KR101147791B1 - Secondary battery having vent hole - Google Patents

Abstract

Secondary battery according to the present invention, the electrode assembly; An outer case in which the electrode assembly is received; A terminal mounted on the outer case such that one side thereof protrudes outside the outer case and electrically connected to the electrode assembly, the terminal having a vent hole communicating inside and outside of the outer case; And a sealing cap for sealing the vent hole with a coupling medium using a low melting point material having a lower melting point than the outer case or the terminal. In the secondary battery according to the present invention, since the vent hole is automatically opened when the internal temperature or pressure is raised above the reference value, the secondary battery can prevent explosion due to expansion of the outer case, and discharge the gas generated from the inside to the outside. It can be designed precisely, there is an advantage that can prevent human injury because the break site is not formed when the vent hole is opened.

Description

Secondary battery having a vent hole {Secondary battery having vent hole}

The present invention relates to a secondary battery having a vent hole for discharging gas generated therein to the outside, and more particularly, to a secondary battery configured to open a vent hole when an internal temperature or pressure is raised above a reference value. will be.

Recently, the development and dissemination of portable electronic devices and hybrid electric vehicles has been expanded, and the development of secondary batteries having high energy density while being rechargeable to be used as their power sources is being actively made.

A low-capacity battery in which one of the secondary batteries is packed in a pack form is used in a portable electronic device such as a mobile phone, a laptop, a computer, a camcorder, and a large-capacity battery in a battery pack unit in which dozens of battery cells are connected. It is widely used as a power source for driving motors of hybrid electric vehicles.

The secondary battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte, and is charged and discharged by electromotive force generated when ions move between the positive electrode plate and the negative electrode plate through an electrochemical rebound.

However, since the secondary battery has a high operating potential of the battery, high energy may flow instantaneously, and the positive electrode material rapidly reacts with the electrolyte to generate a large amount of gas because chemical activation is greatly increased by overcharge or short circuit. As a result, the pressure or temperature inside the secondary battery is rapidly increased, leading to an explosion of the battery, which may damage the peripheral device or damage the human body. Therefore, various types of safety devices for preventing explosions have been proposed.

For example, Japanese Patent Laid-Open Nos. 2-284350 and 9-320549 disclose a technique of forming a straight or straight X-shaped groove on the surface of an outer case as a safety device of a secondary battery. As such, when the groove is formed in the outer case, when the outer case is inflated due to an increase in internal pressure, cracks are generated in the grooved portion and the inner gas is released to the outside, so that the secondary battery does not explode. It has the advantage of being.

However, as mentioned above, the secondary battery in which the groove is formed in the outer case has various disadvantages such as the size and location of the groove, and thus the crack generation time is variously changed, so it is difficult to accurately design the crack generation time. . For example, if the depth of the groove is slightly lowered, even if the outer case is expanded beyond the reference value, there is a risk of explosion because no crack is generated. If the depth of the groove is slightly deep, the crack is generated even if the outer case is slightly expanded.

In addition, when a groove is formed in the outer case, explosion of the battery may be prevented, but a fracture portion of the groove may be sharpened, which may cause injury to a human body.

The present invention has been proposed to solve the above problems, by having a vent hole that is automatically opened when the internal temperature or pressure is raised above the reference value, it is possible to prevent the explosion due to the expansion of the outer case and occur inside It is an object of the present invention to provide a secondary battery configured to accurately design a time for discharging the gas to the outside and to prevent a fracture site from being formed when the gas discharge port is formed.

Secondary battery according to the present invention for achieving the above object, the electrode assembly; An outer case in which the electrode assembly is received; A terminal mounted on the outer case such that one side thereof protrudes outside the outer case and electrically connected to the electrode assembly, the terminal having a vent hole communicating inside and outside of the outer case; The vent hole may be filled in the whole or part of the vent hole so as to be blocked, and may include a low melting point material having a lower melting point than the outer case or the terminal.

The vent hole is formed to penetrate the terminal up and down, and a stepped portion is formed in the middle portion so that the lower inlet is narrower than the upper inlet.

The vent hole is formed to penetrate the terminal up and down, and the side wall is formed to be inclined so that the inner diameter thereof becomes narrower toward the lower side.

The length of the vent hole is set larger than the wall thickness of the outer case.

Secondary battery according to the present invention, the electrode assembly; An outer case in which the electrode assembly is received; A terminal mounted on the outer case such that one side thereof protrudes outside the outer case and electrically connected to the electrode assembly, the terminal having a vent hole communicating inside and outside of the outer case; And a sealing cap that seals the vent hole with a coupling medium with a low melting point material having a lower melting point than the outer case or the terminal.

The vent hole is formed to penetrate the terminal up and down, and the sealing cap is coupled to cover the upper inlet of the vent hole.

The length of the vent hole is set larger than the wall thickness of the outer case.

Secondary battery according to the present invention, the electrode assembly; An outer case accommodating the electrode assembly and having a through hole formed therein so as to communicate internal and external parts; And a sealing cap that seals the through hole with a coupling medium using a low melting point material having a lower melting point than the outer case.

Secondary battery according to the present invention, the electrode assembly; An outer case in which the electrode assembly is received; A terminal mounted on the outer case such that one side thereof protrudes outside the outer case and electrically connected to the electrode assembly, the terminal having a vent hole communicating inside and outside of the outer case; A pipe, a base plate extending in a direction intersecting the longitudinal direction of the pipe from one outer peripheral surface of the pipe, and a low melting point material having a lower melting point than the outer case or the terminal to cover one end of the pipe with a coupling medium; It comprises a sealing assembly is composed of a sealing cap coupled to the base plate, the other side of the pipe is inserted into the vent hole.

The pipe may be coupled such that the other outer peripheral surface is in close contact with the inner peripheral surface of the vent hole.

The base plate is mounted to cover an outer end of the terminal.

Secondary battery according to the present invention, the electrode assembly; An outer case accommodating the electrode assembly and having a vent hole formed therein so as to communicate internal and external parts; The base plate to cover one end of the pipe with a coupling medium, a base plate extending from the outer peripheral surface of one side of the pipe in a direction intersecting the longitudinal direction of the pipe, and a low melting point material having a lower melting point than the outer case Consists of a sealing cap coupled to, the other side of the pipe is a sealing assembly inserted into the vent hole; includes.

The pipe may be coupled such that the other outer peripheral surface is in close contact with the inner peripheral surface of the vent hole.

The base plate is mounted to cover the outer surface of the outer case.

The low melting point material is any one of tin (Sn), zinc (Zn), lead (Pb), bismuth (Bi), indium (In), or tin (Sn), zinc (Zn), lead (Pb). ), Bismuth (Bi) and indium (In) may include any one or more.

In the secondary battery according to the present invention, since the vent hole is automatically opened when the internal temperature or pressure rises above the reference value, it is possible to prevent explosion due to expansion of the outer case and to discharge the gas generated from the inside to the outside. It can be designed accurately, and there is an advantage that can prevent human injury because no break is formed when opening the vent hole.

Hereinafter, an embodiment of a secondary battery according to the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are a perspective view and a cross-sectional view of a secondary battery according to the present invention, Figure 3 and Figure 4 is a vertical cross-sectional view of the terminal included in the secondary battery according to the present invention, showing the shape before and after opening the vent hole.

The secondary battery according to the present invention includes an electrode assembly 100 including a positive electrode plate, a negative electrode plate, and a separator, an outer case 200 in which the electrode assembly 100 and an electrolytic material are accommodated, and one side of the outer case 200. The terminal unit 300 is mounted to the outer case 200 so as to protrude outward and electrically connected to the electrode assembly 100.

The outer case 200 is a component for accommodating the above-described electrode assembly 100 and the electrolytic material, the inner case is provided so that the electrode assembly 100 can be accommodated, and the body case of the lower side is opened and The cover case 220 is coupled to cover the open lower side of the body case to isolate the internal space of the body case from the outside. In this case, the outer case 200 may be replaced with any structure as long as the outer case 200 has an inner space to accommodate the electrode assembly 100 therein.

In addition, the terminal part 300 is divided into a positive electrode terminal 310 electrically connected to the positive electrode plate of the electrode assembly 100 and a negative electrode terminal 320 electrically connected to the negative electrode plate of the electrode assembly 100. In this embodiment, the structure in which the positive electrode terminal 310 and the negative electrode terminal 320 are manufactured separately is described, but the negative electrode plate is electrically connected to the outer case 200 so that the outer case 200 is the negative electrode terminal ( 320, the negative electrode terminal 320 may be omitted. On the contrary, when the positive electrode plate is electrically connected to the outer case 200 and the outer case 200 is configured to serve as the positive electrode terminal 310, the positive electrode terminal 310 may be omitted.

In this case, the secondary battery according to the present invention is formed with a vent hole (H) for discharging the gas generated in the outer case 200 to the outside, the melt is melted when the vent hole (H) receives heat above the reference value The biggest feature of the composition is that it is sealed with a low melting point material 500 (a material having a melting point lower than that of the outer case 200 or the terminal). 1 to 4 illustrate a case in which the vent hole H is formed in the positive electrode terminal 310, the vent hole H may be formed in the negative electrode terminal 320. 7 to 8 may be formed in the outer case 200. Hereinafter, the case where the vent hole H is formed in the anode terminal 310 will be described in detail.

As shown in FIGS. 3 and 4, when the vent hole H sealed with the low melting point material 500 is provided in the anode terminal 310, the vent hole H may be low as shown in FIG. 3. It is sealed by the melting point material 500. In this state, when the gas is generated by the electrochemical reaction between the electrode assembly 100 and the electrolytic material, and the temperature and the pressure inside the outer case 200 are increased, the low melting point material 500 changes into a fluid state. The low melting point material 500 that is fluidly changed into phase is discharged to the outside by the internal pressure of the outer case 200, and the vent hole H is opened as illustrated in FIG. 4. As such, when the vent hole H is opened, the gas generated in the outer case 200 is discharged to the outside of the outer case 200 through the vent hole H, so that the explosion due to the internal pressure of the outer case 200 increases. This has the advantage of being prevented. In addition, in the case of the secondary battery mentioned in the related art, a gas discharge part is formed through a process of tearing the outer case 200. In the process of tearing the outer case 200, a sharp breakage part is formed, thereby causing the user to be injured. There is a concern. However, the secondary battery according to the present invention has an advantage in that the break site is not formed when the vent hole H is opened for gas discharge, so that the user may not be injured. In addition, the low melting point material 500 will have a variety of melting temperature according to the component and composition ratio, the manufacturer by appropriately selecting the type of low melting point material 500 vent according to the temperature and pressure inside the outer case 200 Hall (H) has the advantage that can be designed in a variety of accurate opening time.

On the other hand, the vent hole (H) formed in the positive electrode terminal 310 is preferably mounted so as to penetrate the outer case 200 in order to communicate stably inside and outside the outer case 200, When the anode terminal 310 is in direct contact with the exterior case 200, a short may occur. Therefore, it is preferable that an insulator 400 is provided between the terminal and the outer case 200 so that the terminal does not directly contact the outer case 200.

In addition, when the vent hole H is formed in the positive electrode terminal 310 or the negative electrode terminal 320, the positive electrode terminal 310 and the negative electrode terminal 320 may have a vent hole H formed therein. It is desirable to have a sufficient width and at the same time the length is made in a block shape significantly larger than the wall thickness of the outer case (100). As such, when the vent hole H is formed to penetrate through the positive electrode terminal 310 or the negative electrode terminal 320, the length of the vent hole H is secured by the length of the positive electrode terminal 310 or the negative electrode terminal 320. As can be seen, the contact area between the vent hole (H) and the low melting point material 500 is increased, and thus, the low melting point material 500 inserted into the vent hole (H) may not easily fall out. .

At this time, the positive electrode terminal 310 and the negative electrode terminal 320 is not limited to the cylindrical shape shown in the present embodiment, the vent hole (H) has a width enough to form a through-hole shape therein vent If the length of the direction in which the hole H is formed (ie, the direction parallel to the longitudinal direction of the vent hole H) is significantly larger than the thickness of the outer case 200, it may be replaced with various shapes such as a polygonal column or a polyhedron. .

In addition, when the vent hole (H) is formed to have the same inner diameter from the upper side to the lower side, there is a fear that the low melting point material 500 inserted into the vent hole (H) will fall to the lower side by the downward pressure applied from the outside have. Therefore, the vent hole H is formed so as to penetrate the anode terminal 310 up and down, but a stepped portion is formed in the middle portion so that the lower inlet is narrower than the upper inlet, or the side wall is inclined so that the inner diameter is narrowed toward the lower side. Preferably formed.

On the other hand, since the outer case 200 applied to the secondary battery is typically made of stainless steel or aluminum alloy and the terminal portion 300 is made of copper or copper alloy, the low melting point material 500 is stainless steel, aluminum, copper, copper It should be chosen to have a lower melting point than the alloy. In this case, the low melting point material 500 is any one metal of tin (Sn), zinc (Zn), lead (Pb), bismuth (Bi), indium (In) while having a relatively low melting point and excellent moldability. (Sn), zinc (Zn), lead (Pb), bismuth (Bi), is preferably made of an alloy containing any one of indium (In).

5 and 6 are vertical cross-sectional views of terminals included in the second embodiment of the secondary battery according to the present invention, and show shapes before and after opening of the vent hole H. FIG.

Secondary battery according to the present invention may be configured such that the vent hole (H) formed in the terminal portion 300 is sealed by a separate sealing cap 610. At this time, the sealing cap 610 is coupled to the terminal portion 300 to cover and seal the top of the vent hole (H), the low melting point material 500 having a melting point lower than the outer case 200 or the terminal is coupled It is coupled to the terminal portion 300 by a medium. At this time, the low melting point material 500 should be formed in a ring shape along the inlet edge of the vent hole (H) of the upper surface of the terminal portion 300, so that the upper side of the vent hole (H) is completely sealed. The vent hole H and the sealing cap 610 may be provided at either the positive terminal 310 or the negative terminal 320 of the terminal part 300, but in the present embodiment, the vent hole H and the sealing cap 610 may be provided. ) Is provided in the positive terminal 310 will be representatively described.

As mentioned above, when the vent hole H is configured to be sealed by the sealing cap 610, the vent hole H as shown in FIG. 5 is normally used when the internal temperature and the pressure of the outer case 200 are lower than the reference value. H) is blocked. However, when the internal temperature and pressure of the outer case 200 rises above the reference value, the low melting point material 500 begins to melt, and the sealing cap 610 is the pressure of the gas generated inside the outer case 200. Since all or part of the anode terminal 310 is separated by the gas, the gas inside the outer case 200 is discharged to the outside through the vent hole H (see FIG. 6).

In this case, not only the internal temperature and the pressure of the outer case 200 are all raised above the reference value, but only the internal temperature of the outer case 200 is raised above the reference value or only the internal pressure of the outer case 200 is increased. The vent hole H may be opened even when the temperature is raised above this reference value. For example, when only the internal temperature of the outer case 200 is raised above the reference value, the sealing cap 610 by melting the low melting point material 500 for bonding the sealing cap 610 to the anode terminal 310 The vent hole H is opened by separating all or part of the anode terminal 310 even by a very small force. In addition, when only the internal pressure of the outer case 200 is raised above the reference value, even if the low melting point material 500 for bonding the sealing cap 610 to the anode terminal 310 is not melted at all the outer case 200 The vent hole H is opened by rupturing the sealing cap 610 or separating the sealing cap 610 and the anode terminal 310 by an internal pressure of the sealing cap 610. Therefore, the manufacturer may adjust the vent hole (H) opening time by appropriately selecting the material of the low melting point material 500 and the sealing cap 610.

On the other hand, the sealing cap 610 may be mounted so that the outer end is coupled to the inner circumferential surface of the vent hole (H), that is to be inserted into the vent hole (H), as shown in this embodiment for improving assembly It may be coupled to cover the upper inlet of the vent hole (H). In addition, the sealing cap 610 is not limited to the coupling structure mentioned in the present embodiment, as long as the structure capable of sealing the vent hole (H) to the low melting point material 500 as a coupling medium is coupled to any structure Can be.

7 and 8 are vertical cross-sectional views of terminals included in the secondary battery according to the third embodiment of the present invention, and show shapes before and after opening of the vent hole H. FIG.

The vent hole H for communicating the inside and outside of the exterior case 200 may be formed in the terminal portion 300 as illustrated in FIGS. 1 to 6, and the exterior case 200 as illustrated in FIGS. 7 and 8. ) May be formed. At this time, the vent hole (H) may be formed anywhere in the body case 210 or the cover case 220 of the outer case 200, in the present embodiment, the vent hole (H) in the body case 210 The case where it forms is represented typically.

When the vent hole H is formed in the main body case 210, the vent hole H is sealed by being covered with a sealing cap 610, and the sealing cap 610 has a melting point lower than that of the outer case 200. A low melting point material 500 having a coupling medium is coupled to the body case 210. As described above, when the vent hole H formed in the body case 210 is configured to be sealed by the sealing cap 610, the internal temperature and the pressure of the outer case 200 are normally lower than those shown in FIG. 7. As described above, the vent hole H is blocked. However, when the internal temperature of the outer case 200 is heated above the melting temperature of the low melting point material 500 and the internal pressure of the outer case 200 increases, the low melting point material 500 begins to melt and the sealing cap. 610 is pushed to the outside by the internal pressure of the outer case 200, as shown in Figure 8, the whole or part is separated from the body case 210, the gas inside the outer case 200 is vent hole ( It is discharged to outside through H).

In the embodiment in which the vent hole H is formed in the main body case 210 as described above, the vent hole H is not only when the internal temperature and the pressure of the outer case 200 are raised above the reference value, but also the outer case. When only the internal temperature of the 200 is raised above the reference value or only the internal pressure of the outer case 200 may be opened when it is raised above the reference value. Since the vent hole H is opened by temperature and pressure, opened by temperature, or opened by pressure, the principle of the vent hole H is substantially the same as that shown in FIGS. 5 and 6, and thus a detailed description thereof is omitted. do.

As such, when the vent hole H is formed in the outer case 200, the vent hole H may be formed very easily, and the sealing cap 610 may be easily installed. In addition, as shown in FIGS. 1 to 6, in order to form the vent hole H in the terminal unit 300, a positive electrode terminal 310 or a negative electrode terminal 320 having a certain volume in the secondary battery is essentially required. Although required, as shown in FIGS. 7 and 8, when the vent hole H is formed in the outer case 200, the positive electrode terminal 310 or the negative electrode terminal 320 having a certain volume is not required. The vent hole (H) structure according to the present invention has an advantage that it can be applied to a conventional secondary battery (a secondary battery formed in a positive electrode terminal and a negative electrode terminal plate or a pin shape).

9 is an exploded cross-sectional view of a second embodiment of a secondary battery according to the present invention, and FIGS. 10 and 11 are vertical cross-sectional views of terminals included in the second embodiment of the secondary battery according to the present invention, showing a shape before and after opening of a vent hole. .

Secondary battery according to the present invention, the means for sealing the vent hole (H) may be configured to be mounted in the vent hole (H) is made of a separate assembly.

That is, in the secondary battery according to the present invention, as shown in FIG. 9, a separate sealing assembly 600 composed of a pipe 620, a base plate 630, and a sealing cap 610 may have a vent hole (H). It can be configured to seal. At this time, the pipe 620 is inserted into the vent hole (H) so that one side is facing the outside of the terminal 310, the base plate 630 of the pipe 620 from one outer peripheral surface of the pipe 620 It is formed to extend in the direction crossing the longitudinal direction (in this embodiment, the direction perpendicular to the longitudinal direction of the pipe 620), the sealing cap 610 is a melting point lower than the outer case 210 or the terminal 310 A low melting point material 500 having a coupling medium is coupled to the base plate 630 so as to cover one end (the upper end in the present embodiment) of the pipe 620.

When the separately prepared sealing assembly 600 is coupled to the terminal, as shown in FIG. 10, the vent hole H is sealed by the sealing assembly 600, so that the sealing assembly 600 is not ruptured. The interior and exterior of one exterior case 210 is completely isolated.

When the temperature and pressure inside the outer case 210 in the state shown in FIG. 10 rises above a set value, the low melting point material 500 connecting the base plate 630 and the sealing cap 610 starts to melt and is sealed. The cap 610 is pressured to be pushed outward, the sealing cap 610 is finally separated from the base plate 630 as shown in FIG. When the sealing cap 610 is separated from the base plate 630 as described above, one end of the pipe 620 is opened, so that the gas inside the outer case 210 is discharged to the outside through the pipe 620. Therefore, the secondary battery according to the present invention does not have to be exploded even if the temperature and pressure inside the outer case 210 increase above a set value.

At this time, the low melting point material 500 is melted by conducting heat through the pipe 620 and the base plate 630, the pipe 620 and the base plate 630 is made of a good thermal conductivity metal desirable.

Meanwhile, in the present embodiment, only the case in which the sealing cap 610 is separated from the base plate 630 and thus one end of the pipe 620 is opened by increasing both the temperature and the pressure inside the outer case 210 is increased. One end of the pipe 620 may be opened only by a pressure increase in the outer case 210, or may be opened only by a temperature increase in the outer case 210.

That is, even if the low melting point material 500 is not melted, one end of the pipe 620 may be opened by rupturing the sealing cap 610 due to the pressure inside the case 210. As such, the sealing cap 610 may be configured in a thin foil structure so that the sealing cap 610 may be ruptured by the internal pressure of the outer case 210.

In addition, when the low melting point material 500 is sufficiently melted as the temperature inside the case 210 rises, the sealing cap 610 is separated from the base plate 630 by a small force, so that the pipe 620 One end may be open.

On the other hand, if a gap is generated between the inner circumferential surface of the vent hole H and the outer circumferential surface of the pipe 620, the gas inside the outer case 210 may be discharged to the outside through the gap between the vent hole H and the pipe 620. have. Therefore, the pipe 620 is preferably coupled so that the outer peripheral surface is in close contact with the inner peripheral surface of the vent hole (H). To this end, the pipe 620 may be vented in a variety of ways to maintain the airtight between the pipe 620 and the vent hole H or the terminal 310, including interference fitting, welding or riveting. It may be mounted in the hole (H).

In addition, when the terminal 310 and the pipe 620 are exposed to the outside, water or foreign matter may flow between the terminal 310 and the pipe 620, and thus, the pipe 620 and the terminal 310 may be corroded. The base plate 630 may be mounted to cover an outer end of the terminal 310.

9 to 11 illustrate only the structure in which the sealing assembly 600 is mounted in the vent hole H formed in the terminal 310, the sealing assembly 600 is illustrated in FIGS. 7 and 8. Likewise, it may be mounted in the vent hole H formed in the exterior case 210. In this case, the pipe 620 is coupled to the other side of the vent hole H, and the base plate 630 may be mounted to cover the outer surface of the outer case 210.

Even if the sealing assembly 600 is mounted in the vent hole H formed in the outer case 210, the configuration and operation of the sealing assembly 600 are the same as those of the embodiment shown in FIGS. Description is omitted.

As mentioned above, although this invention was demonstrated in detail using the preferable embodiment, the scope of the present invention is not limited to a specific embodiment, Comprising: It should be interpreted by the attached Claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

1 and 2 are a perspective view and a cross-sectional view of a secondary battery according to the present invention.

3 and 4 are vertical cross-sectional views of terminals included in the secondary battery according to the present invention, and show shapes before and after opening the vent hole.

5 and 6 are vertical cross-sectional views of terminals included in the second embodiment of the secondary battery according to the present invention, and show shapes before and after opening the vent hole.

7 and 8 are vertical cross-sectional views of terminals included in the second embodiment of the secondary battery according to the present invention, and show shapes before and after opening the vent hole.

9 is an exploded cross-sectional view of a secondary battery according to a fourth embodiment of the present invention.

10 and 11 are vertical cross-sectional views of terminals included in the second embodiment of the secondary battery according to the present invention, and show shapes before and after opening the vent hole.

<Description of the symbols for the main parts of the drawings>

100: electrode assembly 200: outer case

210: body case 220: cover case

300: terminal 310: positive terminal

320: negative electrode terminal 400: insulator

500: low melting point material 600: sealing assembly

610: sealing cap 620: pipe

630: base plate H: vent hole

Claims (15)

Electrode assembly; An outer case in which the electrode assembly is received; A terminal mounted on the outer case such that one side thereof protrudes outside the outer case and electrically connected to the electrode assembly, the terminal having a vent hole communicating inside and outside of the outer case; A low melting point material filled in all or a part of the vent hole so that the vent hole is blocked, and having a melting point lower than that of the outer case or the terminal; Including, And a low melting point material is melted and discharged outside the vent hole when the temperature inside the outer case rises above a reference value, thereby opening the vent hole. The method of claim 1, The vent hole is formed to penetrate the terminal up and down, and the secondary battery is characterized in that the step is formed in the middle so that the lower inlet is narrower than the upper inlet. The method of claim 1, The vent hole is formed to penetrate the terminal up and down, and the secondary battery, characterized in that the side wall is formed to be inclined so as to narrow the inner diameter toward the lower side. The method of claim 1, The length of the vent hole is a secondary battery, characterized in that larger than the wall thickness of the outer case. Electrode assembly; An outer case in which the electrode assembly is received; A terminal mounted on the outer case such that one side thereof protrudes outside the outer case and electrically connected to the electrode assembly, the terminal having a vent hole communicating inside and outside of the outer case; A sealing cap that seals the vent hole with a coupling medium with a low melting point material having a lower melting point than the outer case or the terminal; Secondary battery comprising a. The method of claim 5, The vent hole is formed to penetrate the terminal up and down, and the sealing cap is coupled to cover the upper inlet of the vent hole. The method of claim 5, The length of the vent hole is a secondary battery, characterized in that larger than the wall thickness of the outer case. Electrode assembly; An outer case accommodating the electrode assembly and having a through hole formed therein so as to communicate internal and external parts; A sealing cap that seals the through hole with a coupling medium using a low melting point material having a lower melting point than the outer case; Secondary battery comprising a. Electrode assembly; An outer case in which the electrode assembly is received; A terminal mounted on the outer case such that one side thereof protrudes outside the outer case and electrically connected to the electrode assembly, the terminal having a vent hole communicating inside and outside of the outer case; A pipe, a base plate extending in a direction intersecting the longitudinal direction of the pipe from one outer peripheral surface of the pipe, and a low melting point material having a lower melting point than the outer case or the terminal to cover one end of the pipe with a coupling medium; A sealing assembly having a sealing cap coupled to a base plate, wherein the other side of the pipe is inserted into the vent hole; Secondary battery comprising a. 10. The method of claim 9, The pipe is secondary battery, characterized in that the other outer peripheral surface is coupled to be in close contact with the inner peripheral surface of the vent hole. 10. The method of claim 9, The base plate is a secondary battery, characterized in that mounted to cover the outer end of the terminal. Electrode assembly; An outer case accommodating the electrode assembly and having a vent hole formed therein so as to communicate internal and external parts; The base plate to cover one end of the pipe with a coupling medium, a base plate extending from the outer peripheral surface of one side of the pipe in a direction intersecting the longitudinal direction of the pipe, and a low melting point material having a lower melting point than the outer case It is composed of a sealing cap coupled to, the sealing assembly that the other side of the pipe is inserted into the vent hole; Secondary battery comprising a. The method of claim 12, The pipe is secondary battery, characterized in that the other outer peripheral surface is coupled to be in close contact with the inner peripheral surface of the vent hole. The method of claim 12, The base plate is a secondary battery, characterized in that mounted to cover the outer surface of the outer case. The method according to any one of claims 1 to 14, The low melting point material is any one of tin (Sn), zinc (Zn), lead (Pb), bismuth (Bi), indium (In), or tin (Sn), zinc (Zn), lead (Pb). ), A secondary battery characterized in that the alloy containing at least one of bismuth (Bi), indium (In).

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