KR100489016B1 - the Method of Sealing Covered Battery - Google Patents

Abstract

A cathode terminal and a cathode terminal are provided inside the case 1 serving as a cathode, and a jelly roll 2 composed of a cathode material, a cathode material, a membrane, and an insulating paper is inserted into the case 1, and fixed with a support cap 3. In the method of sealing by bonding the positive electrode cap (4), the gasket sealing portion and the safety edge portion of the combined positive electrode cap (4) and the welding portion of the positive electrode cap (4) and the case (1) and the electrolyte injection opening sealing portion By applying UV-curable resin on the surface and curing it by irradiating ultraviolet rays, it seals close to perfection to prevent leakage of electrolyte solution from the contacting area and at the same time, it is firmly bonded, and it is possible to mass-produce by shortening drying time in the production process. It is to provide a sealing method that can be.

Description

{The Method of Sealing Covered Battery}

The present invention relates to a sealing method for preventing leakage of a sealed battery, and more particularly, to a sealing method for preventing leakage of an electrolyte generated due to internal pressure generated by thermal and chemical actions of a lithium battery, which is a secondary battery. It is about.

In general, a lithium battery, which is a secondary battery, is capable of rapid charging due to an inflow reaction of lithium ions in which a charging reaction of a negative electrode is relatively fast, and is stable as a high voltage battery because it exists in a state of lithium ions (Li ⁺ ).

In addition, lithium batteries have the advantages of large charging capacity and miniaturization, and are widely used as a power source for portable devices such as mobile phones, notebook computers, and portable audio devices, and are classified into cylindrical lithium batteries and rectangular lithium batteries according to their shapes. Has been produced and used.

A rectangular lithium battery generally includes a case 1 and a positive electrode material 23, a negative electrode material 24, and a positive electrode material 23, which serve as a negative electrode while accommodating an electrolyte and an electrolyte as shown in FIGS. 1 and 2. It is withdrawn from the insulating paper 26 and the positive electrode material 23 to prevent the membrane 25 and the positive electrode material 23 and the negative electrode material 24 from passing through the ions between the negative electrode material 24 and the negative electrode material 24. And a jelly roll (2) formed by rolling an electrolyte having a plate-like structure composed of a cathode terminal (21) in contact with the anode (41) and a cathode terminal (22) drawn out from the cathode material and in contact with the case (1); To prevent the movement of the jelly roll 2 and to secure a space between the anode cap and to connect the through hole 31 and the anode terminal 21 for supplying the electrolyte to the jelly roll 2 to the anode 41. Amount having the support cap 3 and the anode 41 having the long hole 32, the electrolyte injection hole 42 and the explosion-proof side 43 It consists of a cap 4.

The positive electrode 41 formed on the positive electrode cap 4 is coupled to the positive electrode terminal 21 connected to the jelly roll 2 via an insulating material 44 for preventing current from spreading to the positive electrode cap. The positive electrode cap 4 is firmly coupled to the case 1 which finally forms the negative electrode.

When the separation occurs in the above coupling process, not only the electrolyte solution filled inside leaks to the outside, but also the problem that the anode cap 4 is separated from the case 1 due to internal pressure and decomposes. Will be raised.

In order to solve the above problems, conventionally, as can be seen from Japanese Patent Laid-Open No. 7-37561, the case of the case 1 to firmly couple the case 1 and the positive electrode cap 4 A technique of applying and bonding an adhesive on the inside of the top has been generally used, and as an adhesive for sealing, an anti-aging agent may be mixed with a rubber-based adhesive, or adhesive tape may be used. come.

In addition to rubber adhesives, silicone adhesives and resin adhesives may be used as adhesives. However, silicone adhesives have excellent thermal and chemical stability, but have been avoided because they increase the manufacturing cost of batteries at relatively high costs. When the discharged battery is in an over-discharge state due to its low stability and chemical stability, the temperature inside the battery rises, resulting in the resin decomposing and weakening of the bonding force.As the curing time of the adhesive is long, it is difficult to automate due to difficulty in automation. It became.

As another method, there is a method of welding the contact area between the case 1 and the anode cap 4 with a laser or the like, but in this case, the sealing by the laser is impossible to completely seal the electrolyte leakage to the outside. Problems have arisen, and in order to prevent this, a method of coating a contact portion between the welded case 1 and the anode cap 4 as an adhesive has been generally adopted.

However, when the contact part of the welded case 1 and the positive electrode cap 4 is treated with an adhesive, the solvent must be completely removed from the adhesive. Therefore, the production time is delayed in the production process due to the delay of drying time to remove the solvent. There was a problem.

In the present invention, when the case 1 and the positive electrode cap 4 of the lithium battery are combined, the seal is close to perfection and firmly secured to prevent leakage of the electrolyte from the contact portion between the case 1 and the positive electrode cap 4. It is intended to provide a sealing method that can be combined to make a mass production by shortening the drying time in the production process.

The present invention for solving the above problems is provided with a positive electrode terminal and a negative electrode terminal inside the case (1) acting as a negative electrode and sandwiching the jelly roll (2) consisting of a positive electrode material, a negative electrode material, a membrane and an insulating paper After fixing with the support cap (3), in the method of sealing by bonding the positive electrode cap (4), the gasket sealing portion and the safety edge of the combined positive electrode cap (4) and the positive electrode cap (4) and the case (1) It can be achieved by applying a UV-curable resin to the welding part and the sealing portion of the electrolyte injection hole, and sealing by irradiating with ultraviolet rays.

As the ultraviolet curable resin that can be used in the present invention, either one-component or two-component type may be used, and as this type of resin, monofunctional monomers are isobutyl acrylate, t-butyl acrylate and lauryl acrylate. , Alkyl acrylate, cetyl acrylate, stearyl acrylate, cyclohexyl acrylate, isobornyl acrylate, benzyl acrylate, 2-methoxy ethyl acrylate, 3-methoxy butyl acrylate, ethyl carbitol acrylate, Phenoxyethyl acrylate, tetrahydroprryl acrylate, phenoxy polyethylene glycol acrylate, methoxy tripropylene glycol acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-acryloyloxy Ethyl-2-hydroxypropylphthalate, 2-hydroxy-3-phenoxypropylacrylate, 2 -Acryloyloxyethylhydrogenphthalate, 2-acryloyloxypropylhydrogenphthalate, 2-acryloyloxypropylhexahydrogenphthalate, 2-acryloyloxypropyltetrahydrohydrogenphthalate, dimethylaminoethyl Acrylate, anhydrous erynoethyl methacrylate, trifluoroethyl acrylate, trifluoroethyl methacrylate, tetrafluoropropyl acrylate, tetrafluoropropyl methacrylate, hexafluoropropyl methacrylate, octafluoropentyl acrylate, Octafluoropentyl methacrylate, heptadecafluorodecyl acrylate, heptadecafluorodecyl methacrylate, tribromophenol 3 EO addition methacrylate, trimethylsiloxyethyl methacrylate, 1,4 as bifunctional monomer Butanediol diacrylate, 1, 6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, bisphenol A EO addition There are water diacrylate and glycerin methacrylate acrylate, and trimethylolpropane triacrylate, pentaerythritol triacrylate, trimetholpropane EO added triacrylate, glycerin PO added triacrylate, and trifunctional as polyfunctional monomers Stearolyloxyethyl phosphate, pentaerystirol tetraacrylate, and other resins include bisphenol A-diepoxyacrylic acid adduct, 2-isopropylthioxane, azobis (isobutylnitrile), benzoyl peroxide, di- tert-butylperoxide, 2-ethylanthraquinone, P-chlorobenzophenone, 2-acyloxime ester, 1,1-dichloroacetophenone, acetophenone, P-tert-butyltrichloroacetophenone, 2,2-diethoxyacetophenone, 4-dialkylaminoacetophenone, benzophenone, benzoylbenzoate, thioxanthone, 2 -Chlorothioxanthone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, mycloskone, benzyl, benzoin, benzoin ether, benzyl dimethyl ketal , 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2,4-diethyl thioxanthane, 2-hydroxy-2-methyl-1- (4-decyl Phenyl) propane-1-one and the like can be used.

Among them, the viscosity is 30,000 cps or less, and excellent in bonding strength with metal, and it is preferable to use a material resistant to heat and impact.

In the present invention, when the viscosity of the ultraviolet curable resin is 30,000 cps or more, the problem of not quantitatively discharging occurs, which causes manufacturing problems that require a long time for curing, thereby inhibiting productivity, and preferably 40 to 2000 cps. It is preferable to use an ultraviolet curable resin having a viscosity of.

The apparatus and method used for ultraviolet irradiation are not limited, but the distance between the ultraviolet light source and the applied curable resin is appropriately 2 to 10 mm, and when the distance is less than 2 mm, the light wavelength is not wide and only a small portion is hardened. When it exceeds 10 mm, a problem arises that the ultraviolet curing time is long.

In addition, the ultraviolet irradiation time is preferably 2 to 8 seconds, but when the irradiation time is less than 2 seconds, the problem of uncuring occurs, and when it exceeds 8 seconds, the problem of lowering the productivity occurs.

On the other hand, the coating thickness of the ultraviolet curable resin is preferably 0.03mm to 0.6mm, the problem of leakage occurs when the coating thickness is less than 0.03mm, the problem that the inner part is maintained in an uncured state when it exceeds 0.6mm Occurs.

At this time, by using a dye having a color inherent to the metal and the color inherent to the UV-curable resin, it is more effective because it is easy to distinguish whether the leakage in the sealing portion, pinholes and the like.

Hereinafter, the sealing method of the present invention will be described in more detail with reference to the following examples.

<Example 1>

A cathode terminal and a cathode terminal are provided inside the case 1, and a jelly roll 2 composed of a cathode material, a cathode material, a membrane, and an insulating paper is inserted into the case 1 and fixed with a support cap 3, and then a cathode cap 4 ) And the welding part of the case 1 and the sealing part of the electrolyte inlet were respectively coated with a thickness of 0.10 mm using A-1058, an epoxy acrylate-based one-component UV-curable resin manufactured by Desk Japan, having a viscosity of 1,000 cps. The distance to the light source was set to 5 mm with an ultraviolet irradiating apparatus (UVF-203S), and the ultraviolet rays were irradiated for 5 seconds. Then, the experiment was conducted by the method described below and the results are shown in Table 1.

<Example 2>

The same apparatus and method as in Example 1 were used, but the coating was applied at a thickness of 0.10 mm using 1114A, an epoxy acrylate-based one-component UV curable resin having a viscosity of 200 cps, as an ultraviolet curable resin. After 5 mm was irradiated with ultraviolet light for 5 seconds, the experiment was conducted by the method described below, and the results are shown in Table 1 together with Example 1.

<Example 3>

Using the same apparatus and method as in Example 1, UV curable resin was coated with 0.10 mm in thickness using 1114C, an epoxy acrylate one-component UV curable resin of Japan Test Co., Ltd., having a viscosity of 40 cps, and a distance of 5 mm from the light source. After irradiating with ultraviolet light for 5 seconds, the experiment was carried out by the method described below and the results are shown in Table 1 together with Example 1.

Comparative Example 4

Using the same apparatus and method as in Example 1, the UV curable resin was coated with a thickness of 0.70 mm using A-1058, an epoxy acrylate one-component UV curable resin of Japan Test Co., Ltd., having a viscosity of 1000 cps. After 5 mm was irradiated with ultraviolet light for 5 seconds, the experiment was conducted by the method described below, and the results are shown in Table 1 together with Example 1.

Comparative Example 2

Using the same apparatus and method as in Example 1, UV curable resin was coated with a thickness of 0.70 mm using 1114A, an epoxy acrylate one-component UV curable resin of Japan Test Co., Ltd., having a viscosity of 200 cps, and a distance of 5 mm from a light source. After irradiating with ultraviolet light for 5 seconds, the experiment was carried out by the method described below and the results are shown in Table 1 together with Example 1.

Comparative Example 3

Using the same apparatus and method as in Example 1, the UV curable resin was applied with a thickness of 0.01 mm using A-1058, an epoxy acrylate one-component UV curable resin of Japan Test Co., Ltd., having a viscosity of 1000 cps. After 5 mm was irradiated with ultraviolet light for 5 seconds, the experiment was conducted by the method described below, and the results are shown in Table 1 together with Example 1.

Comparative Example 4

Using the same apparatus and method as in Example 1, UV curable resin was coated with a thickness of 0.01 mm using 1114A, an epoxy acrylate one-component UV curable resin of Japan Test Co., Ltd., having a viscosity of 200 cps, and a distance of 5 mm from a light source. After irradiating with ultraviolet light for 5 seconds, the experiment was carried out by the method described below and the results are shown in Table 1 together with Example 1.

Comparative Example 5

Using the same apparatus and method as in Example 1, the UV curable resin was coated with a thickness of 0.10 mm using A-1058, an epoxy acrylate one-component UV curable resin of Japan Test Co., Ltd., having a viscosity of 1000 cps. After 12 mm was irradiated with ultraviolet light for 5 seconds, the experiment was conducted by the method described below, and the results are shown in Table 1 together with Example 1.

Comparative Example 6

Using the same apparatus and method as in Example 1, the UV curable resin was coated with a thickness of 0.10 mm using 1114A, an epoxy acrylate one-component UV curable resin manufactured by Japan Test Co., Ltd., having a viscosity of 200 cps, and a distance of 12 mm from the light source. After irradiating with ultraviolet light for 5 seconds, the experiment was carried out by the method described below and the results

It is shown in Table 1 together with Example 1.

Comparative Example 7

Using the same apparatus and method as in Example 1, the curable resin was applied to the sealing portion of the electrolyte inlet with a thickness of 1.80 mm using Altcoco F-05 manufactured by Alpha Techno Co., Ltd., Japan, having a viscosity of 20,000 cps. After storage, the experiment was conducted by the method described below, and the results are shown in Table 1 together with Example 1.

Comparative Example 8

Using the same apparatus and method as in Example 7, the sample was stored in a drying room for 10 minutes, and then experimented by the method described below, and the results are shown in Table 1 together with Example 1.

Comparative Example 9

Using the same apparatus and method as in Example 7, but stored in a drying room for 1 hour, and then experimented by the method described below and the results are shown in Table 1 together with Example 1.

Comparative Example 10

Using the same apparatus and method as in Example 7, but stored in a drying room for 3 hours, then experimented by the method described below and the results are shown in Table 1 together with Example 1.

Curing time Sealing effect Temperature cycle experiment Drop test Electrolyte Impregnation Before sealing After sealing 80 ℃ -20 ℃ 80 ℃ -20 ℃ Example 1 5 sec One 30 30 30 30 30 30 30 Example 2 5 sec One 30 30 30 30 30 30 30 Example 3 5 sec One 30 30 30 30 30 30 30 Comparative Example 1 5 sec One 30 30 30 28 26 30 28 Comparative Example 2 5 sec One 30 30 28 26 17 30 26 Comparative Example 3 5 sec One 30 29 28 21 11 30 22 Comparative Example 4 5 sec One 30 28 24 24 17 29 21 Comparative Example 5 5 sec One 30 28 21 20 14 25 21 Comparative Example 6 5 sec One 30 27 21 19 13 28 19 Comparative Example 7 5 sec One One One One One One One One Comparative Example 8 10 minutes One 3 One One One One One One Comparative Example 9 1 hours One 25 22 20 19 17 25 10 Comparative Example 10 3 hours One 30 30 30 30 28 30 25

-Sealing effect

Before and after sealing, the cell was measured for pressure at which electrolyte began to leak according to the internal pressure specific method of US Safety (UL) Standard No. 1642.

Temperature cycle test

The sealed battery was left at 80 ° C. for 2 hours, then left at -20 ° C. for 2 hours, and then raised to 80 ° C. and left for 2 hours according to the temperature cycle test method of US Safety (UL) No. 1642. After standing for 2 hours at, the pressure at which the electrolyte began to leak was measured.

Drop test

The pressure at which the electrolyte began to leak was measured according to the drop test method of US safety (UL) standard 1642.

-Electrolyte impregnation test

The sealed cell was impregnated into the electrolyte bath for 60 hours, and the pressure at which the electrolyte began to leak was measured using a sealing effect test equipment.

The results obtained by the same method as in Examples 1 to 3 and Comparative Examples 1 to 10 were measured as shown in Table 1 below.

According to the present invention, an ultraviolet curable resin having a viscosity of 30,000 cps or less was applied to a thickness of 0.03 mm to 0.6 mm, and the distance between the ultraviolet light source and the applied curable resin was 2 to 10 mm, and the ultraviolet irradiation time was 2 to 8 seconds. In the case of Examples 1 to 3, it was confirmed to withstand up to 10 Kg / cm 2 or more internal pressure.

Coating Examples of Comparative Examples 1 and 2 in which the coating thickness of the ultraviolet curable resin exceeded 0.6 mm, the coating thickness was less than 0.03 mm in Comparative Example 3 and Comparative Example 4 due to the influence of the uncured resin existing inside. In the case of the lack of cured resin, it appeared that leakage occurs due to thermal and chemical action, Comparative Example 5 and Comparative Example where the distance between the ultraviolet light source and the applied curable resin exceeds 10 mm In Fig. 6, due to insufficient UV curing, the overall electrolyte leakage pressure was weak, including the sealing effect.

In particular, compared to Comparative Example 8 to Comparative Example 10 using the thermosetting agent as well as the sealing effect through the results of the temperature cycle experiment and the electrolyte impregnation experiment was confirmed to be excellent sealing security without electrolyte leakage.

As described above, the present invention provides a sealing method capable of producing a mass by shortening the drying time in the production process while simultaneously close-sealing and sealing tightly so that the electrolyte is not leaked from the contact portion between the case and the anode cap. It is a preferred invention to provide.

Although the present invention has been described with reference to one embodiment and the illustrated drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible.

       1 is a schematic exploded view of a secondary battery

       2 is a state of coupling with the positive electrode cap

Claims (3)

delete delete In a sealed battery sealing method in which a case (1) and a positive electrode cap (4) of a lithium battery are combined and sealed, the gasket sealing portion, the safety edge portion, and the positive electrode cap (4) and the case (1) of the combined positive electrode cap (4) In a sealed battery sealing method in which a UV curable resin having a viscosity of 30,000 cps or less is applied to a welding part and a sealing part of an electrolyte inlet, and irradiated with UV light, the coating thickness of the UV curable resin is 0.03 mm to 0.6 mm. And the distance between the ultraviolet light source and the applied curable resin is 2 to 10 mm and the ultraviolet irradiation time is 2 to 8 seconds.