assembly including a positive electrode and a negative electrode; A can including a top opening; A cap assembly formed on an upper circumferential surface of the can and coupled to the can by a crimping portion formed by bending a portion of the upper opening inwardly; A secondary battery gasket may be included, and the secondary battery gasket may be interposed between the can and the cap assembly. Here, since the gasket for secondary batteries is the same as the gasket for secondary batteries of the above-mentioned embodiment, description is abbreviate | omitted.

The secondary battery may have a cylindrical shape, a square shape, or the like, and specifically, may have a cylindrical shape. When the secondary battery is cylindrical, the top opening of the can may also be circular.

1 and 2, the secondary battery 100 includes a can 20 for accommodating the electrode assembly 10 together with an electrolyte, a cap assembly 30 sealingly coupled to an open end of the can 20, A gasket 40 interposed between the cylindrical can 20 and the cap assembly 30. The gasket 40 is the same as the gasket for the secondary battery of the above-described embodiment.

The material of the can 20 is not particularly limited, and may be formed of at least one of stainless steel, steel (Fe), aluminum, or an equivalent thereof. The can 20 uses a metal component because it has to be conductive, and this metal component may be vulnerable to corrosion due to moisture contact from the outside. In this regard, the can 20 may include a layer made of Fe and a layer made of Ni which prevents the layer made of Fe from corrosion.

The can 20 may be cylindrical, rectangular, or the like, and specifically, may be cylindrical. The open end of the can 20 may include a trimming portion 21a, and the trimming portion 21a may expose the Fe component of the can. Specifically, in the final product state, the trimming portion 21a can be seen to be included in the crimping portion 21.

The cap assembly 30 may include a top cap that seals the open end of the can 20, and a safety vent 36. One surface of the safety vent 36 may be in contact with all of the side surface, the upper surface and the lower surface of the top cap, and the other surface may be bent and disposed to contact the inner surface of the gasket 40. The safety vent 36 may be electrically connected to the electrode assembly 10. When the battery having the cap assembly 30 is used as a power source of a power tool such as a power drill, the battery may provide a high output instantaneously and may be stable against external physical shocks such as vibration and dropping.

In particular, the cap assembly 30 having a shape in which the safety vent 36 is bent to surround the top cap may have a contact surface between the safety vent 36 and the top cap to form at least one connection part. Is formed. The term "welding" used in the present invention is used as a concept that includes not only welding in a literal sense such as laser welding, ultrasonic welding, resistance welding, but also a fastening method such as soldering. Welding may be performed in the process of assembling the cap assembly 30 itself, or may be performed even when the cap assembly 30 is installed in the can 20.

The safety vent 36 serves to cut off a current or exhaust gas when the pressure inside the battery rises, and is preferably made of metal. The thickness of the safety vent 36 may vary depending on the material, structure, and the like, and the thickness of the safety vent 36 is not particularly limited as long as the safety vent 36 may burst while generating a high pressure inside the battery, and may be, for example, 0.2 to 0.6 mm. .

The thickness of the top cap portion in contact with the safety vent 36 is not particularly limited as long as it can protect various components of the cap assembly 30 from pressure applied from the outside, for example, 0.3 To 0.5 mm. If the thickness of the top cap is too thin, it is difficult to exert mechanical rigidity. On the contrary, if the thickness of the top cap is too thick, the capacity of the battery may be reduced by increasing the size and weight.

The gasket 40 may be formed in a cylindrical shape, each end of which is open at both ends as a whole, may vary depending on the shape of the top opening of the can, specifically, may be a cylindrical shape. One side end facing the inner surface of the can 20 is preferably a structure bent at an angle, specifically at a right angle toward the center so as to be placed in the opening of the can 20, that is, the crimping portion 21. The other end of the gasket 40 is first straight and is oriented in the axial direction of the gasket 40, and is bent at an angle toward the center during the pressing process with the can 20 so that the inner and outer circumferential surfaces of the gasket 40 are cap assemblies ( The top cap of 30 and the inner side of the can 20 are folded in close contact.

The crimping portion 21 is formed at the top of the can so that the cap assembly 30 can be mounted at the open end of the can. More specifically, the crimping portion 21 forms an indentation inward by beading the upper end of the can 20, mounts the gasket 40 at the open end, and top cap, PTC element, safety vent 36. It is formed by inserting the outer circumferential surface of and then bending the upper end of the can inward. As a result, the gasket 40 positioned on the inner side of the crimping portion 21 is enclosed, and the cap assembly 30 is mounted by performing a crimping and pressing process.

The crimping portion 21 has a structure in which an end portion is bent inward so that the cap assembly 30 can be stably mounted on an open upper end of the can 20 in a state where the gasket 40 is interposed therebetween. The side wall of the crimping portion 21 is formed perpendicular to the side of the battery.

The electrode assembly 10 may include a positive electrode and a negative electrode. Referring to FIG. 2, the electrode assembly 10 is interposed between two electrode plates 11 having different polarities and having a wide plate shape in a roll form, and the electrode plates 11 to mutually insulate the electrode plates 11. Or a separator 12 disposed on the left side or the right side of any one electrode plate 11. In this case, the electrode plates 11 spaced apart from each other by the separator 12 may be a cathode and an anode. The electrode assembly 10 is preferably a structure wound in a so-called 'Jelly Roll' shape. Of course, a positive electrode plate and a negative electrode plate of a predetermined standard may be stacked in the separator 12.

An electrode assembly 10 and an electrolyte (not shown) are accommodated in the inner space of the can 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.

Meanwhile, a center pin (not shown) may be inserted into the center of the can 20 to prevent the electrode assembly 10 wound in a jelly roll form from being loosened and to serve as a gas passageway inside the secondary battery 100. It may be. An upper portion of the can 20, that is, an upper portion of the upper portion of the electrode assembly 10 may be provided with a beading portion 24 which is bent from outside to the inside to prevent the up and down flow of the electrode assembly 10.

Cylindrical battery 100 according to an embodiment of the present invention may further include an auxiliary gasket 42. The auxiliary gasket 42 is configured to surround the outer circumferential surface of the current blocking device 38 as a gasket for the current blocking device 38. In particular, the auxiliary gasket 42 contacts the upper and side portions at the outer circumferential surface of the current blocking element 38 to support the upper and side portions of the current blocking element 38. The auxiliary gasket 42 serves to electrically insulate the current blocking device 38 and the safety vent 36 from each other, except for a portion where the protruding portion of the safety vent 36 contacts with the current blocking element 38. Do it.

3 illustrates a battery 100 according to another embodiment of the present invention. The same components as those described in FIG. 2 are the same members having the same functions. Referring to FIG. 3, the cap assembly 30 may include a top cap disposed to seal the open end of the can 20 and contact the protrusion of the gasket 40, and a PTC element disposed to contact the top cap. Positive temperature coefficient 34 and one surface may include a safety vent 36 disposed in contact with the PTC element 34 and with a portion of the other surface in contact with the gasket 40.

The PTC element 34 serves to block the current by greatly increasing the battery resistance when the temperature inside the battery increases, and the thickness of the PTC element 34 may also vary depending on the material and structure, for example, 0.2 mm. To 0.4 mm. When the thickness of the PTC element 34 is greater than 0.4 mm, the internal resistance may increase, and the size of the battery may be increased to reduce the capacity of the battery compared to the same standard. On the contrary, when the thickness of the PTC element 34 is thinner than 0.2 mm, it is difficult to exert a desired current interruption effect at a high temperature and can be destroyed even by a weak external impact. Accordingly, the thickness of the PTC element 34 may be appropriately determined within the above thickness range in consideration of these points in combination.

The thickness of the top cap portion in contact with the PTC element 34 is not particularly limited as long as it can protect various components of the cap assembly 30 from the pressure applied from the outside, for example, 0.3 to 0.5 May be mm. If the thickness of the top cap is too thin, it is difficult to exert mechanical rigidity. On the contrary, if the thickness of the top cap is too thick, the capacity of the battery may be reduced by increasing the size and weight.

The secondary battery including the top cap, the PTC element 34, and the cap assembly 30 having the safety vent may be used as a power source for a mobile phone or a notebook, which stably provides a constant output.

The present invention can provide a battery pack comprising a plurality of lithium secondary batteries prepared by the above embodiment by electrically connecting, the battery pack is a power tool (Electric Tool, Electric Vehicle, EV), hybrid Medium to large in one or more devices selected from the group consisting of electric vehicles, electric trucks, electric commercial vehicles, or power storage systems, including electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). The battery pack may be used as a device power source.

Hereinafter, the present invention is further described through Examples and Comparative Examples, but the following Examples are provided to illustrate the present invention, but the scope of the present invention is not limited thereto.

Example 1 Fabrication of Cells

(1) manufacture of gaskets

A copolymer comprising an ethylene-derived unit and a methyl acrylate-derived unit and lauric acid were mixed at 100 ° C. in a weight ratio of 95: 5, and then pelletized to prepare a rust inhibitor in the form of a pellet. 240 g of the rust preventive agent and 3,000 g of polybutylene terephthalate were mixed and then injected at a temperature of 280 ° C. to prepare a gasket.

(2) production of batteries

The can consisted of an inner layer of Fe and a Ni layer disposed on both sides of the inner layer. After placing a gasket in the top opening of the can, the cap assembly was placed in contact with the inner circumferential surface of the gasket, and then a crimping portion was formed. Through this, a battery including the gasket was manufactured.

Example 2: Preparation of Cells

(1) manufacture of gaskets

A copolymer comprising an ethylene derived unit and a methyl acrylate derived unit and lauric acid were mixed at 100 ° C. in a weight ratio of 95: 5, and then pelletized to prepare a rust preventive agent in pellet form. 150 g of the rust inhibitor and 3,000 g of polybutylene terephthalate were mixed, and then injected at a temperature of 280 ° C. to prepare a gasket.

(2) production of batteries

The can consisted of an inner layer of Fe and a Ni layer disposed on both sides of the inner layer. After placing a gasket in the top opening of the can, the cap assembly was placed in contact with the inner circumferential surface of the gasket, and then a crimping portion was formed. Through this, a battery including the gasket was manufactured.

Example 3: Fabrication of Batteries

(1) manufacture of gaskets

A copolymer comprising ethylene derived units and methyl acrylate derived units and decanoic acid were mixed at 100 ° C. in a weight ratio of 95: 5, and then pelletized to prepare a rust preventive agent in pellet form. 240 g of the rust preventive agent and 3,000 g of polybutylene terephthalate were mixed and then injected at a temperature of 280 ° C. to prepare a gasket.

(2) production of batteries

The can consisted of an inner layer of Fe and a Ni layer disposed on both sides of the inner layer. After placing a gasket in the top opening of the can, the cap assembly was placed in contact with the inner circumferential surface of the gasket, and then a crimping portion was formed. Through this, a battery including the gasket was manufactured.

Comparative Example 1: Preparation of Battery

(1) manufacture of gaskets

Polybutylene terephthalate was injected at 280 ° C to prepare a gasket.

(2) production of batteries

The can consisted of an inner layer of Fe and a Ni layer disposed on both sides of the inner layer. After placing a gasket in the top opening of the can, the cap assembly was placed in contact with the inner circumferential surface of the gasket, and then a crimping portion was formed. Through this, a battery including the gasket was manufactured.

Comparative Example 2: Preparation of Battery

(1) manufacture of gaskets

Polyethylene and NaNO ₂ were mixed at 140 ° C. in a weight ratio of 70:30, and then pelletized to prepare a rust preventive agent in pellet form. 240 g of the rust preventive agent and 3,000 g of polybutylene terephthalate were mixed and then injected at a temperature of 280 ° C. to prepare a gasket.

(2) production of batteries

The can consisted of an inner layer of Fe and a Ni layer disposed on both sides of the inner layer. After placing a gasket in the top opening of the can, the cap assembly was placed in contact with the inner circumferential surface of the gasket, and then a crimping portion was formed. Through this, a battery including the gasket was manufactured.

Comparative Example 3: Preparation of Battery

(1) manufacture of gaskets

12 g of lauric acid and 3,228 g of polybutylene terephthalate were mixed and then injected at a temperature of 280 ° C to prepare a gasket.

(2) production of batteries

The can consisted of an inner layer of Fe and a Ni layer disposed on both sides of the inner layer. After placing a gasket in the top opening of the can, the cap assembly was placed in contact with the inner circumferential surface of the gasket, and then a crimping portion was formed. Through this, a battery including the gasket was manufactured.

Experimental Example 1: Evaluation of Antirust Function

Each of the batteries of Examples 1 to 3 and Comparative Examples 1 to 3 were stored for 2 weeks in an environment of 65 ° C. and 90% humidity, and then the antirust properties were evaluated and shown in Table 1 below.

Specifically, the percentage of the area where corrosion occurred based on the area of the trimming part of the upper outer circumferential surface of the can is expressed in%. Corrosion occurred at 3 points over 50%, 2 points over 10% and below 50%, 1 point below 10%, and 0 points without corrosion. After scoring the 30 cells in this way, the average value of the scores were converted to 10 out of 10 points (mean value x (10/3)) to evaluate the antirust function by the final score derived. On the other hand, the extent to which corrosion occurred was visually confirmed with a microscope.

	Antirust function evaluation score
Example 1	0.4
Example 2	1.1
Example 3	0.5
Comparative Example 1	9.7
Comparative Example 2	1.9
Comparative Example 3	4.9

Referring to Table 1, in the case of Examples 1 to 3 using the gasket rust inhibitor of the present invention, compared to Comparative Example 1 using the rust preventive agent and Comparative Example 2 using the conventional rust inhibitor including NaNO ₂ You can see that it is much higher. In addition, in the case of Comparative Example 3, since the rust preventive agent only contains the rust preventive substance and does not contain the polymer resin, it can be seen that the dispersion of the rust preventive substance is not smooth and the rust preventive function is reduced.

Experimental Example 2: Evaluation of Seal Function

Each of the batteries of Examples 1 to 3 and Comparative Examples 1 to 3 was stored at 72 ° C. at SOC 100% for 40 days. The weight of the battery before and after storage was evaluated and shown in Table 2 below. The weight change rate of Table 2 was calculated by the following formula.

Percent Change in Weight = [(Weight before Storage-Battery Weight after Storage) / Weight before Storage] × 100

	Battery weight before storage (g)	Battery weight after storage (g)	% Change in weight
Example 1	48.03	48.02	0.0208
Example 2	47.97	47.96	0.0208
Example 3	47.94	47.93	0.0208
Comparative Example 1	47.90	47.89	0.0209
Comparative Example 2	47.97	47.27	1.4592
Comparative Example 3	47.99	47.98	0.0208

Referring to Table 2, in the case of Example 1, despite the evaporation of the rust preventive material, since the voids in the gasket is not large, it can be confirmed that the sealing function can be effectively maintained as in Comparative Example 1 not containing the rust preventive material . On the other hand, in the case of Comparative Example 2 using NaNO ₂ as the rust-preventing material, it can be seen that a large number of large pores exist in the gasket, and the sealing function is greatly reduced.

Claims (8)

1. Antirust material and polymer resin,

   The polymer resin is polyethylene; And a copolymer comprising two or more derived units selected from the group consisting of ethylene derived units, propylene derived units, butylene terephthalate derived units, ethylene terephthalate derived units and methyl acrylate derived units; At least one of,

   The anti-corrosive material is a gasket rust inhibitor comprising a compound of the following formula 1:

   [Equation 1]

   

   In Formula 1,

   R is any one of a saturated or unsaturated aliphatic hydrocarbon group having 5 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 18 carbon atoms,

   A is a functional group containing at least one of an oxygen atom, a nitrogen atom, and a fluorine atom, wherein the functional group is substituted at the hydrogen atom site of R;

   M is 1 to 3.
2. The method according to claim 1,

   The anti-corrosive material is a gasket anti-corrosive agent comprising at least one of a compound of Formula 1-1 and a compound of Formula 1-2:

   Equation 1-1

   

   Formula 1-2

   

   R ₁ is selected from the group consisting of a linear alkyl group having 8 to 20 carbon atoms, a branched alkyl group having 8 to 20 carbon atoms, an alkenyl group having 8 to 20 carbon atoms, alkynyl group having 8 to 20 carbon atoms, and an aryl group having 8 to 18 carbon atoms. Which one,

   R ₂ is a linear alkylene group having 8 to 20 carbon atoms, a branched alkylene group having 8 to 20 carbon atoms, an alkenylene group having 8 to 20 carbon atoms, an alkenylene group having 8 to 20 carbon atoms, and an arylene group having 8 to 18 carbon atoms. Any one selected from the group consisting of,

   A ₁ and A ₂ are each independently any one selected from the group consisting of a carboxyl group, an amino group, a nitro group, a hydroxyl group, and a fluorine group.
3. The method according to claim 2,

   The anti-corrosive material is a gasket anti-corrosive agent comprising at least one of a compound of Formula 1-3 and a compound of Formula 1-4;

   [Equation 1-3]

   

   [Equation 1-4]

   

   In Equation 1-3 and Equation 1-4,

   P is 4 to 10,

   Q is 3 to 6;
4. The method according to claim 3,

   The rust preventive material is a rust preventive agent for a gasket comprising at least one selected from the group consisting of decanoic acid, lauric acid, and myristic acid.
5. The method according to claim 1,

   A weight ratio of the polymer resin and the rust preventing material is 99: 1 to 80:20 rust inhibitor for gaskets.
6. Anticorrosive for gaskets of at least one of claims 1 to 5; And

   A gasket for a secondary battery containing a base resin.
7. The method according to claim 6,

   The anti-corrosive agent is a gasket for secondary batteries contained in the secondary battery gasket 2% by weight to 15% by weight.
8. An electrode assembly comprising an anode and a cathode;

   A can including a top opening;

   A cap assembly formed on an upper circumferential surface of the can and coupled to the can by a crimping portion formed by bending a portion of the upper opening inwardly;

   Including a gasket for a secondary battery of claim 6,

   The secondary battery gasket is interposed between the can and the cap assembly.

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