KR101051958B1 - Lead Tab Assembly for Secondary Battery Using Insert Injection and Secondary Battery Using the Same - Google Patents

Abstract

The present invention relates to a lead tab assembly for a secondary battery having excellent airtightness and a secondary battery using the same, comprising: an electrode assembly; A lead tab assembly including a positive lead tab and a negative lead tab electrically connected to two different polarities of the electrode assembly, and a sealant injection molded injection-molded by each of the positive and negative lead tabs; An accommodating part accommodating the electrode assembly, a first sealing part extending in a direction in which at least one of the positive electrode and the negative electrode lead tabs are drawn out from the accommodating part, and the positive or negative lead tabs are not drawn out from the accommodating part. And a battery packaging material including a sealing part including a second sealing part extending in a direction not to be sealed, wherein at least the first sealing part of the sealing part is sealed by bonding with the sealant injection body. It provides a secondary battery.

Lead Tap Assembly, Secondary Battery, Airtight, Insert Injection, Welding, Butyl Rubber

Description

LEAD TAB ASSEMBLY FOR SECONDARY BATTERY USING INSERT MOLDING AND SECONDARY BATTERY USING THE SAME

The present invention relates to a lead tab assembly for a secondary battery having improved airtightness and a secondary battery using the same.

Secondary batteries are widely used in the field of electronic devices such as cellular phones, notebook computers, camcorders, and recently, are also used as a power source for hybrid electric vehicles.

As the exterior material of the secondary battery, a can formed by forming a metal, such as aluminum, into a cylindrical or rectangular parallelepiped shape, or the like, or a pouch type battery exterior material manufactured by laminating an aluminum thin plate and a heat-sealed film or the like is used.

In particular, in a battery for an electric vehicle that requires a high capacity and a high rate discharge, a pouch type battery exterior material having a form advantage of the battery is mainly used. However, in spite of the morphological advantages of the battery, the pouch type battery exterior material does not sufficiently satisfy the characteristics such as sealing property (ie, airtightness), corrosion resistance, moldability, stability against external impact, and the like, which are required for electric vehicle batteries. .

The pouch-type battery casing is a structure in which a thin aluminum foil (foil) and a multilayer film are laminated, and the aluminum layer and the polypropylene layer are peeled off due to the difference in elongation between dissimilar materials such as the aluminum layer and the polypropylene layer when the battery case is molded to a predetermined depth or more. Phenomenon occurs, and molding is impossible beyond a certain depth due to these factors.

In addition, when the battery is vacuum-sealed, deformation of the aluminum pouch sheathing material is crushed, such as a pinhole. To improve this, aluminum pouch sheaths have been proposed which increase the thickness and strength of aluminum foil, but still have problems with molding. In particular, when the battery is sealed using an aluminum pouch-type exterior material, the exterior material is easily damaged and penetrated by an external object.

In addition, when the hydrofluoric acid (HF) is increased in the electrolyte, the pouch-type lithium ion secondary battery acts as a factor causing rapid corrosion of the aluminum layer of the aluminum pouch, which is a cause of lowering the corrosion resistance of the battery and leakage of the electrolyte. It is becoming.

In addition, when the electrode assembly of the pouch-type lithium ion secondary battery is sealed with a battery packaging material, airtightness of the lead tab connected to the grid portion of the electrode assembly is very important. In the case of the conventional pouch type lithium ion secondary battery, the lead tab is sealed using several layers of sealant films using an acid-modified polyolefin resin or the like. In order to thermally fusion such a sealant film on a lead tab made of aluminum, nickel, or the like, there must be a film layer that is resistant to heat and has little deformation such as shrinkage. In addition, in the battery for small IT devices, such a sealant film may be used to seal the lead tab and the battery exterior material. However, a battery that requires a high rate discharge, such as in an electric vehicle, has a thick and wide width of the lead tab. As shown in FIGS. 1A and 1B, a plurality of layers of sealant film are laminated on the lead tabs, so that the edges of the lead tabs are laminated. Difficult to seal completely to the part.

In addition, as shown in FIG. 2, when a top seal of a battery is formed using a lead tab assembly manufactured by laminating a plurality of layers of sealant film on a lead tab, the thicknesses of the sealant film and the lead tab may be reduced. The gap between the two lead tabs and the width of the sealant film should be manufactured to produce a sealing portion of the pouch. During mass production, alignment between the sealing portion of the pouch and the lead tab assembly is not easy, and these factors adversely affect the sealing of the battery. there is a problem.

The present invention has been made to solve these conventional problems, the object of the present invention,

First, to provide a lead tab assembly for a secondary battery that is completely sealed to the edge of the lead tab for secondary batteries to improve the airtightness of the lead tab,

Second, to minimize the atmospheric exposure of the electrolyte during battery manufacturing to suppress the generation of hydrogen fluoride (HF) in the electrolyte, and the lead tab assembly to perform the vacuum heat seal function of the pouch-type battery casing complex,

Third, to improve the moldability, corrosion resistance and safety against external impact of the battery packaging material.

These objects can be achieved by the following configuration of the present invention.

(1) a positive electrode lead tab and a negative electrode lead tab for secondary batteries spaced apart from each other on the same plane or parallel planes;

And a sealant injection molded injection molded to be penetrated by each of the positive electrode lead tab and the negative electrode lead tab.

(2) an electrode assembly;

A lead tab assembly including a positive lead tab and a negative lead tab electrically connected to two different polarities of the electrode assembly, and a sealant injection molded injection-molded by each of the positive and negative lead tabs;

An accommodating part accommodating the electrode assembly, a first sealing part extending in a direction in which at least one of the positive electrode and the negative electrode lead tabs are drawn out from the accommodating part, and the positive or negative lead tabs are not drawn out from the accommodating part. It includes a battery packaging material having a sealing portion including a second sealing portion extending extending in the non-direction,

At least the first sealing part of the sealing part is sealed by bonding with the sealant injection molded body.

According to the present invention, by inserting the positive lead tab and the negative lead tab into the mold and integrating by injection molding using an adhesive resin, the airtightness of the lead tab can be improved by completely sealing up to the edge of the lead tab. . Moreover, only the adhesive resin can be used by injection molding alone, so that it is possible to improve the delamination phenomenon of several layers of sealant films that have been conventionally used.

In addition, by integrating the lead tab assembly with the electrolyte inlet and / or the gas outlet, it is possible to minimize the exposure of the electrolyte to the atmosphere and thereby suppress the generation of hydrogen fluoride (HF) in the electrolyte.

In addition, by using a stainless steel sheet or the like as the battery exterior material to improve the moldability, corrosion resistance and safety against external impact, it is possible to further improve the corrosion resistance by passivating the stainless steel sheet surface.

In addition, components such as a battery packaging material and a lead tab assembly constituting the secondary battery may be simplified, thereby reducing manufacturing costs.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3A and 3B, the lead tab assembly 1 for a secondary battery according to the present invention includes a positive lead tab 10, a negative lead tab 20, and a sealant injection body 30.

The positive and negative lead tabs 10 and 20 are spaced apart on two planes that are coplanar or parallel. The positive lead tab 10 may include aluminum, and is electrically connected to the positive electrode of the electrode assembly that generates electricity. The negative lead tab 20 may include nickel and / or copper and is electrically connected to the negative electrode of the electrode assembly. However, the present invention does not limit the materials of the positive and negative lead tabs 10 and 20.

The sealant injection molded body 30 is injection molded to penetrate the gaps by the positive and negative lead tabs 10 and 20, respectively. In this case, it is preferable to smooth the mold release of the adhesive resin by coating the cavity of the mold for insert injection. The sealant injection body 30 may be injection molded using an adhesive resin such as an acid-modified polyolefin resin. For example, a polyolefin-based heat adhesive resin polymerized with maleic anhydride or unsaturated carboxylic acid is injected into the mold while the positive and negative lead tabs 10 and 20 are inserted into the mold and molded. However, this invention does not limit the kind of said adhesive resin.

In the case of the sealant film in the conventional film form, the acid-modified polypropylene resin is severely deformed at a certain temperature or higher when thermally fused with the lead tab, and has been used in combination with another film having excellent heat resistance. On the contrary, according to the present invention, since the positive and negative lead tabs 10 and 20 and the sealant injection body 30 are integrated by insert injection molding, only acid-modified polyolefin resins can be used alone, and thus the conventional The delamination phenomenon etc. of the sealant film which came may be improved. In particular, when manufacturing the lead tab assembly using the conventional sealant film, bubbles are very easily generated at the edge portion of the lead tab, which directly affects leakage of the electrolyte (see FIG. 1B). Conventionally, although a fine bubble at such a lead tab edge part is tolerated to some extent, a battery is manufactured. In the present invention, this problem is solved by manufacturing the lead tab assembly by insert injection.

The lead tab assembly according to the present invention may have various embodiments. Hereinafter, three embodiments will be described in detail, but the lead tab assembly according to the present invention is not limited to these embodiments.

As a first embodiment, as shown in FIGS. 3A and 3B, the sealant injection body 30 is a tab through bar penetrated by at least one of the positive and negative lead tabs 10, 20 ( 30) may be included only. In this case, the tab through bar 30 may be bonded by thermal fusion with each battery case in a state sandwiched between two battery case pieces superimposed on each other. Here, the tab through bar 30 may be a straight bar penetrated by the positive and negative lead tabs 10 and 20 arranged side by side on the same plane.

As a second embodiment, as shown in FIG. 4, the sealant injection body 30 ′ is a tab through bar 31 ′ penetrated by at least one of the positive and negative lead tabs 10, 20. ) And a tab non-penetrating bar 32 'that is not penetrated by the positive or negative lead tabs 10 and 20. Here, the tab through bar 31 ′ and the tab non-penetrating bar 32 ′ may be integrally injection molded to the same thickness. In this case, the tab through bar 31 ′ and the tab non-penetrating bar 32 ′ may be bonded to each battery facer by thermal fusion in a state sandwiched between two battery facers superposed on each other. The positive and negative lead tabs 10, 20 may be aligned side by side on the same plane or in two parallel planes (see FIG. 4), but may also be arranged facing in opposite directions or perpendicular to each other (see FIG. 4). Not shown). As an example of the present embodiment, the sealant injection body 30 ′ may be formed in a rectangular frame shape so as to correspond to the entire sealing portion in which two battery packaging materials overlap each other, as shown in FIGS. 4 and 6A. This form overcomes the disadvantages of the moldability of the conventional pouch-type battery packaging material and makes the best use of the pouch-type packaging material.

As a third embodiment, as shown in FIG. 5, the sealant injection body 30 ″ is a tab through bar 31 ″ penetrated by at least one of the positive and negative lead tabs 10, 20. ) And a tab non-penetrating bar 32 "not penetrated by the positive or negative lead tabs 10 and 20. Here, the tab non-penetrating bar 32" is the tab. At both ends of the through bar 31 ", a vertical connection is made in the same direction so as to include the same plane on which the positive and negative lead tabs 10 and 20 are disposed, and a thickness larger than the thickness of the tab through bar 31 " It can be injection molded integrally to have. In this case, the tab through bar 31 "may be joined by thermal fusion with each battery case in a state sandwiched between two battery case materials superimposed on each other. Further, the tab non-penetrating bars 32" may be bonded to each other. When the nested battery enclosure is sealed by welding, it is placed between the welding site and the electrode assembly to prevent damage to the electrode assembly by the heat of welding. A protrusion 32a "may be formed on the outer surface of the tab non-penetrating bar 32" along the longitudinal direction. This projection 32a "may be sandwiched between two battery packaging materials superimposed on each other, and may also be joined to each battery packaging material by thermal fusion.

In the first to third embodiments, the joining surface of the tab through bars 30, 31 ', and 31' 'with the battery packaging material is preferably flat. In the conventional pouch type battery, the portion where the lead tab is drawn out is Looking at the sealing portion, as shown in Figure 2, since the thickness of the lead tab assembly is different for each part, a sealing portion having a stepped shape that can correct this thickness was required, and also to ensure the sealing step In contrast, the lead tab assembly had to be aligned at the correct position of the shaped sealing part, whereas the heat-sealing of the lead tab assembly and the battery case manufactured using the insert molding according to the present invention, the tab through bar 30, 31 ', 31 ") can be flattened so as to maximize the sealing property of the battery. Moreover, in the said 2nd Embodiment, it is preferable that it is flat in terms of the convenience of joining by the shaving thermal fusion of the said tab non-penetrating bar 32 'with the battery exterior material, and the maximization of battery sealing property.

4 and 5, the sealant injection bodies 30 ′ and 30 ″ have the sealant injection bodies 30 ′ and 30 ″ in a direction parallel to the lead tabs 10 and 20. One or more long holes may be formed. In the embodiment of Figs. 4 and 5, two long holes are formed, one of which is an electrolyte injection hole 33 ', 33 ", and the other is a gas discharge hole 34', 34". The electrolyte inlets 33 'and 33 "and the gas outlets 34' and 34" insert the respective pins for forming the electrolyte inlet and the gas outlet together with the lead tab in the mold cavity during the aforementioned insert injection process. It is manufactured by injection molding in a state. In this case, it is preferable to teflon-coated and insert the pin in order to facilitate the release of the pin. The sealant injection-molded part in which the electrolyte injection holes 33 'and 33 "and the gas discharge holes 34' and 34" are formed has a sealant as shown in FIGS. 4 and 5 to secure an injection pipe of a predetermined length or more. It may protrude outward relative to other parts of the injection molded body. The electrolyte injection openings 33 'and 33 "and the gas discharge openings 34' and 34" are sealed by thermal fusion after electrolyte injection and degassing by initial charging and discharging. After sealing, the protruding portion may be cut. In some cases, only one long hole may be formed, and the electrolyte injection holes 33 ′ and 33 ″ may also serve as the gas discharge holes 34 ′ and 34 ″.

Hereinafter, the secondary battery according to the present invention using the lead tab assembly manufactured by insert injection molding as described above will be described.

6A to 6C, the secondary battery according to the present invention includes an electrode assembly 100, a lead tab assembly 200, and a battery exterior material 300.

The electrode assembly 100 is a part for generating electricity, and an anode and a cathode are alternately stacked or wound in a jelly-roll form with a separator interposed between these two electrodes. However, the electrode assembly of the present invention is not limited thereto, and may have various conventional forms.

The lead tab assembly 200 includes a positive lead tab 210 and a negative lead tab 220 electrically connected to two different polarities of the electrode assembly 100, respectively, and the positive and negative lead tabs 210, respectively. 220) includes a sealant injection molding 230 injection-molded so as to penetrate without gap by each. This lead tap assembly 200 has been described in detail above.

The battery packaging material 300 includes two housing parts in which all or part of the battery packaging material 300 is separated (eg, three of four sides) from each other, and includes an accommodating part 310 accommodating the electrode assembly and the accommodating part 310. It extends from the outside to the sealing portion 320 is provided. Here, the sealing part 320 extends in a direction in which at least one of the positive and negative lead tabs 210 and 220 is drawn out from the receiving part, and is sealed to the first sealing part 321 and the receiving part 310. A second sealing part 322 which extends and is sealed in a direction in which the positive or negative lead tabs 210 and 220 are not drawn out. At least the first sealing part 321 of the sealing part 320 is sealed by bonding to the sealant injection body 230.

In the present invention, although the conventional pouch type exterior material may be used as the battery exterior material 300, it is preferable to use a stainless steel sheet (foil) to improve the formability, corrosion resistance and safety against external impact of the exterior material. Do. In particular, the stainless steel sheet has excellent seam weldability and hardly deforms and generates heat, thus enabling sealing by welding. Furthermore, in order to further improve the corrosion resistance, the stainless steel foil may be molded and its surface may be degreased and passivated and then thermally fused with the lead tab assembly. In addition, in order to further enhance adhesion to the acid-modified polyolefin resin, the passivation treatment and coating the surface of the foil with a compound containing polyvinyl alcohol, followed by drying at 200 degrees or more, and then heat-sealed with the lead tab assembly It may be. In addition, after plating nickel on the surface of the stainless steel (stainless steel), a chemical conversion coating may be performed to increase the sealing strength in the electrolyte. When using a stainless steel thin plate as the battery packaging material 300, a thickness of about 0.06 ~ 0.12 mm is preferred. Conventional aluminum pouches have a problem that crushing of corners frequently occurs during vacuum sealing, and this problem is solved by using a stainless steel sheet (foil) that is stronger than aluminum. In particular, when a large capacity battery such as an electric vehicle is required and exposed to a harsh environment, it is suitable in a situation where a more robust and corrosion-resistant battery exterior material is required.

According to the embodiment of the lead tab assembly described above, the sealing part 320 may be sealed in various ways.

For example, when the lead tab assembly is in accordance with the first embodiment described above (see FIGS. 3A and 3B), the first sealing portion 321 may be a sealant injection body of the lead tab assembly between two outer cladding portions. (That is, a tab through bar) can be heat sealed by sealing. In this case, as described above, the joining surface of the tab through bar with the first sealing portion is preferably flat. The second sealing part 322 may be sealed by heat fusion or welding the two parts of the outer material that are directly overlapped with each other.

In addition, when the lead tab assembly follows the above-described second embodiment (see FIG. 4), as shown in FIGS. 6A to 6C, the first sealing portion 321 and the second sealing portion 322 are described. The sealant injection body of the lead tab assembly (ie, the tab through bar and the tab non-penetrating bar) can be sealed by heat fusion between two externally overlapping parts of each other. In this case, as described above, the bonding surface of the tab through bar 231 with the first sealing portion 321, and the bonding surface of the tab non-penetrating bar 232 with the second sealing portion 322 are as follows. It is preferable that all are flat.

In addition, when the lead tab assembly is in accordance with the above-described third embodiment (see FIG. 5), as shown in FIG. 7, the first sealing portion 321 ′ may have the lead between two outer packaging portions overlapped with each other. The sealant injection body (i.e., tab through bar) 231 'of the tab assembly can be sealed by heat fusion. In this case, as described above, the bonding surface of the tab through bar 231 'with the first sealing portion 321' is preferably flat. The second sealing portion 322 ′ may seal the two exterior member portions that overlap each other and directly contact with each other by thermal fusion, but may also seal by welding. As described above, when the tab unperforated bar 232 ′ of the sealant injection body seals two overlapping exterior parts by welding, the electrode assembly is located between the welding part and the electrode assembly to damage the electrode assembly by the heat of welding. To prevent. In addition, a protrusion 232a 'may be formed on an outer side surface of the tab non-penetrating bar 232' along a length direction, and the protrusion 232a 'is inside the welded portion of the second sealing portion 322'. It may be sandwiched between the two envelope parts overlapped with each other, or may be bonded by thermal bonding with each of the envelope parts.

Pouch-type cells in which films are usually laminated have problems with water and gas permeation. That is, water and gas permeation through the resin is a problem by sealing the battery case using the resin. In order to solve this problem, in the present invention, as shown in Fig. 7, the second sealing portion 322 'except for the first sealing portion 321' was sealed by welding. In this case, it was found that the water permeation is significantly reduced. Therefore, a battery sealed by welding the second sealing part is preferable for a battery used for a long life and used in a harsh environment. However, the water permeability problem of the first sealing portion 321 'sealed with the resin still remains. In order to solve this problem, as shown in FIG. 8, it is preferable to further seal the first sealing portion 321 ′ using a butyl rubber 410 having excellent airtightness. Meanwhile, referring to FIGS. 6A and 6B, the second sealing parts 322 on both sides of the battery are sealed and bonded to the sealant injection molded body by thermal fusion, and the resin is exposed to the outside, which may cause a problem of water permeation. have. Therefore, as shown in FIG. 9, it is preferable to cut the protruding portions to form the electrolyte inlet and the gas outlet, and to further seal the second sealing portions 322 on both sides of the battery using the butyl rubber 420. Do. In other words, it is preferable that at least a portion of the seal portion in which the sealant injection molded body is exposed to the outside is further sealed using butyl rubber.

Hereinafter, the present invention will be described in detail with reference to examples, but these examples are only presented to more clearly understand the present invention, and are not intended to limit the scope of the present invention. It will be determined within the scope of the technical spirit of the claims.

Example

The anode lead tab is made of soft aluminum foil having a purity of 99.5% or more in aluminum, 0.2 mm thick, 20 mm wide, and 35 mm long, coated with water for 30 seconds in an aqueous solution containing trivalent chromium, fluorine, and cobalt, and washed with water. It was.

The negative electrode lead tab was prepared with a thickness of 0.2 mm, a width of 20 mm, and a length of 35 mm with a soft copper foil having a purity of 99.9% or more, and electrolytic plating in an aqueous solution containing a compound such as nickel chloride, nickel sulfate, boric acid, and the like on the surface of the copper foil. Nickel was coated to a thickness of 0.002 mm.

As the resin for injection molding, acid-modified polypropylene resin was used, and a mold cavity was coated for injection molding to facilitate mold release between the mold and the injection molded product.

Two metal pins having a diameter of 1.0 mm and a length of 50 mm were respectively coated with Teflon and inserted into a mold cavity, such as the positive and negative lead tabs, to perform injection molding. The two metal pins are formed to form an electrolyte inlet and a gas outlet, respectively, and are teflon-coated to facilitate release of the lead tab assembly and release during electrolyte injection after thermal fusion of the battery packaging material and the lead tab assembly. As such, by providing a separate electrolyte inlet and a gas outlet, the electrolyte infusion and the electrolyte impregnation process of the electrode assembly can be performed in a closed system, thereby minimizing the atmospheric exposure of the electrolyte.

In order to prepare a battery exterior material, a stainless steel sheet having a thickness of 0.08 mm containing nickel, chromium, molybdenum, etc. was formed, degreased, and then immersed in a mixed acid such as hydrofluoric acid and nitric acid for 2 hours, and then immersed in a nitric acid solution for 2 hours after pickling. Passivation treatment. In general stainless steel foil, the acid-modified polypropylene resin swells in the organic solvent of the electrolytic solution, and due to the influence that the stainless steel is impaired by hydrofluoric acid, there is a factor that can reduce the adhesive strength. Therefore, it is preferable that a corrosion resistant film is formed in the stainless steel surface layer, and the inorganic substance containing chromium, phosphorus, etc. is effective as a constituent material of a corrosion resistant film. To form this inorganic film, stainless steel can be passivated to increase the amount of chromium on the surface. In addition, in order to improve the characteristics of the inorganic coating, an additional organic coating may be considered, and PVA, which does not invade the hydrocarbon-based electrolyte, was used as an auxiliary. The adhesive strength is further increased by polyvinyl etherification of polyvinyl alcohol by coating and heat treatment after coating with a polyvinyl alcohol-containing coating agent (see Table 1). After passivation of the stainless steel, the amount of chromium on the surface of the stainless steel is increased to increase the adhesive strength with the acid-modified polyolefin resin, but the acid-modified polyolefin adhesive resin swells in the organic solvent of the electrolyte, and the stainless steel is caused by hydrofluoric acid. Due to the influence of this infringement, there is a factor that can lower the adhesive force. For the purpose of improving this, the coating liquid containing polyvinyl alcohol was coated and dried at 220 ° C., and there was almost no change in the sealing strength in the electrolyte. In addition, after plating nickel about 0.001 mm in stainless steel, a chemical conversion coating was performed on the surface thereof, and it was confirmed that the sealing strength increased in the electrolyte. This is because nickel is relatively less affected by hydrofluoric acid.

TABLE 1

                                 (Sealing strength in electrolyte at 80 ℃, kgf / 10mm)

5 days 10 days 15th 20 days Passivation 7 7 6 6 Passive treatment + coating 7 7 7 7 Nickel Plating + Chemical Coating 8 8 8 8

In the present embodiment, the stainless steel is passivated, coated after passivation, or nickel-coated and then chemically coated, but the battery exterior material used in the present invention is not limited to stainless steel. For example, a chemical coating may be used for aluminum and aluminum alloy steel, or chrome plating may be used for a rolled steel sheet. In the case of the stainless steel sheet, a thin plate having a thickness of 0.06 to 0.12 mm was suitable as a battery exterior material.

On the other hand, a pouch type battery in which a film is usually laminated has problems with water and gas permeation. That is, the problem of water and gas permeation arises by sealing a battery case using resin. In order to solve this problem, in the present embodiment, the side portions except for the top seal portion of the battery were welded (see FIG. 7). The stainless steel sheet of the side portion was extended by a certain length to perform seam welding with a welding width of 1 mm, and the heat-adhesive resin portion was heat-sealed and sealed. In particular, the stainless steel sheet had a good seam weldability, so there was almost no deformation and heat generation of the material. Moreover, the damage of the electrode assembly by welding heat was not concerned by the heat insulation effect of the resin part. In addition, in order to block heat transfer of the welded part, as shown in FIG. 5, the lead tab assembly formed by molding the resin part may be more reliable.

The water permeability of the product welded to the side of the battery as described above and the general pouch type battery product (no welding) was tested.

TABLE 2

                              (60 ° C 90% Rh, ppm)

20 days 40 days 60 days No welding - 80 150 Side seam welding - - 70

As shown in Table 2, it was found that the water permeation was significantly reduced when the side of the battery envelope was welded and only the top seal of the battery was sealed with the resin. Therefore, batteries that are welded and sealed to side surfaces are preferred for batteries that require long life and are used in harsh environments. However, the problem of airtightness of the tower seal remains. In order to solve this problem, the top seal portion was sealed using butyl rubber having excellent airtightness (see FIG. 8). Side surfaces can also be easily sealed using butyl rubber (see FIG. 9).

In the above, the present invention has been described with reference to the illustrated examples, which are only examples, and the present invention carries out various modifications and other equivalent embodiments that are obvious to those skilled in the art. Understand that you can.

1A and 1B are a perspective view and an X-X 'cross-sectional view, respectively, of a lead tab assembly using a conventional sealant film.

2 is a cross-sectional view of a top seal portion of a rechargeable battery using a conventional lead tab assembly.

3A and 3B are a perspective view and a sectional view taken along the line Y-Y 'of the lead tab assembly according to the first embodiment of the present invention, respectively.

4 is a perspective view of a lead tab assembly according to a second embodiment of the present invention.

5 is a perspective view of a lead tab assembly according to a third embodiment of the present invention.

6A to 6C are exploded perspective views, a coupled perspective view, and a cross-sectional view taken along line Z-Z 'of the secondary battery using the lead tab assembly according to the second embodiment, respectively.

7 is a perspective view of a secondary battery using the lead tab assembly according to the third embodiment.

FIG. 8 is a perspective view of a secondary battery in which the first sealing portion of the secondary battery shown in FIG. 7 is further sealed with butyl rubber.

FIG. 9 is a perspective view of the secondary battery in which the second sealing portions on both sides of the secondary battery shown in FIG. 6B are additionally sealed using butyl rubber.

Claims (18)

A positive electrode lead tab and a negative electrode lead tab for secondary batteries spaced apart from each other on the same plane or parallel planes; And a sealant injection molded injection molded to be penetrated by the positive lead tab and the negative lead tab, respectively. The sealant injection body includes a tab through bar penetrated by at least one of the positive and negative lead tabs, and a tab non-penetrating bar penetrated by the positive or negative lead tab, the tab penetrating The bonding surface of the bar with the battery packaging material and the non-tapping bar of the battery packaging material are flat, and the tab penetration bar and the tab non-penetrating bar are injection molded integrally with the same thickness. Tab assembly. delete 2. The lead tab assembly of claim 1, wherein the tab through bar is a straight bar penetrated by the positive and negative lead tabs aligned side by side on the same plane. delete The method of claim 3, wherein the sealant injection body further comprises a tab unperforated bar having a thickness greater than the thickness of the tab through bar, respectively vertically connected in the same direction so as to include the same plane at both ends of the tab through bar. A lead tab assembly for a secondary battery. The lead tab assembly for a secondary battery according to claim 5, wherein protrusions are formed on an outer surface of the tab non-penetrating bar along a length direction. The lead tab assembly of claim 1, wherein the sealant injection body has at least one long hole for penetrating the sealant injection body in a direction parallel to the lead tab and for injecting electrolyte or discharging gas. . The lead tab assembly for a secondary battery of claim 1, wherein the sealant injection molded product is injection molded using an adhesive resin. The lead tab assembly for a secondary battery of claim 8, wherein the adhesive resin is an acid-modified polyolefin resin. An electrode assembly; A lead tab assembly including a positive lead tab and a negative lead tab electrically connected to electrodes of two different polarities of the electrode assembly, and a sealant injection molded injection-molded by the positive and negative lead tabs, respectively; ; An accommodating part accommodating the electrode assembly, a first sealing part extending in a direction in which at least one of the positive electrode and the negative electrode lead tabs are drawn out from the accommodating part, and the positive or negative lead tabs are not drawn out from the accommodating part. It includes a battery packaging material having a sealing portion including a second sealing portion extending extending in the non-direction, At least the first sealing part of the sealing part is sealed by bonding with the sealant injection molded part, The sealant injection body includes a tab through bar penetrated by at least one of the positive and negative lead tabs and a tab non-penetrated bar not penetrated by the positive or negative lead tabs, The tab through bar and the tab non-penetrating bar are sealed by joining with the first sealing part, and a bonding surface of the tab through bar with the first sealing part and the second sealing part of the tab non-penetrating bar. The joint surface with is flat, And the tab through bar and the tab non-penetrating bar are integrally injection molded to the same thickness. delete delete The secondary battery of claim 10, wherein the second sealing part is sealed by welding. The secondary battery of claim 13, wherein the tab non-penetrating bar is positioned between a welding portion of the second sealing portion and the electrode assembly. 15. The method of claim 14, wherein the outer surface of the tab non-penetrating bar is formed with a projection along the longitudinal direction, the projection is joined to the second sealing portion inside the welding portion of the second sealing portion. Secondary battery. The secondary battery according to claim 10, wherein the battery packaging material is a stainless steel thin plate. The secondary battery according to claim 16, wherein the surface of the stainless steel sheet is passivated, coated with a polyvinyl alcohol-containing coating, or coated with nickel after plating. The secondary battery according to claim 10, wherein at least a portion of the seal portion in which the sealant injection body is exposed to the outside is further sealed using butyl rubber.

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